Characteristics of biochemical tail water from coking wastewater and current progress in advanced treatment technologies

Abstract

Coking wastewater is one of refractory coal chemical wastewater with a high pollution load，complex organic pollutant composition and strong biological toxicity. The biochemical tail water still retains refractory organic compounds and exhibits a certain level of biological toxicity after conventional physical-chemical and biological treatment. COD fails to meet the discharge standards for pollutants from Emission Standard of Pollutants for Coking Chemical Industry （GB 16171-2012），and further processing is required. The characteristics of residual organic matter and biological toxicity in the biochemical tail water of coking wastewater were analyzed firstly. Subsequently，this review summarized the COD removal efficiency，the change rules of different organic components and biological toxicity in biochemical tail water after application of separation technologies （coagulation，adsorption，membrane filtration），transformation technologies （Fenton，catalytic ozone oxidation，electromagnetic enhanced oxidation technology，persulfate oxidation and electrochemical oxidation） and collaborative processes. It was pointed out that on the basis of understanding the characteristics of the biochemical tail water and biological toxicity transformation rules with various advanced technologies，the collaborative combination process and short process technology would be desired for the efficient treatment and the biological safety.

Keywords

• coking wastewater
• biochemical tail water
• refractory organics
• biological toxicity
• advanced treatment