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<br />~~t-'=.c_! re_0,:"en!~? nt Prod uc!i()~_ Study________________________ _______ <br /> <br />~~~~~~~.,~::"~2.~:'i:.~~~~_of:::_:....::::..~~':'::.::..".,.,_.=:2:_~r~:'~~~~~-- ,~--.~'~:..~'-~,-~~:.:~:::..-:::,-~:'--~~~~~~~~~..............~~-.:..~'~ ----- <br /> <br />-~-~ <br /> <br />SAFE DRINKING WATER ACT IMPLEMENTATION <br /> <br />GREENBELT MUNICIPAL & INDUSTRIAL WATER AUTHORIlY <br />Freese and Nichols. Inc was authorized by the GMIWA to assist the Authority in <br />conducting a plant evaluation to meet the Stage 1 Disinfection Byproduct Rule (Stage <br />1 DBPR) and Interim Enhanced Surface Water Treatment Rule (IESWfR). The <br />Stage 1 DBPR and IESwrR were promulgated on December 16,1998 and the <br />compliance date for both regulations is set for the GMIWA on January 01, 2002. The <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 IESWfR. The Stage! DBPR lowers the <br />existing total trihalomethanes (TIHMs) limit and set a new limit for haloacetic acids <br />(HAAs). In addition, depending on raw water quality, certain percentages of total <br />organic carbon (TOC) removal are required by this rule. <br /> <br />A principal area investigated with respect to TOC removal was the basic chemical <br />treatment process, coagulation using ferric sulfate and alum. Promulgated Stage! <br />DBPR would likely require the GMIWA 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 TIHMs <br />and HAAs. <br /> <br />The purpose of this report was to present the results of the enhanced coagulation jar <br />testing performed from Winter 1999 to Fall 2000, and to develop a compliance plan <br />with respect to the TOC removal requirements, turbidity removal requirements, and <br />TIHMs and HAAs limits of the Stage 1 DBPR. <br /> <br /> <br /> <br />.... <br /> <br />UNDERORAlNS BENEATH <br />GRAvEL SUPPORTED MEDIA <br />lTERED <br />CHANNEL <br />UNDERDRAIN <br />WITH 'RA l.1 <br /> <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 />the corresponding doses of alum and ferric sulfate were not obtained because the <br />PO DR 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 amenable to <br />coagulation. <br /> <br />, <br />i <br />VIA! <br /> <br /> <br />FIGURE 4. 1 <br /> <br /> <br />- <br /> <br />.EXISTING_ FlLTER_ <br /> <br />.. <br />FREESE-NICHOLS <br />....u.....".......,..........zoo <br />r.-l ---. '-- '.I"....e <br />8".'.-uoo <br />._._.,._---_..__.~-- <br /> <br /> <br />I III o'/cliil/c' Approoche:;.,. Procticc! <br />