Study on the Influence of Different Pretreatment Methods on Residual Sludge

With the continuous advancement of industrialization and urbanization in our country, the discharge rate of industrial wastewater and domestic sewage increases rapidly. A large quantity of activated sludge is produced in the process of sewage purification, and proper treatment of activated sludge has become a difficult problem. Based on this, this study compared the effects of four pretreatment methods and treatment conditions on the degree of sludge breakage, and selected the best pretreatment methods and conditions according to various indexes. The results showed that: When the pH of alkaline treatment was 12 and the treatment time was 3 h, the cracking degree of sludge was the best, the protein concentration reached 0.3113 mg/L, the TOC concentration reached 70.5 mg/L. When the pH of acid treatment is 2 and the treatment time is 2 h, the protein concentration is 0.2625 mg/L and the TOC concentration is 47.70 mg/L, and the cracking effect is the best. When the ultrasonic treatment time was 60 min, the protein concentration was 0.1125 mg/L, the TOC concentration was 23.2 mg/L, and the cracking effect of sludge was the best. When the heat treatment temperature is 90 ℃, the heating time reaches 80 min, the protein concentration is 0.4000 mg/L, the TOC concentration is 9.63 mg/L, the sludge cracking effect is the best. According to the analysis of three-dimensional fluorescence spectrum, heat treatment is the best method to crack the degree of sludge, followed by alkali treatment, ultrasonic treatment and acid treatment.