本文提供了开发设计的关键假设和决策的基本原理 东湾厂内循环流处理系统的紫外线（UV）系统 市政公用事业区（EBMUD）核桃溪过滤水处理厂（WTP）。 分析结果如下: 隐孢子虫是循环流中紫外线灭活的目标病原体； 自由游动的病原体是紫外线剂量选择的基础； 系统的设计剂量为40 mJ/cm2； 可接受的紫外线系统 验证紫外线剂量和紫外线传感器响应， 密闭容器配置，以及 石英套管和紫外线传感器探头的机械清洗； 紫外线透射率为85%（254nm和10mm光程）； 当前条件下的资本成本约为110万美元；和 在当前条件下，每1000加仑的运行维护成本约为0.06美元。包括表格、数字。

This paper provides a rationale for key assumptions and decisions made to develop the design for the Ultraviolet (UV) system for the in-plant recycle stream treatment system at the East Bay Municipal Utility District (EBMUD) Walnut Creek Filtration Water Treatment Plant (WTP). Results of the analysis are as follows: Cryptosporidium is the target pathogen for UV inactivation in the recycle stream; free-swimming pathogens are the basis of UV dose selection; design dose for the system is 40 mJ/cm2; acceptable UV systems have validated UV dose and UV sensor response, closed-vessel configuration, and mechanical cleaning of quartz sleeves and UV sensor probes; UV transmittance of 85% (254 nm and 10 mm pathlength); approximate Capital Cost of $1.1 million for current conditions; and, approximate O&M Cost of $0.06 per 1,000 gallon for current conditions. Includes tables, figures.