Use of Advanced (i.e., Membrane) Technology for the Wastewater Treatment of Coke Ovens

Abstract

Coke plants produce gas, and coke for metallurgical purposes and also supply the raw materials for the manufacture of dyes, drugs, and high explosives. Naturally found coal is converted into coke in coke ovens. A large quantity of water is used for quenching hot coke and for washing gas. After quenching the wastewater contains high-suspended solids, high biochemical oxygen demand (BOD) (600–1300 mg/L), chemical oxygen demand (COD) (1500–3000mg/L), phenols(500–650 mg/L), ammonia(150–250 mg/L), cyanide(5–10 mg/L), suspended solids(100–350 mg/L)and other toxic substances, which cause serious water pollution. So these effluents are treated from biological oxidation and de-phenolisation plants and may be recycled and again used for quenching hot coke. However, because of upcoming projects like coke dry quenching (CDQ), where the treated water cannot be used for quenching, it has to be discharged to environmental bodies. Secondary treated wastewater from coke ovens contains very low organics but high conductivity (2700–3000 µs/cm), which is attributed to the high concentration of many dissolved monovalent and divalent ions. Since they cannot be removed by conventional treatment methods, a commercial ultrafiltration (UF) and reverse osmosis (RO) membrane can be used for coke oven wastewater reuse and discharge. By using membrane technology and biological treatment the maximum treatment of waste water can be achieved. This paper presents the membrane technology used in wastewater reclaimed characteristics and some results of reduction in various wastewater parameters.