Crockett Christopher S
Philadelphia Water Department, Office of Watersheds, 1101 Market Street, 4th Floor, Philadelphia, PA 19107, USA.
Water Environ Res. 2007 Mar;79(3):221-32. doi: 10.2175/106143006x111952.
Traditionally, regulators, dischargers, and even water suppliers believed that wastewater discharge meeting the levels of 200 cfu/ 100 mL of fecal coliforms in wastewater effluent was sufficient to protect against downstream microbial effects. However, these beliefs are now being challenged by emerging pathogens that are resistant to standard water and wastewater treatment processes, exhibit extended survival periods in the environment, can adversely affect sensitive subpopulations, and require extremely low doses for human infection. Based on this new information, it is estimated that discharges of emerging pathogens from conventional wastewater treatment plants as far as 160 km upstream and cumulative amounts of wastewater discharge ranging from 2 to 20 ML/d have the potential to reach a water supply intake in a viable state at significant concentrations that could exceed regulatory limits for drinking water supplies, increase endemic risk from drinking water, and/or require additional drinking water treatment. Wastewater dischargers may be able mitigate this potential effect and achieve upwards of 6 log combined removal and inactivation of emerging pathogens to mitigate drinking water effects by using alternative treatment processes, such as filtration or UV light disinfection, or optimizing these processes based on site-specific conditions.
传统上，监管机构、排放者甚至供水企业都认为，废水排放中粪便大肠菌群含量达到200 cfu/100 mL的水平足以防止对下游产生微生物影响。然而，这些观念现在正受到新出现病原体的挑战，这些病原体对标准的水和废水处理工艺具有抗性，在环境中的存活期延长，会对敏感亚群产生不利影响，并且只需极低剂量就能使人感染。基于这些新信息，据估计，传统污水处理厂排放的新出现病原体在上游160公里处、日累计废水量在2至20立方米的情况下，有可能以相当高的浓度达到饮用水取水口，其浓度可能超过饮用水供应的监管限值，增加饮用水的地方病风险，和/或需要额外的饮用水处理。废水排放者可以通过使用替代处理工艺，如过滤或紫外线消毒，或根据现场特定条件优化这些工艺，来减轻这种潜在影响，并实现对新出现病原体6个对数级的综合去除和灭活，以减轻对饮用水的影响。
