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Urban Wastewater Treatment 287

more and more people are moving into the cities, and the figures are
expected to reach about 600 million by 2030, making India more semi-
urban than rural. Already, there is enormous pressure to provide utility
services and industrial use, so water supply is a priority, especially where
semi-urban water is exported formally or informally to fulfill city require-
ments. At the same time, the urban return flow (wastewater) is also increas-
ing, and is usually about 70–80% of the water supply. This study attempted
to estimate the current status of wastewater generation, its uses, and liveli-
hood benefits especially in agriculture, based on national data and case stud-
ies from specific regions and cities such as Ahmedabad, New Delhi,
Hyderabad, Kanpur and Kolkata.
The challenge of the growing Indian economy is that, in many cities, the
wastewater processed is a mixture of domestic and industrial wastewater,
which makes the system complicated, and resulting reuse remains a chal-
lenge. Lack of systematic data on the different discharges makes it difficult
to estimate the volume and quality of wastewater discharged and the total
area under (usually informal) wastewater irrigation. Data from more than
900 Class I cities and Class II towns (with the population of each over 1 mil-
lion and between 0.5 and 1 million, respectively) have shown that more
wastewater gets collected than eventually treated. In general, wastewater
generation is around 60–70% over the established treatment capacity, which
varies from city to city.

7.2.2 Urban Water Supply System
Urbanization and rapid industrialization have revamped the present ideas on
the reversible nature of water resources. A large population of India does not
have access to safe water. Treatment of wastewater, sewage treatment,
industrial liquid and chemical waste treatment, and sludge from desalination
(Indian Desalination Association INDACON, 2008) requires a cost-
effective sustainable solution facilitating a lead on zero liquid discharge
(ZLD) with carbon neutral mechanisms. The total water requirements for
2050 and 2065, as estimated by the government in 1999 with revisions based
on 2011, predicts that India would face a water demand of 90 bcm in 2050 as
compared to 20 bcm by the Water Commission’s predictions (Garg and
Hassan, 2007). With the large, growing demand for water, India would
experience a huge deficit in water and energy in 2030 (Ministry of Water
Resources, 2008). A worldwide trend toward acceptance of the concept
of reuse is currently visible, because water shortages are intensifying in India