Study On Biological Enhanced Dewatering And Resource Technology Of Excess Sludge In Cold Region

This study was aimed at the winter climatic characteristics in northern China,investigated the impact of low temperature on biological dewatering technology,through strengthened the important factors in the process of biological dewatering,explored the optimal low temperature condition maintenance technology and operating parameters of microorganism.Used rice husk and straw as conditioning agent,mixed with biological in-deep dewatered sludge cake for aerobic composting test,studied on the effect of composting.The acidified sludge contained in-deep dewatering microorganisms was obtained by domestication,inoculated it into WWTP thick sludge to biological dewatering treatment,by controlled the key process parameters,which had a significant impact on sludge dewatering performance,to explore the optimal process conditions.The results showed that when the inoculation amount of acidified sludge was 10%,the initial concentration of sludge was 2%,the dosage of nutrient agent S was 1g/L,Fe²⁺was 1.2g/L,and the biological dewatered treatment 2d,the dewatering performance of sludge can be the best.Under the optimum process condition,sludge biological dewatering experiment was carried out at 10?and 28?respectively,studied on the change of dewatering microbiological activity and sludge dewatering performance.In light of microbial activity reduced and sludge dewatering performance got worse at low temperature,by increased the amount of acidified sludge inoculation,the dosage of nutrient agent,decreased the initial concentration of sludge,added H₂O₂ into sludge,which had been biological in-deep dewatering treated,investigated the impact of different strengthening measures on microbial activity and sludge dewatering performance at low temperature.The results showed that when the amount of acidified sludge inoculation was increased to 15%,the dosage of nutrient agent S and Fe²⁺was increased to 5g/L and 2.4g/L respectively,the initial concentration of sludge was decreased to 1%,the dosage of H₂O₂ was1mL/L and treated 60min,the microbial activity and the sludge dewatering performance could be significantly improved at low temperature.The liquid sludge,which treated by biological in-deep dewatering technology,through filter pressing could formed mud cake,used the broken mud cake as raw material,aerobic composting test was carried out by mixing with crop conditioner,studied on the changed of sludge physical and chemical indexes in the process of composting.The results showed that the temperature of stack rose rapidly in the initial stage,it could be maintained at high temperature stage?>50??for 5 days,met the temperature standards of Sanitary standard for non-hazardous treatment of night soil?GB7959-2012?.At the end of composting,the water content of stack decreased from 58.56%to 37.35%,the effect of sludge reduction was remarkable,the organic matter of the stack decreased from 46.40%to 40.28%,both p H and NH₄⁺-N of the stack increased at first and then decreased,compared with those before composting,the total phosphorus content of the stack increased by 60.6%.The physical indexes,chemical indexes,nutrient indexes and pollutant indexes of the composted sludge all meet the Disposal of Sludge from Municipal Wastewater Treatment Plant—Quality of Sludge Used in Gardens or Parks?GB/T 23486-2009?,the composted sludge could be used for landscaping.