maintenance of existing plants and sewage pumping stations is not satisfactory.
Moreover, nearly 39% plants are not conforming to the general standards prescribed
under the Environmental (Protection) Rules for discharge into streams as per the
CPCB’s survey.
8 Thus, across towns and cities, the existing treatment capacity
remains underutilized, resulting in the discharge of untreated sewage.
Decentralized treatment systems correspond to systems which ensure collection,
treatment and reuse or disposal of the waste generated from a/few confined areas.
Rather than setting up one 500 MLD plant, for example, it is more economical and
efficient to set up 10–20 small, decentralized plants. This will require lesser capital
cost for setting up of equivalent capacity small, decentralized wastewater treatment
plants, with lower maintenance cost and energy requirements, and make it a preferred choice which also makes available treated water for reuse, resulting in
reduced water requirements.
Decentralized wastewater treatment systems generally have 2 units, one primary
treatment and the other secondary treatment. Primary wastewater treatment refers to
the water treatment involving settlement where heavy solids converted to flocs get
settled at the bottom of the tank and other particles like grease and oil can float to
the surface. The settled and floating materials are removed to get partially treated
water. Secondary treatment is done to get a better-quality effluent by removing
dissolved and suspended solids.
9
The conventional approach to wastewater treatment in India has been focused on
centralized sewage treatment plant (STP) models, resulting in operation and
maintenance problems and underutilization, plus lesser reuse of treated water and
pumping back over a longer distance of treated water. However, looking at challenge of operation and maintenance, cost and efficiency, high energy use and great
risk of damages in case of an accident, there is merit in exploring the use of
decentralized systems and having the advantage of reuse of treated water in the
areas where the wastewater was collected.
The benefits of decentralized systems include almost no use of power, low
maintenance and minimal expenses setting up a network of pipelines. Given that
these are locally managed systems, users should be able to bear the O&M costs of
plants, such as cost recovery by selling the treated water.
10
3.4 Industrial Pollution
Following are some of the examples of industrial pollution in India: In Kochi, the
Kadambrayar acts as the main source of water for several industrial units, InfoPark,
8
See Footnote 5.
9
Arora et al. (2016).
10
Starkl Markus; Centralized Versus Decentralized Systems: Which is Which For You?:
University of Natural Resources and Life Sciences, Vienna.
Tackling Water Quality Issues
73
Moreover, nearly 39% plants are not conforming to the general standards prescribed
under the Environmental (Protection) Rules for discharge into streams as per the
CPCB’s survey.
8 Thus, across towns and cities, the existing treatment capacity
remains underutilized, resulting in the discharge of untreated sewage.
Decentralized treatment systems correspond to systems which ensure collection,
treatment and reuse or disposal of the waste generated from a/few confined areas.
Rather than setting up one 500 MLD plant, for example, it is more economical and
efficient to set up 10–20 small, decentralized plants. This will require lesser capital
cost for setting up of equivalent capacity small, decentralized wastewater treatment
plants, with lower maintenance cost and energy requirements, and make it a preferred choice which also makes available treated water for reuse, resulting in
reduced water requirements.
Decentralized wastewater treatment systems generally have 2 units, one primary
treatment and the other secondary treatment. Primary wastewater treatment refers to
the water treatment involving settlement where heavy solids converted to flocs get
settled at the bottom of the tank and other particles like grease and oil can float to
the surface. The settled and floating materials are removed to get partially treated
water. Secondary treatment is done to get a better-quality effluent by removing
dissolved and suspended solids.
9
The conventional approach to wastewater treatment in India has been focused on
centralized sewage treatment plant (STP) models, resulting in operation and
maintenance problems and underutilization, plus lesser reuse of treated water and
pumping back over a longer distance of treated water. However, looking at challenge of operation and maintenance, cost and efficiency, high energy use and great
risk of damages in case of an accident, there is merit in exploring the use of
decentralized systems and having the advantage of reuse of treated water in the
areas where the wastewater was collected.
The benefits of decentralized systems include almost no use of power, low
maintenance and minimal expenses setting up a network of pipelines. Given that
these are locally managed systems, users should be able to bear the O&M costs of
plants, such as cost recovery by selling the treated water.
10
3.4 Industrial Pollution
Following are some of the examples of industrial pollution in India: In Kochi, the
Kadambrayar acts as the main source of water for several industrial units, InfoPark,
8
See Footnote 5.
9
Arora et al. (2016).
10
Starkl Markus; Centralized Versus Decentralized Systems: Which is Which For You?:
University of Natural Resources and Life Sciences, Vienna.
Tackling Water Quality Issues
73