2021 Seed Grant Award Problem Statements 

WASH / Water Management / Irrigation

Problem #17: Component and cost optimization of a functioning, self-contained & energy positive on-site toilet & fecal sludge treatment system whose only output is fertilizer

Country/Region of execution:  Eldoret, Kenya
Collaborating Organization: Moi University School of Engineering
Moi University is a public university located in Uasin Gishu County, Kenya. Moi University was established in 1984 by an Act of Parliament (Moi University Act, 1984) as the second public university in Kenya. The University’s current funded research funding totals KSHs 1.8bn. The School of Engineering is one of the oldest schools in Moi University and was formed in 1986 and now has five academic departments. All engineering courses offered at Moi University are recognized in Kenya and internationally and are therefore registered by Engineering Board of Kenya (EBK).
Problem Statement Description:  According to UNDP, 2.3 billion people lack access to basic sanitation facilities and 80% of wastewater enters waterways without adequate treatment. Poor sanitation is linked to transmission of numerous diseases, such as cholera, diarrhea, dysentery, typhoid. The ADPL (Anaerobic Digestion Pasteurization Latrine) is a self-contained fecal treatment system designed to replace pit latrines and eliminate groundwater contamination, while providing liquid fertilizer. The ADPL consists of three toilets built above a baffled anaerobic bio-digester and a biogas driven heat pasteurization system that sanitizes digester effluent. A solar panel & batteries power a micro-controller & resistive ignitor. The ADPL is ideally suited for contexts where pit latrines are not feasible, specifically locales with high water tables & rapidly urbanizing areas with dense population and poor/ no infrastructure. 
The ADPL was first installed as a functioning prototype in 2013 serving continuously 15-25 people per installation. Since then, it has been piloted and improvements have been made through collaboration with communities, feedback from end-users, and Kenyan engineers. The current iteration functions satisfactorily, however, requires updates based on advanced technological innovations occurred over the years in order to improve the efficiency and bring the total cost down. Some of the current challenges include:  improve digester efficiency/ design to eliminate solids – the system currently has solids accumulate in the digester & hinder effluent flow; heater and heat exchanger size/ design – the heater is currently ~8L. The heating system is an area that requires more design work to be optimized due to size and efficiency; ignitor durability – the system currently uses a resistive ignitor (spark ignitor causes surges and damages electronics), but it doesn’t last for long; monitoring system - currently the system uses sim card shield for online monitoring. This has been done for research purposes, but is rudimentary at best. We seek solutions that will optimize the system based on factors of efficiency and cost and to take this community-vetted product across the innovation ‘valley of death’.  At the current stage, the ADPLs also require market research & product guidance to ensure a final product that meets needs of a viable customer base at an affordable price point. This solution requires technical support in partnership with the onsite teams to optimize various components & prepare for commercialization. Additionally, usage of pasteurized effluent as an agricultural input requires further evaluation & optimization.