EVALUATION OF TEMPERATURE AND SYSTEM CONDITIONS ON DBP FORMATION IN SURFACE WATER USING THE RAPID BENCH SCALE MEMBRANE TEST FOR ICR TREATMENT STUDIES

摘要

The Information Collection Rule (ICR) was published in the Federal Registerrnon May 14, 1996, and will require some public water supplies to conduct DBPrn(Disinfection By-Product) precursor removal studies (i.e. treatment studies)rnbeginning in May 1998 (1). The objective of these treatment studies is tornprovide the EPA with cost and performance data using either membranernprocesses or granular activated carbon (GAC) in order to meet the Stage 2rnDBP maximum contaminant levels (MCLs) for the sum of the fourrntrihalomethanes (THMs) at 40 ug/L and the sum of the five haloacetic acidsrn(HHA5) at 30 ug/L. The Rapid Bench Scale Membrane Test (RBSMT) will bernrequired for utilities with treated water total organic carbon (TOC) above 6-8rnmg/L.rnThe ICR Manual for Bench-and-Pilot Scale Treatment Studies states that therntreatment study feed water collected for the RBSMT must be representativernof the source under investigation. A volume of 90 to 110 gallons of waterrnmust be collected for the test. The initial chemistry water quality parametersrnthat must be taken into account in order to assess pretreatment of therninfluent water to the RBSMT are listed in Table 2. Since many of thesernanalytes are in EPA methods that require immediate cooling of the sample torn4℃, sample transportation in a temperature-controlled environment wouldrnbe necessary. The result is increased cost and additional problems withrnmonitoring and maintaining a constant temperature during transport of arnlarge volume of water.rnIt is unclear in the ICR Manual whether the SDS procedure is required forrnthe RBSMT or if UFC can be used or modified to provide constant chlorinationrnconditions to allow for the assessment of DBP breakthrough patterns in arnPWS. If SDS conditions are required it will be difficult for laboratories tornperform because SDS conditions change over time and if several bench-scalernsamples from different utilities are being evaluated simultaneously, each willrnrequire a specific incubation temperature, incubation time, pH, and finalrnchlorine residual.rnThe two issues under study in this paper are 1) the effects of samplerntransportation temperature on the integrity of source water used in thernRBSMT treatment studies and 2) a comparison between the DBPs formedrnunder actual plant conditions (simulated distribution system conditions-SDS)rnand those formed under the standard UFC (uniform formation conditions).rnA representative surface water sample was chosen for the studies. For the