Close behind our lead biofilter concept are two alternative approaches, the Black Soldier Fly Larvae and Next-generation Bio-additives.
Both are extremely promising in their potential for reducing pit-filling, but both involve key challenges which we need to address before we can consider their commercial application.
We’re researching both these options to the point where we can decide whether they’re ready to be moved into application development.
Black Soldier Fly Larvae
The larvae of the Black Soldier Fly are very hungry – and very useful – creatures. As well as feeding voraciously on excrement, they can be readily harvested at their pre-pupae stage and processed into animal or fish food, or biodiesel.
We’re seeing if we can harness the ability of Black Soldier Fly larvae to process and reduce sludge – either inside a latrine or at some central point to which latrine waste is transported. (A central point would probably be more acceptable to users and more readily controlled.) An attraction of this route is the potential to recover value from the pre-pupae after larval digestion of the latrine waste. Before entering the application stage with this idea, we want to explore further its commercial viability and the ability of larvae to develop into pre-pupae on latrine material.
The assessment of latrine waste digestion is being carried out by Ian Banks, a PhD student at the London School of Hygiene and Tropical Medicine. Ian’s MSc thesis showed how the larvae developed successfully on human faeces from vegetarian and omnivore diets, and how after feeding they reduced the mass and odour of the faeces significantly.
A team of MBA students from the Haas Business School, UC Berkeley, has assessed the commercial viability of this approach. They’ve found that sufficient value can be recovered as animal food or biodiesel to drive a low-cost emptying service linked to centralised treatment. Read more their about their findings and download their full report.
We are exploring collaborations with two organisations actively looking at value recovery linked to emptying services. WaterSHED works on enterprise development in water, sanitation and hygiene in Cambodia, and Sanergy develops novel business approaches around the collection and transportation of latrine waste in Kenya.
We're also designing BSF larvae systems that can be retrofitted into latrines, working with the winners of our Innocentive Challenge. Find out more about our progress.
We’re seeing if we can develop bio-additives (such as micro-organisms and enzymes) that speed up sludge breakdown in full or filling latrines. We believe there’s a significant market opportunity for a product that’s easily administered and scientifically proven to work.
The largest segment would be householders, especially in urban areas where space is limited and at key moments, such as when a pit is becoming noticeably full or has just been emptied. The market could also include humanitarian emergency camps, where pit filling can be a major problem.
Before moving into the application stage, we need to identify ingredients superior to those already available. We plan to do this in collaboration with Dr Grietje Zeeman at Wageningen University and a major biotechnology company. By our project completion, we aim to have identified promising candidate ingredients for further development into a final product to reduce pit filling in latrines.