Neeri's natural tree-atment for sewage

NAGPUR: The city-based National Environmental Engineering Research Institute (Neeri) has developed a new, economical and simpler technology for sewage treatment. Its big advantage is using natural systems for treatment. The research funded by the union Department of Science and Technology (DST) will be used to set up two plants in city- Ordnance Factory Ambajhari and Dayanand Park in Jaripatka-and another four in Pune at a cost of Rs5.53 crore.
Neeri director Satish Wate told TOI this research project was a part of an Indo-European Union (EU) venture in which the EU would provide guidance in the use of natural systems for sewage treatment and also fund it to some extent. The construction for the first demonstration plant at Ordnance factory was started on Monday and is likely to be completed by December end.
The project coordinator and senior principal scientist Pawan Labshetwar said sewage contained three types of pollutants viz primary, secondary and tertiary. Ordnance Factory always faced water scarcity and the use of this treatment would generate 1 lakh litres treated water daily that could be used for varied purposes within the residential area.
The principal scientist and technical leader of the project Girish Pophali stated the ordnance factory had a residential population of over one thousand people. The treated water would be utilized for maintaining a multipurpose park of 1.5 acre and irrigating a mango orchard in the factory area in Ambazari.
The other members of the research team included Pranav Nagarnaik, Nilesh Sahu, Achal Khilnani, Harikant Kaur, Sandip Yadav and Minakshi Bagde.
What's new?
* The technology uses Natural Water Systems and Treatment Technologies (NaWAtech).
* Sludge management through constructed wetlands called 'sludge drying reed beds' is being demonstrated for the first time in India with EU support. Reeds are tall grass like plants.
* Also for the first time, certain small duration species of plants with very high water intake capacity are being used in a pilot scale project using French Reed Bed System. Treated sewage using this technique generates water enough to irrigate one acre land per day
* It uses submersible plastic cylinders which carry the bacteria that work in absence of oxygen and that consume organic pollutants in the sewage. These cylinders act as a filter
* Cost Comparison - treatment cost is about Rs1000 per 1 lakh lit per day, almost half of conventional cost
How it works
* The sewage passes through cylindrical plastic filters having a variety of anaerobic bacteria that eat up 60-70% of organic pollutants
* A horizontal subsurface wetland constructed below it absorbs nitrogen and phosphorus
* This treated sewage is then passed through a pressure sand filter having activated carbon columns that remove the non biodegradable organic matter
* Finally, it is disinfected using chlorine or ultraviolet rays and used for non potable purposes like irrigation
Benefits
* It involves very low operational and maintenance cost
* Highly efficient in removing all organic pollutants as per norms
* Requires very low energy as well as manpower that too not very skilled
* Suitable for small townships, commercial complexes, municipal councils and decentralized sewage management