Environmental and biological characteristics of coking wastewater

The complicated nature of coking wastewater is an obstruction to satisfying the all-around Water Quality Standard and is harmful to the environment. COD, BOD, color, ammonia nitrogen, volatile phenol, cyanide, anions, cations, heavy metals and organic compounds of a coke plant wastewater were analyzed by ion chromatography, ICP/MS, GC/MS and other regulatory methods of analysis. The constituents were evaluated from environmental and biological perspectives. COD, ammonia nitrogen, volatile phenol, cyanide, sulphide, fluoride and oil are harmful, especially the organics. Phenols, polycyclic aromatic hydrocarbons and heterocyclic compounds all exist in the coking wastewater and m-cresol, long chain alkanes, benzene series compounds, esters, alcohols, halogenated hydrocarbons, and amines could be detected in the outflow from the filter tank. The accumulated heavy metals like Cr, Cd, Hg, As, Ni and Pb are safe to the water environment. The Na+∶ K+ ratio did not match the optimum value of metabolism, so K+ and PO3-4 must be provided to maintain ATPase activity. The treatment of toxic compounds which are difficult to biodegrade should consider the pollutants present, appropriate technologies and ecological security.