Wasser und Entwicklung

Processing of biowaste with larvae of the black soldier fly, Hermetia illucens L. (Diptera: Stratiomyidae), is an emerging waste treatment technology. Larvae grown on biowaste can be a relevant raw material for animal feed production and can therefore provide revenues for financially viable waste management systems. In addition, when produced on biowaste, insect-based feeds can be more sustainable than conventional feeds. Among others, the scalability of the technology will depend on the availability of large amounts of biowaste with a high process performance (e.g. bioconversion of organic matter to proteins and lipids) and microbial and chemical product safety. Currently, in contrast to other waste treatment technologies, such as composting or anaerobic digestion, the process performance is variable and the processes driving the decomposition of biowaste macronutrients, inactivation of microbes and fate of chemicals is poorly understood. This review presents the first summary of the most important processes involved in black soldier fly larvae (BSFL) treatment, based on the available knowledge concerning five well-studied fly species. This is a starting point to increase understanding regarding the processes of this technology, with the potential to increase its efficiency and uptake, and support the development of appropriate regulations. Based on this review, formulating different types of biowaste, e.g. to produce a diet with a similar protein content, a balanced amino acid profile and/or pre- and co-treatment of biowaste with beneficial microbes, has the potential to increase process performance. Following harvest, larvae require heat or other treatments for microbial inactivation and safety.

The study assessed changes in water quality between the water source and the tap of locally produced low cost ceramic water filters used by a community living in hygienically critical conditions in a remote mountainous area in Western Nepal. Data was collected from 42 rural households during two visits. The effectiveness of filter handling on its performance was assessed through microbiological analysis, structured household interviews and structured observations. Water quality decreased significantly when source water was filled into transport containers, while the use of the filters improved drinking water quality for about 40% of the households. Highly inadequate filter cleaning practices involving the use of contaminated raw water, hands (geo mean = 110 E. coli CFU/100 mL) and cleaning tools (geo mean = 80 E. coli CFU/100 mL) stained hygienic parts of the filter. The use of boiling water to disinfect the filters was significantly correlated with improved filter performance and should be further promoted. However, even disinfected filters achieved a very low average LRV for E. coli of 0.4 in the field and performed worse than during laboratory tests (LRV for E. coli of 1.5-2). Comprehensive training on adequate filter handling, as well as better filter products, are required to improve the impact of filter use.

Household water treatment (HWT) can effectively reduce exposure to unsafe drinking water at home. Understanding thecharacteristics of target groups who successfully adopt HWT, such as perception about water quality and usefulness of HWT,income, or parental education, is essential for enhancing the adoption of HWT in developing countries. The objective of this study isto analyze the interactions between such socio-environmental characteristics, rather than a single characteristic, in order to explainthe adoption of HWT. Five socio-environmental characteristics and behavior determinants were analyzed using QualitativeComparative Analysis (QCA) from 41 case studies in Africa, Asia, and South America. Results show that there is no singlecharacteristic that alone explains the adoption of HWT. QCA identified five pathways leading to high adoption of HWT. Perceivedthreat due to bad water quality is a pre-condition for three of the pathways. However, perceived threat does not alone explainadoption of HWT and must be accompanied by other conditions. Households connected to piped water schemes can also bepotential HWT adopters as long as they perceive poor tap water quality. Finally, households who are able to afford the full cost ofHWT tend to adopt it only when they neither have prior experience with HWT nor a connection to a piped scheme. Our findingstherefore highlight the necessity to analyze interactions between socio-environmental characteristics of households and behaviordeterminants in order to determine the adoption of HWT.

Ensuring universal access to safe drinking water is a global challenge, especially in rural areas. This research aimed to assess the effectiveness of a risk-based strategy to improve drinking water safety for five gravity-fed piped schemes in rural communities of the Mid-Western Region of Nepal. The strategy was based on establishing community-led monitoring of the microbial water quality and the sanitary status of the schemes. The interventions examined included field-robust laboratories, centralized data management, targeted infrastructure improvements, household hygiene and filter promotion, and community training. The results indicate a statistically significant improvement in the microbial water quality eight months after intervention implementation, with the share of taps and household stored water containers meeting the international guidelines increasing from 7% to 50% and from 17% to 53%, respectively. At the study endline, all taps had a concentration of <10 CFU Escherichia coli/100 mL. These water quality improvements were driven by scheme-level chlorination, improved hygiene behavior, and the universal uptake of household water treatment. Sanitary inspection tools did not predict microbial water quality and, alone, are not sufficient for decision making. Implementation of this risk-based water safety strategy in remote rural communities can support efforts towards achieving universal water safety.

Today's rapid global urbanization highlights the need for long-term transformations of basic service sectors in developing cities in order to improve the livelihoods of the urban poor. Sustainability transitions frameworks have proven fruitful for addressing these sort of challenges. However, they have been at pains so far in accounting for the heterogeneity and complexities that typically characterize informal settlements in the Global South. We therefore propose a conceptual framework that extends the conventional analysis of socio-technical regimes by distinguishing the two levels of sectoral regime and service regime. Challenges for sustainability transitions may then be identified by missing alignments within and among the two regime levels. The framework is applied to the sanitation sector of Nairobi, Kenya, a city experiencing rapid population growth and a highly uneven provision of basic services. Drawing on a set of 152 in-depth interviews, observations, and five focus group discussions, the paper reconstructs the prevailing service regimes and shows how they suffer from misalignments and dysfunctionalities creating all sorts of problems at a sectoral level. We conclude that Nairobi's sanitation sector can best be characterized as representing a splintered regime. The paper concludes with a discussion of how the new conceptualization of socio-technical regimes suggests some new sustainable transition pathways and how this framework might also be instructive for transition challenges in cities of the Global North.