No person shall discharge wastewater that does not comply with the following
limits:
Oil/Grease equal to or less than 94 mg/L.
pH equal to or greater than 5.0 S.U.
pH equal to or less than 9.0 S.U.
BOD equal to or less than 250 mg/L.
COD equal to or less than 368 mg/L.
SS equal to or less than 250 mg/L.
If, in the judgment of the City Water Reclamation Center Superintendent or the Pretreatment Coordinator, any industrial/commercial user activity requires City monitoring and/or sampling and/or laboratory analytical services at regular established intervals or as a result of specific events, then the user shall be surcharged in accordance with Section 916.11(b)(7) to cover the City's associated labor and material consumption costs. The user may opt to hire, at the user's expense, an EPA approved commercial laboratory to perform any or all of the required monitoring, sampling, or analyzing. If such a commercial lab is used, the user(s) shall, at the user's expense, ensure that the commercial lab sends or delivers a copy of the analytical results to the Water Reclamation Center.
If analysis reveals a user's discharge exceeds the following domestic average
concentrations, d,
d = BOD = 250 mg/L, and/or
d = COD = 368 mg/L, and/or
d = SS = 250 mg/L,
then the Water Reclamation Center Superintendent or the Pretreatment Coordinator shall determine if the City treatment system has enough excess capacity to treat the high strength waste without jeopardizing the system. If not, the user shall comply with the limits established herein. If yes, the user shall be given the option of discharging to the City sanitary sewer subject to limitations (if required) as determined by the Water Reclamation Center Superintendent or the Pretreatment Coordinator. If given the option and the user chooses to discharge to the City sanitary sewer, then the user shall be surcharged in accordance with Section 916.11(b)(7) for the additional costs associated with treating the high strength wastewater.
The surcharge shall be computed as follows:
Define the following variables as shown.
SC = surcharge
TMC = time and material charge
TC = t reatment charge
CSR = City sewage rate
Gs = gallons subject to surcharge (daily discharge or daily batch volume)
WS; = waste strength
RF = risk factor
r = risk coefficient, 1 r 10, base value r = 1.0
DF = plant's design flow in gallons/day
AF = plant's average daily flow in gallons
ECR = excess capacity reduction due to user
h = duration of discharge in hours
L = plant’s design limit parameter concentration in mg/L
d = average domestic/background parameter concentration in mg/L
p = plant’s average parameter concentration in mg/L
u = user’s parameter concentration in mg/L
Let
SC = TMC + TC
where TC = CSR/748 x Gs x WS x RF WS = [(u/d) - 1] RF = [r/(1-ECR)] ECR = Gs (u) [sqrt(24/h)]/[(DF x L) - (AF x p)] and u d, (DF x L) > (AF x p), 1 h 24 |
The plant’s average parameter concentration, p, may be a daily, monthly or yearly average. The averaging period for each parameter shall be determined by the Water Reclamation Center.
In situations where operational considerations indicate that the risk coefficient r, shall be set at a value other than the baseline value defined herein, the Water Reclamation Center shall provide recommended values.
To minimize complexity, the Water Reclamation Center shall use the above general formula and substitute the appropriate values for TMC, CSR, DF, AF, r, L, d and p. The resulting equations shall then be incorporated into an Administrative Memo to establish specific surcharges. Labor costs shall reflect pay rates and the cost of fringe benefits. An administrative charge of fifteen percent (15%) shall be added to the TMC portion of the surcharge. The values used for CSR, r and p shall be explicitly stated. The averaging periods shall also be explicitly stated. This Memo shall be updated by the Water Reclamation Center as required to keep surcharges current. The Memo and all subsequent updates shall become effective when signed by the City Manager.
(Ord. 61-93. Passed 9-20-93.)