Science and Technology Branch, Environment Canada, 867 Lakeshore Rd., P.O. Box 5050, Burlington, ON L7R 4A6, Canada.
Water Res. 2013 Nov 1;47(17):6496-505. doi: 10.1016/j.watres.2013.08.022. Epub 2013 Sep 2.
Polybrominated diphenyl ether (PBDE) flame retardants have been consistently detected in sewage sludge and treated biosolids. Two hundred and eighty-eight samples including primary sludge (PS), waste biological sludge (WBS) and treated biosolids from fifteen wastewater treatment plants (WWTPs) in Canada were analyzed to investigate the factors affecting accumulation of PBDEs in sludge and biosolids. Factors examined included environmental/sewershed conditions and operational parameters of the WWTPs. PBDE concentrations in PS, WBS and treated biosolids were 230-82,000 ng/g, 530-8800 ng/g and 420-6000 ng/g, respectively; BDE-209,-99, and -47 were the predominant congeners. Concentrations were influenced by industrial input, leachate, and temperature. Several examinations including the measurement of BDE-202 indicated minimal debromination during wastewater treatment. Estimated solids-liquid distribution coefficients were moderately correlated to hydraulic retention time, solids loading rate, mixed liquor suspended solids, solids retention time, and removal of organic solids, indicating that PBDE partitioning to solids can be optimized by WWTPs' operational conditions. Solids treatment type strongly affected PBDE levels in biosolids: 1.5 times increase after solids digestion, therefore, digestion efficiency could be a potential factor for variability of PBDEs concentration. In contrast, alkaline treatment reduced PBDE concentrations in biosolids. Overall, mass balance approaches confirmed that PBDEs were removed from the liquid stream through partitioning to solids. Variability of PBDE levels in biosolids could result in different PBDEs burdens to agricultural land, and different exposure levels to soil organisms.
多溴二苯醚（PBDE）阻燃剂在污水污泥和处理生物固体中一直被检测到。分析了加拿大 15 个污水处理厂（WWTP）的 288 个样本，包括初沉污泥（PS）、废生物污泥（WBS）和处理生物固体，以研究影响污泥和生物固体中 PBDE 积累的因素。检查的因素包括环境/污水流域条件和 WWTP 的操作参数。PS、WBS 和处理生物固体中的 PBDE 浓度分别为 230-82000ng/g、530-8800ng/g 和 420-6000ng/g；BDE-209、-99 和-47 是主要的同系物。浓度受工业投入、渗滤液和温度的影响。包括测量 BDE-202 在内的几次检查表明，在废水处理过程中几乎没有脱溴。估计的固液分配系数与水力停留时间、固体负荷率、混合液悬浮固体、固体停留时间和有机固体去除率中度相关，表明 PBDE 与固体的分配可以通过 WWTP 的操作条件进行优化。固体处理类型强烈影响生物固体中的 PBDE 水平：固体消化后增加 1.5 倍，因此，消化效率可能是 PBDE 浓度变化的潜在因素。相比之下，碱性处理降低了生物固体中的 PBDE 浓度。总体而言，质量平衡方法证实 PBDE 通过分配到固体中从液体流中去除。生物固体中 PBDE 水平的变化可能导致农业用地的 PBDE 负担不同，以及土壤生物的暴露水平不同。
