污泥预处理对微生物絮凝剂制备及性能的影响

试验研究了不同污泥预处理方法对微生物絮凝剂的制备及其絮凝性能的影响.结果表明,污泥经碱热预处理后释放的有机物质量最大,SCOD/TCOD可达到0.56.以碱热预处理污泥作为基质制备的微生物絮凝剂,其产量为2.3 g·L-1,高于热预处理的1.6 g·L-1,酸热预处理的0.6 g·L-1,以及未接种污泥絮凝剂的18 mg·L-1.采用响应面分析法对碱热预处理污泥制备的微生物絮凝剂与PAM复配改善污泥脱水的过程进行了优化,实验分别拟合了关于污泥比阻(SRF)和干污泥量(DS)的二次模型,决定系数(R2)分别为0.9057和0.9171,表明拟合情况良好.实验中最佳的污泥脱水条件为微生物絮凝剂投加量12.6 g·kg-1,PAM投加量1.0 g·kg-1,Ca Cl2投加量59.7 mg·L-1,p H值6.7,搅拌速度185r·min-1.在此条件下,DS和SRF分别为29.1%和2.2×1012m·kg-1,表明碱热预处理污泥制备的微生物絮凝剂与PAM的联合使用有助于改善污泥脱水性能.

Effects of sludge pre-treatments on the preparation and performances of bioflocculants from sludge

Effects of sludge pre-treatments on the preparation and performances of bioflocculants from sludge were investigated. Results showed that the organic quality released from sludge was the highest after the alkali-heat-treatment (ALT), with SCOD/TCOD reaching 0.56. Concentration of the bioflocculant from ALT sludge was 2.3 g·L^-1, which was higher than that from the sterilized (ST), acid-heat-treatment (ACT), and the unvaccinated sludge (1.6 g·L^-1, 0.6 g·L^-1, and 18 mg·L^-1, respectively). Response surface methodology was employed to optimize the sludge dewatering processes by the composite of bioflocculant from ALT sludge and PAM, with correlation coefficients (R²) of 0.9057 and 0.9171, the quadratic models of SRF and DS could well fit to experimental data. The optimal conditions for sludge dewatering were at the dosage of bioflocculant 12.6 g·kg^-1, PAM 1.0 g·kg^-1, CaCl₂ 59.7 mg·L^-1, pH=6.7, with an agitation speed of 185 r·min^-1. Under the optimal conditions, DS and SRF of the sludge reached 29.1% and 2.2×10¹² m·kg^-1, respectively, indicating that the sludge dewatering was greatly improved by the combination of the bioflocculant and PAM.