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bVater Treaiment Plant Production Study <br />SAFE DRINKING WATER ACT IMPLEMENTATION <br />GAEENBELT MUNICIPAL & INDUSTRIAL WATER AUTHORITY <br />Freese and Nichols, Inc was authorized by the GMIWA to assist the Authority in <br />conducting a plant evaluation to meet the Stagel Disinfection Byproduct Rule (Stage <br />1 DBPR) and Interim Enhanced Surface Water Treahnent Rule (IESWTR). The <br />Stage 1 DBPR and IFSWfR were promulgated on December 16, 1998 and the <br />compliance date for both regulations is set for the GMIWA on January Ol, 2002.1'he <br />IESWTR sets more stringent turbidity limits in the finished water to reduce the risk of <br />Cryptosporidium outbreaks in the distribution system. Also, continuous turbidity <br />monitoring for each filter is required by the IESWTR. The Stagel DBPR lowers the <br />existing total trihalomethanes (TTHMs) limit and set a new limit for haloacetic acids <br />(HAAs). [n addition, depending on raw water qualiiy, certain percentages of total <br />organic carbon (TOC) removal are required by this rule. <br />A principal area investigated with respect to TOC removal was the basic chemical <br />treatrnent process, coagulation using femc sulfate and alum. Promulgated Stagel <br />DBPR would likefy require the GM[WA WTP plant to operate in AEnhanced <br />Coagulation@ mode, increasing the cost of operation and possibly making turbidity <br />removal more difficult. The purpose of enhanced coagulation is to remove higher <br />percentages of TOC removal and reduce disinfection byproducts such as TTHMs <br />and HAAs. <br />The purpose of this report was to present the results of the enhanced coagulation jar <br />testing performed from Winter 1999 to Fa112000, and to develop a compliance plan <br />with respect to the TOC removal requirements, turbidity removal requirements, and <br />TTHMs and HAAs limits of the Stage 1 DBPR. <br />~ The STEP 1 TOC removal requirement could be obtained throughout the year with <br />varying alum and ferric sulfate doses. The STEP 2 TOC removal requirement and <br />F~REE3~ E'.•NI~NOA <br />EX/Sr/NG FILTFR - FIGURE 4. 1, the corresponding doses of alum and ferric sulfate were not obtained because the <br />PODR criteria could not be determined. The slopes of TOC versus coagulant doses <br />were always below -0.03. That indicates the raw water TOC is not amenab(e to <br />coagulation. <br />Inno~. i ~;p;.,,~c <br />PR! L3[ • NICHOLS <br />UNDERDRA/N <br />WIrH GRAVEL SUPPORTED MED/A <br />