城镇污水处理厂污泥中磷的形态分布及生物可利用性分析

Fractionation and bioavailability of phosphorus in sludge from municipal wastewater treatment plants

以上海市2家污水处理厂为对象,对比了SMT法与碱性过硫酸钾消解（APPD）法对污泥总磷（TP）的提取效果,应用SMT法分析了污泥处理流程中磷赋存形态的变化规律,探究了污泥中生物可利用磷与TP的关系。结果表明,SMT法对污泥磷的提取较APPD法更为彻底,深度脱水污泥含磷量明显低于其他污泥。无机磷（IP）为污泥中磷的主要形态,占TP的62%以上;IP中又以磷灰石磷（AP）为主,特别是深度脱水污泥中,AP约占IP的90%。污泥中TP与生物有效磷和非磷灰石磷呈极显著正相关关系。深度脱水污泥中生物有效磷约占TP的20%,明显低于其他污泥的52%-66%。这表明,深度脱水污泥中磷潜在的生物可利用性较低,填埋处置的生态风险较低。

Sludge samples were collected from two municipal wastewater treatment plants（ WWTPs） in Shanghai. Extraction efficiencies for total phosphorus（ TP） from sludge by SMT and the alkaline potassium persulfate digestion（ APPD） method were compared. Variations in phosphorus fractions based on the sludge treatment process were analyzed by the SMT method. The relationship between bioavailable phosphorus and TP was also investigated. The results indicated that extraction of phosphorus by SMT was more complete than by the APPD method. The phosphorus content in ADS was considerably lower than in the other types of sludge. In all types of sludge samples,inorganic phosphorus（ IP） dominated the TP（ above 62%）,whereas apatite phosphorus（ AP） dominated the IP,especially in ADS,where AP accounted for 90% of IP. Both bioavailable phosphorus and non-apatite phosphorus had significant positive correlations with TP. The fraction of bioavailable phosphorus in ADS was 20% of TP,which was significantly lower than in the other types of sludge（ from 52% to 66%）.The results also indicated that phosphorus in ADS had low bioavailable potential,and therefore had low ecological risk for landfill disposal.