Study On Comprehensive Pretreatment Process Of Liquor Distillery Spent Wash

With the improvement of liquor consumption,the liquor industry has developed rapidly in recent years.At the same time,the environmental problems caused by liquor production are becoming increasingly serious,especially caused by the distillery spent wash in the process of steaming,which can aggravate pollution load on the liquor wastewater.This study through componential analysis and on-site monitoring,analyzed pollution characteristics and yield as well as components of distillery spent wash,and using single-factor experiments and orthogonal experiment to study the effect of CPAFC flocculation on the treatment of distillery spent wash,then improving the treatment efficiency through polyacrylamide?PAM?coagulant.Moreover,we use the Fenton reagent method to treat the flocculated effluent,and optimize pretreatment process conditions.Finally,the concussion of distillery spent wash on the liquor wastewater can be reduced to a minimum.The results of the study show that:1.The distillery spent wash is a kind of high concentration and easily degradable organic wastewater.Its turbidity is in 1500¹800 NTU,COD_Cr is in 10000¹2000 mg/L,pH value is in 2.8³.2,conductivity?EC?is in1100¹200 S/cm,suspended substance?SS?is in 1600¹900 mg/L,and its main components are starch,cellulose,low molecular sugar and low molecular acid.2.The distillery spent wash production only accounted for 3%of the liquor waste production,but the COD_Cr contribution rate of distillery spent wash was up to 75%and the turbidity contribution rate of distillery spent wash reached 45%respectively.3.Regulating the pH value to 6.Then adding 23.3 ml/L CPAFC flocculent?Fe/Al ratio is 5:5;base degree value is 1.5?to distillery spent wash,then350r/min rapid stir for 2 min and 40 r/min slow stir for 10 min,after 20 min standing,it can achieve the best removal effect,and the turbidity removal rate reached 95.97%.It almost eliminates the effect of distillery spent wash.4.Adding 16.7 ml/L positive PAM coagulant?0.8 g/L?at the beginning of slow stir can shorten the slow stir time to 2 min,and make the distillery spent wash quickly precipitate and clarify after standing for dozens of seconds.5.Adding 85.3 ml/L H₂O₂?concentration is 30%?and 5.3 g/L FeSO₄·7H₂O(H₂O₂/Fe²⁺molar ratio is 50:1)to the supernatant after treated by PAM and CPAFC,40 r/min slow stir for 60 min,which can achieve the best removal efficiency of COD_Cr and the highest removal rate can reach 80%,remaining COD_Cr only accounted for 6%of the liquor waste.To conclude,using CPAFC combined with PAM to treat the distillery spent wash,then using Fenton reagent to treat supernatant can greatly reduce the turbidity and COD_Cr of distillery spent wash,and minimum the effect of the distillery spent wash on the liquor wastewater,which has important practical significance for treatment of distillery spent wash.