Advanced waste treatment of industrial waste waters by physicochemical processes

The primary objective of this investigation was to determine the general applicability of using physicochemical processes for treating different types of industrial wastes. Emphasis was placed on the evaluation of the treatment efficiency and the performance difficulties encountered in the treatment of each waste. Two types of waste were studied, one a high strength acidic industrial chemical waste and the other a petroleum refinery waste. The physicochemical system utilized included chemical coagulation and clarification plus activated carbon adsorption. Parallel operations of fixed-bed and expanded-bed carbon adsorbers were conducted. Treatment efficiencies were evaluated in terms of the removals of chemical oxygen demand, total organic carbon, turbidity, and inorganic nutrients. Because of the low suspended solids level contained in the acidic chemical waste, carbon adsorption was the only treatment needed for this waste. It was found that soluble organics were effectively removed from the chemical waste by carbon adsorption. Initial pH adjustments for the chemical waste to 3.2, 7.0, and 11.4 did not significantly affect the COD removal efficiency. Turbidity and nitrogen (total kjeldahl and ammonia-N) were removed to some extent by carbon adsorbers, while phosphorus (total and ortho-P) was totally unaffected. Treatment of the refinery waste used a combination of iron coagulation at a dosage of 2.50 mg/1 as FeCl₃[middot]6H₂O and 3 ft carbon column adsorption. Exceptionally high water quality having a TOC of less than 3 mg/1 and turbidity of less than 1 JTU was obtained. However, small quantities of organic leakage were observed consistently in all the carbon adsorber effluents. The nature of the nonadsorbable organic material was not established. Orthophosphate removal was effected by chemical coagulation while nitrogen (ammonia and organic-N) was not. Carbon adsorbers were not found to remove any of the inorganic nutrients from the refinery waste --Abstract, pages ii-iii