Authors : Vasudevan Rajaram and John R. Sheaffer
In addition, a case study of the Kurkhumbh wastewater recycling plant near Pune, India, will be provided to demonstrate that a Common Effluent Treatment Plant (CETP) can conserve a lot of fresh water in industrial estates. The two case studies demonstrate that wastewater can be economically recycled for reuse.
The paper concludes that every drop of wastewater in rural and urban India should be recycled for reuse so that it does not contaminate our drinking water supplies and conserves scarce water resources for satisfying the thirst of the entire population.
Introduction
Water is critical for all life on the planet. Rapid industrialization and urbanization has caused India to face a water crisis since it has only 4 percent of the world's water resources. In order to resolve the crisis, India has to look for alternative water resources which may include rain water harvesting, grey water and sewage reuse and desalination. Rain water harvesting is practiced in many parts of India, with many projects working well in Tamilnadu and Karnataka. Grey water is defined as wastewater generated from the bathroom, laundry and kitchen. Nearly 70 percent of the water used in households results in grey water which can be treated using simple technology and reused. Reuse of grey water reduces the fresh water requirement and reduces the amount of sewage sent to treatment plants. This integrated approach to water and wastewater management is needed to assure water conservation, improvement in public health, and building economically viable water infrastructure.
This paper will present two case studies of integrated water management. One case study involves the recycling of treated wastewater for agriculture in Northwest Indiana, USA, which is being planned by the Hammond Sanitary District of Indiana and the Center for Transformation of Waste Technology of Illinois. The other involves an industrial wastewater recycling project near Pune, India, where the wastewater was treated for use within the industrial estate. Such recycling projects are critical for conservation of water resources and to ensure that economic development is facilitated through proper water management.
Economics of integrated water management
Water is not evenly distributed on the planet. There are many populated areas which suffer from water shortages. In India, the monsoons bring an abundance of water followed by periods of drought. Water use in India is roughly in the following categories: agriculture (80%), industry (15%) and domestic consumption. In order to ensure adequate water for domestic consumption, the large users in agriculture and industry have to be efficient in their use of water and practice wastewater recycling. Municipal wastewater has to be treated as a resource by reuse of nutrients in the wastewater for improving agricultural productivity, and for pisciculture, as is done in Kolkata. Municipal wastewater recycling programs manage the carbon, nutrient and hydrologic cycles in nature very effectively. This will dramatically increase the water available for domestic purposes and minimize the use of borewells for domestic water supplies. Recycling programs will fail unless the economics are favorable.
For example, in 1998, in the Kurkumbh Industrial Estate near Pune, India, the government was supplying clean water to the industries at a subsidised rate of Rs. 8 per cubic meter. They built a wastewater recycling plant and wanted industries to recycle their wastewater for reuse. However, the cost of treating and recycling wastewater was Rs. 15 per cubic meter. Hence, industries were not recycling their wastewater but illegally disposing it and contaminating the surface and groundwater resources. When the government increased the price of clean water to Rs. 18 per cubic meter (the true cost of water delivery), the industries willingly sent their wastewater to the treatment plant and bought the recycled water at Rs. 15 per cubic meter. Hence, the policies of the government in pricing water are critical for implementing integrated water management.
Water used in agriculture can be reduced if there are economic incentives provided for recycling treated wastewater and wasteful water use is priced exorbitantly. In Israel, such pricing policies have resulted in innovations in water recycling and agricultural practices that minimize water usage. Such policies are badly needed in India if the cycle of drought and reduced agricultural productivity resulting from water shortages are to be avoided. The Hammond case study presents such an opportunity in agricultural areas of India, and should be carefully studied for replication.