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VJater Treatment Plant Production Study <br />SAFE DRINKING WATER ACT COMPLIANCE <br />CITY OF LONGVIEW <br />Freese and Nichols, Inc. was authorized by the City of Longview to conduct <br />treatrnent plant evaluations for the Sabine Water Treatrnent Plant (16 MGD) and the <br />Cherokee Water Treatrnent Plant (27 MGD) in order to meet the newly promulgated <br />Stage 1 Disinfection Byproduct Rule (Stage 1 DBPR) and Interim Enhanced Surface <br />Water Treatrnent Rule (IESWTR); especially the TOC removal requirement of the <br />DBPR. The Stage 1 DBPR and IESWfR were promulgated on December 16, 1998 <br />and the compliance date for the City of Longview for both regulations is January Ol, <br />2002. The IESW'I'R sets more stringent turbidity limits in the finished water to reduce <br />the risk of Cryptosporidium outbreaks in the disfibution system. Also, continuous <br />turbidity monitoring for each filter is required by the IFSWT'1?. The Stage 1 DBPR <br />lowers the exisfing total trihalomethanes'(TTHM) limit and set a new limit for <br />haloacetic acids (HAAs). In addition, depending on raw water quality, a certain <br />percent of total organic carbon (TOC) removal is required by this rule. <br />kT~CFD COAGULATIUV'IP_Sl5 Bl' NYI'EN IO\ 7502A <br />A principal area investigated with respect to TOC removal was the basic chemical <br />Sewtl Qmrter <br />l" treatrnent process, coagulation using alum, Polymer Blend "A" and Polymer Blend <br />- a•1nRTM -I " "B°. The two polymer chemicals are made by a single manufacturer. Promulgated <br />0.W wT1tiR ALIULW fM1 = Il inyl. v <br />Stage 1 DBPR would require the City of Longview to operate both water plants in <br />SI~'IiXRCNOYAL1194 fu <br />"Enhanced Coagulation" mode, increasing the cost of opemtion and possibly <br />--.•o~ making turbidity removal more difficult. The purpose of enhanced coagulation is to <br />.neP2z " achieve higher percentages of TOC removal and reduce disinfection byproducts such <br />........ICCRF.MPYALIiIKI <br />as TTHMs and HAAs. <br />• _ <br />WRF.~16J .n <br />~ The second area of the study was a preozonation evaluafion, to assess the potential <br />following benefits in water heatment: <br />-~M• ~ Improves turbidity removal <br />~ Improves color removal <br />♦ Improves taste and odor reduction <br />~ Conh-ols chlorination byproducts such as TTHMs and HAAs <br />♦ Stronger disinfectant than other commonly used disinfectants <br />I-RYI55C-NICHOLS <br />