壳聚糖和溶菌酶联用强化污泥脱水性能研究

发布时间：2018-05-20 18:29

  本文选题：壳聚糖 + 溶菌酶　； 参考：《湖南大学》2015年硕士论文

【摘要】：本文以强化活性污泥沉降及脱水性能为目标,研究了壳聚糖和溶菌酶联合调理污泥对污泥沉降性能、脱水速度以及脱水程度的影响,确定了壳聚糖和溶菌酶最佳投加量、最优加药方式及最优实验条件。实验通过测量污泥Zeta电位、分析和研究污泥絮体形态结构以及污泥上清液SMP的EEM光谱,对污泥脱水机理进行了初步探讨。壳聚糖作为弱阳离子型高分子絮凝剂,可以显著改善污泥的沉降性能,联用时可以克服溶菌酶调理污泥导致污泥沉降性能变差的缺点。通过单因素及正交实验确定了壳聚糖的最佳投加量为0.01g/gDS,溶菌酶最佳投加量为0.10g/gDS,最优加药次序为壳聚糖+溶菌酶联用调理污泥。在此条件下,污泥初期沉降速度达到7.13mm/min左右,相比原泥提高将近14倍,真空抽滤泥饼含水率降至为71.3%,污泥比阻降至0.25×1 012m/kg,比原泥分别下降了23.3%和95.8%。此外,通过实验还进一步确定了壳聚糖和溶菌酶联用调理污泥时的最优实验条件：污泥最佳浓度范围为15000-25000mg/L,最佳调理温度为30℃,最佳调理pH值为7。通过观测发现,污泥Zeta电位、絮体形态结构、分形维数和EPS对污泥沉降及脱水性能具有重要影响。由于壳聚糖和溶菌酶分子均含有阳离子氨基基团,适量的壳聚糖和溶菌酶调理可以压缩污泥双电层,降低污泥吲电位。0.01g/gDS壳聚糖+0.10g/gDS溶菌酶联用时污泥(?)电位由原泥的4.23mV降低至0.28mV,促进了污泥脱稳、絮凝。未经药剂调理的污泥絮体细小分散,二维分形维数D2值仅为1.48；壳聚糖的絮凝作用使得污泥胶体絮凝形成硕大絮体,污泥絮体颗粒D2值升至1.69,但絮体结构疏松,内部存在较多孔隙；溶菌酶调理进一步压缩污泥絮体,减少絮体内部孔隙,因此两者联用调理时污泥絮体大而致密,D2值升至最大值1.74,污泥沉降、脱水速度变快。对污泥上清液溶解性有机物SMP的EEMs分析表明,SMP的主要成分为类蛋白质、类腐殖质和类富里酸,其荧光特征峰中心位置分别在(Ex/Em=280/350)、(Ex/Em=290/370)、(Ex/Em=230/385、360/450)附近。污泥经壳聚糖调理后类蛋白荧光峰强度变化不大,而经壳聚糖+溶菌酶调理后类蛋白荧光峰强度相对原泥增加25.8%。实验结果表明,壳聚糖调理主要对污泥胶体颗粒起脱稳、絮凝作用,不会改变污泥溶液中的有机物质成分；溶菌酶调理时,一方面通过溶胞作用致使大量与细胞分泌有关的色氨酸类蛋白质溶出,同时胞内水分也流出,另一方面改变了EPS成分组成和结构,导致EPS中的类蛋白物质溶出并扩散到污泥上清液中形成SMP物质,同时也使EPS束缚的水分释放。因此先投加壳聚糖调理污泥时,胶体颗粒凝聚形成了大颗粒絮体,再经溶菌酶调理破坏污泥细胞壁结构,改善污泥EPS成分组成和结构,释放微生物细胞内水分和EPS束缚的水分,从而显著改善污泥脱水性能。
[Abstract]:In order to enhance the sedimentation and dewatering performance of activated sludge, the effects of chitosan and lysozyme on sludge sedimentation, dewatering rate and dewatering degree were studied, and the optimum dosage of chitosan and lysozyme was determined. Optimal dosing method and optimal experimental conditions. By measuring sludge Zeta potential, analyzing and studying the morphological structure of sludge floc and the EEM spectrum of sludge supernatant SMP, the mechanism of sludge dehydration was preliminarily discussed. Chitosan as a weak cationic macromolecule flocculant can significantly improve the settling performance of sludge and can overcome the shortcoming of sludge sedimentation caused by lysozyme conditioning sludge. The optimum dosage of chitosan and lysozyme was 0.01g / g DS and 0.10g / g DS by single factor and orthogonal experiment respectively. The optimal dosage order was chitosan lysozyme combined with sludge conditioning. Under these conditions, the initial settling rate of sludge reached about 7.13mm/min, which was nearly 14 times higher than that of raw sludge. The water content of vacuum filter cake was reduced to 71.3%, and the specific sludge resistance was decreased to 0.25 脳 10 12 m / kg, which was 23.3% and 95.8% lower than that of raw sludge, respectively. In addition, the optimum conditions of sludge conditioning with chitosan and lysozyme were determined: the optimum concentration range of sludge was 15000-25000mg / L, the optimum conditioning temperature was 30 鈩，

本文编号：1915761