Wastewater use in irrigated agriculture: management challenges in developing countries.

Abstract

Cities in developing countries are experiencing unparalleled growth and rapidly increasing water supply and sanitation coverage that will continue to release growing volumes of wastewater. In many developing countries, untreated or partially treated wastewater is used to irrigate the cities' own food, fodder, and green spaces. Farmers have been using untreated wastewater for centuries, but greater numbers now depend on it for their livelihoods and this demand has ushered in a range of new wastewater use practices. The diversity of conditions is perhaps matched only by the complexity of managing the risks to human health and the environment that are posed by this practice. An integrated stepwise management approach is called for, one that is pragmatic in the short-and medium terms, and that recognises the fundamental economic niche and users' perceptions of the comparative advantages of wastewater irrigation that drive its expansion in urban and peri-urban areas. Comprehensive management approaches in the longer term will need to encompass treatment, regulation, farmer user groups, forward market linkages that ensure food and consumer safety, and effective public awareness campaigns. In order to propose realistic, effective, and sustainable management approaches, it is crucial to understand the context-specific tradeoffs between the health of producers and consumers of wastewater-irrigated produce as well as the quality of soils and water, on the one hand, and wastewater irrigation benefits, farmers' perceptions, and institutional arrangements on the other. This introductory chapter to the current volume on wastewater use in agriculture highlights a series of tradeoffs associated with continued use of untreated wastewater in agriculture. Empirical results from the case studies presented in the volume shed light on devising workable solutions.

Heavy metal accumulation and health risk assessment in wastewater-irrigated urban vegetable farming sites of Addis Ababa, Ethiopia

“…Wastewater (untreated, partially treated or diluted) has been widely used for agriculture in most urban and peri-urban cities of developing countries (Scott et al 2004). Market proximity, high opportunities for income generation, reliable and free irrigation water supply, and minimum artificial fertilizer requirement are the often cited benefits of irrigation within cities (Drechsel et al 2006;Qadir et al 2010).…”

Phosphorus recycling and food security in the long run: a conceptual modelling approach

“…Harvest -and the P it contains -is largely transported to the urban centres, consumed as food and enters the sewage systems as human excreta. In many countries urban waste water is hardly treated (Scott et al 2004) and where it receives treatment, the P-rich wastes are hardly recovered as they are contaminated with 2 Dawson and Hilton (2011) calculate a global human nutritional P requirement between 1.7 and 3.7 Mt. P/year which is about 10 % of the P extracted from mines (Koppelaar and Weikard 2013), indicating some slackness in the chain of P flows.…”

Global Experiences on Wastewater Irrigation: Challenges and Prospects

“…Comprehensive management approaches in the longer term will need to encompass treatment, regulation, farmer user groups, forward market linkages that ensure food and consumer safety, and effective public awareness campaigns (Scott et al 2004 ). Clear policy guidelines on how to optimise the benefi ts and minimise the risks of untreated wastewater are lacking (van der Hoek 2004 ).…”

“…Planned reuse that seeks to maintain the benefi ts and minimise risks will require an integrated approach. The key to the success of endeavors to make the transition to planned strategic reuse programmers is a coherent legal and institutional framework with formal mechanisms to coordinate the actions of multiple government authorities, sound application of the 'polluter pays' principle, conversion of farmers towards more appropriate practices for wastewater use, public awareness campaigns to establish social acceptability for reuse, and consistent government and civil society commitment over the long term with the realisation that there are no immediate solutions (Scott et al 2004 ). Institutions and organisations at the level of village or neighborhood shape the ways in which wastewater is managed through members active in these organisations (Buechler 2004 ).…”