Can compost be made from domestic effluent?
The universities of Pretoria (UP) and (UKZN) KwaZulu-Natal are collaborating on potentially ground-breaking research to investigate the likelihood of agricultural compost made from domestic effluent.
The study was initiated and is led by the UKZN, enlisting the support and expertise of the UP’s researchers. It found that rural farmers in KwaZulu-Natal are receptive to the idea of using compost made from human effluent if it is safe, affordable and works. As part of the research, 341 farmers were asked what influenced their choice of fertilisers or compost before presenting them with a type made from domestic effluent as a potential choice.
Design and data analysis
The UKZN’s Dr Simon Gwara led the study with Dr Damien Jourdain of UP’s Department of Agricultural Economics, Extension and Rural Development and Dr Thomas Lundhede, an extra-ordinary professor in Environmental Economics, as co-authors of the research. UP’s researchers provided specific assistance with design and data analysis using a method called “choice experiments”. These experiments allow researchers to understand consumer choices based on how much they value specific characteristics of products, explained Dr Jourdain, an expert in choice experiments and choice modelling.
Fortification and Certification of Human Compost Preferred
The key question researchers sought to answer was whether farmers were concerned about the packaging of human compost and whether or not it was fortified with additional nutrients. They also investigated potential health and safety risks associated with the process. “We found that farmers care more concerned about fortification and certification of domestic effluent, with perceived health risks as a potential barrier to the use of such compost in agriculture. Certification would mitigate some of the safety concerns,” explained Dr Gwara.
Commercial compost
The main findings of the research suggest that faecal sludge management businesses and similar entrepreneurial endeavours within the waste value recovery chain should create human compost products more acceptable to farmers. For instance, human excrement can be co-composed with other organic waste to ensure it is fortified with the necessary nutrients and minerals. It could also be sold as pellets resembling other commercial fertilisers. Clear safety certifications should also be placed on faecal waste products to address any real or perceived risks.
Addressing socio-economic issues
Dr Gwara said he came to understand and appreciate the potential of these experiments after attending a seminar presented by Dr Jourdain in 2018. He said what also prompted him to undertake this research was to understand what consumers wanted in human compost products. Most importantly, these products could address critical socio-economic issues such as waste management, sanitation, agriculture and climate change mitigation.
Importance of Choice Experiments in Market Research
According to Dr Jourdain, this study represents the first step towards creating human compost products which farmers are prepared to buy into. He said this is a perfect example of the versatility and use of choice experiments for market research, adding that he and his colleagues have been working with PhD students across South Africa (SA) to build capacity in choice experiments for agricultural economics. “Personally, this work is very important to me and I hope to establish a community of practice in SA through these student networks and with others involved in choice experiments,” he said.
Emerging Choice Experiments in Africa
Some students are using choice experiments to study preferences with regards to pasture insurance, illegal hunting and even re-wilding animals in national parks. According to Dr Jourdain, many others are using choice experiments in health research while pointing out that although these choice experiments are widely used globally, they are only emerging in Africa. He however cautioned that this approach is based on hypothetical choices, necessitating this research to be carefully crafted to minimise biases in respondent preferences.
Regarding the human compost pellets, Dr Jourdain said: “we are talking about a product that doesn’t exist yet. People may say they would buy it, but in practice, when the products arrive, they might not.” He said the next step for human compost market research might be to offer an actual test product at an auction where the actual buying behaviour of consumers can be observed.
