Ministry of Science & Technology
Aqua Rejuvenation for Irrigation Unit-- comprehensively treats Waste Water
--Prof.  Harish Hirani, Director, CSIR-CMERI, DURGAPUR
-- Dr.Priyabrata Banerjee, Principal Scientist
PURPOSE OF THIS TECHNOLOGY: It has been observed that most old Drainage systems are choked and have Improper Sanitation Infrastructure such as cracks in the Drain Surfaces. This Sewage Water seeps down through the cracks and contaminates the soil and ground water. In a recent study, it was observed that untreated sewage water is rampantly being used for agriculture, against NGT protocols, which may have adverse health consequences. Recent studies also revealed that the Coronavirus can thrive in Waste Water for over a month.
The effluents in household water discharge includes: organoleptic water pollutants such as colour, odour, pH, turbidity, TSS, TDS, oil & grease etc. along with some undesirable toxic compounds, and bacteriological components . To remove the water contaminants & to purify the sewage water ,CSIR-CMERI developed innovative technology in combination with chemical & physical processes such as i) mechanical segregation & filtration, ii) coagulation-flocculation techniques and iii) chemical/physical adsorption.
Aqua Rejuvenation Plant  comprehensively treats Waste Water, based upon diverse purification parameters. The approx. 24,000 litres of Water that can be rejuvenated using ARP, will be sufficient for almost 4 acres of Agricultural Land . The CSIR-CMERI developed technology is capable of removing all pollutants from sewage  and based upon geographical variations they may be modified. The filter media is also locally source-able so as to ensure that there would not be any stress in the supply chain for scaled-up manufacturing of ARP.
CSIR-CMERI has recently transferred four indigenously developed Water Purification Technologies to three prominent MSMEs engaged in the Water Purification domain. The MSME partners hailed the indigenously developed Water Purification technologies as a major stepping stone towards Self-Reliance and Import-Substitution.
HOW TO PURIFY SEWAGE WATER:
The methods of purification applied by CSIR-CMERI in this technology are Sedimentation , Filtration  and Aeration . The Adsorbent media in the filtration components also plays a major role. They are abundantly available naturally and thus are easily source able.
IS THIS TECHNOLOGY PATENTED? HOW IT WILL BE BENEFIT THE SOCIETY?
The technology is already IP protected.
The Aqua Rejuvenation Pilot Plant  installed at CSIR-CMERI has a maximum capacity to treat 40,000 litres/day in its scaled-up version. With this technology, CSIR-CMERI will incrementally reach towards a Zero Liquid Discharge Ecology. The treated water processed from the ARP is preferable for agricultural purposes and with enhanced settling time it can be used for drinking purposes. This treated water will help to improve the environment by fixation of carbon dioxide and will also provide food security.
UNIQUENESS OF THIS TECHNOLOGY:
The presently developed technology combines both mechanical and physico-chemical treatment processes in order to purify the municipal sewage water from the household uses. A five compartmental chamber is implemented herein for removal of unwanted suspended solids . Thereafter addition of another water tank  helps for proper settling of the remaining unwanted TSS/TDS/oily substances etc. with the help of coagulation-flocculation technique. Moreover, in cartridges various low-cost, R&D tuned adsorbents are kept in an unique wt % ratio in sequential manner to get the best contaminants removal efficiency  from the ETP. An additional micron filter further allows to remove any residual suspended/dissolved solids in the treated water.
All the aforementioned scientific works were controlled by wet chemical experimentations, duly supported from contemporary literature review in the relevant domain. The salient features of the developed technology are:
- The technology will help in solving two problems at one go:
In one hand it converts sewage water to potable water which may be used for agricultural purposes thereby conserving the fresh water resources on the other hand it helps to reduce the burden of pollutant enriched grey water converting it into potable one.
- An integrated mechanical and physico-chemical treatment processes based water purification system for effective removal of sewage water contaminants.
- The technology is economical in terms of maintenance and affordable in terms of operation.
- Sustainability towards healthy livelihood generation
- Selective backwash without dismantling any part of the plant; less cumbersome approach.