本专栏总结了美国环境保护局（USEPA）去年11月发布的长期2强化地表水处理规则（LT2ESWTR）提案草案。LT2ESWTR的目标是确保地表水系统的所有客户都受到同等保护，免受氯抗性密码的影响，方法是对其水源水中高于正常密码水平的过滤系统施加额外的处理要求，并要求未过滤系统提高其当前对贾第虫和病毒的消毒性能，以杀死或杀死贾第虫否则也可以解除加密病毒的毒。尽管监管协议的签署者能够为15种治疗和管理方案推荐量化的原木清除和灭活信用，但他们将每个方案的具体设计和实施标准留给美国环保局制定。 该草案是该机构首次披露其关于这些标准的结论，本专栏将对此进行讨论。包括桌子。

This column summarizes a draft proposal of the Long-Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) released last November by the US Environmental Protection Agency (USEPA). The objective of the LT2ESWTR is to ensure that all customers of surface water systems are equally protected against chlorine-resistant crypto by imposing additional treatment requirements on filtered systems with higher-than-normal crypto levels in their source waters and by requiring unfiltered systems to boost their current disinfection performance against Giardia and viruses to kill or otherwise detoxify crypto as well. Although signers of the regulatory agreement were able to recommend quantified log removal and inactivation credits for 15 treatment and management options, they left it up to USEPA to develop specific design and implementation criteria for each option. The draft is the first time the agency has disclosed its conclusions regarding these criteria, which are discussed in this column. Includes tables.