Ammonia removal from coal dry distillation wastewater

The article used coke oven gas as desorption agent, pilot-scale packed tower as desorption equipment, removed ammonia from wastewater produced by coal dry distillation process. Gas stripping method is a new technology for ammonia removal. Through experiments conducted in the coking plant, when the temperature of wastewater T=85°C, pH=11.5, the ratio of liquid and gas volume n=550:1 and the addition of surfactant ρ=15 mg·L^-1, handling wastewater containing 3668.4 mg·L^-1 of ammonia, the desorption efficiency η can be 92.84%. And the ammonia concentration of the effluent is 262.6 mg·L^-1. After the pretreatment, wastewater can be more suitable for biochemical treatmentmeet, which makes the effluent quality meet well with discharging standard. Comparing with steam-stripping method, gas stripping can improve ammonia desorption efficiency 5%, and save 4,725,000 Yuan per year for 1,000,000 tons scale of coke plant.