加利福尼亚州文图拉县的Casitas市政供水区使用地表水供应饮用水，而目前仅提供消毒。根据地表水处理规则（SWTR），Casitas将被要求实施过滤处理。虽然Casitas的水质非常好，平均原水浊度小于1 NTU，大肠菌群和平板菌数非常低，但它无法满足联邦法规中的所有豁免标准。此外，加州卫生服务部（CDHS）正在开发自己的SWTR，该系统将要求所有地表水源都进行过滤，没有例外。 一项处理可行性研究建议使用在线过滤过程（仅限于凝固和过滤），包括臭氧作为预污染剂，氯胺作为残留消毒剂。这类工艺不是经批准的CDHS过滤工艺（即常规、直接、慢砂或硅藻土），因此需要进行初步研究，以证明与其中一种经批准的工艺等效。本文包括试点研究所采用的方法和程序、获得的结果以及相关结论。

The Casitas Municipal Water District in Ventura County, California uses a surface water supply for drinking water while currently providing disinfection only. As a result of the Surface Water Treatment Rule (SWTR), Casitas will be required to implement filtration treatment. Although Casitas has excellent water quality with average raw water turbidities less than 1 NTU and very low coliforms and plate counts, it cannot meet all of the exemption criteria in the federal rule. In addition, the California Department of Health Services (CDHS) is developing its own SWTR which will require all surface water sources to filter with no exceptions. A treatment feasibility study recommended that an in-line filtration process (coagulation and filtration only) be used including ozone as a predisinfectant and chloramines as a residual disinfectant. This type of process is not an approved CDHS filtration process (i.e. conventional, direct, slow sand, or diatomaceous earth), so a pilot study was required to prove equivalency to one of the approved processes. This paper includes the methods and procedures used for the pilot study, the results obtained, and relevant conclusions.