In many cities, sewage is used for cultivation: study

Global study covers Chennai and Bangalore

STOCKHOLM: Cities in developing countries around the world, including at least some in India, are using untreated or partially treated wastewater for agriculture, posing serious health risks to urban consumers, a study released on Monday said.

“Irrigating with wastewater isn’t a rare practice limited to a few of the poorest countries,” said researcher Liqa Raschid-Sally, a researcher for the International Water Management Institute (IWMI). “It’s a widespread phenomenon, occurring on 20 million hectares across the developing world, especially in Asian countries, like China, India and Vietnam, but also around nearly every city of sub-Saharan Africa and in many Latin American cities as well.”

The IWMI said wastewater was most commonly used to produce vegetables and cereals, especially rice.

The study looked at 53 cities in Latin America, West Asia, Africa and Asia. In a report released to coincide with an annual water conference in Sweden, it found that 80 per cent were using untreated or partially treated wastewater. At the same time, the IWMI noted that wastewater agriculture contributes to urban food supplies and helps provide a livelihood for the urban poor.

Few developing countries reported having official guidelines for use of wastewater in agriculture and in the cases where they did exist there was little enforcement, the IWMI said.

The institute saw no quick fixes. “In the face of water scarcity generally and a lack of access to clean water, urban farmers will have no alternative except to use diluted or untreated wastewater or polluted river water,” it said.

One option is to build on local practices. In Indonesia, Nepal, Ghana and Vietnam, for example, farmers store wastewater in ponds to allow suspended solids to settle out.

Some experts said that 1.4 million children die every year from diarrhoea-related diseases and poor hygiene, and described the global sanitation crisis as “the world’s largest environmental problem.”

An increasing demand for water and food has spurred the use of sewage to water crops but in many cases is the only form of irrigation for farmers who lack clean water, the study showed.

Conference participants stressed the need to increase transparency in the water production chain. Up to 45 per cent “of costs for providing clean water around the world go toward corruption,” Transparency International global programmes director Christiaan Poorter said on the sidelines of the meetings.

In India

The 53 cities covered by the survey included Bangalore and Chennai.

As far as Bangalore is concerned the study has pointed out that as hi-tech professional demand good quality infrastructure and services, the city is not moving at the pace with which the demands have been registered.

“This has resulted in significant increase in pressure on natural resources and infrastructure and also several inadequacies.” the study on Bangalore said, pointing to the fact that the city faces several health and environmental problems.

“One such inadequacy is water resources, and the problem is compounded due to its location in the water deficit zone. In fact, inefficient urban and environmental planning have sealed off additional water potentials which would have other wise solved the city water problems in a much easier way. The use of untreated waste water in agriculture has been posing health problems to the farmers in the city region,” the study has said.

The study pertaining to Bangalore listed several policy recommendations that includes the rehabilitation and extension of sewage network in the city and its extension areas for proper and cent percent collection of all sewage water generated in the city, and its 100 per cent treatment up to the tertiary level for effective reuse in agriculture, industry, residential and commercial use. This would reduce the pressure on fresh water resources.

World Water Week is a conference attended by 2,500 scientists, politicians and officials from 140 countries. On the Net it is at http://www.worldwaterweek.org/.