Laserfiche WebLink
u <br />cO:.ORe1D0 DEPART:SEYT OF HEALTH f <br />Water Quality Control Division <br />Rationale - Page 14 <br />Permit No.: CO-0038776 <br />C2 recuired TRC concentration is WWT? discharge to meet the <br />proposed instream standard of .003 mg/L unknown <br />Q3 = Q downstream of WWTP 21.31 MGD <br />C3 = downstream TRC concentration (proposed Water Quality standard)=,003 mg/1 <br />C2 (21.31 :SCD) (.003 mg/1) - (21.3 i1GD) (0.0 ma/1) 6.4 mg/L <br />0.01 MGD <br />An effluent limitation of 0.5 mg/1 TRC will be specified in the <br />permit, since the maximum allowable effluent limitation for TRC under <br />the state effluent standards is 0.5 mg/1. <br />C. Fecal Caliform Bacteria <br />The following mass balance vas used for evaluation of this effluent <br />Li.m1C: <br />Q3C3 ' Q1C1 + Q2C2 ' Q3C3-Q1C1 <br />~' <br />where <br />Q1 Q7-10 upatream ~ 33.0 cfs ~ 21.3 YGD <br />n <br />LJ <br />Cl = maximum background fecal coliform concentration upstream 93 <br />org./100 ml <br />Q2 = design flow from ARCO WIiTP = O.C1 MCD <br />C2 = required fecal coliform concentration is wti7TP discharge to meet <br />proposed instream concentrations of 200 organisms/100 ml = unknown <br />Q3 Q downstream of WWTP = Q1+Q2 = 21.31 MCD <br />C3 dowstream proposed fecal coliform concentration ~ 200 <br />organisms/loo ml <br />C2 = (21.31)(200)-(21.3)(93) ~ 228,000 organisms/100 ml <br />.O1 <br />In accordance with the State Fecal Coliform Policy, the maximum 30-day <br />average fecal coliform effluent limitation which is allowed from domestic <br />WWTP discharges is 6000 organisms per 100 ml. Thus, the fecal coLiform <br />limits to be included is this permit are 6000/12000 organisms per 100 ml. <br />• <br />