Department Sanitation, Water and Solid Waste for Development

Management of Excreta, Wastewater and Sludge (MEWS)

The research group Management of Excreta, Wastewater, and Sludge (MEWS) addresses solutions for city-wide inclusive sanitation (CWIS) through applied and fundamental research, design and optimization of treatment technologies, development of analytical and monitoring methods, and training and reference materials. The goal of city-wide inclusive sanitation is equitable, safe, and sustainable sanitation for everyone. The development of management solutions for the entire service chain are essential to fulfill the sanitation needs of urban areas, including containment, collection, transport, treatment, and resource recovery, and will vary depending on the associated infrastructure. Access to safely managed sanitation can be achieved through the implementation of a range of appropriate technologies tailored to the realities of rapidly growing cities, with integrated combinations of sewered and non-sewered, off-grid, and decentralised and centralised technologies. One third of the world’s population currently relies on non-sewered sanitation, predominantly in low- and middle-income countries, with only a fraction safely managed. There is an urgent need to find immediate solutions to bridge this gap, while in parallel researching more globally relevant and sustainable solutions for the future.

Faecal sludge (FS) is defined very broadly as what accumulates in onsite sanitation technologies and specifically is not transported through a sewer. It is composed of excreta, but also anything else that goes into an onsite containment technology, such as flushwater, cleansing materials and menstrual hygiene products, greywater (i.e. bathing or kitchen water, including fats, oils and grease), and solid waste. The importance and need for faecal sludge management (FSM) has been recognised worldwide, with rapidly occurring developments. Other possibilities for non-sewered sanitation include community scale solutions, emergency and humanitarian settings, and even co-treatment with sewered sanitation. Off-grid solutions include the reinvent the toilet challenge, in-building treatment in urban areas, and on property treatment in rural areas. Non-sewered sanitation can provide more sustainable options, however, there are major gaps in fundamental, scientific knowledge, applied research to scale-up solutions, standard methods for monitoring, design, and analysis, and reference materials. To address these gaps, our research has a focus on development of innovative but practical and reliable solutions, along with the resources that will allow practitioners to integrate management solutions into city-wide inclusive sanitation.

Contact

Dr. Linda Strande Tel. +41 58 765 5553 Send Mail

Ongoing Research Projects

MEWS researches fundamental processes governing dewatering and the possible biological treatment trains of supernatant following dewatering.

Fecal sludge dewatering and supernatant treatment
The Volaser measuring device measures in situ volumes of faecal sludge in order to estimate Q&Q.

Volaser measuring device
Smart phone app that can predict characteristics of faecal sludge.

Sludge Snap App
Measures for monitoring need to be in place to ensure adequate protection of public health, and to evaluate progress towards achieving SDGs.

Sustainable implementation of city-wide inclusive sanitation
Sustainable management requires estimates of the Q&Q that are accumulating at community to city-wide scales.

Estimating quantities and qualities (Q&Q)
The provision of adequate sanitation at every step of a crisis is crucial in order to protect human and environmental health.

Emergency and humanitarian contexts
Resource recovery, market based approaches, and business models, are key to sustainable management.

Resource recovery
MEWS conducts applied research to push technologies from innovative and transferring, to technologies that are field-ready for implementation.

Scaling up technologies
Vermifiltration for domestic wastewater treatment.

Vermifiltration
As countries strive for net zero emissions, managing greenhouse gases from non-sewered sanitation is becoming a pivotal focus, emphasizing the need for detailed emission studies and the inclusion of climate-smart strategies.

Greenhouse Gas Emissions from Non-Sewered Sanitation Systems
Scaling efficient dewatering for urban practicioners.

Sedup
Environmental Monitoring of Community Health: in Urban Non-Sewered Catchments

EMoCH

Training Material and Key Resources

FSM Book

WHO Guidelines

Highlights and Exercises

Publications

Methods book

MOOC

eFSTP

Past Research Projects

Sandec is working in collaboration with the Hanoi University of Civil Engineering to evaluate the feasibility of treating faecal sludge through anaerobic digestion

PURR - Partnership for Urban Resource Recovery
The SEEK project aims to increase revenue potential by processing sludge together with other urban waste streams into fuel pellets and electricity through gasification.

SEEK - Sludge to Energy Enterprises in Kampala

Publications

Coppens, K., Geyer, T., Monod, A., Strande, L., & Stoll, S. (2025). Evaluation of vermifilter-treated domestic wastewater for irrigation and fertigation: opportunities and challenges for implementation. Journal of Water Process Engineering, 77, 108295 (11 pp.). doi:10.1016/j.jwpe.2025.108295, Institutional Repository

Water reclamation can help meet agricultural irrigation and nutrient demands. Due to high nutrient loads, vermifiltration is often considered a suitable treatment solution for reclamation in agriculture. However, the ability of vermifiltration to meet irrigation standards is understudied. This study explores the feasibility of reclamation through irrigation and fertigation from two full-scale vermifilters treating black- and sedimented greywater in parallel and evaluates the removal efficiencies of metallic trace elements (MTEs), E. coli, and 15 organic micropollutants (OMPs). Microplastics in the effluent were also quantified. The results show that, for reclamation in agriculture, post-treatment of the vermifilter effluent is necessary to ensure reliable and sufficient effluent quality. Despite an overall log removal of 3.67, E. coli is the most restrictive parameter, conforming to irrigation standards only after the second post-treatment step. Various constraints, due to high nitrate concentrations and salinity, would also be necessary to avoid negative environmental and agronomic impacts. For fertigation, careful planning is needed to overcome excessive and variable nitrogen loads. Despite low and variable MTE removal, the effluent quality meets irrigation standards. Average removal of OMPs is 91 ± 15 %, and the coefficient of variation is <10 % for two-thirds of the OMPs. Suggested optimizations to improve the usability in agriculture include adding a disinfection step and urine separation. Future studies should focus on the impacts of vermifilter reclamation in agriculture on soil and crops, as well as the potential for designations such as toilet flushing and street cleaning, which are likely more advantageous in urban settings.
Coppens, K., Strande, L., & Stoll, S. (2025). Performance analysis and impact of operating conditions on the treatment capacity of two full-scale vermifilters. Journal of Environmental Management, 391, 126328 (11 pp.). doi:10.1016/j.jenvman.2025.126328, Institutional Repository

Due to low investment and operational costs, chemical and energy independence, and a high potential to contribute to circular wastewater management practices, vermifiltration is a globally relevant wastewater treatment solution. Despite its potential, insufficient knowledge of the full-scale performance and the absence of guidelines for optimal design and operation impede vermifiltration from being widely implemented. This study analyzed the performance of two full-scale vermifilters treating domestic blackwater and greywater sediments in winter and summer in Switzerland. For the first time, the operating conditions of both vermifilters were determined empirically, where the blackwater vermifilter observed 4 times lower hydraulic loading rates, though 10 times larger nitrogen loading rates than the greywater sediments vermifilter. Both vermifilters demonstrated the ability to maintain high removal efficiencies for organics and solids (>75 % for BOD5, COD, and TSS), though nutrient removal was lacking (<30 % for TN and TP). The design and operation used in the full-scale vermifilters are, in general, recommendable, as no clogging was observed, and the performance of the vermifilters did not vary with season. In addition, with post-treatment, the effluent complied with discharge standards 100 % of the time. Insights into optimal design and operation include separate urine treatment, increased vermifilter depth, and alternative and intermittent feeding regimes. Such modifications would likely decrease the post-treatment requirements, spatial footprint, and investment costs. Overall, the results of this study conclude that when employing favorable design and operation conditions, vermifiltration is a relevant, reliable, and resilient wastewater treatment solution for both urban and rural areas worldwide.
Sam, S. B., Smith, S. K., Niederdorfer, R., Scheidegger, A., Ward, B. J., Tembo, J. M., … Strande, L. (2025). Microbial community composition reflects water usage and storage conditions in a city-wide study of non-sewered wastewater (fecal sludge). PLoS Water, 4(6), e0000386 (16 pp.). doi:10.1371/journal.pwat.0000386, Institutional Repository

Nearly half (46%) the world’s population is now served by non-sewered sanitation. In urban areas of low- and middle-income countries, this translates to onsite storage of wastewater in tanks and pits until it can be collected and transported by road to treatment, which is commonly referred to as fecal sludge management. The microbial communities that develop during storage of this wastewater remain understudied, leaving practitioners and scientists to speculate on best management practices such as downstream treatment and climate mitigation measures. In this study, we collected samples from 135 randomly selected containments across the city of Lusaka, Zambia, and evaluated statistical relations of 16S rRNA gene sequence data to types and volume of wastewater going into containments, disturbances (i.e., emptying events), characteristics of accumulated wastewater during storage, and metrics of downstream treatment processes. At the phyla level, 80% of the identified microorganisms belonged to Firmicutes, Proteobacteria and Bacteroidota. Focusing in at the genera level, microbial diversity and composition were statistically related to volumes of water usage, properties of wastewater in containments (total organic carbon, total kjeldahl nitrogen, ammonium nitrogen, pH), and metrics of stabilization and dewatering performance. In Lusaka, a core community was identified with 104 of the 1,247 identified genera being present in >90% of the containments. In contrast, 936 genera were present in <60% of the containments, indicating that niche or transient organisms may also be important in unravelling metabolic processes such as sulfur reduction, methanogenesis, and ammonia tolerance. Community similarity was independent of time since last emptied, indicating stability of microbial communities over time. Identified metabolic differences between pit latrines (i.e., less water usage) and septic tanks (i.e., more water usage) indicate that methanogens more actively convert organic matter to methane in the more dilute wastewater in septic tanks, which could be globally relevant for greenhouse gas mitigation from non-sewered sanitation.
Vogel, M., Bergström, M., Al JahJah, R., Hankache, C., Touma, R., & Strande, L. (2025). Comparing total suspended solids sensors for improved dewatering of wastewater from non-sewered sanitation. Journal of Environmental Management, 373, 123554 (11 pp.). doi:10.1016/j.jenvman.2024.123554, Institutional Repository

Almost half of the global population relies on non-sewered sanitation, wherein wastewater is treated directly at source or stored onsite and transported by road to treatment facilities (i.e., fecal sludge management). For the protection of public health and environmental ecosystems, efficient non-sewered sanitation systems are needed, in particular in urban areas where infrastructure lags behind rapid urbanization. Wastewater delivered to treatment plants in non-sewered areas has highly variable characteristics, as it arrives in batches from variable infrastructure. Established systems to handle this variability are often land- or energy-intensive, while operation of low-footprint alternatives strongly depends on the wastewater characteristics, making them difficult to implement for highly variable wastewater. The use of sensors could improve process control and increase the robustness of treatment technologies, while reducing the required footprint. However, there are no studies comparing the effectiveness of different sensor methods to measure solids in non-sewered wastewater. We therefore chose six sensors for predicting solids in wastewater and evaluated their performance in variable wastewater with a range of solids content, inorganic particles, salts, and fats. This work demonstrated that the sensors were affected differently by the variable wastewater. Micro-wave and Coriolis-flow technologies were strongly impacted by the addition of fat, oil, and grease as well as salts and inorganics, whereas optical sensors were mostly affected by inorganics, with optical light-attenuation having the lowest overall error, making it the best option for variable wastewater. A low-cost optical light-attenuation sensor had similar accuracy as a more expensive one when the solids content was low, indicating its value for inexpensive monitoring of effluent solids in decentralized settings. Additionally, three sensors were applied for process control of chemically enhanced dewatering with conditioners and geotextiles. Controlling conditioner dosing with sensors in the flocculation tank improved performance with 77% solids reduction, which is in the range of the alternative, time-intensive jar-test method (83% reduction). This study reveals that sensors can be useful in non-sewered wastewater management when the type of input wastewater is accounted for and that even low-cost sensors (<100 USD) can be suitable for many applications.
Donahue, P., & Strande, L. (Eds.). (2025). Sandec News, 26. Sandec News (26). doi:10.55408/eawag:35587, Institutional Repository
Kapanda, K., Sam, S., Andriessen, N., Ward, B. J., Strande, L., & Tembo, J. M. (2024). Metrics for stabilization of fecal sludge and relation to dewatering metrics. Journal of Water, Sanitation and Hygiene for Development, 14(5), 389-399. doi:10.2166/washdev.2024.318, Institutional Repository

Stabilization and dewatering are essential treatment mechanisms for the management of fecal sludge (FS) that accumulates in onsite containment, but reliable predictors of treatment performance are lacking. FS in Lusaka, Zambia is typically 80–98% water, which when delivered to treatment first requires dewatering, followed by stabilization of varying levels of organic matter. In addition, varying levels of stabilization are themselves observed to influence dewatering performance. Therefore, this study evaluated rapid and low-cost metrics of stabilization and their relation to dewaterability. Fourteen metrics of stabilization were evaluated based on 11 criteria in a decision matrix. Four metrics were selected to then evaluate method performance and suitability with FS samples (n = 27). The relation between stabilization and dewatering performance of collected samples were analyzed, and also following anaerobic stabilization in the laboratory. The study found that metrics based on physical–chemical characteristics such as volatile/total solids (VS/TS) and biological oxygen demand/chemical oxygen demand (BOD/COD) were not reliable for measuring FS stabilization and its relation to dewaterability. Metrics that rely on microbial activity such as SOUR (specific oxygen uptake rate) are more promising based on the consistent results obtained throughout this study.
Maqbool, N., Sam, S., Khan, S. J., & Strande, L. (2024). Relation of organic fractions in fresh and stored fecal sludge and foodwaste to biogas production. Journal of Water, Sanitation and Hygiene for Development, 14(3), 277-290. doi:10.2166/washdev.2024.319, Institutional Repository

There is limited understanding of the potential for anaerobic digestion and biogas production from fecal sludge. In this study, biomethane potential (BMP) tests from fresh, stored, and dewatered fecal sludge, together with co-digestion with fresh foodwaste, revealed that fresh fecal sludge produced similar cumulative biogas (CBG) to fresh foodwaste (615–627 mL/gVS), while stored fecal sludge showed a wide range of gas production (13–449 mL/gVS). Co-digestion significantly enhanced the CBG production of fresh (1.2×), dewatered (1.5×), and stored (29–36×) fecal sludge. In BMP tests with the higher range of gas production, a biphasic CBG production was observed, with degradation of readily biodegradable organics occurring during the first week. The first-order rate coefficients indicated hydrolysis limitation, which was also confirmed by the presence of slow-growing methanogens (Halobacterota). Priming with co-digestion significantly enhanced CBG from stored fecal sludge. The physical–chemical metrics VS/TS and TOC/TN were not predictors of biogas production, while BOD/COD and sCOD were better indicators, suggesting that metrics of stabilization representing biologically available fractions are more representative than metrics of entire pools of organic matter. This study suggests that biogas production from anaerobic digestion is viable for fresh fecal sludge, whereas for stored fecal sludge it requires co-treatment or pretreatment.
Strande, L. (2024). Integrating recent scientific advances to enhance non-sewered sanitation in urban areas. Nature Water, 2(5), 405-418. doi:10.1038/s44221-024-00240-7, Institutional Repository

Half of the world’s population is now served by non-sewered sanitation, yet the field remains fragmented, with a focus on individual research agendas, and prevalence of imprecise terminology that hinders scientific learnings and leads to misconceptions. The field is at a decisive juncture, with scientific knowledge taking off that holds the potential to fulfil the urgent need for inclusive sanitation in a rapidly urbanizing world. In this critical Review, relevant and diverse research results are assembled with findings translated to one consistent terminology, to provide scientific evidence to draw out interlinkages and learnings, debunk common misconceptions and identify key research needs. Properties of non-sewered wastewater are highly variable, and degradation during storage has a direct impact on greenhouse gas emissions and downstream treatment processes, which facilitate different resource recovery. New technologies and wastewater-based epidemiology can help to address the lack of monitoring. The findings are presented by wastewater properties, biological processes during storage, treatment processes and monitoring.
Andriessen, N., Appiah-Effah, E., Browne, S. J. I., al Jahjah, R., Kabika, J., Kinobe, J. R., … Strande, L. (2023). Quantities and qualities of fecal sludge: experiences from field implementation with a Volaser in 7 countries during a pandemic. Frontiers in Water, 5, 1130081 (14 pp.). doi:10.3389/frwa.2023.1130081, Institutional Repository

Reasonable estimates for quantities and qualities (Q&Q) of fecal sludge that accumulate in onsite sanitation containments are fundamental for the design of appropriate management and treatment solutions, from community to city-scale. There are increasing attempts to improve Q&Q estimates, but current approaches are still at a conceptual level, and are not yet standardized with confirmed statistical relationships. To reach this level, we will need consistent approaches for planning, measuring, and global collaborations. Hence, the objectives of this study were: (1) to assess and compare Q&Q of fecal sludge from seven cities and communities, and explore statistical relationships that could be used to increase accuracy of Q&Q estimations; (2) to test and launch the Volaser device for measuring in situ volumes of fecal sludge; and (3) to capture lessons learned from field implementation with collaborators in seven countries during a global pandemic when no international travel was possible. The study took place in Ghana, India, Lebanon, Kenya, Sierra Leone, Uganda, and Zambia during the COVID-19 pandemic. Q&Qs were measured in 204 containments with a Volaser, laboratory analysis, and questionnaire. Results indicate that there are differences in Total Solids (TS) and Chemical Oxygen Demand (COD) in fecal sludge based on containment type, toilet type, source, and whether there is a water connection on the premises. Based on the results of this study, together with previously published open-source data, an empirical relationship for Volatile Solids (VS) and TS of 0.49 (R2 = 0.88) was established using 1,206 data points. For COD/TS, no significant relationship was observed. Developing such empirical relationships will be useful for planning and modeling approaches. An external evaluation was conducted to evaluate overall project management, Volaser technology transfer, and effects of collaborating during the COVID-19 pandemic. Success factors for collaborating with new and existing partners without face-to-face meetings included laboratory capacity and experience with analytical methods, study objectives that were relevant for the partner and locality, and a strong quality assurance plan to ensure comparability of results. The lessons learned can be taken forward as ways to reduce carbon footprint, and contribute to resilient, inclusive development research projects.
Sam, S. B., Morgenroth, E., & Strande, L. (2023). Changes in organic fractions, cations, and stabilization from feces to fecal sludge: implications for dewatering performance and management solutions. Journal of Water, Sanitation and Hygiene for Development, 13(9), 699-710. doi:10.2166/washdev.2023.086, Institutional Repository

Reliable dewatering performance remains a key challenge in fecal sludge management, and the controlling factors or mechanisms are not well understood. There remain limited studies on constituents in feces and fecal sludge and how they affect the dewaterability of fecal sludge. This study aimed at evaluating a range of constituents in feces, and to gain empirical knowledge toward a mechanistic understanding of how they influence dewaterability. In this study, cellulose reduced capillary suction time, decreased supernatant turbidity, and increased cake solids. While hemicellulose decreased supernatant turbidity, lignin increased supernatant turbidity, capillary suction time, and cake solids. Extracellular polymeric substances (EPS) increased both capillary suction time and supernatant turbidity and decreased cake solids, whereas lipids increased turbidity. Cations had no significant effect on dewatering properties. Overall, fecal sludge stored in containments had better dewatering performance than ‘fresh’ fecal sludge, which was attributed to stabilization. Field fecal sludge had a higher relative abundance of Pseudomonas, which is associated with better aggregation, and fewer small particles (<10 μm) that clog filters to reduce dewatering performance. Further understanding of stabilization and developing an agreed-upon metrics of stabilization are essential for predicting fecal sludge dewatering performance, and developing smaller footprint dewatering treatment technologies.
Strande, L., Evans, B., von Sperling, M., Bartram, J., Harada, H., Nakagiri, A., & Nguyen, V. A. (2023). Urban sanitation: new terminology for globally relevant solutions?. Environmental Science and Technology, 57(42), 15771-15779. doi:10.1021/acs.est.3c04431, Institutional Repository

Progress toward Sustainable Development Goals for global access to safe sanitation is lagging significantly. In this Feature, we propose that misleading terminology leads to errors of categorization and hinders progress toward sanitation service provision in urban areas. Binary classifications such as "offsite/onsite" and "sewered/nonsewered" do not capture the need for "transport to treatment" or the complexity of urban sanitation and should be discarded. "Fecal sludge management" is used only in the development context of low- or middle-income countries, implying separate solutions for "poor" or "southern" contexts, which is unhelpful. Terminology alone does not solve problems, but rather than using outdated or "special" terminology, we argue that a robust terminology that is globally relevant across low-, middle-, and upper-income contexts is required to overcome increasingly unhelpful assumptions and stereotypes. The use of accurate, technically robust vocabulary and definitions can improve decisions about management and selection of treatment, promote a circular economy, provide a basis for evidence-based science and technology research, and lead to critical shifts and transformations to set policy goals around truly safely managed sanitation. In this Feature, the three current modes of sanitation are defined, examples of misconceptions based on existing terminology are presented, and a new terminology for collection and conveyance is proposed: (I) fully road transported, (II) source-separated mixed transport, (III) mixed transport, and (IV) fully pipe transported.
Ward, B. J., Nguyen, M. T., Sam, S. B., Korir, N., Niwagaba, C. B., Morgenroth, E., & Strande, L. (2023). Particle size as a driver of dewatering performance and its relationship to stabilization in fecal sludge. Journal of Environmental Management, 326, 116801 (12 pp.). doi:10.1016/j.jenvman.2022.116801, Institutional Repository

Poor and unpredictable dewatering performance of fecal sludge is a major barrier to sanitation provision in urban areas not served by sewers. Fecal sludge comprises everything that accumulates in onsite containments, and its characteristics are distinct from wastewater sludges and from feces. There is little fundamental understanding of what causes poor dewatering in fecal sludge. For the first time, we demonstrate that particle size distribution is a driver of dewatering performance in fecal sludge, and is associated with level of stabilization. Higher concentrations of small particles (<10 μm) and smaller median aggregate size (D50) corresponded to poor dewatering performance (measured by capillary suction time (CST) and supernatant turbidity) in field samples from Kenya and Uganda and in controlled laboratory anaerobic storage experiments. More stabilized fecal sludge (higher C/N, lower VSS/TSS) had better dewatering performance, corresponding to lower concentrations of small particles. Samples with the largest aggregates (D50 > 90 μm) had higher abundance of Gammaproteobacteria Pseudomonas, and samples with the smallest aggregates (D50 ≤ 50 μm) were characterized by higher abundance of Bacteroidetes Vadin HA17 and Rikenellaceae. Contrary to common perceptions, stabilization, particle size distribution, and dewatering performance were not dependent on time intervals between emptying of onsite containments or on time in controlled anaerobic storage experiments. Our results suggest that the stabilization process in onsite containments, and hence the dewaterability of sludge arriving at treatment facilities, is not dependent on time in containment but is more likely associated with specific microbial populations and the in-situ environmental conditions which promote or discourage their growth.
Sam, S. B., Ward, B. J., Niederdorfer, R., Morgenroth, E., & Strande, L. (2022). Elucidating the role of extracellular polymeric substances (EPS) in dewaterability of fecal sludge from onsite sanitation systems, and changes during anaerobic storage. Water Research, 222, 118915 (12 pp.). doi:10.1016/j.watres.2022.118915, Institutional Repository

As the importance of fecal sludge management (FSM) is increasingly being realized, the need for adequately designed and functioning fecal sludge (FS) treatment plants is also increasing. Research to fill this gap is only emerging and dewatering is a key challenge for developing sustainable treatment solutions. This study evaluated the effect of extracellular polymeric substances (EPS) on dewaterability of FS, and how EPS and dewaterability change during anaerobic storage (as a proxy for time in onsite containment). EPS was extracted from FS and activated sludge using Na2CO3 and sonication and added to sludge samples to determine the effect on dewaterability. The results confirmed that an increase in EPS had a direct impact of decreasing FS dewaterability (as capillary suction time). In this context, we evaluated FS degradation during anaerobic storage, the effect of anaerobic storage time on EPS, EPS fractions and particle size distribution, and the effect of variations in these factors on FS dewaterability. Variations in EPS, EPS fraction and particle size distribution during anaerobic storage were less than expected and average VS reduction of 20% was recorded over 7 weeks. Although anaerobic digestion was verified (biogas production), the results indicate that kinetics of degradation of FS is different from wastewater sludges. Comparatively, EPS fractions in FS were 70 – 75% lower and with higher fractions of humic-like substances than wastewater sludges. Although EPS significantly affects FS dewaterability, anaerobic storage time is not a predictor of dewaterability.
Shaw, K., Vogel, M., Andriessen, N., Hardeman, T., Dorea, C. C., & Strande, L. (2022). Towards globally relevant, small-footprint dewatering solutions: Optimal conditioner dose for highly variable blackwater from non-sewered sanitation. Journal of Environmental Management, 321, 115961 (11 pp.). doi:10.1016/j.jenvman.2022.115961, Institutional Repository

Globally, the sanitation needs of three billion people are met by non-sewered sanitation. Small-footprint treatment technologies are needed that are appropriate for dense urban areas. Blackwater (BW) (or fecal sludge), contains more than 95% liquid, and dewatering it without conditioning requires large footprints. Chemically-enhanced dewatering with conditioners is a promising option to increase dewatering performance and reduce required footprints. However, before implementation of this solution there is a need for increased knowledge on selection and dosing of conditioners. This study evaluated bio-based and synthetic conditioners (chitosan, tannin-, and starch-based, synthetic with and without poly-acrylamide) with 14 types of BW from five countries. The supernatant after settling with jar-tests was analyzed to quantify optimal dose and dewatering performance. The reduction of total chemical oxygen demand (COD) was >55%, achieved by removal of particulate constituents with mainly soluble COD remaining in the supernatant. A reduction in particulate COD could lead to increased efficiency of soluble COD in supernatant treatment. Bio-based conditioners are as effective as synthetic conditioners, and when performance was variable, it was due to differing properties of TSS, TS, EC and pH. Optimal conditioner dose for synthetic conditioners and chitosan could be predicted using concentrations of total solids (TS) (R2 > 0.7), whereas optimal dose for starch- and tannin-based conditioners could be predicted with electrical conductivity (EC) (R2 > 0.8), and colloid titration (R2 > 0.8). In addition, real-time optical TSS and EC sensors could accurately predict chitosan dose for fresh BW treated at source (R2 = 0.97, R2 = 0.95). This study validates that use of conditioners for dewatering with highly variable BW can be implemented with real-time measurements for optimal dose, in globally relevant implementations.
Ward, B. J. (2022). Settling and dewatering of fecal sludge: building fundamental knowledge for improved global sanitation (Doctoral dissertation). ETH Zurich, Zurich, 206 p. , Institutional Repository

More than 1/3 of the global population relies on onsite sanitation systems, and in some cases entire urban areas in low- and middle-income countries are not served by sewers. Improved options for the management of fecal sludge that accumulates in these onsite systems are required immediately, as the majority of it is currently discharged untreated into the urban environment, placing a huge burden on public and environmental health. One of the greatest obstacles to establishing more reliable and accessible fecal sludge treatment is inconsistent and unpredictable solid-liquid separation. Extreme influent variability in influent fecal sludge poses operational problems with settling and dewatering, reducing the capacity of existing centralized and semi-centralized treatment facilities and hindering the transfer of low-footprint technologies which could extend decentralized and community-scale sanitation coverage in high-density urban areas. [...]
Bleuler, M., Gold, M., Strande, L., & Schönborn, A. (2021). Pyrolysis of dry toilet substrate as a means of nutrient recycling in agricultural systems: potential risks and benefits. Waste and Biomass Valorization, 12, 4171-4183. doi:10.1007/s12649-020-01220-0, Institutional Repository

Biochar is increasingly being applied as a soil amendment in agriculture. Biochar is typically produced from plant biomass and contains relatively low amounts of plant nutrients (e.g., N, P, and K), thus providing limited fertilizer value. Human excreta contains plant nutrients that could be recycled to create sustainable agricultural nutrient cycles. This study investigated the potential of biochar derived from a dry toilet substrate as soil amendment. The substrate consisted of urine, faeces, and wood chips, and was pyrolyzed at 500–650 °C for 10 min. The biochar was analyzed for plant available P, water leachable P and K, carbon stability, pH, electrical conductivity, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dioxins, and germination tests with barley and lettuce were conducted to estimate the biochar fertilizer value and potential bio-toxicity. The biochar contained 25.0 ± 1.0 g N/kg dry mass (DM), 33.1 ± 2.1 g P/kg DM and 20.7 ± 0.2 g K/kg DM. 65% DM P was extractable by formic acid solution, 31.7% DM P and 60.5% DM K were water leachable in a ten-day column water-leaching experiment. The biochar complied with European regulations for PAHs, PCBs, dioxins and heavy metal concentrations, except for Zn and Ni. Germination of salt-resistant barley was not affected by biochar doses < 50% DM, while salt-sensitive lettuce germination was inhibited at doses ≥ 2% DM, indicating that the dry toilet substrate biochar induced salt stress. Based on these results, it is recommended that urine separation should be considered for biochar of excreta, which could reduce salt stress while maintaining concentrations of “fixed” or bioavailable nitrogen. Graphic Abstract: [Figure not available: see fulltext.]
Koottatep, T., Ferré, A., Chapagain, S., Fakkaew, K., & Strande, L. (2021). Faecal sludge sample collection and handling. In K. Velkushanova, L. Strande, M. Ronteltap, T. Koottatep, D. Brdjanovic, & C. Buckley (Eds.), Methods for faecal sludge analysis (pp. 55-84). London: IWA Publishing. , Institutional Repository
Narayan, A. S., Marks, S. J., Meierhofer, R., Strande, L., Tilley, E., Zurbrügg, C., & Lüthi, C. (2021). Advancements in and integration of water, sanitation, and solid waste for low- and middle-income countries. Annual Review of Environment and Resources, 46, 193-219. doi:10.1146/annurev-environ-030620-042304, Institutional Repository

The water, sanitation, and solid waste sectors are closely related and have many interactions between their respective service chains in low-and middle-income countries. Currently, these interactions mostly lead to cross-contamination, and opportunities for co-benefits are seldom realized. This review presents the key advancements within each of these three development sectors in the past two decades. We identify numerous similarities such as decentralization, resource recovery, community involved planning, and digitalization. Despite the potential for synergies and the opportunities to maximize positive interactions, there have been few attempts to break the existing sectoral silos in order to integrate these three service chains. We argue that, with the right enabling environment, an integrated approach to holistically planning and implementing water supply, sanitation, and solid waste management can create positive interactions resulting in co-benefits among complementary development goals.
Penn, R., Ward, B. J., Strande, L., & Maurer, M. (2021). Faecal sludge simulants: review of synthetic human faeces and faecal sludge for sanitation and wastewater research. In K. Velkushanova, L. Strande, M. Ronteltap, T. Koottatep, D. Brdjanovic, & C. Buckley (Eds.), Methods for faecal sludge analysis (pp. 195-234). London: IWA Publishing. , Institutional Repository
Prasad, P., Andriessen, N., Moorthy, A., Das, A., Coppens, K., Pradeep, R., & Strande, L. (2021). Methods for estimating quantities and qualities (Q&Q) of faecal sludge: field evaluation in Sircilla, India. Journal of Water, Sanitation and Hygiene for Development, 11(3), 494-504. doi:10.2166/washdev.2021.269, Institutional Repository

Estimates of accumulated quantities and qualities (Q&Q) of faecal sludge are essential for developing city-wide management plans. However, standardized approaches are lacking, and examples in scientific literature make use of diverse methodologies and parameters, making their comparability and transferability difficult. This study field-tested an approach for estimating Q&Q in Sircilla, India, and compared three methods for measuring accumulated sludge: (1) faecal sludge accumulation rate from in situ measurement with a core sampler; (2) faecal sludge accumulation rate with volume emptied by desludging truck; and (3) sludge blanket accumulation rate in situ with a core sampler. Measurements were taken at households and commercial establishments, samples were analysed for characteristics, and demographic, environmental, and technical data were collected with a questionnaire. The median TS, VS, and COD concentrations for all containments were 26.8, 17.8, and 32.0 g/L, respectively. The median faecal sludge accumulation rate estimated with the core sampler and truck were 53 and 96 L/cap·year, respectively. The median sludge blanket accumulation rate was 17 L/cap·year. Continued data collection in this fashion will lead to a better understanding of what is accumulating in onsite containments at regional levels.
Strande, L., Englund, M., Andriessen, N., Carbajal, J. P., & Scheidegger, A. (2021). Estimating quantities and qualities (Q&Q) of faecal sludge at community to city‐wide scales. In K. Velkushanova, L. Strande, M. Ronteltap, T. Koottatep, D. Brdjanovic, & C. Buckley (Eds.), Methods for faecal sludge analysis (pp. 115-144). London: IWA Publishing. , Institutional Repository
Strande, L., Velkushanova, K., & Brdjanovic, D. (2021). Setting the stage. In K. Velkushanova, L. Strande, M. Ronteltap, T. Koottatep, D. Brdjanovic, & C. Buckley (Eds.), Methods for faecal sludge analysis (pp. 1-14). London: IWA Publishing. , Institutional Repository
Velkushanova, K., & Strande, L. (2021). Faecal sludge properties and considerations for characterisation. In K. Velkushanova, L. Strande, M. Ronteltap, T. Koottatep, D. Brdjanovic, & C. Buckley (Eds.), Methods for faecal sludge analysis (pp. 15-54). London: IWA Publishing. , Institutional Repository
Velkushanova, K., Reddy, M., Zikalala, T., Gumbi, B., Archer, C., Ward, B. J., … Strande, L. (2021). Laboratory procedures and methods for characterisation of faecal sludge. In K. Velkushanova, L. Strande, M. Ronteltap, T. Koottatep, D. Brdjanovic, & C. Buckley (Eds.), Methods for faecal sludge analysis (pp. 235-395). London: IWA Publishing. , Institutional Repository
Ward, B. J., Septien, S., Ronteltap, M., & Strande, L. (2021). Experimental design for the development, transfer, scaling‐up, and optimisation of treatment technologies: case studies of dewatering and drying. In K. Velkushanova, L. Strande, M. Ronteltap, T. Koottatep, D. Brdjanovic, & C. Buckley (Eds.), Methods for faecal sludge analysis (pp. 85-114). London: IWA Publishing. , Institutional Repository
Ward, B. J., Andriessen, N., Tembo, J. M., Kabika, J., Grau, M., Scheidegger, A., … Strande, L. (2021). Predictive models using "cheap and easy" field measurements: can they fill a gap in planning, monitoring, and implementing fecal sludge management solutions?. Water Research, 196, 116997 (12 pp.). doi:10.1016/j.watres.2021.116997, Institutional Repository

The characteristics of fecal sludge delivered to treatment plants are highly variable. Adapting treatment process operations accordingly is challenging due to a lack of analytical capacity for characterization and monitoring at many treatment plants. Cost-efficient and simple field measurements such as photographs and probe readings could be proxies for process control parameters that normally require laboratory analysis. To investigate this, we evaluated questionnaire data, expert assessments, and simple analytical measurements for fecal sludge collected from 421 onsite containments. This data served as inputs to models of varying complexity. Random forest and linear regression models were able to predict physical-chemical characteristics including total solids (TS) and ammonium (NH4+-N) concentrations, and solid-liquid separation performance including settling efficiency and filtration time (R2 from 0.51-0.66) based on image analysis of photographs (sludge color, supernatant color, and texture) and probe readings (conductivity (EC) and pH). Supernatant color was the best predictor of settling efficiency and filtration time, EC was the best predictor of NH4+-N, and texture was the best predictor of TS. Predictive models have the potential to be applied for real-time monitoring and process control if a database of measurements is developed and models are validated in other cities. Simple decision tree models based on the single classifier of containment type can also be used to make predictions about citywide planning, where a lower degree of accuracy is required.
Ward, B. J., Allen, J., Escamilla, A., Sivick, D., Sun, B., Yu, K., … Strande, L. (2021). Sludge snap: a machine learning approach to fecal sludge characterization in the field. In Equitable and sustainable WASH services: future challenges in a rapidly changing world. Proceedings of the 42nd WEDC international conference (p. 3307 (2 pp.). Retrieved from https://hdl.handle.net/2134/16866394.v1, Institutional Repository
Velkushanova, K., Strande, L., Ronteltap, M., Koottatep, T., Brdjanovic, D., & Buckley, C. (Eds.). (2021). Methods for faecal sludge analysis. doi:10.2166/9781780409122, Institutional Repository
Doll, C., Larsen, T. A., Strande, L., Udert, K. M., & Morgenroth, E. (2020). Water Hub im NEST-Gebäude. Eine Plattform zum Testen von innovativen ressourcenorientierten Sanitärsystemen. Aqua & Gas, 100(2), 52-57. , Institutional Repository

Mit innovativen Technologien werden im Water Hub unter realen Bedingungen Ressourcen aus dem Abwasser gewonnen und Kreisläufe geschlossen. Die Forschung in diesem Living Lab erlaubt es, praxisnahe Erfahrungen zu machen, Schwachstellen schnell zu identifizieren und das System zu optimieren. Bei der Implementierung dieser dezentralen Technologien spielen die lokalen Herausforderungen und Begebenheiten stets eine wichtige Rolle.
Englund, M., Carbajal, J. P., Ferré, A., Bassan, M., Hoai Vu, A. T., Nguyen, V. A., & Strande, L. (2020). Modelling quantities and qualities (Q&Q) of faecal sludge in Hanoi, Vietnam and Kampala, Uganda for improved management solutions. Journal of Environmental Management, 261, 110202 (13 pp.). doi:10.1016/j.jenvman.2020.110202, Institutional Repository

The importance of faecal sludge management is gaining recognition. However, methods are still lacking to reasonably estimate the quantities and qualities (Q&Q) that need to be managed, which makes the planning for and implementing of management solutions quite difficult. The objective of this study was to collect and analyse Q&Q of faecal sludge at a citywide scale, and to evaluate whether "SPA-DET" data (=> spatially analysable - demographic, environmental and technical) could then be used as predictors of Q&Q of faecal sludge. 60 field samples and questionnaires from Hanoi and 180 from Kampala were analysed. Software tools were used in an iterative process to predict total solids (TS) and emptying frequency in both Hanoi, Vietnam and Kampala, Uganda. City-specific data could be predicted with types of "SPA-DET" data as input variables, and model performance was improved by analysing septic tanks and pit latrines separately. Individual models were built for TS concentrations and emptying frequency. In addition, a model was built across both cities for emptying frequency of septic tanks based on number of users and containment volume, indicating predictive models can be relevant for multiple cities. Number of users, containment volume, truck volume and income level were identified as the most common variables for the correction function. Results confirm the high intrinsic variability of faecal sludge characteristics, and illustrate the importance of moving beyond simple reporting of city-wide average values for estimations of Q&Q. The collected data and developed scripts have been made available for replication in future studies.
Peal, A., Evans, B., Ahilan, S., Ban, R., Blackett, I., Hawkins, P., … Veses, O. (2020). Estimating safely managed sanitation in urban areas; lessons learned from a global implementation of excreta-flow diagrams. Frontiers in Environmental Science, 8, 1 (13 pp.). doi:10.3389/fenvs.2020.00001, Institutional Repository

The urban population will rise to 6.7 billion by 2050. The United Nations has committed to provide everyone with safely managed sanitation, but there is limited understanding of the scale of the challenge. This paper describes a methodology for rapid assessment of sanitation in cities including a graphical representation (a shit-flow diagram or SFD) and reports on findings from implementation in 39 cities. The SFD provides high level information for planning purposes covering the entire sanitation system in a city. More than half of the human excreta produced in these cities is not safely managed. The most significant portions of the unsafely managed excreta are: (i) contents of pits and tanks which are not emptied and are overflowing, leaking, or discharging to the surrounding environment (14%); (ii) contents of pits and tanks which are emptied but not delivered to treatment (18%); (iii) fecal sludge and supernatant delivered to treatment but not treated (3%); (iv) wastewater in sewers not delivered to treatment (14%); and (v) wastewater delivered to treatment but not treated (6%). Many cities currently relying on onsite sanitation for safe storage, particularly in Africa, will need new strategies as populations grow. Containment systems that discharge to open drains are common in some Asian cities; these pose a public health risk. Dumping of excreta is widespread and there is a lack of realistic performance data on which estimates of the extent and effectiveness of treatment can be made. The SFD production process can be challenging due to a lack of data and low technical capacity in cities. There is often uncertainty over terminology and over the status of infrastructure. Formalizing definitions for the SFD preparation process was found to be useful in overcoming capacity constraints in cities. The SFD produces a credible snapshot of the sanitation situation in a city. The paper provides evidence of the urgent need for improved management and monitoring of urban sanitation in cities around the world and highlights the role of the SFD as a planning tool.
Andriessen, N., & Strande, L. (2019). Solid fuels from faecal sludge. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 163-170). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Andriessen, N., & Strande, L. (2019). The Market-Driven Approach to selecting treatment products. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 43-52). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Andriessen, N., Ward, B. J., & Strande, L. (2019). To char or not to char? Review of technologies to produce solid fuels for resource recovery from faecal sludge. Journal of Water, Sanitation and Hygiene for Development, 9(2), 210-224. doi:10.2166/washdev.2019.184, Institutional Repository

Resource recovery from faecal sludge can take many forms, including as a fuel, soil amendment, building material, protein, animal fodder, and water for irrigation. Resource recovery as a solid fuel has been found to have high market potential in Sub-Saharan Africa. Laboratory- and pilot-scale research on faecal sludge solid fuel production exists, but it is unclear which technology option is most suitable in which conditions. This review offers an overview and critical analysis of the current state of technologies that can produce a dried or carbonized solid fuel, including drying, pelletizing, hydrothermal carbonization, and slow-pyrolysis. Carbonization alters fuel properties, and in faecal sludge, it concentrates the ash content and decreases the calorific value. Overall, a non-carbonized faecal sludge fuel is recommended, unless a carbonized product is specifically required by the combustion technology or end user. Carbonized and non-carbonized fuels have distinct characteristics, and deciding whether to char or not to char is a key judgement in determining the optimal solid fuel technology option. Based on the existing evidence, this review provides a decision-making structure for selecting the optimal technology to produce a faecal sludge solid fuel and identifies the top research needs prior to full-scale implementation.
Englund, M., & Strande, L. (2019). Anaerobic digestion. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 141-150). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Englund, M., & Strande, L. (2019). Co-composting. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 101-110). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Englund, M., & Strande, L. (2019). Co-treatment of faecal sludge with wastewater. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 111-118). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Englund, M., & Strande, L. (2019). Collection and transport technologies. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 53-62). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Englund, M., & Strande, L. (2019). Effluent treatment technologies. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 119-128). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Englund, M., & Strande, L. (2019). Engineering design approach for design of treatment technologies. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 11-20). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Englund, M., & Strande, L. (2019). Lime stabilization and ammonia treatment. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 179-186). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Englund, M., & Strande, L. (2019). Overview of treatment technologies. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 63-70). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Englund, M., & Strande, L. (2019). Planted drying beds. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 93-99). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Englund, M., & Strande, L. (2019). Resource recovery. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 33-42). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Englund, M., & Strande, L. (2019). Settling-thickening tanks. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 71-80). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Englund, M., & Strande, L. (2019). Treatment objectives. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 21-26). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Englund, M., & Strande, L. (2019). Unplanted drying beds. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 81-92). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Englund, M., Gold, M., & Strande, L. (2019). Vermi and fly larvae treatment. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 171-178). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Englund, M., & Strande, L. (2019). What is faecal sludge?. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 1-10). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Fischer, M., Nguyen, M., & Strande, L. (2019). Context matters: horizontal and hierarchical network governance structures in Vietnam's sanitation sector. Ecology and Society, 24(3), 17 (14 pp.). doi:10.5751/ES-11036-240317, Institutional Repository

Governance networks describe the complex relations among different types of actors involved in the governance of a policy issue. Here, we ask how different institutional and socioeconomic contextual conditions influence the structure of these networks and result in more horizontal or hierarchical types of governance networks. To answer this question, we study Vietnam’s sanitation sector and compare two different provinces, Hanoi and Ben Tre. More specifically, we analyze networks of information exchange among key actors based on face-to-face interviews and prestructured questionnaires. We find that in the highly urbanized capital city of Hanoi, which serves as a national leader of innovation, where national and international actors are present, and where local actors have high capacities, information exchange tends to follow horizontal network structures. In the more rural, typical province of Ben Tre, hierarchical structures dominate.
Klinger, M., Gueye, A., Manandhar Sherpa, A., & Strande, L. (2019). Scoping study: faecal sludge treatment plants in South-Asia and sub-Saharan Africa. eFSTP Project report. doi:10.21955/gatesopenres.1116557.1, Institutional Repository
Sam, S., & Strande, L. (2019). Overview of treatment mechanisms. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 27-32). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Ward, B. J., & Strande, L. (2019). Conditioning. In M. Englund & L. Strande (Eds.), Faecal sludge management. Highlights and exercises (pp. 151-162). Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Ward, B. J., Traber, J., Gueye, A., Diop, B., Morgenroth, E., & Strande, L. (2019). Evaluation of conceptual model and predictors of faecal sludge dewatering performance in Senegal and Tanzania. Water Research, 167, 115101 (13 pp.). doi:10.1016/j.watres.2019.115101, Institutional Repository

Unpredictable dewatering performance is a barrier to the effective management and treatment of faecal sludge. While mechanisms of dewatering in sludges from wastewater treatment are well understood, it is not clear how dewatering of faecal sludge fits into the framework of existing knowledge. We evaluate physical-chemical parameters, including EPS and cations, and demographic (source), environmental (microbial community), and technical factors (residence time) as possible predictors of dewatering performance in faecal sludge, and make comparisons to the existing conceptual model for wastewater sludge. Faecal sludge from public toilets took longer to dewater than sludge from other sources, and had turbid supernatant after settling. Slow dewatering and turbid supernatant corresponded to high EPS and monovalent cation concentrations, conductivity, and pH, but cake solids after dewatering was not correlated with EPS or other factors. Faecal sludges with higher EPS appeared less stabilised than those with lower EPS, potentially a result of inhibition of biological degradation due to high urine concentrations. However, distinct microbial community compositions were also observed in samples with higher and lower EPS concentrations. Higher EPS faecal sludge was comparable in dewatering behaviour and EPS content to anaerobically digested and primary wastewater sludges. However lower EPS faecal sludges had different dewatering behaviour than wastewater sludges and may be governed by different mechanisms.
Englund, M., & Strande, L. (Eds.). (2019). Faecal sludge management. Highlights and exercises. Dübendorf: Eawag: Swiss Federal Institute of Aquatic Science and Technology. , Institutional Repository
Apoya, P., Bartram, J., Bhagwan, J., Burgers, L., Byigero, A., Callahan, K., … Wijesuriya, G. (2018). Guidelines on sanitation and health. Geneva: World Health Organization (WHO). , Institutional Repository
Englund, M., Carbajal, J. P., & Strande, L. (2018). Method to estimate quantities and qualities of faecal sludge. Sandec News, 19, 8-9. , Institutional Repository

The design of appropriate management and treatment solutions for faecal sludge depends on knowing its quantities and qualities. Previously there has been no method to determine reasonable estimates of quantities and qualities; however, Sandec's research is addressing this need.
Gold, M., Harada, H., Therrien, J. D., Nishida, T., Cunningham, M., Semiyaga, S., … Strande, L. (2018). Cross-country analysis of faecal sludge dewatering. Environmental Technology, 39(23), 3077-3087. doi:10.1080/09593330.2017.1374472, Institutional Repository

Dewatering of faecal sludge (FS) is indispensable for adequate FS management. However, comprehensive knowledge is lacking on FS dewatering performance. This study compared the dewatering performance of FS from different countries and onsite sanitation technologies, to assess influential characteristics on dewatering, and to compare dewatering performance of FS with wastewater sludge. We collected 73 FS samples from septic tanks, lined pit latrines, unlined pit latrines and johkasou tanks in Uganda, Vietnam and Japan, and 18 samples of wastewater sludge in Switzerland. Capillary suction time (CST) and total solids (TS) of centrifuged sludge (%TSfinal) were determined as metrics of dewatering rate and dewaterability, respectively, together with relevant sludge characteristics. Data were analysed by bootstrapping comparison of median results of each sample category and by bootstrapping multiple regression analysis to quantify the relative importance of sludge characteristics on dewatering performance. Results showed that the dewatering rate was significantly different between FS from different technologies, whereas dewaterability was significantly different within the same technology. FS had a significantly lower dewatering rate than wastewater sludge. In contrast, FS dewaterability was greater than wastewater sludge. However, this could be attributed to higher concentrations of sand in FS. Electrochemical properties such as NH4-N and surface charge had the strongest correlation to dewatering rate, and solid properties such as sand content and total volatile solids to dewaterability. The results identify potential characteristics that could explain and predict the high variability of FS dewatering performance that is observed in the field.
Gold, M., Cunningham, M., Arnheiter, R., Schönborn, A., Niwagaba, C., & Strande, L. (2018). Operating parameters for three resource recovery options from slow-pyrolysis of faecal sludge. Journal of Water, Sanitation and Hygiene for Development, 8(4), 707-717. doi:10.2166/washdev.2018.009, Institutional Repository

Slow-pyrolysis is a treatment technology that is being explored for treatment of faecal sludge (FS) from onsite sanitation technologies. Next to pathogen inactivation, the technology produces treatment products. Revenues from these products could offset treatment costs and contribute to financially viable sanitation. In comparison to lignocellulosic biomass and other biowastes, little information is available on operating parameters for FS pyrolysis to produce char for different resource recovery options. In Kampala, Uganda, this bench-scale study investigated the influence of two major operating parameters, hold time (10, 20 and 40 minutes) and pyrolysis temperature (350, 450 and 600 °C) for pyrolysis of FS into char for solid fuel production, soil enhancement and carbon sequestration. Hold time: 10 min was the most suitable hold time for all resource recovery options as char characteristics had only minor variations between hold times. Temperature: Char characteristics identified 350 °C as the most suitable for fuel production and 450 or 600 °C for carbon sequestration. FS char had characteristics for soil enhancement comparable to biowaste and lignocellulosic biomass chars, with heavy metal concentration exceeding guideline concentrations. The most suitable temperature needs to be selected based on plant and soil type, and legal regulations.
Moto, N., Esanju, M., Andriessen, N., Kimwaga, R., & Strande, L. (2018). Use of chitosan and Moringa oleifera as conditioners for improved dewatering of faecal sludge (p. (6 pp.). Presented at the 41st WEDC international conference. Transformation towards sustainable and relisient wash services. Nakuru, Kenya. , Institutional Repository

A pilot-scale dewatering research facility was built in Dar es Salaam, Tanzania, and was used to test chitosan and Moringa oleifera as conditioners to improve the dewatering of faecal sludge. Laboratory-scale jar tests were first conducted to determine optimal dosages for the conditioners in faecal sludge samples with varying total solids concentrations. The results for chitosan were 0.5-0.6 mL/gTS, and for Moringa oleifera 5-15mL/gTS. Based on these results, pilot-scale tests were conducted with chitosan, but the use of Moringa was ruled out as it was too resource intensive. Three loading cycles were conducted, and an average of 15.3% reduction in dewatering time was achieved. Based on the laboratory and pilot-scale tests, chitosan is recommended as a conditioner for improved FS dewatering performance. It could be employed at full-scale, but still requires jar tests to determine optimal dosing.
Penn, R., Ward, B. J., Strande, L., & Maurer, M. (2018). Review of synthetic human faeces and faecal sludge for sanitation and wastewater research. Water Research, 132, 222-240. doi:10.1016/j.watres.2017.12.063, Institutional Repository

Investigations involving human faeces and faecal sludge are of great importance for urban sanitation, such as operation and maintenance of sewer systems, or implementation of faecal sludge management. However, working with real faecal matter is difficult as it not only involves working with a pathogenic, malodorous material but also individual faeces and faecal sludge samples are highly variable, making it difficult to execute repeatable experiments. Synthetic faeces and faecal sludge can provide consistently reproducible substrate and alleviate these challenges. A critical literature review of simulants developed for various wastewater and faecal sludge related research is provided. Most individual studies sought to develop a simulant representative of specific physical, chemical, or thermal properties depending on their research objectives. Based on the review, a suitable simulant can be chosen and used or further developed according to the research needs. As an example, the authors present such a modification for the development of a simulant that can be used for investigating the motion (movement, settling and sedimentation) of faeces and their physical and biological disintegration in sewers and in on-site sanitation systems.
Reynoso-Lobo, J., Otoo, M., Schoebitz, L., & Strande, L. (2018). Livestock waste for compost production (ProBio/Viohache Mexico). In M. Otoo & P. Drechsel (Eds.), Resource recovery from waste. Business models for energy, nutrient and water reuse in low- and middle-income countries (pp. 468-477). Retrieved from https://www.taylorfrancis.com/books/e/9781317703785, Institutional Repository

Productos Bioorganicos (ProBio) is Mexico's largest compost and vermicompost producer with the well-known Humibac brand. Although recently, its name changed to Viohache, this presentation is still using "ProBio". ProBio is a private company created in 2003 to manage the animal waste generated by SuKarne – the largest beef producer and marketer in Mexico. Given the significant quantities of livestock waste produced by SuKarne, traditional waste disposal (i.e. landfilling) systems no longer seemed sustainable and the identification of viable and environmentally safe alternatives was imperative. ProBio maintains a strategic partnership with SuKarne by providing pen-cleaning services in return for their feedstock – animal waste. The business processes 420,000 tons of livestock waste per annum to produce a total of 231,000 tons of compost and 500,000 liters of nutrient-rich liquid fertilizer from processed leachate. It operates in five locations around the country, and supplies a low cost, high quality organic fertilizer to the vegetable, fruit and grain crop sectors. ProBio implements a commodity-value based business model by using simple, low-cost and innovative strategies for the production and branding of the products they offer. It has garnered significant market demand through third party certification and the tailoring of its products to specific clients and agricultural purposes. The business also takes advantage of economies of scale and focuses on low cost, yet efficient technologies for organic fertilizer production and improved waste management. ProBio's operations have had a strong impact on society and the environment as its activities contribute to the reduction of greenhouse gas emissions, on-site waste odor, groundwater and surface water contamination, agricultural crop burning, and local air and soil pollution, among a few.
Reynoso-Lobo, J., Rao, K. C., Schoebitz, L., & Strande, L. (2018). Power from manure and slaughterhouse waste for industry's internal use (SuKarne, Mexico). In M. Otoo & P. Drechsel (Eds.), Resource recovery from waste. Business models for energy, nutrient and water reuse in low- and middle-income countries (pp. 172-181). Retrieved from https://www.taylorfrancis.com/books/e/9781317703785, Institutional Repository

Grupo Viz (GV), a family business in the commercial cattle industry, was established in 1969 in Mexico. SuKarne, one of the five business entities of GV group, with annual sales of over USD 2 billion is the third largest feedlot grain-fed company in the world and fifth largest beef provider in North America. SuKarne's business chain produces both animal and slaughter waste, and it sells some of the waste to its affiliated companies (also owned by GV). In 2012, SuKarne began construction of a biogas pilot plant, a first for the cattle industry that uses a mixture of animal waste and residual biomass, with the lagoon's water, to produce biogas for electricity and thermal energy. At full capacity, it is expected to generate approximately 3.2 MW of electricity for self-consumption and 3 MJ to displace boiler diesel with the heat generated. It will also be possible to further treat the biogas to produce liquid fuel or compressed gas to feed the trucks used throughout the whole operation. The plant will also generate organic bio-fertilizer to be sold to an affiliated company. The project was at the time of assessment under commercial-scale development and expected for construction and commissioning in 2015, with possibilities to replicate the model in its other four facilities in Mexico. The plan is that each plant will be self-sufficient in both electricity and thermal energy. The project's feasibility study is registered in the Clean Development Mechanism (CDM) and subject for final approval for a Certified Emission Reductions (CERs) agreement.
Strande, L., Schoebitz, L., Bischoff, F., Ddiba, D., Okello, F., Englund, M., … Niwagaba, C. B. (2018). Methods to reliably estimate faecal sludge quantities and qualities for the design of treatment technologies and management solutions. Journal of Environmental Management, 223, 898-907. doi:10.1016/j.jenvman.2018.06.100, Institutional Repository

Sanitation access in urban areas of low-income countries is provided through unstandardized onsite technologies containing accumulated faecal sludge. The demand for infrastructure to manage faecal sludge is increasing, however, no reliable method exists to estimate total accumulated quantities and qualities (Q&Q) This proposed approach averages out complexities to estimate conditions at a centralized to semi-centralized scale required for management and treatment technology solutions, as opposed to previous approaches evaluating what happens in individual containments. Empirical data, demographic data, and questionnaires were used in Kampala, Uganda to estimate total faecal sludge accumulation in the city, resulting in 270 L/cap∙year for pit latrines and 280 L/cap∙year for septic tanks. Septic tank sludge was more dilute than pit latrine sludge, however, public toilet was not a distinguishing factor. Non-household sources of sludge represent a significant fraction of the total and have different characteristics than household-level sludge. Income level, water connection, black water only, solid waste, number of users, containment volume, emptying frequency, and truck size were predictors of sludge quality. Empirical relationships such as a COD:TS of 1.09 ± 0.56 could be used for more resource efficient sampling campaigns. Based on this approach, spatially available demographic, technical and environmental (SPA-DET) data and statistical relationships between parameters could be used to predict Q&Q of faecal sludge.
Ward, B. J., Sam, S., Andriessen, N., Morgenroth, E., & Strande, L. (2018). Research priorities and progress in faecal sludge dewatering. Sandec News, 19, 10-11. , Institutional Repository

Difficulties in dewatering of faecal sludge are a crucial barrier to implementation of effective faecal sludge management. This article focuses on progress with locally available conditioners and the next steps toward implementing high-throughput, low-footprint dewatering technologies.
Strande, L., Ronteltap, M., & Brdjanovic, D. (Eds.). (2018). Gestion des boues de vidange. Approche intégrée pour la mise en oeuvre et l'exploitation. London: IWA Publishing. , Institutional Repository
Andriessen, N., Schoebitz, L., Bassan, M., Bollier, S., & Strande, L. (2017). Market driven approach for faecal sludge treatment products. In WEDC conference papers. WEDC conference 40 (p. 2807 (6 pp.). Retrieved from https://wedc-knowledge.lboro.ac.uk/details.html?id=22628, Institutional Repository

Inadequate management and treatment of faecal sludge continues to pose risks for public and environmental health. Given the variability of faecal sludge and location-specific nature of solutions, it is difficult to decide on treatment objectives and performance goals for treatment. The Market Driven Approach was developed as a quantitative methodology to determine which faecal sludge treatment products have the highest market potential in a defined location. This methodology provides a way to compare treatment products based on their real value for resource recovery. This paper discusses the results and lessons learned from field-testing in five cities across Africa and South-East Asia.
Gold, M., Ddiba, D. I. W., Seck, A., Sekigongo, P., Diene, A., Diaw, S., … Strande, L. (2017). Faecal sludge as a solid industrial fuel: a pilot-scale study. Journal of Water, Sanitation and Hygiene for Development, 7(2), 243-251. doi:10.2166/washdev.2017.089, Institutional Repository

Revenues from faecal sludge (FS) treatment end products could offset treatment costs and contribute to financially viable sanitation. In urban sub-Saharan Africa, energy-producing resource recovery has the potential to generate greater revenue than use as soil conditioner. In contrast with wastewater sludge, the technical feasibility of using dried FS as solid fuel in industries has not been investigated. This study evaluated it through characterization of dried FS from drying beds and by assessing the combustion performance in two pilot-scale kilns, in Kampala and Dakar. Results from the fuel characterization demonstrate that dried FS had comparable fuel characteristics as wastewater sludge considering calorific value and ash content. The calorific values and ash contents were 10.9–13.4 MJ/kg dry matter (DM) and 47.0–58.7%, respectively. Results from pilot-scale experiments suggest that dried FS can be effective in providing energy for industries. Temperatures in pilot-scale kilns fueled by FS were 800W C, sufficient for curing of clay bricks, and 437W C, sufficient for waste oil regeneration. In Kampala and Dakar, an estimated 20,000 tons of FS DM per year accumulate. Tapping the industrial fuel market and financial benefits could be realized through optimization of onsite sanitation and treatment technologies.
Schoebitz, L., Bischoff, F., Lohri, C. R., Niwagaba, C. B., Siber, R., & Strande, L. (2017). GIS analysis and optimisation of faecal sludge logistics at city-wide scale in Kampala, Uganda. Sustainability, 9(2), 194 (16 pp.). doi:10.3390/su9020194, Institutional Repository

The majority of residents in low- and middle-income countries are served by onsite sanitation. Equitable access to sanitation, including emptying, collection, and transport services for the accumulation of faecal sludge remains a major challenge. Comprehensive information on service coverage by mechanical faecal sludge emptying service providers is lacking. The purpose of this study is to analyse the spatial distribution of service coverage and identify areas without faecal sludge emptying services in Kampala, Uganda. The study uses GIS (geographic information systems) as a tool to analyse real-time data of service providers based on GPS (global positioning system) units that were installed in a representative number of trucks. Of the total recorded 5653 emptying events, 27% were located outside Kampala city boundaries. Of those within Kampala city boundaries, 37% were classified as non-household customers. Areas without service provision accounted for 13% of the total area. Service provision normalised by population density revealed much greater service provision in medium- and high-income areas than low- and very low-income areas. The employed method provides a powerful tool to optimise faecal sludge management on a city-wide scale by increasing sustainability of the planning and decision-making process, increasing access to service provision and reducing faecal sludge transport times and costs.
Ward, B. J., Gold, M., Turyasiima, D., Studer, F., Getkate, W., Maiteki, J. M., … Strande, L. (2017). SEEK (sludge to energy enterprises in Kampala): co-processing faecal sludge for fuel production. In WEDC conference papers. WEDC conference 40 (p. 2808 (6 pp.). Retrieved from https://wedc-knowledge.lboro.ac.uk/details.html?id=22760, Institutional Repository

The goal of this project was to improve the resource-recovery value of faecal sludge treatment products. A market assessment identified coffee husks, spent grain, and sawdust as optimal organic wastes to co-process with faecal sludge to increase its fuel value. Drying times of faecal sludge to 90% solids were reduced by half with co-pelletizing with these organic wastes. Briquettes produced with char had comparable heating value, fuel performance, and emissions to charcoal briquettes currently being sold. Use of pellets as a fuel was tested in a gasifier and in several industrial clay kilns (after crushing). High ash content led to clinker formation in the gasifier, but performed well in kilns. The potential market for co-processed faecal sludge fuels is high in Kampala, Uganda, especially among industries, however, the market for pellets needs to be developed.
Brandes, K., Schoebitz, L., Nguyen, V. A., & Strande, L. (2016). SFD Promotion Initiative. Hanoi Vietnam. Final report. Dübendorf: Eawag. , Institutional Repository
Cunningham, M., Gold, M., & Strande, L. (2016). Literature review: slow pyrolysis of faecal sludge. Dübendorf; Zürich: Eawag; ETH Zürich. , Institutional Repository
Englund, M., Turyasiima, D., Gold, M., Niwagaba, C., Studer, F., & Strande, L. (2016). Sludge to Energy Enterprises in Kampala (SEEK) project. Co-pelletizing of faecal sludge with different biowastes for gasification. Dübendorf: Eawag. , Institutional Repository
Gold, M., Dayer, P., Faye, M. C. A. S., Clair, G., Seck, A., Niang, S., … Strande, L. (2016). Locally produced natural conditioners for dewatering of faecal sludge. Environmental Technology, 37(21), 1-13. doi:10.1080/09593330.2016.1165293, Institutional Repository

In urban areas of low-income countries, treatment of faecal sludge (FS) is insufficient or non-existent. This results in large amounts of FS being dumped into the environment. Existing treatment technologies for FS, such as settling-thickening tanks and drying beds, are land intensive which is limiting in urban areas. Enhanced settling and dewatering by conditioning was evaluated in order to reduce the treatment footprint (or increase treatment capacity). Conventional wastewater conditioners, such as commercially available lime and polymers, are expensive, and commonly rely on complex supply chains for use in low-income countries. Therefore, the treatment performance of five conditioners which could be produced locally was evaluated: Moringa oleifera seeds and press cake, Jatropha curcas seeds, Jatropha Calotropis leaves and chitosan. M. oleifera seeds and press cake, and chitosan improved settling and dewatering and had a similar performance compared to lime and polymers. Optimal dosages were 400–500 kg M. oleifera/t TS, 300–800 kg lime/t TS and 25–50 kg polymer solution/t TS. In comparison, chitosan required 1.5–3.75 kg/t TS. These dosages are comparable to those recommended for wastewater (sludge). The results indicate that conditioning of FS can reduce total suspended solids (TSS) in the effluent of settling-thickening tanks by 22–81% and reduce dewatering time with drying beds by 59–97%. This means that the area of drying beds could be reduced by 59–97% with end-use as soil conditioner, or 9–26% as solid fuel. Least expensive options and availability will depend on the local context. In Dakar, Senegal, chitosan produced from shrimp waste appears to be most promising.
Gueye, A., Mbéguéré, M., Niang, S., Diop, C., & Strande, L. (2016). Novel plant species for faecal sludge drying beds: survival, biomass response and forage quality. Ecological Engineering, 94, 617-621. doi:10.1016/j.ecoleng.2016.05.027, Institutional Repository

This study investigated the ability of forage plant species that have not previously been used in the treatment of faecal sludge to grow in planted drying beds. Experiments were conducted in 11 L and 25 L pots with layers of sand and gravel to replicate drying beds, and three loading rates (100, 200, 300 kg TS/m2*year). Plant density with faecal sludge was increased for Echinocloa colona, Echinochloa crus-galli, Echinochloa pyramidalis, Paspalidium geminatum, and Paspalum vaginatum (196, 64, 171, 170 and 98% respectively), whereas Eleusine indica and Imperata cylindrica had reduced growth with faecal sludge (−21, −80%, respectively). Protein, minerals, nutrients and fibers as metrics of forage quality all indicated that the species in these trials improved with growth in faecal sludge drying bed conditions. Different species should be selected based on treatment objectives, for example E. crus-galli had optimal forage production characteristics at 200 and 300 kg TS/m2*year loading rates, whereas P. geminatum and P. vaginatum at 100 and 200 kg TS/m2*year. This study suggested that in addition to E. pyramidalis – E. crus-galli, P. geminatum, and P. vaginatum are also good candidates for treatment of faecal sludge with simultaneous forage production to offset treatment costs.
Harada, H., Strande, L., & Fujii, S. (2016). Challenges and opportunities of faecal sludge management for global sanitation. In T. Kutsumi & S. Hashimoto (Eds.), Towards future earth. Challenges and progress of global environmental studies (pp. 81-100). Tokyo: Kaisei Publishing. , Institutional Repository

Excreta is a part of everyday life. The negative part of all this excreta, is that if it is not managed properly, these waste products cause waterborne diseases and water pollution. And a lack of access to clean, functioning toilets threatens human dignity. However, that is the case for 2.4 billion people worldwide without access to adequate sanitation. Onsite sanitation technologies that are used by 2.7 billion people will play a vital role in solving this global sanitation problem. Faecal sludge is the excreta and wastewater that accumulates in onsite-sanitation technologies. It needs to be safely contained onsite, and then the accumulated faecal sludge needs to be safely emptied, transported to a treatment plant, treated, and used for resource recovery or disposed of safely. However, most faecal sludge is not properly managed with a lack of adequate and safe emptying, no treatment plants, and illegal dumping directly in the environment. How can this faecal sludge management (i.e. FSM) problem be addressed? First we will introduce you to innovations of resource recovery from faecal sludge in low-income countries, providing a promising approach. Second, we show the lessons learned from the experience of unique FSM in Japan, which has around 1000 faecal sludge treatment plants with good enabling environment for FSM. Third we will introduce our collaboration to research and develop solutions for FSM in Asia and Africa with a focus on dewatering of faecal sludge, one of the main process challenges to overcome to achieve efficient and reliable treatment.
Ndounla, J., Schoebitz, L., Sonko, E. hadji M., & Strande, L. (2016). SFD Promotion Initiative. Bignona Senegal. Final report. Dübendorf: Eawag. , Institutional Repository
Schoebitz, L., Bischoff, F., Lohri, C. R., Niwagaba, C. B., Siber, R., & Strande, L. (2016). GIS analysis and optimization of faecal sludge logistics at city-wide scale in Kampala, Uganda. Supplementary information. Dübendorf: Eawag. , Institutional Repository
Schoebitz, L., Andriessen, N., Bollier, S., Bassan, M., & Strande, L. (2016). Market driven approach for selection of faecal sludge treatment products. Dübendorf: Eawag. , Institutional Repository

The goal for selecting treatment products based on resource recovery, is to define appropriate levels of treatment based on the desired end-use; generate revenue to offset treatment costs; and help ensure adequate operation of treatment plants, as they are producing a product to meet customer demand.
This market driven approach provides a framework to explore potential markets for faecal sludge treatment products. As markets vary significantly based on the local context, it is essential not to make assumptions based on experiences in other regions. The market driven approach can be applied in any context and region and provides a way to consistently and comparably determine potential market applications for faecal sludge treatment products. This information can then be used as a basis to evaluate appropriate market and business model strategies.
Implementation of this market driven approach requires a certain level of technical knowledge of faecal sludge management. A minimum level of required knowledge is covered in the following chapters from Faecal Sludge Management: Systems Approach for Implementation and Operation, which can be downloaded for free at www.sandec.ch/fsm_book (Strande et al. 2014): [...]
Schoebitz, L., Niwagaba, C. B., & Strande, L. (2016). SFD Promotion Initiative. Kampala Uganda. Final Report. Dübendorf: Eawag. , Institutional Repository
Bassan, M., Koné, D., Mbéguéré, M., Holliger, C., & Strande, L. (2015). Success and failure assessment methodology for wastewater and faecal sludge treatment projects in low-income countries. Journal of Environmental Planning and Management, 58(10), 1690-1710. doi:10.1080/09640568.2014.943343, Institutional Repository

Many factors influence success and failure of large-scale faecal sludge and wastewater treatment projects in low-income countries. Benchmarking indicators and multicriteria analysis were adapted to define key institutional, technical and financial factors, to analyse their interrelations, and understand priorities to consider when planning and managing treatment plants. For the first time, these methods have been combined in a quantitative manner to assess planned and on-going treatment plant projects. This new methodology will aid sanitation utilities, private consultants, and funding institutions to prioritise activities and organise the operation of treatment plants.
Bischel, H. N., Özel Duygan, B. D., Strande, L., McArdell, C. S., Udert, K. M., & Kohn, T. (2015). Pathogens and pharmaceuticals in source-separated urine in eThekwini, South Africa. Water Research, 85, 57-65. doi:10.1016/j.watres.2015.08.022, Institutional Repository

In eThekwini, South Africa, the production of agricultural fertilizers from human urine collected from urine-diverting dry toilets is being evaluated at a municipality scale as a way to help finance a decentralized, dry sanitation system. The present study aimed to assess a range of human and environmental health hazards in source-separated urine, which was presumed to be contaminated with feces, by evaluating the presence of human pathogens, pharmaceuticals, and an antibiotic resistance gene. Composite urine samples from households enrolled in a urine collection trial were obtained from urine storage tanks installed in three regions of eThekwini. Polymerase chain reaction (PCR) assays targeted 9 viral and 10 bacterial human pathogens transmitted by the fecal–oral route. The most frequently detected viral pathogens were JC polyomavirus, rotavirus, and human adenovirus in 100%, 34% and 31% of samples, respectively. Aeromonas spp. and Shigella spp. were frequently detected gram negative bacteria, in 94% and 61% of samples, respectively. The gram positive bacterium, Clostridium perfringens, which is known to survive for extended times in urine, was found in 72% of samples. A screening of 41 trace organic compounds in the urine facilitated selection of 12 priority pharmaceuticals for further evaluation. The antibiotics sulfamethoxazole and trimethoprim, which are frequently prescribed as prophylaxis for HIV-positive patients, were detected in 95% and 85% of samples, reaching maximum concentrations of 6800 μg/L and 1280 μg/L, respectively. The antiretroviral drug emtricitabine was also detected in 40% of urine samples. A sulfonamide antibiotic resistance gene (sul1) was detected in 100% of urine samples. By coupling analysis of pathogens and pharmaceuticals in geographically dispersed samples in eThekwini, this study reveals a range of human and environmental health hazards in urine intended for fertilizer production. Collection of urine offers the benefit of sequestering contaminants from environmental release and allows for targeted treatment of potential health hazards prior to agricultural application. The efficacy of pathogen and pharmaceutical inactivation, transformation or removal during urine nutrient recovery processes is thus briefly reviewed.
Brandes, K., Schoebitz, L., Kimwaga, R., & Strande, L. (2015). SFD Promotion Initiative. Dar es Salaam Tanzania. Final report. Dübendorf: Eawag. , Institutional Repository
Byrne, A., Gold, M., Turyasiima, D., Getkate, W., Niwagaba, C., Babu, M., … Strande, L. (2015). Suitable biowastes for energy recovery. Dübendorf: Eawag. , Institutional Repository

Previous research in Sub-Saharan Africa determined that energy recovery from faecal sludge (FS) as solid fuel has a higher revenue potential compared to the use as soil conditioner in agriculture. Revenues from resource recovery of FS treatment endproducts can be used to offset FS treatment costs. However, currently the available quantities of treated FS are insufficient to meet demands of large-scale industries, which are the target market. Co-processing of FS with other biowastes could be a way to increase the quantity of a solid FS fuel, as well as reducing FS drying requirements and improving FS properties such as ash content and calorific value. In this study, Multi-Criteria Analysis (MCA) using criteria on biowaste availability-accessibility and physical-chemical properties was used to identify suitable biowastes for energy recovery in Kampala, Uganda (e.g. fuel pellets, gasification). In a preliminary assessment, 28 biowastes were identified to be available in Kampala and nine were selected for in-depth analysis. This included proximate and ultimate analysis of all biowastes. MCA identified sawdust, coffee husks, spent grain, market waste, malt/sorghum husks and maize cobs as the most suitable biowastes for energy recovery. Water treatment and wastewater treatment sludge have similar physical-chemical characteristics compared to FS and therefore they do not increase the fuel quality for energy recovery. Sufficient quantities of sawdust, coffee husks, spent grain, market waste, malt/sorghum husks and maize cobs are available for co-processing with FS with a contribution of biowaste of up to 80%. However, these biowastes already have a significant market value. Both, pelletizing and gasification experiments and financial modelling needs to investigate the technical and financial benefits of co-processing of FS with most suitable waste streams identified in this study. Proximate and ultimate analysis results of this study can be used to estimate the proximate and ultimate composition of FS co-processed in different ratios with biowastes.
Gunawan, A., Schoebitz, L., & Strande, L. (2015). SFD Promotion Initiative. Khulna Bangladesh. Final report. Dübendorf: Eawag. , Institutional Repository
Harada, H., Schoebitz, L., & Strande, L. (2015). SFD Promotion Initiative. Danang Vietnam. Final report. Dübendorf: Eawag. , Institutional Repository
Harada, H., Schoebitz, L., & Strande, L. (2015). SFD Promotion Initiative. Nonthaburi Thailand. Final report. Dübendorf: Eawag. , Institutional Repository
Seck, A., Gold, M., Niang, S., Mbéguéré, M., Diop, C., & Strande, L. (2015). Faecal sludge drying beds: increasing drying rates for fuel resource recovery in Sub-Saharan Africa. Journal of Water, Sanitation and Hygiene for Development, 5(1), 72-80. doi:10.2166/washdev.2014.213, Institutional Repository

In urban Sub-Saharan Africa, the collection and transport of faecal sludge (FS) typically ends up with FS directly dumped into the urban environment, as safe treatment and disposal options are too expensive or non-existent. Resource recovery from FS treatment, such as dried FS as an industrial fuel, could provide a financial incentive to increase access to FS management services. In Dakar, Senegal, enhanced drying to reduce the footprint of drying beds for fuel production was evaluated. Greenhouses did not increase drying rates over uncovered beds, however, daily mixing of FS on the surface of the beds resulted in a 6 day reduction to achieve 90% total solids (TS). FS was dried to 90% TS in 2 weeks for loading rates of 100 kg TS/m2*year, and 3 weeks for 150 kg TS/m2*year. The results indicate that with simple but innovative adaptations, footprints of treatment plants could be reduced and/or treatment capacities increased by 20%. FS can be adequately dried in Dakar to produce fuel, meaning 8.25 tons of dried FS could currently be produced daily, contributing 31,403 GJ/year fuel to industries. In addition, this financial incentive could reduce FS that is currently discharged untreated to the environment, and provide an additional 116,705 GJ/year.
Udert, K. M., Buckley, C. A., Wächter, M., McArdell, C. S., Kohn, T., Strande, L., … Etter, B. (2015). Technologies for the treatment of source-separated urine in the eThekwini Municipality. Water SA, 41(2), 212-221. doi:10.4314/wsa.v41i2.06, Institutional Repository

In recent years, a large number of urine-diverting dehydration toilets (UDDTs) have been installed in eThekwini to ensure access to adequate sanitation. The initial purpose of these toilets was to facilitate faeces drying, while the urine was diverted into a soak pit. This practice can lead to environmental pollution, since urine contains high amounts of nutrients. Instead of polluting the environment, these nutrients should be recovered and used as fertiliser. In 2010 the international and transdisciplinary research project VUNA was initiated in order to explore technologies and management methods for better urine management in eThekwini. Three treatment technologies have been chosen for the VUNA project. The first is struvite precipitation, a technology which has already been tested in multiple projects on urine treatment. Struvite precipitation is a simple and fast process for phosphorus recovery. Other nutrients, such as nitrogen and potassium, remain in the effluent and pathogens are not completely inactivated. Therefore, struvite precipitation has to be combined with other treatment processes to prevent environmental pollution and hygiene risks. The second process is a combination of nitrification and distillation. This process combination is more complex than struvite precipitation, but it recovers all nutrients in one concentrated solution, ensures safe sanitisation and produces only distilled water and a small amount of sludge as by-products. The third process is electrolysis. This process could be used for very small on-site reactors, because conversion rates are high and the operation is simple, as long as appropriate electrodes and voltages are used. However, nitrogen is removed and not recovered and chlorinated by-products are formed, which can be hazardous for human health. While urine electrolysis requires further research in the laboratory, struvite precipitation and nitrification/distillation have already been operated at pilot scale.
Bassan, M., Nguyen-Viet, V. A., Holliger, C., & Strande, L. (2014). Optimization of the sampling and laboratory methods for faecal sludge. Sandec News, 15, 6-7. , Institutional Repository

The implementation of anaerobic digestion and other treatment technologies on faecal sludge requires reliable methods to understand its characteristics and the treatment mechanisms. The PURR Project is addressing the current lack of standardized sampling and laboratory methods for faecal sludge.
Bassan, M., Dao, N., Nguyen, V. A., Holliger, C., & Strande, L. (2014). Technologies for sanitation: how to determine appropriate sludge treatment strategies in Vietnam. In WEDC conference papers. WEDC conference 37 (p. 2018 (6 pp.). Retrieved from https://wedc-knowledge.lboro.ac.uk/details.html?id=21856, Institutional Repository

Developing appropriate technologies for the sanitation chain in low- and middle-income countries is crucial to protect public and environmental health. This includes treatment systems for the sludge produced in onsite and centralized systems (i.e., faecal and wastewater sludge). As the quantities and characteristics of sludge differ from city to city, this requires context-specific technologies. This case study was conducted to identify potential management strategies in five cities in Vietnam. The influence of the enabling environment, existing infrastructures, local sanitation practices and socioeconomic contexts on the selection of technology was assessed through literature reviews, household surveys and interviews. A checklist of influential aspects is presented to make best use of local opportunities and minimize the risks of technology failure. This approach is applicable to develop sludge management strategies in other cities.
Bassan, M., Dodane, P. H., & Strande, L. (2014). Treatment mechanisms. In L. Strande, M. Ronteltap, & D. Brdjanovic (Eds.), Faecal sludge management. Systems approach for implementation and operation (pp. 45-66). London: IWA Publishing. , Institutional Repository

This chapter presents an overview of the mechanisms on which faecal sludge (FS) treatment processes are based, and highlights those on which the treatment technologies discussed in subsequent chapters rely. Many FS treatment technologies are based on those developed for wastewater and wastewater sludge treatment, but it is important to remember that these technologies cannot be directly transferred. FS characteristics differ greatly from wastewater, and have a direct impact on the efficiency of treatment mechanisms (Spellman, 1997; Kopp and Dichtl, 2001). Important properties of the sludge to consider include stabilisation, organic load, particle size and density, dissolved oxygen, temperature, pH, water content and viscosity. The current understanding of physical, biological and chemical mechanisms in FS management (FSM) is limited and has been acquired via empirical observations over the years. It is important that this lack of knowledge is overcome in order to improve the design and operation of FS treatment technologies. For more detailed background information on wastewater treatment mechanisms, it is recommended that the reader refers to an engineering textbook specific to this topic. [...]
Diener, S., Semiyaga, S., Niwagaba, C. B., Muspratt, A. M., Gning, J. B., Mbéguéré, M., … Strande, L. (2014). A value proposition: resource recovery from faecal sludge—can it be the driver for improved sanitation?. Resources, Conservation and Recycling, 88(1), 32-38. doi:10.1016/j.resconrec.2014.04.005, Institutional Repository

There is currently a lack of access to affordable sanitation in urban areas of Sub-Saharan Africa. This study evaluated the potential for resource recovery from innovative faecal sludge treatment processes to generate a profit that could help sustain the sanitation service chain. A total of 242 interviews were conducted in Accra, Ghana; Dakar, Senegal; and Kampala, Uganda to compare markets in different cultural and regional contexts. Products identified to have potential market value include dry sludge as a fuel for combustion, biogas from anaerobic digestion, protein derived from sludge processing as animal feed, sludge as a component in building materials, and sludge as a soil conditioner. The market demand and potential revenue varied from city to city based on factors such as sludge characteristics, existing markets, local and regional industrial sectors, subsidies, and locally available materials. Use as a soil conditioner, which has been the most common end use of treated sludge, was not as profitable as other end uses. These findings should help policy and decision makers of sanitation service provision to design financially viable management systems based on resource recovery options.
Gold, M., Murray Muspratt, A., Niwagaba, C. B., Niang, S., Diop, P. S., & Strande, L. (2014). Faecal sludge to fuel: a financial incentive to improve sanitation services. Sandec News, 15, 8-9. , Institutional Repository

FaME research has shown that dried faecal sludge can be used as an industrial combustible fuel. The revenue earned from its sale as fuel has the potential to be a game changer in terms of improving faecal sludge management services in Sub-Saharan Africa.
Gold, M., & Strande, L. (2014). Faecal sludge to fuel: revenue to improve sanitation services. Eawag News [engl. ed.] (3), 1-7. Retrieved from http://newsletter.eawag.ch/e/8bbab41cc9ae86ac/nl/webversion/5790336ba18f3849eebdf48c/en.html, Institutional Repository

Cities in sub-Saharan Africa grapple with the management of faecal sludge from on-site sanitation technologies. There is a lack of funding for sanitation services, resulting in the dumping of faecal sludge directly in the urban environment. Revenues generated from using dried faecal sludge as a combustible fuel in industries could provide an incentive to improve faecal sludge collection, transport and treatment services.
Gold, M., & Strande, L. (2014). Fäkalschlamm sorgt für Zündstoff in Afrika. Eawag News [dtsch. Ausg.] (3), 1-7. Retrieved from http://newsletter.eawag.ch/e/8bbab41cc9ae86ac/nl/webversion/5790336ba18f3849eebdf48c/de.html, Institutional Repository

Getrockneter Fäkalschlamm kann als Brennstoff für die Industrie dienen. Der dadurch generierte Umsatz könnte einen Anreiz für die fachgerechte Sammlung und Behandlung von Fäkalschlamm darstellen und dadurch die sanitäre Versorgung in Subsahara-Afrika verbessern. Denn in vielen Städten dieser Region wird der Fäkalschlamm auf Freiflächen und in Gewässern entsorgt.
Gold, M., & Strande, L. (2014). Matières fécales: un nouveau combustible pour l’Afrique. Eawag News [éd. fr.] (3), 1-7. Retrieved from http://newsletter.eawag.ch/e/8bbab41cc9ae86ac/nl/webversion/5790336ba18f3849eebdf48c/fr.html, Institutional Repository

Une fois séchées, les boues de vidange peuvent constituer un combustible intéressant pour l’industrie. Les revenus alors envisageables pourraient fortement accroître la motivation des entreprises subsahariennes à développer des filières de collecte et de traitement efficaces des matières fécales, ce qui contribuerait fortement à améliorer les conditions d’hygiène dans ces régions où il est fréquent, en milieu urbain, de déverser les boues dans le milieu aquatique ou de les épandre sur les terres inoccupées
Gold, M., Niang, S., Niwagaba, C. B., Eder, G., Murray Muspratt, A., Diop, P. S., & Strande, L. (2014). Results from FaME (Faecal Management Enterprises) – can dried faecal sludge fuel the sanitation service chain?. In WEDC conference papers. WEDC conference 37 (p. 2026 (6 pp.). Retrieved from https://wedc-knowledge.lboro.ac.uk/details.html?id=21886, Institutional Repository

In Sub-Saharan Africa, sanitation needs for the majority of the urban population are met by onsite sanitation technologies. Cities grapple with management of faecal sludge (FS) once these technologies become full, while at the same time the urban economy is resource intensive. The FaME (Faecal Management Enterprises) project addressed both of these issues by identifying untapped markets for FS treatment products. Industries have a high fuel demand and FaME demonstrated that dried FS could be used as a solid combustible in industrial kilns. Existing treatment technologies were adapted for fuel production, and its application was demonstrated in two pilot kilns. Historically used as a soil conditioner, processing of FS to a solid biofuel could provide higher revenues, thereby providing a financial incentive for stakeholders to enhance FS management service along the entire sanitation chain.
Kengne, E. S., Kengne, I. M., Nguetsop, V. F., Foubi, I. S., Akoa, A., & Strande, L. (2014). Algal diversity and distribution in waste stabilization ponds treating faecal sludge leachate from drying vegetated beds. International Journal of Biological and Chemical Sciences, 8(3), 946 (10 pp.). doi:10.4314/ijbcs.v8i3.11, Institutional Repository

Waste Stabilization Ponds (WSP) were tested at pilot scale for the polishing of faecal sludge leachate from planted drying beds in Yaoundé, Cameroon. Water was sampled at three different depths (10, 30, 45 cm) and three different hydraulic retention times (HRT) (4, 7 and 10 days) in two  maturation basins in series for physico-chemical and biological analyses. As a removal mechanism, algae diversity, density and biomass were assessed and correlated to the physical parameters within the ponds. Results showed the presence of nine algal species belonging to three divisions, four classes, six orders, eight families and eight genera. Among these species found in WSPs, Chlamydomonas globosa, Monoraphidium convolutum and pseudanabaena catena were the most abundant whatever the basin, the hydraulic retention time (HRT) and depth. PO4P, NH4N and the total chlorophyll showed strong correlation with the algal biomass (0.582, 0.731 and 0.895 respectively) at the surface (0-15 cm) followed by TSS, temperature and COD (0.556, 0.509 and 0.533 respectively) at HRT 4 days. These correlations were not observed at HRT 7 and 10 days.
Kengne, I., Diaz-Aquado, B. M., & Strande, L. (2014). Enduse of treatment products. In L. Strande, M. Ronteltap, & D. Brdjanovic (Eds.), Faecal sludge management. Systems approach for implementation and operation (pp. 203-226). London: IWA Publishing. , Institutional Repository

The previous chapters covered how stabilisation, drying, and pathogen reduction of faecal sludge (FS) can be achieved with different treatment technologies, and combinations of these various technologies. Each treatment technology results in endproducts which need to be further treated, disposed of, or harnessed for some type of resource recovery. Endproducts, for example dried or partially dried sludge, compost, leachate, and biogas, each have an intrinsic value, which can turn treatment from merely a method for environmental and public health protection to resource recovery and value creation. This chapter focuses on the endproducts produced from the various FS treatment processes, addresses potential difficulties and restrictions with their enduse, and discusses additional steps that can or should be applied to turn a treatment endproduct into a valuable asset. [...]
Kengne, E. S., Kengne, I. M., Nzouebet, W. A. L., Akoa, A., Nguyeng Viet, H., & Strande, L. (2014). Performance of vertical flow constructed wetlands for faecal sludge drying bed leachate: effect of hydraulic loading. Ecological Engineering, 71, 384-393. doi:10.1016/j.ecoleng.2014.07.041, Institutional Repository

The discharge of raw faecal sludge directly into the environment is a common practice that threatens environmental and public health in low-income countries. Planted drying beds are a promising and low-cost option for treatment of faecal sludge and the production of fodder plants, but current research shows the leachate quality does not meet guidelines for discharge. This paper investigates the use of Vertical Flow Constructed Wetlands (VFCWs) planted with Echinochloa pyramidalis for polishing of leachate from faecal sludge drying beds. At a pilot-scale, three hydraulic loads (50, 100 and 150 mm/d) were applied with single loadings once a week on VFCWs (corresponding to 31 ± 9, 63 ± 19, 94 ± 28 g/m2/month of BOD5; 21 ± 6, 42 ± 12, 63 ± 19 TKN; and 2 ± 1; 4 ± 4; 6 ± 6 PO4–P, respectively, for hydraulic loading rates of 50, 100 and 150 mm/d). Infiltration flow rate, plant growth, rhizospheric bacteria, and leachate characteristics were monitored. VFCWs were effective in reducing on average more than 80% of the pollutants monitored (COD, BOD5, NH4–N, TKN, PO4–P, and faecal bioindicators), which met all National Cameroon and WHO guidelines for safe reuse in agriculture, except for total nitrogen and faecal indicators. Results confirmed a correlation between plant density and rhizospheric bacteria growth with increasing hydraulic load. These are important results, demonstrating that VFCWs can operate efficiently at multiple hydraulic loadings, and are hence adaptable to different sized treatment schemes. It also illustrates that if plant production for fodder is a goal, increased loading rates are preferable as they achieve overall treatment goals and result in greater plant production.
Murray Muspratt, A., Nakato, T., Niwagaba, C., Dione, H., Kang, J., Stupin, L., … Strande, L. (2014). Fuel potential of faecal sludge: calorific value results from Uganda, Ghana and Senegal. Journal of Water, Sanitation and Hygiene for Development, 4(2), 223-230. doi:10.2166/washdev.2013.055, Institutional Repository

This research tested the viability of using faecal sludge (FS) as solid fuel – an end use that could unlock an environmentally and financially beneficial replacement for disposal oriented FS management, while replacing fossil energy. FS samples were collected from pit latrines, septic tanks, drying beds and stabilization ponds in three cities, Kumasi, Dakar and Kampala. For each sample, the average calorific value, solids and water content, and their variation with source and age were determined. The average calorific value of untreated FS across the three cities was 17.3 MJ/kg total solids (TS), which compares well with other biomass fuels. The age of FS did not affect its calorific value, nor did the reduction in COD that occurred while it was in drying beds. The TS content of FS depended on its source but ranged from 1 to 6% for sludge from septic tanks and pit latrines, respectively. Harnessing net energy from FS requires partial drying. The results indicate that sufficient drying occurs within two weeks in open-air drying beds, or in a matter of days with simple drying bed innovations.
Niwagaba, C. B., Mbéguéré, M., & Strande, L. (2014). Faecal sludge quantification, characterisation and treatment objectives. In L. Strande, M. Ronteltap, & D. Brdjanovic (Eds.), Faecal sludge management. Systems approach for implementation and operation (pp. 19-44). London: IWA Publishing. , Institutional Repository

The first step in designing faecal sludge (FS) treatment technologies that will meet defined treatment objectives is to quantify and characterise the FS to be treated. Ideally, this should be carried out as part of the Feasibility Study as described in Chapter 17, but is however difficult due to the lack of standardised methodologies for the quantification or characterisation of FS. This complicates the design of adequate and appropriate systems. [...]
Schoebitz, L., Niwagaba, C., Francis, O., Bischoff, F., & Strande, L. (2014). FAQ: faecal sludge quantification and characterization – Kampala. Sandec News, 15, 12-13. , Institutional Repository

Through the collaboration between Sandec, Makerere University and the Private Emptier Association Uganda (PEAU), a new methodology for quantifying and characterizing faecal sludge on a city-wide scale that was developed by Sandec is being field tested in Kampala, Uganda.
Schoebitz, L., Bassan, M., Ferré, A., Vu, T. H. A., Nguyen, V. A., & Strande, L. (2014). FAQ: faecal sludge quantification and characterization – field trial of methodology in Hanoi, Vietnam. In WEDC conference papers. WEDC conference 37 (p. 1954 (6 pp.). Retrieved from https://wedc-knowledge.lboro.ac.uk/details.html?id=21952, Institutional Repository

Characterizing and quantifying faecal sludge (FS) at a city-wide scale in low- and middle-income countries is essential for designing and planning appropriate FS treatment facilities. However, there currently is no accurate methodology for the estimation of these values. The FAQ (faecal sludge quantification and characterization) study developed a methodology, and is validating it in Hanoi, Vietnam and Kampala, Uganda. The method utilizes spatially analysed demographic data as a predictor of FS characteristics. Extensive sampling has been conducted to field test the presented method. This paper presents results of collected and analysed secondary data, and preliminary results of the TS, VS, COD and SCOD concentrations from household septic tanks in Hanoi, which were on average 26,471, 19,395, 37,541 and 713 mg/L respectively, and ongoing data analysis is being conducted.
Schoebitz, L., Nguyen, V. A., Tran, H. H., Dang, T. H., & Strande, L. (2014). From research to implementation. Component 1 - waste supply and availability report - Hanoi. sine loco: sine nomine. , Institutional Repository
Schoebitz, L., Niwagaba, C., & Strande, L. (2014). From research to implementation. Component 1 - waste supply and availability. Report - Kampala. sine loco: sine nomine. , Institutional Repository
Sonko, E. hadji M., Mbéguéré, M., Diop, C., Niang, S., & Strande, L. (2014). Effect of hydraulic loading frequency on performance of planted drying beds for the treatment of faecal sludge. Journal of Water, Sanitation and Hygiene for Development, 4(4), 633-641. doi:10.2166/washdev.2014.024, Institutional Repository

This study was conducted to evaluate the effect of loading frequency on treatment performance of faecal sludge (FS) with drying beds planted with Echinochloa pyramidalis. Beds were loaded at a constant total solids (TS) loading rate of 200 kg TS/m2*year, at a frequency of 1X, 2X or 3X per week. The FS was highly variable, with a range of 2,600–21,492 mg/L TS, which resulted in variable hydraulic loadings. Weekly monitoring was conducted 23 times over a period of nine months. Increased loading frequency resulted in increased plant growth with 211, 265 and 268 plants/m2, respectively, for the 1X, 2X and 3X, and the 2X and 3X loadings had 12–13% more liquid lost due to evapotranspiration versus percolation. Even with high removals that were resistant to variable hydraulic loadings, leachate had 883–5,228 mg/L TS, 49–727 mg/L total suspended solidsand 92–1,853 mg/L chemical oxygen demand due to the high initial concentrations. Increased loading frequency resulted in greater nitrification, with 7–28, 18–43 and 28–51 mg/L NO3− for 1X, 2X and 3X, respectively. FS requires a longer storage time than three months for stabilization and pathogen reduction. These results provide valuable information for FS planted drying bed operation.
Strande, L. (2014). Faecal waste: the next sanitation challenge. Water 21, 16-18. , Institutional Repository

The sanitation needs of 2.7 billion people worldwide are served by onsite sanitation technologies, one billion of these living in urban areas across Africa, Asia and Latin America.This total is expected to grow to five billion by 2030. In many cities, onsite technologies have much wider coverage than sewer systems. For example, in Sub-Saharan Africa, 65-100% of sanitation access in urban areas is provided through onsite technologies.However, in low- and middle-income countries there is typically no management system in place for the resulting faecal sludge (FS). Faecal sludge management (FSM) is therefore essential to the future development of global sanitation.
Strande, L. (2014). The global situation. In L. Strande, M. Ronteltap, & D. Brdjanovic (Eds.), Faecal sludge management. Systems approach for implementation and operation (pp. 1-14). London: IWA Publishing. , Institutional Repository

Solutions for effective and sustainable faecal sludge management (FSM) presents a significant global need. FSM is a relatively new field, however, it is currently rapidly developing and gaining acknowledgement. This chapter provides an introduction to what FSM is, some of the unique challenges of FSM, an overview of the systems level approach for implementation and operation presented in this book, and additional resources that are available on the internet.
Strande, L. (2014). The way forward. In L. Strande, M. Ronteltap, & D. Brdjanovic (Eds.), Faecal sludge management. Systems approach for implementation and operation (pp. 389-403). London: IWA Publishing. , Institutional Repository

The systems level approach to faecal sludge management (FSM) developed in this book should be seen as a building block for the future design and operation of functional and sustainable FSM systems. FSM is a new and rapidly growing field, and improvements and gains in knowledge are rapidly occurring. These advances will continue to build upon each other and improve solutions and approaches for FSM. Each section of this book has drawn important conclusions and has proposed steps to take in the fields of technology, management and planning to develop sustainable FSM systems. Some highlights include: [...]
Tilley, E., Strande, L., Lüthi, C., Mosler, H. J., Udert, K. M., Gebauer, H., & Hering, J. G. (2014). Looking beyond technology: an integrated approach to water, sanitation and hygiene in low income countries. Environmental Science and Technology, 48(17), 9965-9970. doi:10.1021/es501645d, Institutional Repository
Strande, L., Ronteltap, M., & Brdjanovic, D. (Eds.). (2014). Faecal sludge management. Systems approach for implementation and operation. Retrieved from https://iwaponline.com/ebooks/book/384/Faecal-Sludge-Management-Systems-Approach-for, Institutional Repository

Over a billion people in urban and peri-urban areas of Africa, Asia, and Latin America are served by onsite sanitation technologies. Until now, the management of faecal sludge resulting from these onsite technologies has been grossly neglected. Financial resources are often lacking, and onsite sanitation systems tend to be regarded as temporary solutions until sewer-based systems can be implemented. However, the reality is that onsite sanitation is here to stay, either as an intermediate or permanent standalone solution, or in combination with sewer-based systems. The appropriate and adequate management of faecal sludge deriving from onsite technologies is imperative for the protection of human and environmental health.
This is the first book dedicated to faecal sludge management. It compiles the current state of knowledge of this rapidly evolving field, and presents an integrated approach that includes technology, management and planning. It addresses the planning and organization of the entire faecal sludge management service chain, from the collection and transport of sludge and treatment options, to the final en d use or disposal of treated sludge. In addition to providing fundamentals and an overview of technologies, the book goes into details of operational, institutional and financial aspects, and provides guidance on how to plan a city-level faecal sludge management project with the involvement of all the stakeholders.
Strande, L., Ronteltap, M., & Brdjanovic, D. (Eds.). (2014). Manejo de lodos fecales. Un enfoque sistémico para su implementación y operación. London: IWA Publishing. , Institutional Repository
Bassan, M., Tchonda, T., Yiougo, L., Zoellig, H., Mahamane, I., Mbéguéré, M., & Strande, L. (2013). Characterization of faecal sludge during dry and rainy seasons in Ouagadougou, Burkina Faso. In WEDC conference papers. WEDC conference 36 (p. 1814 (6 pp.). Retrieved from https://wedc-knowledge.lboro.ac.uk/details.html?id=20596, Institutional Repository

Faecal sludge (FS) management is a challenging problem in low-income countries where large parts of the urban population rely on onsite sanitation systems. The design of treatment plants relies on accurate knowledge of FS characteristics, but this information is lacking. The goal of this study, conducted between December 2010 and September 2011, was to determine physical and chemical characteristics of raw FS from collection and transport trucks in 5 discharge sites in Ouagadougou. Over 100 samples directly collected during truck discharge were analysed. Analyses included suspended solids, volatile suspended solids, total solids, total volatile solids, sludge volume index, chemical oxygen demand, biological oxygen demand, and heavy metals. The FS characteristics were highly variable, but had similar characteristics for FS collected during the dry and rainy seasons and at different discharge sites. The type of onsite system had an influence on FS characteristics.
Bassan, M., Nguyen, V. A., Holliger, C., & Strande, L. (2013). Co-management of faecal sludge and wastewater sludge in Vietnam. Sandec News, 14, 7. , Institutional Repository

Sandec launched the Partnership for Urban Resource Recovery Project (PURR) in January, 2013. Concentrating on five urban areas in Vietn am, this project will evaluate, develop and test strategies for the co-treatment and resource recovery of faecal sludge and wastewater sludge.
Bassan, M., Mbéguéré, M., Tchonda, T., Zabsonre, F., & Strande, L. (2013). Integrated faecal sludge management scheme for the cities of Burkina Faso. Journal of Water, Sanitation and Hygiene for Development, 3(2), 216-221. doi:10.2166/washdev.2013.156, Institutional Repository

The National Utility for Water and Sanitation in Burkina Faso (ONEA) has recognized the difficulty in providing sewered sanitation to the entire urban population and has opted for a strategy involving onsite sanitation. Most of the country's population is served by onsite systems that generate large amounts of faecal sludge, and are responsible for a high prevalence of water-borne diseases. ONEA and the Department of Water and Sanitation in Developing Countries (Sandec) at the Swiss Federal Institute of Aquatic Science and Technology (Eawag) have a collaborative project that aims to establish an enabling environment for the development of the faecal sludge sector at the institutional and technical level. The project's participatory process has allowed the design of a treatment plant adapted to local conditions, and the elaboration of the first institutional framework for faecal sludge management including several new official documents. Several technical studies filled knowledge gaps of faecal sludge characterization, and the feasibility of implementing planted drying beds. Lessons learned are transferable nationally and internationally.
Bassan, M., Dao, N., Thuy, P., Hoai, A. V., Nguyen, V. A., & Strande, L. (2013). PURR - Partnership for Urban Resource Recovery. Initial assessment of sludge management and context in five cities: Son La, Lang Son, Hoa Binh, Bac Ninh, and Ba Ria. Dübendorf: Eawag. , Institutional Repository

This summary report provides an overview of the highlights and key findings of the Initial Assessment Study that was conducted in Son La, Lang Son, Hoa Binh, Bac Ninh, and Ba Ria Vietnam as part of the PURR (Partnership for Urban Resource Recovery) Project. The purpose of the Initial Assessment Study was to provide an overview of the current status of sanitation and sludge management, the regulatory environment, and to identify local stakeholders. The study was conducted to develop an understanding of the local context to provide a basis for evaluating reasonable management and treatment options of faecal and wastewater sludge in each of the cities. Faecal sludge is the sludge that is stored in onsite sanitation technologies such as septic tanks and pit latrines. Wastewater sludge is produced in wastewater treatment plants (WWTPs) during the treatment of sewerage. Information in the report includes:
• the national institutional framework,
• the local environmental and socio-economic context,
• the water supply system,
• the wastewater management practices, stakeholders and infrastructures,
• the solid waste collection, transport and disposal system,
• the existing faecal sludge management habits. [...]
Gold, M., Murray, A., Niwagaba, C., Niang, S., & Strande, L. (2013). Faecal sludge – from waste to solid biofuel?. Sandec News, 14, 8. , Institutional Repository

Research in urban areas of Senegal, Ghana and Uganda proved that there are widely untapped markets for faecal sludge end-products as financial drivers to sustain reliable and safe faecal sludge management. As a fuel, it especially shows promise as an industrial energy resource and a means to generate revenue.
Kengne, E. S., Magloire, K. I., Letah, W. A., Akoa, A., Nguyen-Viet, H., & Strande, L. (2013). Treatment technology for leachate from faecal sludge drying beds. Sandec News, 14, 10. , Institutional Repository

The use of planted drying beds for faecal sludge treatment is effective for solid-liquid separation, but the leachate produced requires further treatment prior to discharge or reuse. This study investigates the potential of a new and low-cost solution for leachate treatment.
Schöbitz, L., Zurbrügg, C., Gebauer, H., & Strande, L. (2013). Waste-based business models for resource recovery. Sandec News, 14, 6. , Institutional Repository

Waste-based business models for resource recovery could be the solution to the sanitation challenges of low and middle income countries. This is the research aim of the Tr iple R Project (Resource, Recovery and Reuse), which is analysing the factors of business success in this industry.
Bassan, M., & Strande, L. (2012). Institutional framework for faecal sludge collection and transport in Burkina Faso. Sandec News, 13, 17. , Institutional Repository

ONEA, the Burkina Faso National Utility for Water and Sanitation collaborates with Sandec to improve faecal sludge management by strengthening stakeholder capacity and designing an institutional framework.
Bassan, M., Tchonda, T., Mbéguéré, M., & Strande, L. (2012). Optimizing the faecal sludge management scheme in Ouagadougou, Burkina Faso. Sustainable Sanitation Practice, 13(10), 22-24. Retrieved from http://www.ecosan.at/ssp/issue-12-faecal-sludge-management, Institutional Repository

This paper shows the benefits of involving local stakeholders such as collection and transport operators and municipal representatives in the development of an optimized faecal sludge scheme.
Diener, S., Reiser, J. C., Murray, A., Mbéguéré, M., & Strande, L. (2012). Recovery of industrial waste heat for faecal sludge drying. Sandec News, 13, 16. , Institutional Repository

Use of waste heat from industries could enhance the faecal sludge drying process and minimise the treatment footprint.
Dodane, P. H., Mbéguéré, M., Sow, O., & Strande, L. (2012). Capital and operating costs of full-scale fecal sludge management and wastewater treatment systems in Dakar, Senegal. Environmental Science and Technology, 46(7), 3705-3711. doi:10.1021/es2045234, Institutional Repository

A financial comparison of a parallel sewer based (SB) system with activated sludge, and a fecal sludge management (FSM) system with onsite septic tanks, collection and transport (C&T) trucks, and drying beds was conducted. The annualized capital for the SB ($42.66 capita–1 year–1) was ten times higher than the FSM ($4.05 capita–1 year–1), the annual operating cost for the SB ($11.98 capita–1 year–1) was 1.5 times higher than the FSM ($7.58 capita–1 year–1), and the combined capital and operating for the SB ($54.64 capita–1 year–1) was five times higher than FSM ($11.63 capita–1 year–1). In Dakar, costs for SB are almost entirely borne by the sanitation utility, with only 6% of the annualized cost borne by users of the system. In addition to costing less overall, FSM operates with a different business model, with costs spread among households, private companies, and the utility. Hence, SB was 40 times more expensive to implement for the utility than FSM. However, the majority of FSM costs are borne at the household level and are inequitable. The results of the study illustrate that in low-income countries, vast improvements in sanitation can be affordable when employing FSM, whereas SB systems are prohibitively expensive.
Kengne, I. M., Kouassi, D., Doulaye, K., & Strande, L. (2012). Productive treatment of faecal sludge: from waste to fodder and pro­fits. Research evidence for policy. Regional edition West Africa: Vol. 2. Retrieved from http://www.susana.org/en/resources/library/details/1634, Institutional Repository

In developing countries, lack of low-cost, efficient treatment technologies commonly results in faecal sludge (FS) from domestic on-site sanitation systems (e.g. latrines) being dumped untreated onto the land or into drains and watercourses. This puts public health at risk and harms the environment. Sludge drying beds planted with emergent macrophytes (plants that grow in shallow water but have their stems and leaves above the water surface) are a cost-effective and technically feasible approach for treating sludge. They also produce plants that can be used as feed for livestock and biosolids that can be applied as compost to cropland, increasing agricultural productivity.
Robbins, D., Strande, L., & Doczi, J. (2012). Opportunities in fecal sludge management for cities in developing countries: experiences from the Philippines. Water 21, 1-7. , Institutional Repository

In July 2012, a team from RTI International, with assistance and guidance from Eawag/Sandec, deployed to the Philippines to evaluate four fecal sludge management (FSM) programs with the goal of reporting on best practices and lessons learned. FSM includes the collection, transport, reuse, and disposal of septic tank sludge and is seen as a starting point for cities interested in improving sanitation. The four cases—(1) Dumaguete City, (2) San Fernando City, (3) Maynilad Water for the West Zone of Metro Manila, and (4) Manila Water for the East Zone of Metro Manila—were chosen to highlight their different approaches to implementing FSM (Table 1). The information gathered provides insight into how other cities in developing countries can utilize best practices to achieve sustainable FSM programs.
Bassan, M., Mbéguéré, M., & Strande-Gaulke, L. (2011). Capacity strengthening in sanitation – benefits of a research – operator collaboration. Sandec News, 12, 12-13. , Institutional Repository

The National Utility of Water and Sanitation (ONEA) in Burkina Faso and the Department of Water and Sanitation in Developing Countries (Sandec) of the Swiss Federal Institute of Aquatic Science and Technology (Eawag) have struck a three-year collaboration to provide sustainable solutions and skills in the sanitation sector. The developed global approach evaluates existing infrastructure, identifies and fills gaps in operational capacity, local knowledge and institutional procedures for wastewater and faecal sludge management.
Bassan, M., & Strande, L. (2011). Capacity strengthening in sanitation: benefits of a long-term collaboration with a utility and research institute. In R. Shaw (Ed.), WEDC conference: Vol. 35. The future of water, sanitation and hygiene in low-income countries - innovation, adaptation and engagement in a changing world. Proceedings of the 35th WEDC international conference, Loughborough University, Loughborough, UK, 6-8 July 2011. (p. 1116 (8 pp.). Retrieved from https://wedc-knowledge.lboro.ac.uk/details.html?id=12189, Institutional Repository

Sanitation investments in Africa have largely failed to meet the Millennium Development Goals. Many, sewer-based wastewater treatment plants provide inadequate treatment, and faecal sludge from onsite treatment in urban areas is largely untreated. The National Office of Water and Sanitation in Burkina Faso and the Department of Water and Sanitation in Developing Countries in Switzerland are involved in a collaboration designed to increase institutional aptitude, and develop sustainable long-term wastewater and faecal sludge management solutions. The developed approach evaluates and fills gaps in existing infrastructure, operational ability, local knowledge, and institutional procedures. The continuous communication between the partners has resulted in a synergy and increased level of commitment. This paper presents results and future plans of this utility - research approach that has resulted in training and capacity development plans and a much greater understanding of sanitation management. The lessons learned are transferable to other countries, institutes and sectors.
Diener, S., Mbéguéré, M., & Strande-Gaulke, L. (2011). Providing sanitation solutions through value chain management. Sandec News, 12, 17. , Institutional Repository

A newly launched project in Sub-Saharan Africa will transpose faecal sludge from waste to a valuable product.
Dodane, P. H., Mbéguéré, M., Kengne, I. M., & Strande-Gaulke, L. (2011). Planted drying beds for faecal sludge treatment: lessons learned through scaling up in Dakar, Senegal. Sandec News, 12, 14-15. , Institutional Repository

Experiments have revealed that planted drying beds are a promising technology for faecal sludge treatment in tropical climates. However, most of the current knowledge has been developed through lab-scale experiments. Full-scale planted drying beds have been in operation since 2008 at the Cambérène treatment facility in Dakar, Senegal. Monitoring and evaluation have resulted in important conclusions for scaling up and managing the critical start-up phase of this eco-technology.

Team

Dr. Linda Strande Tel. +41 58 765 5553 Send Mail
Nienke Andriessen Project Officer Tel. +41 58 765 5082 Send Mail
Michael Vogel Tel. +41 58 765 5944 Send Mail
Kelsey Shaw Tel. +41 58 765 5551 Send Mail
Kayla Coppens Tel. +41 58 765 6717 Send Mail
Ednah Kemboi Tel. +41 58 765 6860 Send Mail
Natalia Andrea Montoya Arévalo Tel. +41 58 765 6851 Send Mail
Dr. Seju Kang Postdoctoral Researcher Tel. +41 58 765 6839 Send Mail
Julian Fritzsche Tel. +41 58 765 6816 Send Mail

Dr. Nida Maqbool
Tel. +41 58 765 55 53
E-mail: