Wastewater disposal in the major cities of India

In India, out of the total population of 1,027 million, about 285 million live in urban areas. With increasing urbanisation and the pressures of population, the impervious areas in the metropolitan cities are increasing. With increasing water supply to the metro cities, the drainage managers are faced with the task of managing the wastewater from the highly populated areas. However, drainage infrastructure has not kept pace with the rate of population growth. In addition, rainfall occurs mainly in the monsoon season from June to September and a major challenge is to manage the huge volume of monsoon discharges during these four months. This has resulted in increased incidences of urban flooding followed by epidemics not only disrupting the daily life during monsoons but also affecting the overall quality of life in most of the metro cities in India. A series of workshops were conducted by the author in many of the worst affected metros, namely, Mumbai, Kolkata, Delhi, Bangalore, Ahmedabad, and Bhubaneshwar. The aim of this paper is to present the different types of drainage systems and the specific management practices being followed to handle wastewater flows and the high monsoon discharges in the metros.