Department Sanitation, Water and Solid Waste for Development

Vermifiltration is a non-sewered, nature-based sanitation technology that harnesses the symbiotic relationship between earthworms and microorganisms to treat wastewater in aerobic conditions. Earthworms break down solids, aerate the compost via tunnelling, and exctrete their own gut microorganisms and enzymes which enhance the overall treatment process.  Earthworms and microorganisms biologically transform and degrade organic matter, nutrients, and emerging contaminants of concern found in wastewater.  With low installation and maintenance costs, no sludge production and low to null energy needs, vermifiltration has potential to be an economical viable global solution for wastewater management.

Despite full-scale implementations in China, France, India, Rwanda, and the USA, processes in vermifiltration are not clearly defined, and there are many research gaps remaining for reliable and optimized models of treatment performance.

The objectives of this four-year research project are to gain an understanding of operating parameters on treatment mechanisms and performance, longer-term treatment performance, and the validity of scaling-up laboratory results. To accomplish this, full-scale vermifiltration installations are being monitored, and in parallel laboratory-scale installations are used in controlled studies to gain an understanding of the effect of operational parameters, such as wastewater type and loading rates, on treatment performance. The role of microbial communities in these processes is being evaluated, together with the impact on greenhouse gas emissions. The laboratory- and full-scale results will then be compared to evaluate the effects of scaling-up and long-term performance.

• University of Geneva (UniGe), Geneva Switzerland: Prof. Serge Stoll, Prof. John Pote and Prof Laurent Matthey
• aneco, Geneva Switzerland
• Housing cooperative Equilibre, Geneva Switzerland
• Geneva’s Cantonal Water Department (OCEau)

• Institute for Environmental Sciences, Department F.-A. Forel
• Swiss Federal Institute of Aquatic Science and Technology, Eawag 

Vermifiltration: Optimizing and Scaling-up for Domestic Wastewater Treatment, Coppens, K., Stoll, S., Strande, L. Sandec News 2023