A wetland is a land area that is saturated  with water , either permanently or seasonally, such that it takes on the characteristics of a distinct ecosystem . The primary factor that distinguishes wetlands from other land forms or water bodies is the characteristic vegetation of aquatic plants , adapted to the unique hydric soil.

1. DEVELOPING A PILOT SCALE
CONSTRUCTED WETLAND FOR
TREATMENT OF DOMESTIC SEWAGE
Nischay.N
B.E.(CIVIL)., M.Tech. ,IGBC-AP.
,

2. What is a Wetland???
• A wetland is a land area that is saturated with water , either
permanently or seasonally, such that it takes on the
characteristics of a distinct ecosystem .
• The primary factor that distinguishes wetlands from other
land forms or water bodies is the characteristic vegetation
of aquatic plants , adapted to the unique hydric soil.
Wetland
Natural
Constructed

3. .
Natural Wetland
• Naturalwetlandsystemshaveoftenbeendescribedasthe
“earth’skidneys” because they filter pollutants fromwater
that flows through on its way to receiving lakes ,streams
and oceans.

4. Constructed Wetlands
• Constructed wetlands are artificial wastewater treatment
systems consisting of shallow (usually less than 1 m deep)
ponds or channels which have been planted with aquatic
plants, and which rely upon natural microbial, biological,
physical and chemical processes to treat wastewater.
• They typically have impervious clay or synthetic liners, and
engineered structures to control the flow direction, liquid
detention time and water level
LOCATION : JAKKUR LAKE

5. Constructed Wetland
• By various such process chemicals are considerably
removed or settled and clean water is drawn. These
chemicals include Nitrogen, Ammonia, Phosphorous and
pathogens.
• Constructed wetlands are most economical as compared
to conventional treatment units which needs more
energy for its process and this method require cheaper
materials.
LOCATION: NARSIPURA

6. TYPES
Constructed
Wetland
Surface
Flow
Sub Surface
Flow
Vertical Flow
Up Flow
Down Flow
Horizontal
Flow

7. Objectives
• Generally the waste water generated in the houses is released
to the waste water carriage system. However, it is very
difficult to treat the waste water generated in a centralised way
in Bangalore city.
• Hence, there is a necessity of decentralised waste water
treatment facilities at household level.
Necessity of constructed wetlands is to achieve the following
1.To treat domestic waste water generated in the houses at
household level using constructed wetland
2. To test the quality of treated waste by using constructed
wetlands for other beneficial uses (recycling of treated waste
water).

8. Removal mechanism
• Organic matter : Aerobic microbial degradation
Anaerobic microbial degradation
• Suspended solids: Sedimentation
Filtration
• Pathogens : Sedimentation
Filtration
Natural die-off
Predation
UV radiation

9. Removal mechanism
• Nitrogen : Nitrification and denitrification
Plant uptake
Matrix adsorption
• Phosphorus : Matrix absorption
Plant uptake
• Metals : Adsorption and cation exchange
Complexation
Precipitation
Plant uptake
Microbial oxidation/reduction

10. Practical Approach
• Construction of “Horizontal subsurface flow
constructed wetland”.

11. Methodology
• In this experimental set up of buckets with different sizes and
dimensions will be used.
• The vertical buckets as holding tank (Inlet)
will be used to hold the waste water
The water storing capacity of tank will
be 50 litres.
• A rectangular tub of size 62 cm
length and height 35 cm having
suitable outlet.

12. Methodology
• The vertical pipe will be placed above the tub for distribution
of water . Plastic cans will be used for the collection of treated
water.
• Treated water samples will be collected and analyzed in
laboratory.
• The Angular Horizontal Subsurface Flow constructed wetland
will be prepared as follows:
Three layers of support bed in constructed wetland will be
prepared with coarse aggregate , Sand and Garden soil.

13. Methodology
• Coarse aggregate of 20 kg total weight will be used for making
bottom layer of 10 cm height
• Followed by medium sized sand amounting total to 15 kg will
be added to form a middle layer of 10 cm height and small
size, sieved 6 kg of soil to form upper layer of 10 cm height
will be used in construction of bed.
• Selective healthy, small, young, locally available plant will be
transplanted into the bed .
• The rectangular tub with plant bed will be provided with 10
degree slope and kept in the slanting position.
• Inlet flow and outlet flow of wastewater will be adjusted to
maintain Hydraulic retention Time (HRT) of 7 days

14. Work done as per schedule
PROJECT LOCATION :
MALLATHALLI
STARTED ON:
12th MARCH

15. STEP:1 PROVIDING SLOPE
Slope :1:10

16. Layer 1: Coarse Aggregates
1st layer : Gravel stones
Size between >20mm & <40mm
Depth of layer:
100mm

17. Layer 2: Fine Aggregates
2nd layer: Sand
10cm sand, the layer consists of 2
layers of fine sand , each layer is
50mm.

18. Layer 3: Soil
3rd layer: Soil
Red soil or which is locally
available and suitable for plant
growth is filled at the top layer of
about 100mm depth

19. Testing for flow of water

20. Plant location
Plant : Colocasia esculenta.
Location: Herohalli Raj Kaluve.
•Colocasia esculenta is a tropical plant
•The selected plant
Colocasia esculenta belongs to:
• Kingdom - plantae
• Order - Alismatales
• Family - Araceae
•Subfamily - Aroideae
•Tribe - Colocasiodeae
• Genus - Colocasia and
• Species - C. esculenta .
• The plant is locally known as
kesaradantu in Karnataka

21. Planting to setup

22. Project final setup

23. Location of sewage sample: Mallathalli

24. Collection of sewage sample
•For the treatment of
sewage, the grab
samples were
collected from
Mallathalli lake
located near
Nagarbhavi Ring
road, Bangalore.
•Collected
sewage is a
combination of
grey water and
black water.

25. Detention time: 7days
By providing a detention time
of seven days ,the plant
absorbs maximum amount of
impurities present in sewage
water.

26. RESULTS AND DISCUSSION
FOLLOWING PARAMETERS WERE TESTED :-
• PH
• EC
• TP
• TDS
• TSS
• SULPHATE
• NITRATE
• BOD
• COD

27. Results: Sewage and Treated water
PARAMETER RESULT (
sewage
water)
In Mg/l
RESULT
(treated
water)
In Mg/l
PROTOCOL Standard
Limits as
KSPCB
Phosphorus as PO4,
mg/l
0.09 0.03 IS-3025 0.1
Dissolved solids, mg/l 700 885 IS-3025 part-16 2100
Total suspended solid 20 NIL IS-3025 part-17 30
BOD(5days at 20⁰c) 28.5 9.85 IS-3025 part-44 10
COD 220 100 IS-3025 part-58 250
Nitrate as NO3 10.5 8 IS-3025 part-34 45
Sulphates as SO4 160 238 IS-3025 part-24 1000

28. RESULTS: SOIL
PARAMETER LIMITS RESULTS before
treatment in %
RESULTS
after treatment in %
pH 6 - 8.5 7.85 7.15
Electrical Conductivity ........ 0.35 MicroOhms/cm 0.28
Organic Carbon (Nitrogen) >0.51 – 0.75% 0.6 (MEDIUM) 0.88
Available phosphorous as P >10 – 25 kg/acre 12 (MEDIUM) 16
Available potassium as K >60 – 120kg/acre 85 (MEDIUM) 110
Zinc >0.65ppm 0.66(SUFFICIENT) 0.7
Iron >4.5ppm 3.8 (SUFFICIENT) 4.3
Copper >0.21ppm 0.8(SUFFICIENT) 0.83
Manganese >2ppm 1.0 (SUFFICIENT) 1.5
Sulphate 28 30 20

29. Removal Efficiency
Parameter Removal Efficiency (%)
Phosphorus as PO4, mg/l 66.66
Total Dissolved solids, mg/l …..
Total suspended solid 83.35
BOD(5days at 20⁰c) 71.23
COD 61.36
Nitrate as NO3 24.7
Sulphate as SO4 …..

30. Conclusion
• The treatment efficiency of the Angular Horizontal Subsurface Flow
Constructed Wetland unit was examined by wastewater quality
parameters such as pH, EC, TSS, TDS, TS, BOD, COD, Nitrate,
Phosphate and Sulphate respectively, in the inlet and outlet of
wastewater .
• The results in the set of Colocasia esculenta reveal that the
maximum pollution reduction efficiency was observed in 70%
sewage concentration.
• Angular Horizontal Subsurface Flow Constructed wetland through
phytoremediation is an effective green technology for the treatment
of sewage.
• The proper selection of locally adaptive aquatic plant is more trust
worthy and insured technology for better treatment of sewage in
local environment.

31. Field implementation in Bangalore
LOCATION : JAKKUR LAKE
• The project works like this. Out of the 49.63-hectare span of
Jakkur Lake, 4.63 hectares have been set aside adjoining the
BWSSB's existing sewage treatment plant (STP) to create a
man-made wetland integrated with an algal pond.
• First, sewage is treated at the plant using the regular process.
• In the second stage, the treated water is let out into the man-
made wetland where aquatic plants and algae remove
contaminants. In the final stage, wind and sunlight do another
round of cleaning before it's released into the lake proper.

32. Field implementation in Bangalore
• T V Ramachandra, Coordinator, Energy and Wetlands
Research Group at IISc, gives us the scientific perspective.
• "The STP cannot fully remove the nutrients (nitrogen and
phosphorous) from the sewage. Hence it has to be purified in a
natural way using wetlands and the water flows into the main
lake spanning over 45 hectares.“
• Sounds elegant, but does it work?
• For the past eight months, a team of six scientists led by
Ramachandra, have been trying to find out exactly that. They
fanned out into groups to monitor and analyse the water
quality.
JAKKUR LAKE

33. • "At about nine locations within the lake we used to collect
water samples twice at 45-day intervals
• To put it in simple words, the team found that while the STP
and the man-made wetland remove 70 percent of the
contaminants in about 4-5 days, wind, sunlight, and plankton
in the lake proper do the rest of the cleaning.
• The team will soon submit a report to both the state and union
governments to replicate the model in other lakes as well

34. THANK YOU.