A Study On The Changes Of Biological Toxicity And Components Of Petrochemical Industrial Wastewater In The Process Of Biolpgical Treatment

In China, many petrochemical enterprises distribute in the coast or the region along the river. Therefore, the petrochemical wastewater have potential negative effects for aquatic ecosystem and popular health. The conventional water quality index can not reflecte the actual harmful effects of petrochemical industrial wastewater.In the study, the change in dissolved organic matter and the biological toxicity of petrochemical wastewater were observed in the wastewater treatment plant of a large petrochemical enterprise. The influent and effluent water samples were obtained under two different operation states that aniline production facilities were being overhauled and recovered. Every wastewater sample was separated into six fractions through XAD-8, MSC, and DA-7resins.The six fractions were hydrophobic acid (HOA), hydrophobic alkaline (HOB), hydrophobic neutral (HON), hydrophilic acid(HIA), hydrophilic alkaline(HIB), and hydrophilic neutral(HIN). Luminescent bacteria acute toxicological test,SOS/umu-test and yeast two-hybrid system were used to detect the acute toxicity, the genetic toxicity and the environmental endocrine activity of the wastewater samples respectively. Ultraviolet spectrum and fluorescence spectra were also obtained to examine the components of the wastewater samples and to screening the biological toxic substances.The results show that:a) the petrochemical wastewater have biological toxicity that can't reduced effectively by the existing treatment facilities and in which the genetic toxicity that mainly were caused by hydrophobic aromatic acid and the antiestrogenic activity that related to hydrophobic non-aromatic organic; b) the biological treatment facilities of the petrochemical enterprises was of little result on reducing the biological toxicity, sometimes even increasing the toxicity while the removal efficiency of DOC was about70%; c) the mixing of aniline wastewater can increase the amount of organic carbon and can overload facilities; d) it is needed to evaluated the water quality with the assessment of biological toxicity combined with the conventional water quality index.The paper evaluates the biological toxicity of the petrochemical wastewater qualitatively and quantitatively and the results are helpful to the assessment of wastewater quality and optimization of wastewater treatment technology of other petrochemical enterprises. The necessity of the assessment of biological toxicity are confirmed and it should be applied to the management of industrial wastewater. The mixed collection and joint treatment of different types of petrochemical wastewater can affect the water quality of the effluent.Therefore, on the basis of necessary pretreatment for some high pollution wastewater, the collection and treatment respectively for the wastewater with different properties are more beneficial to the improvement of water quality.