Wastewater farming’s ups and downsWith worsening fresh-water scarcity both for expanding cities and many rural regions, there is a corresponding increase in urban and peri-urban agriculture that uses wastewater irrigation, a year-round, consistent water source. Biodiverse urban agriculture in places like Hyderabad can be a key strategy for dealing with the complex urban-ecological puzzle of polluted water, scarce water and land, recycling of water and nutrients, food insecurity and livelihood insecurity.
Keywords: wastewater irrigation, urban agriculture, peri-urban agriculture, biodiversity
Wastewater irrigation in urban and peri-urban agriculture is an ancient practice still used widely today, linked to sustainability problems and solutions. Rapid urbanization puts huge pressures on freshwater resources and sanitation systems. Freshwater scarcity can even drive more migration to cities, where wastewater is a reliable source of irrigation. This is particularly relevant in arid and semi-arid regions.
Human and environmental well-being are both linked to how wastewater and water-borne pollutants are managed. Unfortunately, though worldwide an estimated 200 million farmers irrigate with wastewater, it remains largely unregulated in low-income countries. Making wastewater irrigation a more secure solution for urban and peri-urban farming necessitates better support for farmers, given inherent health risks (see also Hanoi and Shanghai).
Hyderabad / Musi River Belt
Vegetables, rice, green fodder, and dairy products are all produced in peri-urban Hyderabad with wastewater irrigation from the Musi River. Musi water is classified as wastewater because of wastewater – estimates range from 200 to 600 million litres - polluting it daily.
Hyderabad’s peri-urban cultivation is intensive, with some 5 persons farming per acre in usually highly biodiverse vegetable production. Spinach, fennel, cabbage, amaranthis, fenugreek, mint, and coriander are among the leafy vegetables in high demand, particularly in hotter months when storage capacity is limited. Just in the period 2002-2006, a 188% increase in the total area under leafy vegetable production was observed. The primary agricultural produce however is green fodder (particularly paragrass), which was introduced by area farmers when their traditional production of paddy, sorghum, millet, and vegetables became unsustainable as the Musi River’s content of wastewater increased starting in the 1960s.
Biodiversity and its benefits
The biodiversity of Hyderabad’s peri-urban vegetable agriculture was the focus of a 2007 study by the International Water Management Institute and the University of Freiburg, Germany. A range of key findings and benefits were highlighted. Firstly, researchers found a highly diverse cultivation of vegetables. Secondly, agricultural biodiversity was used to boost resilience against yield loss due to any of several risk factors, e.g pests, heavy monsoon rainfall, and changes in market-demand. Agricultural biodiversity was also reported by farmers as enabling a larger customer base and therefore higher total income. Farmers often sold produce house-to-house themselves. Crop diversity directly raised the farmers’ own food security through dietary diversity and the range of minerals, vitamins, and proteins they got from consuming part of their own produce (see also Havana and Lubumbashi).
Key practices and benefits
In developing-country settings, wastewater irrigation in urban and peri-urban agriculture is associated with:
- a means of raising food and nutritional security via year-round availability, better accessibility and greater affordability of food
- cultivation of leafy vegetables, because these cope better than fruit-bearing vegetables with the larger nitrogen supply
- higher frequency of harvests of leafy vegetables due to the wastewater’s fertilising effect
- regulation of the irrigation by the farmers to reduce risks from pollutants, e.g. not irrigating on days when industrial effluents are released – known to at least some farmers by experience
- a source of livelihoods for urban and peri-urban residents, and micro-enterprise development
- a way to make use of urban solid waste and wastewater
- a way to recycle nutrients to agriculture
- a way to recycle water
- better use of available land
- social and gender goal-attainment by providing livelihoods to a socially diverse group of people by gender, caste, religion, social class
Problems and challenges
For urban and peri-urban agriculture (and aquaculture), a key theme is the lack of institutional/network support and coordination to address the problems of wastewater irrigation, often ignored as an uncomfortable reality, and connected with weaker social groups.
Wastewater irrigation exposes both farmers and consumers to pollutants, including industrial-chemical effluents and high-risk pesticides. There is a lack of research on risks to producers and to consumers from wastewater irrigation.
Separation at source of industrial effluents from domestic effluents is considered to be essential for wastewater irrigation. Similarly, guidelines for farming with wastewater irrigation are needed in all situations where wastewater remains insufficiently treated – to protect health, livelihoods, and the environment. However, urban and peri-urban farmers using wastewater irrigation often lack any institutional/governmental support at all. Yet highly biodiverse urban agriculture is knowledge intensive, so urban and peri-urban farmers could benefit from agricultural extensions services, farmer field schools, etc.
The Hyderabad Declaration on Wastewater Use in Agriculture, 14 November 2002, Hyderabad, India, http://www.iwmi.cgiar.org/health/wastew/hyderabad_declaration.htm
Johanna Jacobi, Axel W. Drescher, Priyanie H. Amerasinghe, Philipp Weckenbrock, “Agricultural Biodiversity Strengthening Livelihoods in Periurban Hyderabad, India”, Urban Agriculture magazine, Number 22, June 2009, www.ruaf.org
G. Krishnagopal, R. Simmons, “Urban and Periurban Agriculture: Towards better Understanding of low Income Producer Organizations. Hyderabad City Case Study.” Access Livelihoods Consulting India (Secunderabad) & International Water Management Institute (IWMI - South Asia Regional Office), 2007, http://faoidrc.files.wordpress.com/2007/08/hyderabad-case-study.pdf
Liqa Raschid-Sally, Priyantha Jayakody / International Water Management Institute, 2008, “Drivers and Characteristics of Wastewater Agriculture in Developing Countries: Results from a Global Assessment”, Research Report 127. http://www.unwater.org/downloads/RR127.pdf
Key data are retrieved from the UN World Urbanization Prospects: The 2011 Revision, http://esa.un.org/unup/unup/index_panel2.html