SOWATT – Selecting Organic Waste Treatment Technologies
Municipal solid waste continues to be a challenge for municipal authorities, and finding best practices and appropriate solutions for its management is of great interest to municipal officers. Whereas in the past, the priority of waste management was the collection and removal of waste with subsequent disposal, the importance of resource recovery and recycling is attracting more attention and priority. Along with this increasing paradigm change focusing on resource recovery, new approaches for the management of biowaste with respective treatment technologies are becoming more popular (e.g. composting, anaerobic digestion, black soldier fly processing, vermicomposting, etc.). We developed the SOWATT manual: Selecting Organic Waste Treatment Technologies to help structure and assist in the process of comparing and selecting the most promising biowaste treatment options for a given case study.
Carbonization of Urban Bio-waste
Carbonization is a process during which biomass is heated in the absence of oxygen; the primary goal is to produce char. This char can be further processed into briquettes and used as household cooking fuel. The objective of our research on slow pyrolysis and hydrothermal carbonization (HTC) is to explore the potential of using organic waste to generate a char product that has a value in the local market as a replacement for wood-based charcoal and thus, could be a financial driver of organic waste processing businesses.
FORWARD - From ORganic WAste to Recycling for Development
FORWARD is an applied research project that develops integrated strategies and technologies for the management of municipal organic solid waste in medium-sized cities of Indonesia. Designing organic waste treatment for value rather than treatment for disposal is at the core of this research project.
Black Soldier Fly Biowaste Processing
Many organic waste sources have a high nutritional potential and thus make an excellent feed substrate for insect larvae in general, and the larvae of the black soldier fly (BSF), Hermetia illucens L. (Diptera: Stratiomyidae), in particular. Given the right circumstances, the larvae are able to reduce the material by 50-80% and they convert up to 20% into larval biomass on a total solids basis within ±14 days. The grown larvae make an excellent protein source in animal feed and their sale can, thus, contribute to lower treatment cost and to a lucrative business with organic waste.
Anaerobic digestion of organic solid waste
Besides composting or direct animal feeding, anaerobic digestion (biomethanation) of organic solid waste is considered a promising treatment option for this particular waste fraction. Anaerobic digestion is a natural biological process that converts biomass into energy (biogas) in the absence of oxygen. Biogas – a mixture of CO2 and methane (CH4) – can be used as a renewable energy source for cooking, lighting or to generate electricity, thereby replacing other fuel sources. Biogas digestate is a nutrient-rich fertiliser that can be applied in gardens or agriculture.
The existing physical plan and socio-economical situation of many cities in low and middle-income countries strongly favours the implementation of decentralised systems. Decentralised composting systems are less technology dependent. Low cost, locally available materials and simple technology can be used. Our research on composting includes co-composting of organic waste and faecal sludge as well as market demand for compost from organic waste.