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The population of Punjab has increased rapidly over the past
fifty years. This has put a great pressure on natural
resources. This, combined with low quality of sanitation and
lack of awareness among the people of rural Punjab, has
resulted in degradation of the natural environment.
Though water supply has increased in rural areas but
wastewater collection and disposal facilities have not
developed concurrently .As a result most of the drains and
storm water flows into the natural village ponds. Flow
of cow-dung & soil into the ponds along with storm-water
adds to the pollution load resulting in degradation of the
water quality. Hence these ponds are no longer fit for their
traditional uses, like, bathing of humans & cattle and
there is a likelihood of water-borne diseases being spread.
The conventional wastewater
treatment systems (like Activated Sludge Plants and
Trickling filters) do not present a viable option in the
rural areas of Punjab owing to the high cost of construction
and maintenance and the lack of technical people to operate
them. This situation demands the need to find economical and
sustainable solutions for water quality improvement in the
ponds situated in the rural area of Punjab. A project has
been taken up by Punjab State Council for Science
&Technology in collaboration with M/s CH2M HILL Canada
to promote an alternative low cost technology for
sustainable water treatment. The project has been taken up
in villages Peepal Majra (District Ropar) and Shekhupur (Distt.
Patiala).The project sites face similar problems of
degrading water quality due to influx of sullage and
storm-water in the village ponds.
Constructed
surface flow treatment wetlands are typically shallow
impoundments planted with emergent, rooted vegetation. Water
flows overland through the wetland and primarily above the
sediment surface. They contain monoculture or diverse
plant communities that are more adaptable under changing
season and water quality conditions. These wetlands
may be planted manually or may be naturally colonized by
volunteer plant communities. The plants in constructed
wetlands are not harvested to remove nutrients, rather the
microbial flora that is attached to the plants have the
natural capacity to remove biodegradable organics and
nitrogen efficiently and reliably. Metals and
phosphorus can be restored in plant materials and wetland
sediments. The treatment wetland can be designed to
regulate water depth and residence time. Much of the
treatment that occurs in wetlands is a result of sediment
trapping and microbial action rather than plant uptake.
Therefore, these systems continue to function during winter
and are not affected by temperature due to buffering effects
of the sediments.
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The
following benefits can be derived using Treatment Wetlands:
· Less
expensive to construct than traditional wastewater treatment
systems.
· Require
less maintenance and less expensive to operate than
traditional
systems.
· The
discharge from treatment wetlands can increase storage in
ground water
aquifers through
combination with rapid infiltration basins.
· With
proper design, portion of treatment wetland may provide
additional
wildlife habitat,
as well as recreational opportunities such as bird watching,
picnicking and
fishing.
· The
system can be combined to provide additional economic
benefits such as
preparation of
handicrafts from plant biomass.
Existing
Conditions:
The
village Pipal Majra currently has two ponds, which receive
wastewater from the village. There are 192 households in the
village with a population of 1,200 discharging their sullage
into these two ponds. One pond with an area of 0.58 ha has
been identified for implementing the project. About 50% of
people discharge their sullage in this pond, with rest of
the community discharging their effluent to the other pond.
Most of the houses have open drainage system. Wastewater
from overflow of soak-pit latrines and domestic waste flows
to the pond through these drains.
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Site
before construction
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Cow-dung
is dumped near the banks and finds its way into the
pond along with the sullage and the storm water
through the open drains.The local community uses the
pond for cattle bathing, which also contributes to
the pollution load. There is a cremation ground on
the west bank and an existing Samadhi contributing
to the pollution. The change in the land use pattern
of the village has resulted in a decrease in the
area of pond (20-25%), resulting in its reduced
carrying capacity and degraded water quality.
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The
Proposed Project:
The
proposed project is designed for an expected population of
1,500 and a flow of 0.15 MLD in the year 2011. The System
comprises of Primary Sedimentation Tanks followed by
Treatment Wetlands.The sullage flow is routed through the
open drains into the treatment pond through four primary
sedimentation tanks, each with detention period of 4 hours,
followed by Bar-Screens.The suspended solids reduction in
the sedimentation tanks is expected to be between 20%-70%
with a consequent decrease in the BOD of the sullage. The
water from the Treatment Wetlands will flow in to the
Treated Water Pond.
For the current project the existing pond has been
divided into two zones: the 'treatment zone' and the
'treated water pond' separated by a berm. The slope
stabilization on the berm is being done by a layer of
compacted earth and a layer of top-soil over it with
vegetation for erosion protection. The area of the treatment
zone is 2,100 m2 or 0.21 ha with a width of 14m and length
of approx. 150 m giving a length to width ratio of
approximately 10:1 with continuous feeding of effluent into
the treatment pond. The
proposed treatment zone consists of deep zones for even
distribution of flow along the width of the treatment pond.
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The depth of the water is 0.30 m with cattails (Typha)
as the predominant plant species in the treatment
zone. An emergency overflow exit is provided at a
level of 0.6 m above the free water level for excess
flows in monsoon season. The water is treated in the
treatment zone by both physico-chemical and
biological processes with vegetation providing
surfaces for microbial activity. The effluent from
the treatment zone is further aerated by routing it
through a cascade before entering into the treated
water pond.
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Construction
of dividing bund
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Expected
Outcome:
The treated water will be finally discharged into the
treated water pond, which would be used by the villagers for
cattle bathing and washing. Steps and ramp are been provided
to allow the villagers and the cattle to enter the pond. On
successful completion of the project the water of the pond
would be treated to a BOD of <30 mg/l and will hence,
provide a better environment and cleaner water to the
villagers. The treated water pond is also expected to be
used for fish farming.
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