Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras
Pulsed Power Technology based Water Treatment Unit for the Removal of Pesticides, Pharmaceutically Active Compounds and Pathogens
Technology Category/Market
Category-Environmental Engineering
Industry Classification:
- NIC (2008)- 3600- Water collection, treatment and supply; 28195- Manufacture of filtering and purifying machinery or apparatus for liquids and gases
- NAICS (2022)- 562910 Remediation Services; 221320 Sewage Treatment Facilities
Applications:
Water treatment, effluent treatment for pharma industry, drinking water etc
Market report:
The global water treatment market size is expected to rise from US$ 69.73 billion in 2024 to US$ 137.17 billion by 2034. The market is estimated to expand at a CAGR of 7% over the forecast period.
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Problem Statement
- The presence of emerging contaminants (ECs) such as Pharmaceutically Active Compounds (PACs) and pesticides in surface water bodies (rivers, lakes, streams etc.) IS increasingly being recognized as threat for aquatic and terrestrial ecosystem. Moreover, pathogen contaminants that impact human health also need to be addressed.
- Conventional methods such as bioremediation, fenton oxidation process, ozone technology, photo-catalytic process, electrochemical process etc. are not cost effective and not generally applicable for mixed ECs in contaminated water.
- Conventional methods of removing pathogens from drinking water include chlorination, UV treatment and ozone treatment. However, these may lead to carcinogenic by-products such as trihalomethanes or haloacetic acid in chlorination and ozone while having high maintenance cost.
- There is a need for an improved cost-effective tertiary water treatment system that removes ECs as well as pathogens from drinking water sources.
Technology
- The “needle to plane“ Continuous flow pulsed plasma reactor can serve the purpose of water disinfection and ECs removal in a single unit. Untreated water flows as a thin film to maximize the surface area of untreated water getting exposed to plasma, where the untreated water undergoes oxidation by different reactive species. Finally the treated water is discharged from the outlet of the reactor.
- Multiple tungsten needles are used as electrodes while a copper plate is used as a ground with thin film of water flowing over it. The distance between needles was kept at 20 mm. Four baffles were provided to avoid channeling in plasma reactor. Distance between needles and water surface could be adjusted, the distance was kept constant at 5 mm throughout the experiment. To maintain a thermostatic condition during the experiment, a water jacket was provided.
- For the high voltage source for electrical pulse generation, a discharge free test transformer (lOOkV, 5kVA) was used to generate AC voltage. The AC voltage was converted DC voltage which was further converted to square pulse using a rotating spark plug
- Five ECs namely diclofenac (DCF), carbamazepine (CBZ), ciprofloxacin (CPF), carbofuran (CRF) and 2-4-D have been used for the degradation study in continuous flow reactor. The pollutant removal in continuous reactor was carried out at 23 kV and 25 Hz frequency in distilled water, lake water (IIT Madras campus) and river water (Adyar river, Chennai) water.
- Plasma discharge in air creates nitrates and hydrogen peroxide that dissolve in the treated water. Hence oxygen gas was purged into the reactor at a flow rate of 200 mL/min to prevent the formation of nitrates. Whereas, to remove residual hydrogen peroxide, the plasma treated samples were incubated for 24 min (HRT of the reactor) with MnO2 catalyst. MnO2 reacts with H2O2 and forms water and oxygen molecules.
Key Features/Value Proposition
- Pesticides, PACs and bacterial contaminated water is successfully treated in a pulsed power reactor to produce treated water, which meets drinking water standards.
- The degree of mineralization was confirmed by TOC analysis. For 10 mg/L PACs, substantial reduction in TOC was observed, reaching almost 70, 65 and 50 % in DW, LW and RW respectively after 24 min of plasma treatment.
- The toxic nature of ECs was completely eradicated in DW and LW water after the plasma treatment. Whereas, conventional Advanced Oxidation Processes (AOPs) such as ozonation and photocatalysis may lead to formation compounds that are more toxic than the parent compound.
- The system uses robust tungsten electrodes that requires very less maintenance. Whereas, conventional water purification methods such as UV irradiation and Reverse Osmosis require frequent changing of lamps that are prone biofilm formation or changing of filters, membranes etc. respectively.
Questions about this Technology?
Contact for Licensing
Research Lab
Prof. Ligy Philip
Department of Civil Engineering
Prof. Sarathi R
Electrical Engineering
Intellectual Property
- IITM IDF Ref 1557
- IN 349146 Patent Granted
- PCT Application No: PCT/IN2018/050727
PCT Publication No: WO/2019/092747
Technology Readiness Level
TRL 5
Technology Validated in Relevant environment