Abstracts Category : Other

Performance Characterization of Coagulation Pretreatment for Two Industrial Effluents

by Jing Wan

In this work, performances of coagulation and flocculation were tested for two different industrial effluents. Coagulation-Flocculation and activated carbon adsorption were applied for the remediation of oil sands process-affected water (OSPW), generated from oil sands operations in Alberta, Canada. OSPW is a complex mixture of suspended solids, various suspended and dissolved organic compounds. Alum and natural coagulant Opuntia ficus-indica (OFI) were used as the coagulants, and the process was optimized to improve the removal of turbidity and dissolved organic carbon (DOC). The maximum removal of 98% and 63% in turbidity and DOC from OSPW, respectively occurred at pH=6.32, with an alum dosage of 190.44 mg/L and activated carbon at 0.28 g/L. Whereas a comparable removal of turbidity and DOC from OSPW occurred at similar pH and carbon loading at a much higher dosage of 780 mg/L for natural coagulant. Adsorption on polymer seems to be the mechanism of removal of DOC from OSPW during coagulation. Natural coagulant increases the DOC of water due to dissolution of sugars and carbohydrates from natural coagulant, but these compounds are highly biodegradable and should not be a problem when treated water is disposed of in natural environment.Large volumes of bilge water are generated by the ships across the world. Due to the abundance of saline water on-board, performance of sodium chloride/ calcium silicate as a coagulant for oily waste water was determined and compared with that of alum/ calcium carbonate. Almost 93% of the oil was recovered at the top and bottom when 100 mg alum/L and 1 g calcium carbonate/L was used, and a very clear effluent was produced in the middle section of the treatment vessel. 5 wt% of NaCl was effective in coagulating the bilge water, but at a much higher dosage than alum.