Making of Reed Water Bedat

PSDA Office

4 Windmill Place, Ayanagar Village New Delhi 110047 IndiaTel +91 (0)11 26503741 / 26503859 Fax +91 (0)11 26502373design@ayanagar.comwww.psda.in

September 09

Introduction

Constructed wetlandsConstructed wetland systems are simple, locally manageable and cost effective biological wastewater treatment systems that utilise wetland plants, soil, and their associated microorganisms to mimic natural wetland eco systems processes for the treatment of waste water.

As the water flows through the bed, it gets treated through natural processes; pollutants in the waste water are mechanically filtered, chemically transformed and biologically consumed. With respect to the direction of waste water flow (i.e. horizontal or vertical flow), constructed wetlands are divided into reed beds, also known as Horizontal Flow Constructed Wetlands and Vertical Flow Planted Gravel Filters.

Preliminary treatment or pre-treatment of wastewater for removal of oil and fat, hair, lint, food residue, large solids etc. by sedimentation and floatation is required upstream the constructed wetland system.

Advantages1. Established technology 2. Natural looking3. Good pathogen removal due to die off and predation4. Minimal maintenance5. Can use wide range of water plants6. Robust7. Treated water if fit for non potable use: surface application, irrigation, and discharge to receiving water bodies

Role of Plants1. Provide beauty , making people more likely to care for the system2. Transport air to their roots, which may enhance treatment locally3. Release selective biocide compounds, killing harmful microbes4. Provide physical filtration and electrostatic attraction of small particles5. Provide a habitat for microorganisms and larger consumer organisms6. Take up some heavy metals

At PSDA office, Horizontal Flow Constructed Wetland has been adopted to treat the wastewater.

Treatment process in wetland at PSDA office Primary treatment takes place in the settler/septic tank, where the sludge settles down and scum floats in top and the clear liquid flows to the collection chamber. From this chamber water is pumped using a small manually operated pump to the root zone treatment system for secondary level treatment.

The secondary treatment takes place in the root zone system where the removal of nitrates and phosphates takes place by plants and through its root system injects oxygen to the wastewater which flows in the gravel bed. The final treated water collected in the storage tank is pumped and used for horticulture purpose.

Water usage for toilet and kitchen 2 KLD

Number of users 30

Area of reed bed 11 m2

Cost of construction Rs. 85,000

Data for reed water bed constructed at PSDA

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Site Plan - PSDA Office, Ayanagar

Tank for overflow water from septic tank

Base preparation

Brick work and plaster

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Stages of Construction

River pebbles at the bottom

Crushed gravel in the middle

Pea gravel at the top

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Tank for treated water

Canna planting with coir around the roots

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Planted cannas

Water being pumped from overflow water tank

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Completed reed water bed

Reed bed section

Water Quality Report - overflow water from septic tank

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Water Quality Report - treated water after root zone treatment

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Water Quality Comparison

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RAW WATER AFTER REED-BED TREATMENT

PH 6.95 7.32

Total Suspended Solids in mg/l 42.8 28

Chemical oxygen Demand 154.6 32.2

BOD for 3days at 27*c 69 13

Faecal Coliform per 100ml 51 17

Oil & Grease 1.3 1.8

Phosphates as PO4 135.3 84.3Nitrates as NO3 0.03 0.05

Water Quality

References

Advisors

• Sewage Solutions: Answering the Call of Nature; Nick Grant, Mark Moodie, Chris Weedon; 2000; Centre for Alternative Technology Publishing, UK

• Do-it-yourself: Recycle and Reuse Wastewater; 2008; Centre for Science and Environment, New Delhi

• R.K. Srinivasan, Centre for science and environment, New Delhi

• Mahesh Babu, Mc D Built Environment and Research Laboratory Pvt. Ltd. Bangalore

• Mukesh Asija, Krim Engineering Services, New Delhi

9Making of reed water bed