不同条件的底泥回流对强化絮凝的影响

为探究不同条件的回流底泥对絮凝强化的影响，采用智能光谱散射分析仪（IPDA）对絮凝过程进行连续监测。通过分析出水浊度和絮体生长曲线，考察了底泥投加量、存放时间和底泥pH对底泥强化作用的影响。结果表明:底泥投加量对于絮体生长FI值（絮凝指数）影响不大，回流单倍底泥时，出水浊度降至1.3 NTU，较常规絮凝下降38%；底泥存放时间越长，絮体生长FI值越小，存放时间<3 d的底泥可保证出水浊度维持在2.0以下；底泥pH为3.0时，出水浊度低至1.2 NTU，酸处理后的底泥，其絮体生长变化曲线不稳定，FI值呈明显震荡波动趋势。回流单倍底泥时，底泥能够强化絮凝的去浊能力，絮体颗粒保持较大尺寸。底泥形成24 h内回流，絮体颗粒之间产生的相互作用力最大，能保持底泥的最大活性。过高或过低的底泥pH导致絮凝效果变差，最适宜的底泥pH为3.0左右。

EFFECTS OF SLUDGE REFLUX UNDER DIFFERENT CONDITIONS ON FLOCCULATION STRENGTHENING

Sludge reflux can increase the flocculation core of the system and achieve the purpose of strengthening flocculation. In order to explore the effect of reflux sludge under different conditions on flocculation strengthening, intelligent photometric dispersion analyzer (IPDA) was used to continuously monitor the flocculation process. By analyzing the residual turbidity and floc growth curve, the effect of sludge dosage, storage time and sludge pH were studied. Results indicated that sludge dosage had little effect on the FI value of flocculation growth, and the residual turbidity decreased to 1.3 NTU and was 38% lower than that of the conventional flocculation. The longer the sludge storage time, the smaller the FI value of floc growth, and the remaining turbidity can be maintained below 2.0 NTU when the sludge was stored within 3 days. When the sludge pH was 3, the remaining turbidity was as low as 1.2 NTU. The curve of floc growth changed unstably corresponding to the sludge treated with acid, and FI value fluctuated obviously. When reflux of single sludge, the sediment could enhance the turbidity removal ability of flocculation, and the floc particles kept bigger size. The reflux of sludge formed within 24 hours was with the largest interaction force between the floc particles, and keep the maximum activity of the sludge. The flocculation effect became worse when the pH of the sludge was too high or too low, and the most suitable pH was about 3.0.