BIOME's article in the Buildotech magazine

1. 62 l BUILDOTECH l May ’16
SSustainability
With Bangalore
water supply and
sewerage board
(BWSSB) failing to
‘cope up’ with the
water demand
of the growing
city, lakhs of
bore wells and
tankers extracting
water from the
groundwater
have led to over
exploitation of
the groundwater.
However, there
have been efforts
from communities
and individuals
to sustainably
manage the water
within their fence.
This is one such
story of a private
gated community
in Bangalore
S
ituated in the south east
of the city, the Rainbow
Drive (RBD) is a private
gated residential layout
with an area of 34-acre
and total of about 360
housing plots. As of now, 260 plots are
occupied. The layout gets absolutely no
formal water supply from BWSSB and is
completely dependent on its bore wells
as a water source. The site developer had
provided initial infrastructure including:
• Storm water drain network to carry
storm water out of the layout
• Six community yielding bore wells
• Two overhead tanks with piped
water supply connections to all plots
• Piped sewage connection to each
plot
• Two Sewage treatment plants
The plot owners’ association
(POA) that took over the ownership
in 2004 manages the water supply
and sanitation. During the same time,
urbanization started to happen in the
neighborhood, making the POA realize
the intensity of water problems in the
near future.
The members observed that a lot
of reinvestment as well as measures
were needed to build the new water
and sanitation infrastructure and
upgrade the existing one. Therefore,
they did a complete research of the
water issues in the layout, collected
data about consumption, demand,
quantum of waste water generated
daily, issues of water quality, etc. to
get an understanding of the problems.
POA initiated some interventions like
creating a tariff policy, banning of bore
well water use for construction and
forbidding digging individual bore wells.
Water Management
Initiatives:
The result of this study was:
• Hydrogeologists were called for
who suggested that this space could
support 10-15 bore wells.
• The community bore wells left by
the builder had dried up and water
shortage was being experienced
• Houses had consumption meters at
the household level. And the tariff
was charged at flat Rs. 6/KL. The
study showed that this was minimal
Case Study:
Integrated urban
water management
Benchmark of consumption No of households
Percentage of
households
Up to 135 LPCD 32 14%
Up to 246 LPCD (layout average) 130 59%
Greater than 246 LPCD 89 40%
Some houses were consuming more water than others

2. May ’16 l BUILDOTECH l 63
Sustainability
and provided no incentive for the
household to save water
• The billing cycle was two months
which resulted in accumulated
issues of faulty meters and/or
demand.
• The most important result was
that, the cost of water in the
tariff scheme did not capture
the cost required for treating the
wastewater.
Sewage treatment plant was
not adequate and the output water
quality was not good enough.
During heavy rains upstream
storm waters entered into the layout
and caused significant flash flooding
at the low end of the layout. This got
mixed with the stagnating sewage
and caused a lot of problems.
Lowering the demand
From the study, it was evident
that 40% of the layout consumed
more than the layout average. Two
scenarios were looked at to address
this. To keep the demand same
@246 LPCD or reducing the demand
to 150 LPCD. This required investing
in rainwater harvesting (RWH) and
recharge and gardening making use
of treated wastewater. Also, a water
balance analysis was done considering
the future full occupancy.
The analysis showed that
reducing the demand @150 LPCD
with all other water conservation
measures was most beneficial. The
analysis also showed that if effectively
implemented, the net recharge
would be more than the overall
withdrawal. Hence, it was made
mandatory for individual houses
to practice rainwater harvesting as
well as recharge. In addition, POA
invested in groundwater recharge in
the common areas.
Changing Pricing
Policy
The bi-monthly billing cycle
was changed to monthly so that
households would come to know
about the faulty meters soon and
fixing could be done immediately.
This also gave an opportunity to
the home owners to be aware of
their consumption with time for
adjustment. The POA moved from
flat rate @6/KL to a block tariff
system corresponding to the actual
production cost of the water. The first
tariff was developed according to the
new slabs:
The plot owners’ association of the Rainbow Drive
engaged with Biome Environmental Solutions Pvt.
Ltd. to develop rainwater harvesting strategies.
Subsequently, with the support of Arghyam Foundation,
they engaged in a monitoring exercise in the layout
over approximately a year to understand the issues in
more detail and evolve relevant solutions.
Consumption slab Tariff
Slab 1 (0-10KL) Rs. 10
Slab 2 (10-20KL) Rs. 15
Slab 3 (20-30KL) Rs. 25
Slab 4 (30-40KL) Rs. 40
Slab 5 (>40KL) Rs. 60
Wells in common stormwater drain invested by
household (Individual investment)
Wells in common stormwater drain invested by POA
(Collective investment)
Wells in individual house (individual investment)
Borewell water was being used for
construction purposes

3. 64 l BUILDOTECH l May ’16
SSustainability
In addition, homes investing
in RWH and recharge were given
a discount of `100. The tariff was
revised in 2008, 2012, and 2014
is the latest revision to drive the
residents towards recharge and
control demand.
The current tariff is:
The water got expensive, almost
equal to the tanker water costs at the
highest slabs of consumption. The
benchmark for what the “highest slab”
has changed from 60 KL & above to
25 KL & above
Ban on private
borewells and
borewell water usage
for construction
T h e r e c o m m e n d a t i o n o f
hydrogeologist that 10-15 bore wells
would be maximum that the layout
can sustain led to discussions about
banning of private bore wells within
the layout. Community bore well
water remained available for domestic
purposes. For construction purposes,
water had to be sourced from outside
at market rates.
Waste water
infrastructure
investment
The existing STP infrastructure
was inadequate and was not treating
the water effectively. The result that
STP pumping was the single most
contributor of the electricity bill, led
to a search for new technology which
would be of less maintenance and
requires less energy. After searching
many options, the POA narrowed
down to Soil Biotechnology (SBT),
and Phytorid. In October 2014, the
Phytorid system of 250 KLD capacity
became operational. The system
receives ~100-150 KLD sewage daily
and the treated wastewater is being
used for gardening in common areas,
gardening in the houses, and a small
quantity of treated water is sold to a
farmer in the adjacent plot.
Mandatory rainwater
harvesting and
recharge
Realizing that the layout
is completely dependent on
groundwater, groundwater recharge
was critical. RWH and recharge was
made mandatory by the POA. As of
now, there are in total 250 recharge
wells in the individual houses as well
as in the common areas (Storm water
drain and open spaces).
Consumption slab Tariff
First 15,000 litres `30 per KL
15KL to 25 KL `50 per KL
Above 25 KL `120 per KL
Below graph shows the demand management timeline over
a period:

4. May ’16 l BUILDOTECH l 65
Sustainability
Impacts of the interventions
Increased compliance with RWH
There seem to exist a correlation with tariff rates and the
compliance with RWH and groundwater recharge. Moreover, the
informed citizenry made aware about RWH and its importance led
the initiative. This probably is the highest
density of recharge wells in urban India.
Decreased per capita demand on
community water supply
Though the occupancy has increased
over a period, total demand has come down
from 246 LPCD to 150 LPCD.
Increased savings from the STP
The Phytorid technology requires
minimal electricity as compared to the other
conventional sewage treatment plants. The
extent of reuse of this waste water for
gardening and consequent reduction in use
of fresh water for gardening is still being
studied. The POA is now closely monitoring
the quality of treated waste water – so
far it has conformed to KSPCB’s discharge
norms.
Going ahead:
The reforms at Rainbow Drive started
in 2004 by efforts of conscious residents of
the layout. The interventions that started
with 20 recharge wells now have reached
to 250. The relationship between shallow
groundwater recharge and the bore well
yields (if any) needs more exploration but,
the demand management with recharge
compliance has worked till now.
Courtesy:
Biome Environmental Trust & Rainbow
Drive POA