城市污泥特性及真空抽滤浓缩实验研究

对某城市6座污水处理厂污泥做真空抽滤浓缩,并对污泥特性进行了研究.结果发现,污泥中每g固体(TS)相当于1 g化学需氧量(COD);每g挥发性固体(VS)相当于1.5 g COD,其线性回归R2分别为0.931 4和0.922 8.污泥中携带的COD占污水去除COD总量的60%.污泥有机物组成表现为高蛋白质低脂肪特征.调查发现传统重力浓缩污泥浓度普遍低于3.3%,浓缩效率低.在真空度-34.7 kPa下的真空抽滤实验表明,浓缩速率受污泥种类、浓度、PAM分子量以及添加量的影响.其中,污泥种类对浓缩速率影响较大,初沉污泥干固体抽滤速率为31 ks/(m2·h),剩余污泥速度低于15 kg,(m2·h),重力浓缩污泥的抽滤浓缩速度达到43 kg/(m2·h).抽滤液悬浮固体浓度普遍低于1.5 g/L.

Characteristics of Municipal Sludge and Vacuum Filtration Thickening Process

It was found that sludge total solid (TS) concentration was equal to chemical oxygen demand (COD), while volatile solid (VS) was 1.5 times of COD concentration. R2 of linear regression of TS and VS with COD was 0.9314 and 0.9228 respectively. Total COD in sludge was approximately 60% of that removed in water treatment process. Sludge contained high level protein and low fat. The TS of present gravity thickening sludge was universally lower than 3.3%. Efficiency of vacuum filtration process was determined by sludge type, sludge solid concentration, PAM molecular weight and PAM addition dose. Under - 34.7 kPa pressure, sludge dry solid filtration thickening rate of primary sludge was up to 31 kg/(m2 x h). While, for wasted actived sludge the rate was lower than 15 kg/(m2 x h). Rate of gravity thickening sludge was up to 43 kg/(m2 x h). TS of vacuum filtrate were lower than 1.5 g/L.