Changes of typical pollutants and water quality safety in a petrochemical wastewater treatment plant

Abstract

Pollution control and water quality safety of petrochemical wastewater are important topics of pollution prevention in the field of water environment. However, the compositional changes of typical pollutants and water quality safety in petrochemical wastewater treatment process have not been deeply explored. The concentration changes and toxicity reduction effects of typical pollutants in the wastewater treatment process of a petrochemical wastewater treatment plant were studied. The results indicated that the removal rates of COD and petroleum in the pretreatment process were 36.38% and 95.16%, respectively. Meanwhile, the biotoxicity of effluent was effectively reduced. The removal rates of COD and ammonia in the biochemical treatment process reached 63.19% and 43.21%, respectively. The relative contents of organics such as phenols, esters, and amines in effluent were significantly reduced. After the advanced treatment, COD, BOD5, petroleum substances, ammonia and total nitrogen were (32.54±4.93) mg/L, (2.19±1.09) mg/L, (0.04±0.01) mg/L, (2.32±0.31) mg/L and (27.08±1.45) mg/L, respectively. Phenols and nitrogen-containing heterocyclic compounds were significantly reduced. The toxic unit(TU) value of final effluent was 0.32, which performed no acute biotoxicity. The wastewater treatment process adopted by the petrochemical wastewater treatment plant could effectively remove various characteristic pollutants in the wastewater, and the effluent had no significant acute biological toxicity, with little impact on the ecological safety of the water environment.

Keywords

• petrochemical wastewater
• full-scale treatment process
• typical pollutant
• acute biotoxicity
• water quality safety