基于蛋白质回收的剩余污泥热碱水解技术研究

发布时间：2018-05-06 19:12

本文选题：污泥水解 + 蛋白质　；参考：《江南大学》2017年硕士论文

【摘要】：随污水处理厂处理规模的不断扩大,副产物剩余污泥产量不断增加,已成为污水处理厂面临的主要问题之一。剩余污泥含有大量有机物,如蛋白质、多糖、核酸等,其中,蛋白质约占细胞干重的50%,若能在水解基础上将剩余污泥中的蛋白质回收利用,则可实现真正意义上的变废为宝,同时实现剩余污泥减量化和无害化。本研究以无锡市滨湖区某污水处理厂剩余污泥为处理对象,以污泥蛋白质溶出率为评价指标,在研究热酸和热碱水解对剩余污泥蛋白质溶出效果影响的基础上,研究联合酶法水解剩余污泥的蛋白质溶出效果,获得剩余污泥水解溶出蛋白质的最佳工艺条件,然后,采用牛血清蛋白和纤维素标准品模拟剩余污泥中的蛋白质和多糖,研究热碱水解期间蛋白质的溶出、转化和降解规律,可为剩余污泥中蛋白质的回收提供技术支撑。主要研究内容和结果如下:(1)基于蛋白质回收的剩余污泥热酸水解技术研究。当热酸水解p H为1.0、反应温度为125oC、反应时间为6.0 h和污泥浓度为30 g/L时,剩余污泥蛋白质溶出效果最佳,上清液中蛋白质浓度及其溶出率分别为1686 mg/L和24.01%。在最佳热酸水解条件下,剩余污泥中53.43%的粗蛋白质未能从污泥细胞中破胞释放,同时不同程度地分解或转变成其他物质,仅有24.01%的污泥蛋白质以可溶蛋白质形式溶解在水解上清液中。(2)基于蛋白质回收的剩余污泥热碱水解技术研究。当热碱水解p H为12.5、反应温度为80oC、水解时间为3.0 h和污泥浓度为30 g/L时,剩余污泥蛋白质溶出效果最佳,上清液中蛋白质浓度及其溶出率分别达2436 mg/L和42.24%。与热酸水解相比,热碱法水解剩余污泥的蛋白质溶出效果较好,污泥蛋白质溶出率高出18.23%左右,同时,热碱水解剩余污泥的水解时间较短,成本较低。(3)基于蛋白质回收的剩余污泥酶解技术研究。碱性蛋白酶和木瓜蛋白酶复合联合热碱水解法水解剩余污泥,效果优于其他复合酶。当二者配比为1:12时,蛋白质溶出率达81.84%。与单一酶解效果相比,碱性蛋白酶与木瓜蛋白酶复配,其蛋白质溶出率比二者单独水解分别提高了48.02%和34.81%。当污泥浓度为30 g/L时,复合酶(碱性蛋白酶:木瓜蛋白酶为1:12)投加量为1%,在体系p H为7.0和反应温度为55oC条件下酶解2.0 h,再调节p H至12.5和反应温度为90oC条件下热碱水解1.5 h后,剩余污泥蛋白质溶出效果最佳,上清液中蛋白质浓度和蛋白质溶出率分别达6050 mg/L和84.33%。(4)热碱水解过程中剩余污泥蛋白质的转化规律研究。当热碱水解温度从80°C升高到100°C时,纤维素标准品水解程度大幅增加,产生大量单糖(还原糖),同时大分子蛋白质体积分数明显下降。依据UV254吸光度的变化,80°C对纤维素标准品造成焦糖化反应程度是微不足道的,与100°C相比,80°C更能有效抑制还原糖与酰胺(蛋白质、多肽、氨基酸)之间的美拉德反应,进而提高蛋白质回收率。在上述最佳水解温度下,剩余污泥中67.59%蛋白质从胞内释放溶出,32.41%蛋白质仍保留在污泥残渣中。其中,36.64%以可溶蛋白质形式存在,剩余30.95%蛋白质被分解或转化为其他小分子物质,如多肽、氨基酸、氨氮、硝态氮、挥发性脂肪酸以及未知物质。
[Abstract]:With the expansion of the treatment scale of the sewage treatment plant, the surplus sludge production of the by-products has been increasing, which has become one of the main problems facing the sewage treatment plant. The residual sludge contains a large amount of organic matter, such as protein, polysaccharide, nucleic acid, etc., in which the protein accounts for about 50% of the dry weight of the cell, and the protein in the surplus sludge can be hydrolyzed on the basis of the protein. In this study, the residual sludge of a sewage treatment plant in Wuxi Binhu District was taken as the treatment object, and the protein dissolution rate of the sludge as the evaluation index was used to study the basis of the study on the effect of hot acid and hot alkali hydrolysis on the protein dissolution of residual sludge. On the base of the study, the protein dissolution of residual sludge was hydrolyzed by combined enzyme method, and the best process conditions for the hydrolysis of residual sludge were obtained. Then, the protein and polysaccharide in the residual sludge were simulated with bovine serum protein and cellulose standard, and the dissolution, transformation and degradation of protein during the hydrolysis of alkaline hydrolysate could be remainder. The main research contents and results are as follows: (1) study on the hydrolysis of residual sludge based on protein recovery. When the hydrolysis of P H is 1, the reaction temperature is 125oC, the reaction time is 6 h and the sludge concentration is 30 g/L, the protein dissolution of residual sludge is the best, the protein in the supernatant The concentration and its dissolution rate are 1686 mg/L and 24.01%., respectively, under the optimum conditions of hot acid hydrolysis. 53.43% of the crude protein in the residual sludge can not be released from the cells in the sludge cells, and at the same time, it decomposes or transforms into other substances in varying degrees. Only 24.01% of the sludge is dissolved in the hydrolysate supernatant in the form of soluble egg white. (2) based on the egg. When the hydrolysis of P H is 12.5, the reaction temperature is 80oC, the hydrolysis time is 3 h and the sludge concentration is 30 g/L, the protein dissolution of the remaining sludge is the best, the protein concentration and the dissolution rate in the supernatant are 2436 mg/L and 42.24%., respectively, compared with the hot acid hydrolysis. The protein dissolution rate of sludge is better than that of 18.23%. At the same time, the hydrolysis time of the residual sludge is shorter and the cost is lower. (3) based on the enzymatic hydrolysis of residual sludge from protein recovery, the effect of alkaline protease and papain combined with hot alkali hydrolysis is better than that of the sludge. When the ratio of the two was at 1:12, the protein dissolution rate reached 81.84%. and the single enzymatic hydrolysis, the alkaline protease was mixed with papain, and the protein dissolution rate was increased by 48.02% and 34.81%. respectively than that of the two ones respectively. When the sludge concentration was 30 g/L, the dosage of the compound enzyme (alkaline protease: papain was 1:12) was 1%. When the system p H is 7 and the reaction temperature is 55oC, the enzyme solution is 2 h, the P H to 12.5 and the reaction temperature are 1.5 h under the reaction temperature 90oC, the protein dissolution of the residual sludge is the best, the protein concentration and the protein dissolution rate in the supernatant are 6050 mg/L and 84.33% respectively. (4) the residual sludge protein during the hot alkali hydrolysis process When the temperature of hot alkali hydrolysis increased from 80 C to 100 C, the hydrolysis degree of cellulose standard products increased greatly and produced a large number of monosaccharides (reducing sugar), while the volume fraction of large molecular proteins decreased obviously. According to the changes of UV254 absorbance, the degree of coke saccharification reaction of cellulose standard products at 80 degree C was negligible, and 100 degrees. Compared with C, 80 degree C can effectively inhibit the mallard reaction between reducing sugar and amide (protein, polypeptide, amino acid), and then increase protein recovery. At the best hydrolysis temperature, the 67.59% protein in the remaining sludge is released from the intracellular release, and the 32.41% protein remains in the sludge residue. Among them, 36.64% are soluble in protein form. In addition, the remaining 30.95% proteins are decomposed or converted to other small molecules, such as peptides, amino acids, ammonia nitrogen, nitrate nitrogen, volatile fatty acids and unknown substances.

【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

【参考文献】