Treatment of Industrial Wastewater

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Contamination of fresh water is one of the most concerning environmental issues. Normally, the main sources of pollution have been organic matter and nutrients. However, chemicals like pharmaceuticals, hormones and personal care products (PPCPs) are finding their way into the receiving waters. The main sources of this pollution have been industrial and municipal wastewater treatment plant effluents. Most conventional treatment plants cannot remove PPCPs efficiently. These putative contaminants, entering the environment as wastewater treatment plant effluents, are known as "contaminants of emerging concern" or simply "emerging contaminants" (ECs). Pharmaceuticals such as acetaminophen, heteroaromatics such as benzothiazoles, and agrochemicals such as halogenated benzonitriles have wide application in commercial and industrial products and have been detected in industrial and domestic wastewater along with other organic contaminants such as azo-dyes, and have also been detected in soil, groundwater, and tap water. Commonly used wastewater treatment techniques are unable to effectively remove these toxic compounds and applying some of the advanced treatment technologies can exasperate the issue through the formation of more toxic byproducts during treatment. Although some of these contaminants have been linked to cancer or have shown endocrine-disrupting properties, their long-term effects on human and ecosystem health are largely unknown. Removal of these chemicals during industrial and domestic wastewater treatment, therefore, is of great importance. This research aims to effectively remove these recalcitrant compounds using enzymatic treatment, by which the compounds are converted to insoluble or less water-soluble oligomers. The insoluble oligomers are then separated from the solution by settling, with or without other unit operations such as coagulation/flocculation assisting in settling. Our goal is to assess the effect of different parameters on enzymatic treatment efficiency of these ECs in synthetic and real wastewater, both industrial and domestic. The key parameters to be investigated for their effects on abatement efficiency are pH, enzyme and peroxide concentrations, and the reaction time. Also, by identifying the treatment byproducts - both in solution as well as in the precipitates, evaluating its possible toxicity, we will propose a possible degradation pathway for these chemicals. Biocompatibility of treated wastewater will be determined by assessing the ecotoxicity of transformation products, and effluents. This research will broaden our knowledge on the fate and impact of widespread bio-refractory contaminants such as ECs and help in developing more viable and promising techniques for the treatment of hazardous pollutants, with the long-term goal is of developing full-scale cost-effective treatment systems.