(A) State requirements. State requirements and limitations on discharges to the POTW shall be met by all dischargers which are subject to such standards in any instance in which they are more stringent than federal or local requirements and limitations.
(B) Supplementary limitations — discharge limits - local limits.
(1) No user shall discharge wastewater containing concentrations (and/or mass limitations) in excess of the following:
Material Concentration (mg/l)
Conventional Pollutants
Ammonia 51
BOD5 900
Total Suspended Solids 625
FOG 200
TPH 49
Phosphorus 27
Material Concentration (µg/l)
Nonconventional Pollutants/upper limits:
METALS
Arsenic 60
Cadmium 90
Copper 950
Cyanide 130
Chromium, Total 2,700
Chromium, Hexavalent 280
Lead 570
Mercury *(LOD)
Molybdenum 780
Nickel 930
Selenium 150
Silver 43
Zinc 3,700
ORGANICS
1,4-Dichlorobenzene 24
Chloroform 50
Lindane 0.5
Benzene 8
Toluene 24
Ethyl Benzene 31
Xylenes, Total 44
Methylene Chloride 41
Tetrachloroethylene 5
Trichloroethylene 21
1,1,1- Trichloroethane 16
* The local discharge limitation for mercury is established at the level of detection (LOD) in accordance with the following:
There shall be no detectable amounts of mercury discharged into the publicly owned treatment works (POTW). Mercury sampling procedures, preservation, handling, and analytical protocol for compliance monitoring shall be in accordance with EPA Method 245.1. The Level of Detection (LOD), developed in accordance with the procedure specified in 40 CFR 136 shall not be greater than 0.2 µg/L for mercury, unless higher levels are appropriate due to matrix interference.
The evaluation of potential matrix interference(s) shall include, at a minimum, the following:
(a) A demonstration that the laboratory conducting the analysis is capable of achieving the LOD of 0.2 ug/L in reagent water;
(b) A demonstration that the LOD of 0.2 µg/L cannot be achieved in the effluent; and
(c) A demonstration that an attempt has been made to resolve the matrix interference(s).
In cases where true matrix interference(s) can be demonstrated, a discharge-specific LOD will be developed in accordance with the procedure in 40 CFR 136. Discharge-specific LOD will be incorporated into the wastewater discharge permit of the nondomestic user.
(2) In addition to penalties for violating the ordinance for discharging wastewater containing concentrations (and/or mass limitations) in excess of the limits stated above, surcharges shall be assessed by the City for any conventional pollutant discharged to the POTW in excess of average domestic influent WWTP concentration according to the City Sewer User Charge System, § 54.12(A), subsection G, "Surcharges." Discharges of any pollutant may not exceed the stated limitation under any circumstance. Surcharges will be based on a pro rated share of the annual costs of operation and maintenance associated with the treatment and handling of a substance, multiplied by the ratio of weight of excess substance over the normal weight of the substance to be treated annually.
(3) (a) The City of Big Rapids sustains costs to operate and maintain the City's sanitary sewer system and wastewater treatment plant. The Utility is paid by user fees that shall be distributed as equitably as possible among the users. The typical user rates employed by the City of Big Rapids cover costs associated with the treatment of normal domestic strength wastewater. Higher strength wastes incur higher costs for treatment. Industrial and commercial users sometimes discharge high strength wastes and the surcharge program allows the City to recover the costs associated with treating this wastewater.
(b) Surcharges are an additional charge used to cover the extra cost of treating conventional pollutants in excess of domestic background concentrations.
(c) The City's surcharge procedure shall include, on at least a semi-annual basis, composite sampling on typically four consecutive days to determine the user concentration in mg/l of conventional pollutants from each non-domestic user. These user concentrations will be compared to the domestic background concentration for each parameter found under "Surcharge" in the City's User Charge Report. When the user concentration exceeds the domestic background concentration for a parameter, the excess amount will be the concentration used to calculate the pounds to be surcharged. The flow used shall be the actual monthly flow. Example: the domestic background concentration for total phosphorus is 5 mg/l. User A has an user concentration of 8 mg/l. The surcharge concentration for User A would be 3 mg/l. This concentration multiplied by the monthly flow in millions of gallons * 8.34 pounds per gallon gives the total pounds of phosphorus. If User A consumed 600,000 gallons of water, that would be 0.6 million gallons * 3 mg/l * 8.34 = 15.01 pounds of surcharge phosphorus @ $2.51/lb = $37.67 for that month. The excess concentration surcharge shall remain in effect until the next sampling. Each user subject to surcharges may be billed monthly or quarterly according to water usage or metered discharge. Sampling and analysis shall be performed by the City. A split of each sample shall be made available to each user upon written request to the Superintendent. The City may obtain additional samples to verify a user's effluent parameters. Any surcharged user may request additional samples based on a changed condition since the last sampling event. Costs for additional samples and analysis shall be paid by the user.
(Ord. 312-3-92, passed 3-16-92; Am. Ord. 347-2-94, passed 2-21-94; Am. Ord. 414-1-97, passed 1-20-97; Am. Ord. 493-05-02, passed 5-20-02; Am. Ord. 521-08-03, passed 8-18-03; Am. Ord. 545-05-05, passed 5-16- 05; Am. Ord. 700-09-16, passed 9-6-16; Am. Ord. 817-09-24, passed 9-16-24)
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