Applying a mixed coagulation agent – Chitosan-polyaluminum chloride - for the treatment of wastewater with petroleum hydrocarbons

The study assessed the efficiency of the coagulation process of wastewater with petroleum hydrocarbons content, by using mixed coagulants derivatives of polyaluminum chloride, (characterized by the molar ratio OH : Al = 2.4), mixed with various amounts of chitosan. Systematic study was conducted to define the mixed coagulant, respectively chitosan:polyaluminum chloride product, by relating its two components, within the context of optimal dosage used in the coagulation process, determined experimentally by the Jar Test method. The coagulation efficiency was examined by conventional parameters: pH, turbidity, COD, TOC, TPH (Total Petroleum Hydrocarbons) and the unconventional parameter - absorbance at wavelength 254 nm, A 254. Coagulation performance determined with the mixed chitosan - polyaluminum chloride coagulant was reported to the results obtained by coagulating with polyaluminum chloride in the absence of chitosan. The results suggest that the use of mixed chitosan - polyaluminum chloride coagulation agent, prepared at a ratio of chitosan : Al = 0.6, can significantly reduce the optimum dose of Al, more than 50%, and obtain treated samples with the same characteristics as the samples treated with optimal doses of polyaluminum chloride