The Physico-chemical Treatment Of Coking Wastewater

Components were complex in coke plant wastewater, in which contains high concentration of ammonia nitrogen and a number of toxic and refractory organic compounds, and great changes happened usually to water quality and water flow. Most of the orginal treatment processes were conventional activated sludge method, though which the COD and ammonia nitrogen removal were not favorable and the effluent concentration couldn't attain the wastewater drainage level, which brought severe harm to our environment and human body.In this paper, a primary study was carried out on the reaction conditions and the factors influencing of the three processes: chemical precipitation, coagulation precipitation and Fenton oxidation , which were used to dispose the COD and ammonia nitrogen in the effluent from a coke plant with actived sludge process. The effects of different coagulants on COD removal efficiency were tested as well.The removal ammonia nitrogen mechanism of chemical precipitation was discussed through academic calculation. The results of chemical precipitation experiments show that by using Mg²⁺ NH₄⁺ PO₄^3- ' (molar ratio) is 1.4 :1 : 0.8 and by adjusting pH=9.0, The ammonia nitrogen removal efficiency is better than others. For example, as for the effluent containing 862mg/L ammonia nitrogen, the ammonia nitrogen removal rate can reach 90%, the ammonia nitrogen concentration in treated water being 84.67mg/L.In this study, the PAC was used for the treating with COD of coking wastewater as a coagulant. As shown by the experiments, with coagulation PAC the percentage removal of CODcr can reach 67%,the CODcr in treated water being 214mg/L.When Fenton reagent was used in dealing with the coking wastewater after treated by biochemical method,the removal rate of CODcr could be reached to 79%.Treatment effects impacted by pH value, temperature, and Fenton reagent with different matchs were discussed, the percentage removal of CODcr was obvious, for instance CODcr concentration in treated water is less than the limited value in...