深度脱水污泥掺混土壤改性及资源化技术研究

Modification and Resource Utilization of Advanced Dewatered Sewage Sludge with Blending Soil

为实现深度脱水污泥的改性和资源化利用,以上海某城市污水处理厂的两种不同含水率的深度脱水污泥A和B为例,通过向污泥中掺混土壤,研究土壤对污泥含水率、有机质、抗压强度、恶臭和植物毒性等的影响,探索其用作填埋场封场覆盖绿化用土的可行性。结果表明,掺混土壤可明显降低污泥含水率、有机质和臭气强度,并显著提高其抗压强度和种子发芽率,且相关性分析表明,土壤对污泥的有机质、臭气强度和浸出液种子发芽率的改善效果较强;当土壤添加量分别为60%和30%时,污泥A和B的抗压强度可分别由32.99kPa和196.67kPa的初始值增加至117.6kPa和227.5kPa,臭气强度可由4.5级和4级下降至2级和1.5级,浸出液白菜种子发芽率可由50%和56.7%增加至90%和80%。改性后的污泥A和B均能满足填埋场封场覆盖绿化用土的要求,实现其资源化利用。

Two types of advanced dewatered sludge A and B with different moisture contents from a municipal sewage treatment plant in Shanghai were modified by mixing them with soil.The characteristics of blended sludge in terms of moisture content,organic matters content,compressive strength,odor,and phytotoxicity were analyzed to study the feasibility of sludge as landfill cover material.The results showed that the blended soil effectively reduced moisture content and organic matters,enhanced compressive strength,and weakened odor and phytotoxicity of dewatered sludge.The correlation analysis showed that soil had a much stronger effect on organic matters,odor and phytotoxicity.The compressive strength increased from the initial 32.99 kPa and 196.67 kPa to 117.6 kPa and 227.5 kPa,odor intensity dropped from level 4.5 and 4 to level 2 and 1.5,and lixivium cabbage seed germination rate raised from 50% and 56.7% to 90% and 80%,when soil addition dosages were 60% and 30% for sludge A and B,respectively.The modified sludge A and B could both meet the requirements of final landfill cover material set in China,and thus could be used directly.