Simultaneous treatment of semiconductor wastewater and distillery slops by mixing and precipitation/coagulation

Abstract

Organic matter (chemical oxygen demand, COD) removal with decolorization in waste distillery slops and copper removal in a semiconductor industry wastewater were achieved in a single step mixing and precipitation/coagulation treatment system. The process utilized the complementary properties of the positively charged copper ions in semiconductor wastewater and net negative charge of melanoidin (organic chromophoric pollutant) in distillery slops to mutually neutralize each other. Copper ions served as coagulant for slops and melanoidin served as precipitant for copper. The volumetric ratio of the wastewater and pH were optimized to attain maximum removal of organic matter and copper. The optimum volumetric ratio for the evaluated semiconductor wastewater to distillery slops was found to be 2-3 with an equilibrium pH of around pH 6. At optimum conditions, average removals of COD and copper were 86% and 92%, respectively, in an actual and undiluted system. Decolorization efficiency using the diluted distillery slops was 89%. The process can be considered an effective pretreatment procedure for simultaneous gross removal of copper and color/COD, particularly in highly concentrated waste streams.

Removal of Copper Ions from Wastewater: A Review

“…Considering the high toxicity response factor of copper (TR = 5) for different water bodies, we have to obtain an effluent with discharge concentrations lower than MCL to effectively avoid possible health risks. Cellulose acetate based biopolymeric mixed matrix membranes 84-88% [141] Chitosan-cellulose acetate-TiO 2 based membrane 97% [142] Ion exchange Y zeolite ion exchangers 64% [143] Ion exchange resin 99.14% [144] Electrochemical reaction Bipolar disc reactor 90.1% [145] Continuous electrochemical cell 91% [146] Bioelectrochemical and electrochemical systems 99.9% [147] Chemical precipitation OM in waste distillery slops-precipitation/coagulation 92% [148] Synthetic nesquehonite 99.97% [149] struvite 99.9% [150] Adsorption Hexagonal boron nitride 92% [151] Zeolite, bentonite, and steel slag 98.47-99.98% [152] Agro-industrial waste 89% [153] Biotechnology Stenotrophomonas maltophilia 88% [154] Microalgae >95% [155] Aspergillus australensis Biomass 79% [156] Table 3. Summary of different copper ion removal technologies [3,157,158].…”