Urban domestic waste water treatment
systems are energy intensive and also a direct or indirect
source of Greenhouse gases (GHGs) emissions. In
developed countries as per estimates it has been found
that Waste water treatment plants (WWTPs) consume
about 1 to 3% of the total electric energy output.
Increase in energy prices and continuously deteriorating
quality of environment because of generation of energy
forced the policy makers and other stakeholders to adopt
suitable measures which not only increases the energy
efficiency of WWTPs but also achieving the desired
effluent quality at the same time.Waste water treatment
requires lot of energy during several stages i.e. collection,
pumping, treatment, handling, storage, disposal etc. On
the other hand, waste water/sewage contains energy in
different forms namely potential, chemical and thermal.
The aim of this paper is to study the application of
process modification techniques and management
practices to achieve energy efficiency in some of WWTPs
in the state of Chhattisgarh. Technical and management
strategies are suggested to enhance the energy efficiency
of the WWTPs. With the implementation of technical
strategies about 184046 kWh of energy can be saved
monthly which is around 18.17 % of the monthly
electrical energy consumption and as a result ₹14.9
Million can be saved annually which otherwise have to
be paid in the form of electricity bills. Anaerobic
digestion helps in recovery of chemical energy entrapped
in wastewater and about 157 MkJ/day of fuel value can
be obtained with the recovery of methane gas. This
energy can be used for heating, production of electricity
through heat turbines which can be used within the
WWTP premises and also transmitted to the grids if
required.
Keywords : Wastewater, Greenhouse Gases, Energy Management, Urban Local Bodies, Waste Activated Sludge, Aeration, Management Strategies And Heat Recovery