污泥干化芦苇床中的渗滤液水质变化特征

Characteristics of percolate quality variation in sludge drying reed beds

对3个中试规模的高有机质剩余污泥干化床中污泥渗滤液水质变化特征进行了为期2年的实验研究。Ⅰ单元作为对照床,未种植植物;Ⅱ单元和Ⅲ单元种植芦苇。Ⅰ单元和Ⅱ单元底部充填炉渣,通过穿孔PVC通风管与大气相连通,目的是通过床体填料空隙提供氧气。3个干化床按照如下周期运行:进泥大约半小时,闲置1周,污泥负荷平均为41.3kg TSS/(m2·a)。实验结果表明,污泥干化芦苇床去除污泥渗滤液中的有机物较传统干化床更有效,通风结构有利于有机物的降解;3个床体的污泥渗滤液总磷浓度均高于进泥,但两个芦苇床渗滤液总磷浓度较低,可能的原因是较传统干化床多了植物吸收作用。根据实验数据分析,3个床体中都发生了氨化、硝化和反硝化作用,单元Ⅲ获得了最高的总氮去除率30.38%,Ⅱ单元和Ⅰ单元获得的总氮去除率分别为25.47%和20.59%。高有机质剩余污泥渗滤液仍含有较高的污染物浓度,需回流至污水处理单元进行进一步处理。

A pilot scale experiment spent two years on three higher organic matter surplus activated sludge drying beds is presented. Bed 1 was unplanted, and considered as a control bed; bed 2 and bed 3 were planted with reeds. The bottoms of bed 1 and bed 2 were filled with slag, connected to the atmosphere through perforated PVC ventilation tubes in order to achieve oxygen diffusion through the overlying porous medium. The three beds were fed according to the following cycle ： about half of hour feeding with SAS at rate 41.3 kg TSS/（m2 ~ a） and resting for one week. The results show that planted sludge drying reed beds can more effectively remove organic matter from sludge percolate than unplanted drying bed, and ventilation contributes to degrading organic matter; the percolate total phosphorus concentrations in the three beds are higher than that of influent sludge, while two reed beds obtain lower percolate total phosphorus than bed 3, probably due to the role of plant adsorption. Am- moniation, nitrification and denitrification occurred in the beds, correspondingly, the bed 3 obtained the highest total nitrogen removal of 30.38% and the bed 2 and bed 1 obtained 25.47% and 20.59% , independently. The percolate of higher organic matter surplus activated sludge in the three beds contains higher pollutant concentra- tions, which need to be re-circulated and treated in the wastewater treatment units.