Reducing the burden of rural water supply through greywater reuse: a case study from northern Malawi

Abstract

Greywater reuse has potential for non-potable applications that conserve freshwater resources in water-stressed areas especially in sub-Saharan Africa. The feasibility of reusing greywater for domestic activities in a rural area of Malawi, Africa, was evaluated from microbiological and public acceptance perspectives. Median Escherichia coli concentrations for eight domestic greywater sources (handwashing, laundry, runoff from a tap apron, bathing, cleaning a home/kitchen, cleaning a water collection container, washing plates and soaking vegetables) ranged from 100 to >20,000 colony forming units (cfu)/100 ml. Twenty-four of 47 greywater samples tested (51%) met the World Health Organization guideline for unrestricted use of greywater for irrigation. Pertinently, 80% (4/5) and 60% (3/5) of greywater samples from handwashing stations and bathing had E. coli less than the WHO guideline. Users reported greatest acceptance of reusing greywater for growing food and washing clothes, especially when the greywater source was bathing. Acceptance was closely tied to a household’s economic standing, geographic location, and first-hand knowledge of reusing greywater. Greywater reuse practices in rural areas, especially targeting bathing water as suitable from bacteriological and user perception criteria, can help mitigate the impacts of water stress in sub-Saharan Africa.