Environmental Engineering Reference
In-Depth Information
surface flow constructed wetland has been
developed at Shantikunj, Haridwar, using effi-
cient aquatic macrophytes,
Typha latifolia
,
Phragmites australis
,
Colocasia esculenta
,
Polygonum hydropiper
,
Alternanthera sessilis
and
Pistia stratiotes
with gravel as medium, and
its sewage treatability potential was evaluated.
All the plants grew well in the gravel media with-
out any symptom of toxicity or nutrient defi-
ciency. After 3 months of plantation, plants were
found established and showed luxuriant growth
during 6 months of operation and monitoring of
wetland (Fig.
3
).
5
Green Technologies
for Ganga Water
Rehabilitation
5.1
Current Initiatives
for Clean Ganga
Now, the Centre has set up the National Ganga
River Basin Authority (NGRBA) on 20 February
2009 under the Environment Protection Act as an
empowered authority to adopt a new holistic river
basin approach to the cleaning of the river Ganga
and address the issue of minimum ecological
flows, besides pollution abatement works com-
prehensive management of the Ganga river basin
under the chairmanship of the Prime Minister.
This body will see that development require-
ments (such as construction of hydropower proj-
ects) are met in a sustainable manner while
ensuring ecological flows. The body will not be a
separate additional clearance mechanism. Rather,
it will develop a management plan for the river
basin and address pollution abatement measures
by ensuring adequate ecological flow in the river.
Specific interventions for sewage treatment have
also been planned.
In last few years, CSIR-National Botanical
Research Institute has undertaken a research pro-
gramme on “Plant based management of Ganga
water pollution” sponsored by the National River
Conservation Directorate, Ministry of
Environment & Forests, New Delhi. In order to
rehabilitate the river Ganga ecosystem, a sub-
5.2
A Case Study
Monitoring results at 6 months of operation of
wetland showed improvement of sewage water
quality as reduction rate of BOD, TSS, TDS,
NO
3
−N, PO
4
−P and NH
3
−N was found to increase
with growth and establishment of the plants and
found maximum in fully established constructed
wetland as compared to pre- and partial estab-
lished after 2 and 4 months. Further, DO level
was increased from 2.67 to 4.71 mgL
−1
in pre-
and fully established constructed wetland after
24 h of retention time, respectively. Similarly,
sewage treatment efficiency of constructed wet-
land increased from pre-established stage (after
2 months) to fully established stage (after
6 months) in terms of BOD and TSS which
increased from 18-90 % to 44-65 %, respec-
tively, after 24 h of treatment. Removal values of
Fig. 3
Sub-surface flow constructed wetland at Shantikunj, Haridwar
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