Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing 210095, China.
Sci Total Environ. 2019 May 15;665:1073-1082. doi: 10.1016/j.scitotenv.2019.02.174. Epub 2019 Feb 12.
Conditioning treatments are extensively employed in wastewater treatment plants (WWTPs) to enhance sludge dewaterability, thereby improving the sludge dehydration during mechanical dewatering. However, it remains unclear whether the sludge conditioning treatments would influence the removal of polycyclic aromatic hydrocarbons (PAHs) during the dewatered sludge composting. In this study, the influences of three sludge conditioning methods, including bioleaching conditioning driven by Acidithiobacillus ferrooxidans, chemical conditioning with Fe[III]/CaO, and chemical conditioning with polyacrylamide (PAM), on the bioavailability of PAHs in dewatered sludge and the PAH removal during the co-compositing of industrial and municipal sewage sludges were investigated. The results showed that bioleaching conditioning was capable to significantly increase the bioavailability of PAHs in dewatered sludge, which was not attained by the other two conditioning methods. During the 39 days composting of dewatered sludge, the total removal efficiency of six detected PAHs (∑PAHs) including acenaphthylene, fluorene, phenanthrene, anthracene, chrysene and benzo(k)fluoranthene was 58.7% in raw sludge, 58.5% in PAM-conditioned sludge, 76.4% in bioleached sludge, and 60.4% in Fe[III]/CaO-conditioned sludge, respectively, and the removal of acenaphthylene, chrysene and benzo(k)fluoranthene was much higher in bioleached sludge than in other sludges. During dewatered sludge composting, PAHs may mainly be degraded by the bacteria belonging to the genera Luteimonas, Glutamicibacter, Alcanivorax, Dechloromonas, Ferribacterium, Truepera and Sphingobacterium. Linear correlation analysis between PAH removal and their bioavailability revealed that the promoted PAH removal during the composting of dewatered bioleached sludge may ascribe to the enhanced bioavailability of individual PAH. Therefore, the combination of bioleaching conditioning and subsequent dewatered sludge composting is effective to remove PAHs in sewage sludge, thus alleviating the loads of PAHs during the land application of sludge compost products.
调理处理在废水处理厂（WWTPs）中广泛应用，以提高污泥的脱水性能，从而改善机械脱水过程中的污泥脱水效果。然而，目前尚不清楚污泥调理处理是否会影响脱水污泥好氧堆肥过程中多环芳烃（PAHs）的去除。在这项研究中，考察了三种污泥调理方法，包括嗜酸氧化亚铁硫杆菌驱动的生物沥滤调理、Fe[III]/CaO 化学调理和聚丙烯酰胺（PAM）化学调理，对脱水污泥中 PAHs 的生物可利用性以及工业和城市污水污泥共堆肥过程中 PAHs 的去除的影响。结果表明，生物沥滤调理能够显著提高脱水污泥中 PAHs 的生物可利用性，而其他两种调理方法则不能。在脱水污泥 39 天的堆肥过程中，在原始污泥中，六种检测到的 PAHs（∑PAHs）包括苊烯、芴、菲、蒽、荧蒽和苯并[k]荧蒽的总去除效率为 58.7%，在 PAM 调理污泥中为 58.5%，在生物沥滤污泥中为 76.4%，在 Fe[III]/CaO 调理污泥中为 60.4%，生物沥滤污泥中苊烯、荧蒽和苯并[k]荧蒽的去除率明显高于其他污泥。在脱水污泥堆肥过程中，PAHs 可能主要被属于 Luteimonas、Glutamicibacter、Alcanivorax、Dechloromonas、Ferribacterium、Truepera 和 Sphingobacterium 属的细菌降解。PAH 去除与生物可利用性之间的线性相关分析表明，在脱水生物沥滤污泥堆肥过程中促进 PAH 去除的原因可能是个别 PAH 的生物可利用性增强。因此，生物沥滤调理与后续脱水污泥好氧堆肥相结合，可有效去除污水污泥中的 PAHs，从而减轻污泥堆肥产品土地应用过程中 PAHs 的负荷。
