Study On Pretreatment Of Ultrahigh-phosphorus Concentration Pharmaceutical Wastewater

Ultrahigh-phosphorus concentration pharmaceutical wastewater is a kind ofrefractory industry wastewater with the characteristics of high organic compounds andphosphorus、low pH and deep color. This kind of wastewater is treated through dilutionmethod at present. However, there are serious issues, such as a waste of resource, largethroughput. Efficient combined treatment process through the physical and chemicalwas developed to pretreat it in order to reduce the processing and recycle resources.Ultrahigh-phosphorus concentration pharmaceutical wastewater from a pharmaceuticalfactory was studied in this paper, the phosphorus content is40248mg/L. The combinedalkali lime-two electrolysis treatment was adopted for the pretreatment ofultrahigh-phosphorus concentration pharmaceutical wastewater by lime, fly ash andelectrolytic. The experiments were conducted to investigate the treatment efficiencies、influence factors and optimal operating parameters.The effect of lime and fly ash to ultrahigh-phosphorus concentrationpharmaceutical wastewater was studied. The results indicated that lime was better thanfly ash, phosphorus removal rate reached72.1%by chemical precipitation. Study foundalkaline conditions may improve treatment efficiency. Keeping lime dosage40g/L、 pH8.5、mixing rate2.5(equivalent units)、reaction time20min and sedimentation time10min,then the removal rates of COD and TP are72.2%,18.9%, respectively. Thus,lime was used as the first step.The effect of electrolysis to artificial wastewater was studied. Fe/Fe and Fe/Celectrode were less different in phosphorus removal and energy consumption, Fe/Celectrode was selected taking post-strengthening electrolysis into account. Treatment ofhigh-phosphorus concentration artificial wastewater with electrolysis found that foundthat the optimal electrode distance was2cm, and energy consumption decreased withthe decrease of the electrode distance. Phosphorus removal rate and the energyconsumption increased along with the increase of current, decreased with the increase ofinitial phosphate concentration, but the total quantity of phosphorus increased. COD hadless effect on phosphorus removal, Sulfate and chloride ions can reduce energyconsumption but affect the phosphorus removal. Treatment of ultrahigh-phosphorusconcentration artificial wastewater with electrolysis found that the optimal current was0.8A and aeration volume was1.6L/min for0.2L wastewater. Also found that aerationhad functions of improving phosphorus removal rate and lowering energy consumption.Double electrode sets promoted phosphorus removal rate from25.9%to42.1%.Aeration and exchanging electrode can reduce electrode passivation in a certain extent.Studies have shown that electrolysis has certain feasibility to remove phosphrous of ultrahigh-phosphorus concentration pharmaceutical wastewater.Electrolytic process is chosen as the second step according to the results ofelectrolysis experiment. Using electrolysis to treat ultrahigh-phosphorus concentrationpharmaceutical wastewater after lime-flocculation has been conducted. The resultsfound that under the optimal conditions of double electrode sets, pH of6.4, current of0.8A, electrode distance of2cm, reaction time of10min followed by2min of electrodeexchanging and mixing rate5(equivalent units), removals of TP and COD were39%and16.3%,with the primary electrolytic40min and Secondary electrolysis40min, pHincreased from6.4to7.83. Using part of raw and other rare wastewater adjusted pH andphosphorus content.Wastewater quality have improved after disposing by alkali lime-two electrolysistreatment, removals of TP and COD were83%and32%, color has decreased to someextent, which reached prospective purpose. And it has got well preparation for thefollowing treatment.