A Strategic Study on the Effect of Coagulation on Hydrodynamic Cavitation Treatment of Real-Time Textile Effluents

An investigation of textile industry wastewater treatment (WWT) using hydrodynamic cavitation (HC) technology was conducted on a laboratory scale. The parameters such as operation time, upstream pressure, geometry parameters, and initial pH were optimized to enhance the performance of HC. The degradation studies were reported in terms of total organic carbon (TOC) and it was identified that the mineralization effect was 14% under optimized conditions. Further, to improve the mineralization effect, oxidizing agents like hydrogen peroxide (H2O2) and Fenton reagent (FR) were externally supplied to the HC reactor. It was observed that the TOC removal was improved with the addition of the oxidants. The maximum TOC removal of 27% was reported when FR was introduced externally at 1:10 of Fe2+ to H2O2. Subsequently, the effect of coagulation as a pretreatment step on the performance of HC was inspected. Various parameters such as the type of coagulant (magnesium chloride, potassium aluminum sulfate, and ferric chloride), effluent pH, and coagulant dosage were optimized for the maximum turbidity removal. Among them, magnesium chloride showed a better effect with 92% turbidity removal. At optimum conditions, coagulation as a pretreatment step enhanced the HC performance from 27% to 54% on TOC removal. The experimental outcomes indicate that the sequence of coagulation and HC for real-time textile effluent treatment has a great potential to replace existing treatment plants since the scaling up of HC is much easier than the other advanced oxidation processes.