@article {48007, title = {Design of hydrodynamic cavitation assisted intensified tertiary treatment unit for effective degradation of organic micropollutants in pharmaceutical industrial effluent: a case study with triclosan}, journal = {Journal of Water Process Engineering}, volume = {49}, year = {2022}, month = {OCT}, pages = {103132}, type = {Article}, abstract = {

Increasing occurrence of micropollutants and trace amount of persistent organic contaminants (POC{\textquoteright}s) in the wastewater streams even after the well-established conventional treatment is a threat to human health, aquatic entities, and constitute a formidable challenge for the ecological security. In this regard, hydrodynamic cavi-tation based advanced oxidation treatment has attracted extensive attention towards removal of such micro scale pollutants from wastewater streams in the present scenario. Hence, the present work demonstrates the design and application of a rotating hydrodynamic cavitation (RHC) reactor with stator-rotor arrangement for effective degradation of organic micropollutants (triclosan being taken as the target pollutant) from tertiary effluents occurring in the pharmaceutical sector. The process performance was evaluated through optimization of geo-metric parameters of the reactor, various operating parameters as well as by studying the sole and synergistic performance of the HC process combined with other AOPs. The maximum degradation of Triclosan (TCS) ach-ieved by RHC alone was found to be 35.2 \% and in synergism, with ozone, a maximum of 97.6 \% degradation was observed. Further, to ensure the mineralization of the components, total organic carbon (TOC) contents of the samples were measured and the degradation pathway was predicted through LC-MS analysis. The techno-economic feasibility of the process were understood through economic and energetic analysis and technology transfer was done for replicating the same study for a pilot scale reactor.

}, keywords = {Advanced oxidation process, Hydrodynamic cavitation, Micropollutant, Pharmaceutical effluent, Tertiary treatment}, issn = {2214-7144}, doi = {10.1016/j.jwpe.2022.103132}, author = {Mishra, Birupakshya and Mukherjee, Anupam and Mullick, Aditi and Bhandari, Vinay M. and Moulik, Siddhartha} } @article {47996, title = {Solvent-assisted cavitation for enhanced removal of organic pollutants - degradation of 4-aminophenol}, journal = {Journal of Environmental Management}, volume = {311}, year = {2022}, month = {JUN }, pages = {114857}, type = {Article}, abstract = {

A new approach of solvent-assisted cavitation process was proposed for degradation of organic pollutants. The process envisages the use of suitable solvent as an additive, (1-5\% v/V), in the conventional cavitation process to enhance the pollutant removal efficiency. A proof of concept was provided for the removal of ammoniacal nitrogen with significantly improved efficiency using solvent-assisted hydrodynamic cavitation (HC) compared to conventional HC. The efficacy of the process was studied on a pilot plant scale (1 m(3)/h) and using vortex flow based vortex diode as a cavitating device. Degradation studies were carried out using a model pollutant, 4-amino phenol and four different solvents as additives, 1-octanol, cyclohexanol, 1-octane and toluene. Relatively polar solvents were found to increase the efficiency of the pollutant removal (\> 65\%) and also increase the rates to an extent of more than 200\%, compared to only HC. A very high removal of ammoniacal nitrogen, more than 90\%, was obtained for solvents 1-octanol and cyclohexanol, indicating the importance of the selection of solvent. Per pass degradation model showed 3 to 4 times increase in the per pass degradation for polar solvents compared to cavitation alone. The results confirm no role of conventional solvent extraction and no specific contamination of wastewater due to the use of solvent as an additive in the process. Further, the cost was 2-3 times lower as compared to the conventional HC. The interesting observations in the proposed process can fuel further research to provide possible improvements in existing methodologies of wastewater treatment, in general, and for removal of ammoniacal nitrogen, in particular.

}, keywords = {Ammoniacal nitrogen, Hydrodynamic cavitation, Oxidation, Pollution Control, Wastewater treatment}, issn = {0301-4797}, doi = {10.1016/j.jenvman.2022.114857}, author = {Patil, Pravin B. and Bhandari, Vinay M.} } @article {48727, title = {Improving hydrodynamic cavitation using newer surface-coated cavitation reactors}, journal = {Chemical Engineering Research \& Design}, volume = {199}, year = {2023}, month = {NOV}, pages = {238-251}, type = {Article}, abstract = {

Surface-coated cavitation devices, vortex diode (SCVD) have been reported for the first time for enhancing efficiency of hydrodynamic cavitation (HC). Two surface-coated cavitation reactors using coating of copper and nickel (-50 mu m) were evaluated, also comparing results with conventional reactor vortex diode. The proof of concept is successfully demonstrated for complete degradation of two model organic pollutants, antibioticscephalexin (CFX) and ciprofloxacin (CIP). The surface-coated reactors provide dual activity, and the catalytic effect is highly pronounced with process intensification using H2O2 and/ or pH alternations. Integration of SCVD, pH and H2O2 was the most effective strategy. Complete degradation of the antibiotics was achieved within minutes with H2O2 (-1000 molar ratio) for both Cu and Ni-surface-coated cavitation reactors compared to lower degradation of-19\% for CFX and-37\% for CIP using only HC. An excellent enhancement of over 300\% for CFX degradation at pH 11 and-170\% for CIP degradation at pH 4 was obtained. Huge enhancements in per-pass degradation and cavitational yields (up to 400 times) clearly highlight the utility of the surface-coated cavitation reactors in various applications and for cost-effectiveness.(c) 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.

}, keywords = {Hydrodynamic cavitation, Oxidation, pollution, Reactor, Technology, Wastewater treatment}, issn = {0263-8762}, doi = {10.1016/j.cherd.2023.10.002}, author = {Dixit, Divya and Thanekar, Pooja and Bhandari, Vinay M.} }