To use city wastewater for crop irrigation

Photo credit: IWMI

One of the 4 workers of farmer Bablu Jana irrigates a fresh batch of celery
on a patch of his 17 katha land using water from the adjacent lake of land near the busy EM Bypass road of Calcutta, India. Jana cultivates Chinese vegetables whose demand has shot up due to the popularity of chinese restaurants. Throughout the year he grows lettuce, celery, chinese cabbage, garlic leaves, etc. He says Chinese vegetables require water. So he owns a pump to draw water from the adjacent lake. During summer, the lake dries up. Then the local farmers pool INR 500 each to pay the lake owner who then pumps water in from an adjacent canal.He has 4 workers to help him irrigate and till the land.

1 katha of land = 2880 sq feet
INR 1 = $ 55

Wastewater Irrigation in Karnataka

India is urbanizing fast. As its cities expand, so more and more food is grown near built up areas – or even in conurbations themselves. For farmers of perishable produce like vegetables, production close to urban markets makes sense: Demand is year-round and freshness can be guaranteed. But the big drawback is access to land and water. Plots near cities quickly become expensive and water may be siphoned off for domestic and industrial use.

Basudev Mondal irrigates a farm near the busy EM Bypass road of Calcutta, India growing brinjal or egg plant. He charges the owner of the land INR 50 for his labour. The cost of the water pump is INR 250. Located adjacent to a landfill and the East Kolkata Wetland, which processes raw sewage into usable water using fish farms, the area produces 150 tonnes of vegetables. The paddy fields in the East Kolkata Wetland (many of which draws irrigation water from the fisheries) produce 15,000 Metric Tonnes of additional paddy per annum. INR 1 = $ 55

One way round this is to use city wastewater for crop irrigation. This has an added benefit in that wastewater is often high in nutrients so improves crop yield. In the summer season when freshwater is scarce and prices are high, wastewater may be the only cost-effective irrigation option for many growers.

With a population of just over 60 million, Karnataka is one of the most urbanized states of India. According to the Central Pollution Control Board, Karnataka generated over 3,700 MLD (million liters per day) of wastewater in 2015. However, sewage treatment capacity of the state is only 1,300 MLD which means that nearly 65 per cent of wastewater is discharged untreated into water bodies, deteriorating water quality.

Untreated wastewater often carries pathogens and other dangerous toxins, but many farmers continue to use this water for irrigation because it is the only source available to them.

So how do Karnataka farmers view the risks of using wastewater? A new study, recently published as apolicy brief by the IWMI-Tata Water Policy Research Program, sought to find out. Researchers surveyed famers around the cities of Hubli Dharwad and Vijayapura. In order to assess the costs and benefits of wastewater irrigation, a representative sample of 43 farms was studied in detail. Twenty-six of the sample farms used wastewater while the remaining 16 used groundwater.

Read the full article: IWMI


%d bloggers like this:
close-alt close collapse comment ellipsis expand gallery heart lock menu next pinned previous reply search share star