Horan N J, Fletcher L, Betmal S M, Wilks S A, Keevil C W
School of Civil Engineering, The University, Leeds LS2 9JT, UK.
Water Res. 2004 Mar;38(5):1113-20. doi: 10.1016/j.watres.2003.12.004.
Conventionally treated sewage sludge may contain high concentrations of potentially pathogenic microorganisms and additional treatment is required to minimise the risks to health if it is to be recycled to agricultural land. Mesophilic anaerobic digestion (MAD) is the most widely used process in the UK for stabilising sludge prior to agricultural recycling, but little is known about the fate of a number of enteric pathogens as the sludge passes through the treatment processes. The aim of this study was to determine the efficiency of MAD in removing the bacterial enteric pathogens, Salmonella senftenberg, Listeria monocytogenes and Campylobacter jejuni which were added as a spike to the digester feedstock, together with the die-off of indigenous Escherichia coli already present in the sludge. The primary sludge digestion stage of MAD was found to achieve a log removal of 1.66 for E. coli, 2.23 for L. monocytogenes and 2.23 for S. senftenberg. However, the extent of die-off was a function of the numbers of pathogens in the feed and as these increased the log removal also increased. The numbers of C. jejuni were not affected by primary sludge digestion. Additional die-off was provided by secondary sludge digestion with log removals of 1.70 for E. coli, 2.10 for S. senftenberg and 0.36 for C. jejuni.
传统处理的污水污泥可能含有高浓度的潜在致病微生物，若要将其回收用于农业土地，则需要进行额外处理以降低对健康的风险。中温厌氧消化（MAD）是英国农业回收前用于稳定污泥的最广泛使用的工艺，但对于污泥在处理过程中多种肠道病原体的去向知之甚少。本研究的目的是确定MAD去除添加到消化器原料中的肠道致病菌（肠炎沙门氏菌、单核细胞增生李斯特菌和空肠弯曲菌）的效率，以及污泥中原本存在的大肠杆菌的死亡情况。发现MAD的初级污泥消化阶段对大肠杆菌的对数去除率为1.66，对单核细胞增生李斯特菌为2.23，对肠炎沙门氏菌为2.23。然而，死亡程度是进料中病原体数量的函数，随着这些数量的增加，对数去除率也会增加。空肠弯曲菌的数量不受初级污泥消化的影响。二级污泥消化提供了额外的死亡减少，对大肠杆菌的对数去除率为1.70，对肠炎沙门氏菌为2.10，对空肠弯曲菌为0.36。
