06-I Water Production Study - Laserfiche WebLink

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Wciter Treatment Plant Production Study WATER TREATMENT PLANT EXPANSION CITY OF GRAPEVINE The Grapevine Water Treatrnent Plant cunenUy pzovides water to approximately 18,000 city residents. An expansion completed in 1990 enables the plant to treat up to 8.0 MGD. The original facility, constructed in 1959, had a capacity of 1.0 MGD. An expansion in 1980 and a variance granted by the Texas Natural Resource Conservation Commission (TNRCC) in 1987 raised the plant's capacity to 4.0 MGD. The 1990 expansion then doubled the plant's capaciiy to 8.0 MGD. The existing facilities were also refurbished to improve the overall appearance of the plant. Freese and Nichols designed the original ptant and subsequent expansions. Freese and Nichols, Inc. (FNI) was authorized by the City of Grapevine to conduct freatrnent plant evaluations for meeting the newly promulgated Stage 1 Disinfection Byproduct Rule (Stage 1 DBPR) and Interim Enhanced Surface Water Treatrnent Rule (IESWTR), especially the Total Organic Carbon (TOC) removal requirement of the DBPR. The Stage 1 DBPR and IESWTR were promulgated on December 16, 1998 and the compliance date for the City of Grapevine for both regulations is January Ol, 2002. The IESWI'R sets more stringent turbidity limits in the finished water to reduce the risk of Cryptosporidium outbreaks in the distribution system. Also, continuous turbidity monitoring for each filter is required by the IFSWTR. The Stage 1 DBPR lowers the existing total trihalomethanes (T"fHM) limit and set a new limit for haloacetic acids (HAAs). In addition, depending on raw water quality, a certain percent of TOC removal is required by this rule. A principal area investigated with respect to TOC removal was the basic chemical treatrnent process, coagulation using alum, and femc sulfate. Promulgated Stage 1 DBPR would require the City of Grapevine to operate in IRI.L51.-MCHOLS'