基于污泥蛋白质溶出的酶-热碱联合水解中试研究

为探究剩余污泥酶-热碱联合水解生产蛋白质工艺工业化利用的可能性，建立了1 m³·d⁻¹的剩余污泥(含水率80%)的中试水解系统。通过对酶解时间、复合添加量及碱解温度等关键工艺因素优化，获得了中试规模污泥联合水解的最佳工艺条件；通过酶和热碱水解动力学研究，明确了联合水解过程的限速步骤。结果表明：在日处理量为1 m³剩余污泥(含水80%)的中试水解过程中，酶解时间为1.5 h、复合酶投加量为1%、污泥浓度为30 g·L⁻¹、碱解时间1.5 h、碱解温度80 ℃时，蛋白质溶出效果最佳，上清液中蛋白质浓度为2 160 mg·L⁻¹；污泥酶解过程符合米氏方程，碱解过程符合零级动力学方程，二者的水解速率分别为0.709 mg·(L·min)⁻¹和11.046 mg·(L·min)⁻¹；与碱解相比，酶解是剩余污泥联合水解的限速步骤。研究结果可为污泥联合水解工艺产蛋白质的产业化应用提供必要的技术参数。

Pilot-scale study on enzymatic-thermo-alkaline joint hydrolysis based on sludge protein dissolution

In order to explore the possibility of industrial utilization of the enzymatic-thermo-alkali joint hydrolysis process of excess sludge to produce protein, a pilot-scale hydrolysis system of 1 m3·d−1 excess sludge (moisture content 80%) was established. The optimal conditions of the pilot-scale enzymatic-thermo-alkali joint hydrolysis were achieved by optimizing key technological factors, such as enzymatic hydrolysis time, compound enzyme dosage and alkali hydrolysis temperature, etc. Then, the rate-limiting step of the joint hydrolysis process was determined by studying the kinetics of enzymatic and alkali hydrolysis. The results showed that during the pilot-scale hydrolysis process of 1 m3 excess sludge (80% water content) per day, the best protein dissolution effect was achieved and the protein concentration in supernatant was 2 160 mg·L−1 at enzymatic hydrolysis time of 1.5 h, compound enzyme dosage of 1%, sludge concentration of 30 g·L−1, alkali hydrolysis time of 1.5 h and alkali hydrolysis temperature of 80 ℃. The sludge enzymatic process followed Michaelis equation with hydrolysis rate of 0.709 mg·(L·min)−1, and the thermo-alkali hydrolysis process followed zero order dynamic equation with hydrolysis rate of 11.046 mg·(L·min)−1. The rate-limiting step of the joint hydrolysis process was enzymatic hydrolysis compared to the thermo-alkali hydrolysis. The research results can provide necessary technological parameters for the industrial application of the sludge joint hydrolysis process to produce protein.