Udaipur : Only 20-30% of about 40,000 mega litres of sewage produced everyday in India is treated. Untreated sewage is commonly discharged into rivers and streams which is the main reason for surface water pollution in India. While the beneficial reuse of wastewater is an absolute necessity for food and water security, the use of untreated sewage is threatening human health and environment. These were few of the observations of the four day Indo-Australian workshop concluded recently in Udaipur which was sponsored by the Crawford Fund of Australia. The delegates discussed the opportunities and challenges of reuse of wastewater.
The event coincided with the announcement of South Australia and Rajasthan as sister states. This workshop, was hosted by VidyaBhavan and MPUAT Udaipur in collaboration with Wolkem India Ltd.,CSIRO Australia and Western Sydney University and was attended by experts and practitioners from India and Australia. “ The workshop called for a concreted and considered action to deal with the growing problem of untreated sewage associated pollution of rivers in India, such as in Ahar (Udaipur) and Yamuna (Delhi)” informed Anil Mehta , a water scientist and activist. Rivers in India are dying or dead and have been converted to drains of untreated sewerage. Yamuna and Ahar in Udaipur are living examples, he said.
“Rivers are living systems but unfortunately we have lost respect for them”, said Prof. Basant Maheswari of Western Sydney University. Dr Rai Kookana, a scientist of CSIRO Australia and the co-convenor of the workshop, presented results from a study on Ahar river which receives city’s untreated sewage, highlighting detection of high levels of some antibiotics and other toxicants in the sewage-impacted river water. The presence of high levels of antibiotics in the Ahar river and elsewhere in India are of particular concern as they cause antibiotic resistance development in pathogenic bacteria and threaten to take humans back to the ‘dark ages’ – the era prior to the invention of antibiotics, Kookana said.
Many people, especially children, die of waterborne diseases and nearly half of hospital beds in the world are taken up by such illnesses. While wastewater being rich source of carbon and nutrient can be a good resource for irrigation in peri-urban agriculture, the untreated sewage causes pathogen and heavy metal contamination of vegetables and salad produced. Farmers and their families who work with untreated wastewater are exposed to high risk of disease. “Consuming salads and raw vegetables produced with untreated sewage can be suicidal” said Dr Chris Derry, an Australian expert in public health. The term reuse implies some form of treatment, he said. Prof. Rishi Shanker of Ahmedabad University suggested soaking of vegetables in clean water for at least 15 min followed by repeated washes before consumption.
A field visit to peri-urban farmers during the workshop was made which highlighted the issue of contamination of soil, crop produce and groundwater quality, all of which are adversely impacted by of urbanization, industrial and domestic wastewater. Impact of wastewater on groundwater quality was also discussed in the workshop in the context of managed aquifer recharge (MAR) during period of excess water. Dr Peter Dillon, a world authority on MAR from Australia, said that there were Indian guidelines for safe recharge of roof runoff and water in rural catchments.
Groundwater replenishment with urban storm water and treated sewage effluent has developed safe irrigation, industrial and drinking water supplies in a number of countries. However, he cautioned on the need to develop water quality monitoring and management capability, appropriate demonstration projects and guidelines in India before widespread use of these water resources for aquifer recharge. Unless these are in place groundwater pollution would be almost inevitable and recharge would be an unacceptable practice.
Surveys of septic tanks in Udaipur by VidyaBhawan and Centre for Policy Research (CPR) revealed that they mostly discharge to open drains and produce poor quality effluent that needs further treatment before release to rivers or for reuse. Few have leach fields and these would pollute groundwater if used for effluent disposal. The workshop findings were shared with the city administrators on the final day of the workshop, who relished the opportunity and the interactions.