Technical Session “Wastewater Management – Recycling & Reuse”
Environmentally Sustainable and Decentralized Municipal Wastewater Treatment Wetlands – An Indian Agricultural Research Institute Experience Ravinder Kaur & HS Gupta Indian Agricultural Research Institute, New Delhi
India Water Week - Efficient Water Management: Challenges & Opportunities, April 8-12, 2013, Vigyan Bhavan, New Delhi
Wastewater Treatment and Use in Agriculture Global wastewater production - 1,500 cu. Kmr (i.e. Six times more than in all the rivers of the world). Managing increasing volumes of wastewaters - An emerging global concern due to soil sodicity, salinity, heavy metal accumulation, loss of microbial diversity; groundwater contamination and human health / food-chain contamination problems. Limitations of Conventional Wastewater Treatment Systems
Conventional Wastewater Treatment Plants
High Installation Cost High Operational/ Maintenance Cost High Energy Requirement Generation of Hazardous sludge Need for skilled labour
Way Forward – Decentralized Engineered Wetland Systems Engineered wetland systems mimic natural physical, biological, and chemical processes of the natural wetlands involving plants, soil, and native microorganisms for wastewater treatment . Engineered Wetlands
System 1 – For Treating Discharges from Small Sized Communities
Capacity: 1500 LPD (4 Households with 4 members) Design: Batch fed Vertical Sub-surface Flow HRT: 14.41 to 53.67 hrs Sewage source: IARI campus Land area: 50 sq. meter SW
CW
PW TW
VW GW
SW: Sewage Water CW: Non –Veg. Wetland water PW: Phragmites Water TW: Typha Water VW: Acorous (Vacch) Water GW: Ground Water
Pollutant Removal Efficiency of Pilot Plant - TURBIDITY
Pollutant Removal Efficiency of Pilot Plant - Nitrate
Pollutant Removal Efficiency of Pilot Plant - Phosphate
Pollutant Removal Efficiency of Pilot Plant - Sulphate
Metal Removal Efficiency of Pilot Plant - Lead
Metal Removal Efficiency of Pilot Plant - Nickel
ECOLOGICAL ECOLOGICAL FOOTPRINT FOOTPRINT & & SUSTAINABILITY SUSTAINABILITY
Experimental Experimental Wetland Wetland Vs. Vs. Conventional Conventional STP STP
Inputs Local renewable resources
Solar Emergy (sej/yr) Experimental Wetlands
Conventional STP
1.14 X 1016
1.82 X 1016
Purchased renewable 3.27 X 1015 Conventional STP had 14 times resources Purchased non renewable More Resource Use than 3.97 X 1016 resources
Experimental Wetlands
0.00 7.68 X 1017
Purchased resources
4.30 X 1016
7.68 X 1017
Total resource use
5.44 X 1016
7.87 X 1017
Emergy Indices Emergy Indices
Experimental Wetland
Conventional Treatment Plant
Environment Load Ratio
1.37
42.19
Emergy Yield Ratio
0.70
0.01
Experimental Wetlands exerts 33 times lesser Stress on STP RenewableEnvironment Percentage than Conventional 0.51 0.02 Experimental Wetlands were 70 times more Efficient in utilizing Emergy Sustainability 0.00034 purchased resourcesIndex & Consumed 250.54 times more Renewable resources than Conventional STP Experimental Wetlands 1500 times more Sustainable than Conventional STP Just 1% energy requirement ; Zero-chemical & Sludge; No mosquito breeding problem; 50-65% reduced cost of treatment; No Skilled manpower requirement
System 2 - For Treating Discharges from Large Sized Communities Capacity: 2.2 MLD Design: Horizontal Sub-surface Flow HRT: 2.2 days Sewage source: Krishi Kunj Colony near IARI campus Land area: 1.42 hectares Irrigation Potential: 132 ha
Treatment Efficiency: Capable of reducing biological oxygen demand (BOD) from 450 mg/l to 100 mg/l; total suspended solids (TSS) from 220 mg/l to about 2.2 mg/l and heavy metals (viz. lead, iron and chromium) by 75 to 85 %.
Eco-friendly Technology for Mitigating Global Environmental Pollution & Health Problems due to Improper Sewage Treatment
Attractive Solution for Developing Countries with Scarce Resources for Investment in Expensive Centralized Sewage Infrastructure