基于多源污泥泥质特性的处理技术路径探析

Treatment Technology Path Based on the Characteristics of Multi-source Sludge

对长江经济带典型城市污水污泥、通沟污泥、河湖底泥采集测试,分析其有机质、含砂量、热值、重金属、微量污染物等指标。结果表明:污水污泥有机质含量为30%~50%,热值一般在5 500~11 000 kJ/kgDS,污泥热值与有机质含量有较大关系,即有机质含量越多,污泥热值越高;污泥含砂量较高,养分含量为6%~8%,重金属含量较低,95%以上脱水污泥样品中的重金属含量远低于《农用污泥污染物控制标准》(GB 4284—2018)A级标准的限值,处于相对清洁水平;多环芳烃浓度较低,风险较小。通沟污泥成分复杂、有机质含量范围广,约5%~90%,通常热值和养分较低。河湖底泥有机质含量通常小于10%,热值不到1 000 kJ/kgDS,养分低。通沟污泥和河湖底泥重金属含量满足《土壤环境质量建设用地土壤污染风险管控标准(试行)》(GB 36600—2018)第一类筛选值,可用于生活居住地的建设用地。

The organic matter, sand content, calorific value, heavy metals, trace pollutants and other indicators of typical municipal sewage sludge, ditch sludge and sediment from rivers and lakes in the Yangtze River economic belt were collected and analyzed. The results showed that the organic matter content of sewage sludge was 30%-50%, and its calorific value was generally in the range of 5 500-11 000 kJ/kgDS;the calorific value of sewage sludge had a great relationship with the organic matter content, that was, the more the organic matter content, the higher the calorific value of sludge;the sand content was high, the nutrient content of sludge was 6%-8%;the heavy metal content was low, and the heavy metals in more than 95% of dehydrated sludge were far lower than the limit of class A criteria specified in the Control Standards of Pollutants in Sludge for Agricultural Use(GB 4284-2018), and at relatively clean level, with low concentration of PAHs and low risk. The composition of ditch sludge was complex, and the organic matter content ranged from 5% to 90%, which was usually low in calorific value and nutrients. The content of organic matter in sediment of river and lake was less than 10%, and the calorific value was low, less than 1 000 kJ/kgDS, with low fertility. The heavy metal content of ditch sludge and sediment of river and lake met the first category screening value of Soil Environmental Quality Risk Control Standard for Soil Contamination of Development Land(GB 36600-2018), which could be used for construction land of residential areas.