Can treated STP water be let into lakes and recharge wells ?
Discharging Excess Treated STP
Water into Lakes, Shallow Recharge
Structures, New Ponds
KSPCB and Citizens' Dialogue
15 Lakes around Sarjapura Road
● Total Watershed Area ~ 33 sq
km ( ~ 8000 acres)
● Total Water Spread Area ~ 428
acres (not including Bellandur
● Volume ~ 1731 million litres
(average 1m depth)
● Evaporation loss ~ 2597 million
litres (1.5 m annual)
● Percolation ~ 6231 million litres
(10mm per day, 3.6m annual)
Lake Classification (as per CPCB)
Class 'A' Drinking water source without conventional
treatment but after disinfection
Class 'B' Outdoor bathing organized
Class 'C' Drinking water source with conventional
treatment followed by disinfection
Class 'D' Propagation of wildlife, fisheries
Class 'E' Irrigation, industrial cooling, controlled waste
Primary Water Quality Criteria for various uses laid down by Central pollution Control Board
Artificial Recharge Volume
● Minimum 600
● Minimum 2.6ML of
● Catchment of < 500
* Data from surveys
8.5 MLD: STP (at least 50% excess treated
● CFE / CFO
● Treated STP water used for landscaping +
● No dual plumbing in older apartments for flushing
● Disposal of excess treated waste water through
● Discharge out of the campus
Water Reuse – Options explored
● Watering of Saplings in common areas –
expensive, difficult to manage
● Reuse as Domestic Water – TZED
● Others ?
Questions - 1
● Which are the specific water quality parameters that should be
monitored and at what frequency?
● What are the acceptable values?
● Would any specific person/organization be given the task of
monitoring these values?
● What would be the process for deciding the volume of sewage
that can be let into the lake?
● Would this specific person/organization be empowered to keep
people from dumping untreated waste water into the lakes/wells?
What would be the process or who would be the person that they
can escalate/discuss issues with?
● Would KSPCB play this role?
● What will be KSPCB’s role in this option?
Questions - 2
● Which are the lakes that are currently
experimenting with this option?
● What level of treatment, type of treatment
(natural/conventional), water quality parameters
is expected for disposing the water into lakes, for
groundwater application, etc.?
● For Apartment complexes that do not have an
STP. What is the enforcement mechanism and
how do we make sure everybody follows the
● Does KSPCB recognize the natural treatment
systems like SBT, DEWATS?