Integrating the safe and sustainable management of wastewater into small-scale vegetable production systems in Malawi


Worldwide, more than 800 million farmers are engaged in urban agriculture. Of these, about 200 million practice market-oriented farming, and often have no other choice but to use wastewater for irrigation [in this proposal we refer to ‘wastewater’ as the use of raw, partly treated, or diluted wastewater, from predominantly domestic sources]. Urban and peri-urban farmers in the developing world can enhance household income by producing perishable crops such as leafy vegetables for sale in local markets. These farmers are crucial for providing a continual supply of vitamin-rich vegetables to the community, and it is estimated that urban farmers who irrigate their crops with wastewater supply about 60% of vegetables sold in African cities. Such production of fresh vegetables is fundamental for alleviating hidden hunger (the deficiency in micronutrients, vitamins and minerals in the diet); furthermore, urban farming can provide significant employment and economic opportunities. Farmers often prefer to use wastewater for irrigation as it provides a free source of nitrogen and phosphorus (and thus, less money spent on fertilisers), and can be more reliable or cheaper than other water sources. Effluent is often in large supply, and compared to groundwater in Malawi, is low in salinity and high in nitrogen. Consequently, it has now become common practice in Malawi for urban farmers to deliberately vandalise wastewater flow channels or drain covers to divert effluent into their vegetable gardens. However, sanitary wastewater contains a variety of human pathogens, such as viruses, bacteria, parasites and helminths (many of which are capable of survival in the environment long enough to be transmitted to humans), together with a risk from anti-microbial resistance (AMR) genes. Thus, farmers are exposed to relatively high concentrations of pathogens, and have an increased risk of enteric disease and infections with worms. Women, who provide much of the labour required to produce vegetables are particularly at risk; women also dominate in the marketing and retail process and are mainly responsible for preparing family meals, which creates the opportunity for transferring pathogens to family members and the wider community. The sale of contaminated vegetables and leafy greens in markets is therefore of significant public health concern and despite international guidelines for using wastewater in agriculture, this knowledge is poorly implemented at the local governmental level, and guidelines are rarely translated to local farmers.


Integrating the safe and sustainable management of wastewater with increased agricultural productivity has recently gained interest in many countries. Therefore, the overarching objective of this studentship is to involve local water management stakeholders, urban water users and agricultural wastewater user groups to provide an interdisciplinary framework for the student to integrate policy, health, environmental and engineering dimensions that cuts across traditional academic disciplines. Specifically, the research objectives of this project are to:

1. Create a ‘Stakeholder-Alliance’ to provide an intersectoral forum to identify and integrate farmer’s and public health leader’s needs and concerns, while addressing food security and public health risks to people and the wider community
2. Map areas of wastewater irrigation within the Blantyre municipal area, and monitor the dynamics of water quality and subsequent contamination of vegetables at four case-study sites
3. Develop and test context-specific interventions (including assessment of the associated trade-offs) for reducing pathogen transfer from wastewater irrigation to vegetables and leafy greens
4. Trial innovative public awareness programmes to inform farmers and consumers of the potential health impacts of wastewater irrigation, and key targets for improved practice
5. Develop a ‘National Policy Framework’ to facilitate the safe use of wastewater in food production

Project Timeline

Year 1

Following a critical review of the literature (months: 0-4), the student will undertake a short ‘Problem-framing’ field mission to Blantyre and create an Alliance of key stakeholders to support co-design of the planned research activities to ensure that the research is both contextually appropriate and delivers for all stakeholders. Using our established networks via WASHTED at the University of Malawi, the student will enlist stakeholders from the water industry, the local government, the food industry, public health, town planning, local markets and consumer groups. In addition, the student will engage with local urban farmer groups and ensure appropriate representation of small-scale farmers and food producers within the Alliance. The Alliance will become a co-operative that provides the means for discussing options for addressing water quality regulations and water management challenges that both integrate farmer’s needs and concerns, whilst addressing public health risks to the wider community. It is anticipated that the student will bi-annually convene the Alliance for workshops/meetings and that the initiative will continue beyond the lifetime of the project, and thus support long-term real-world impact. Back in the UK, the student will attend a range of training courses plan and design (incl. ethics and risk assessments), the experiments for the next field mission

Year 2

During an extended fieldwork mission, the student will use satellite images, local information and knowledge from the Alliance to map all areas of wastewater irrigation in the Blantyre municipal area. This will provide data on the extent and spatial distribution of wastewater use. The student will use four case study sites (as agreed within the Alliance) to quantify the dynamics of temporal water quality used for irrigation (e.g. E. coli, faecal coliforms and helminth eggs) and subsequent contamination of vegetables and leafy greens. In addition, transport and sale points of vegetables will be mapped to identify high-risk markets and consumers.

Year 3

The student will, develop and test context-specific strategies for reducing pathogen transfer, and test the feasibility of strategies to reduce pathogen transfer to vegetable crops (e.g. natural de-contamination from cessation of irrigation, sedimentation ponds, adaptive irrigation methods, activated charcoal), by utilising a citizen science approach among farmers to ensure these methods are fit for purpose. The student will also co-develop an awareness programme with the Stakeholder Alliance (e.g. using a variety of media and social media outlets, radio interviews, posters, workshops) that promote guidelines (e.g. in the form of a simple risk assessment matrix) for farmers and consumers about the potential health impacts of wastewater irrigation. A context-sensitive approach will be used that considers gender, illiteracy and the limited time farmers have available to engage with such programmes.

Year 3.5

The student will co-design a strategic ‘National Policy Framework’ with the Stakeholder Alliance that can be translated to other areas in Malawi, and scaled-up to countries where there are similar management pressures to use wastewater resources to increase food security. The remaining time will be spent writing up the thesis and papers for publication.

& Skills

The student will become fully embedded within the research team of the newly funded £3.85 million NERC SPACES project led by Prof Richard Quilliam, which is based in Malawi and Tanzania. This studentship will provide the platform to build an interdisciplinary research career in sustainable development and public health, and the student will develop broad expertise in the environmental sciences, together with skills in the social sciences & applied anthropology. Extensive skill development in fieldwork will include comprehensive training in sampling & monitoring techniques, while the student will also benefit from working closely with experienced field researchers in Africa.

References & further reading

The ‘Environmental Sustainability and Human Health ‘ research group at Stirling:
Qadir et al. (2010) Agricultural Water Management, 561-568;
“Faeces in your vegies” The Nation newspaper, Malawi, 11/09/2017;
WHO (2006). Guidelines for “Safe Use of Wastewater, Excreta & Grey Water in Agriculture”;
Woldetsadik et al. (2018). Env Syst & Decisions, 38: 52-64

Further Information

Professor Richard Quilliam
Tel: 01786 467769

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