(A) User classes.
(1) Users of the city wastewater treatment works shall be identified as belonging to one of the following user classes: Residential; Commercial; Industrial; Institutional; or Governmental.
(2) The allocation of users to these categories for the purpose of assessing user charges and debt service charges shall be the responsibility of the City Administrator. Allocation of users to user classes shall be based on the substantive intent of the definitions of these classes contained in this subchapter.
(B) Rates. The user shall pay operation, maintenance and replacement costs in proportion to the user's proportionate contribution of wastewater flows and loadings to the treatment plant, with the minimum rate for loadings of BOD and of TSS being the rate established for concentrations of 285 mg/l BOD and 300 TSS (normal domestic strength wastewater).
(C) Unit costs for treatment of flow, BOD and TSS.
(1) Unit costs for treatment of flow, BOD and TSS shall be determined and fixed annually in the Sewer Service Charge System according to the following procedure:
(a) Determine the annual OM&R budget.
(b) Allocate total annual OM&R costs to flow, BOD and TSS proportionally; according to the costs of collections and of the specific treatment process required to affect or reduce flow, BOD and TSS.
(c) Divide the OM&R costs attributable to flow, BOD and TSS respectively, by the total annual billable volume and loadings of flow, BOD and TSS, to arrive at unit costs .
(2) For purposes of determining user charges, the following definitions of unit costs shall apply:
UF = Unit cost for treatment of Flow in $/K gal.
UBOD = Unit cost for treatment of BOD in $/lb.
UTSS = Unit cost for treatment of TSS in $/lb.
(D) User charges for normal domestic strength users.
(1) The billable amount of flow will be calculated from the volume of metered water usage. For residential users, the per quarter, billable flow shall be 80% of the metered spring quarter (February, March, April) water usage. For non-residential users discharging normal domestic strength wastewater, the per quarter billable flow shall be 100% of the metered spring quarter (February, March, April) water usage.
(2) The billable amounts of BOD and TSS will be calculated from the volume of metered usage as determined in division (D)(1) of this section, where the billable quantities will be those attributable to a wastewater concentration of 285 mg/l/BOD and 300 mg/l/TSS (normal domestic strength wastewater).
UC(NDS) = (UF x F) + (UBOD x KBOD x F) + (UTSS x KTSS x F)
Where: U(NDS) = User charge for treatment of normal domestic strength wastewater
UC(NDS) = User charge, for treatment of normal domestic strength wastewater
UF = Unit cost for treatment of flow in $/Kgal
F = Billable flow in Kgal
UBOD = Unit cost for treatment of BOD in $/lb
KBOD = Constant used to calculate the quantity of BOD in lbs/Kgal of normal domestic strength waste (285 mg/l BOD) as follows:
KBOD = 0.00834 x 285 mg/l (BOD concentration of normal domestic strength waste) = 2.38 lb/Kgal
UTSS = Unit cost of treatment of TSS in $/lb
KTSS = Constant used to calculate the quantity of TSS in lbs/Kgal of NDS waste (300 mg/l TSS) as follows:
KTSS = 0.00834 x 300 mg/l (TSS concentration of NDS waste) = 2.50lb/Kgal
(E) User charges for users contributing wasted greater than normal domestic strength.
(1) Calculating billable flows and loadings.
(a) The billable amount of flow will be calculated from the volume of metered water usage, or at the discretion of the city, from the measurement of effluent flow at user's point of discharge. Measurements shall be according to a regular program prescribed by the city.
(b) The billable amounts of BOD and TSS will be calculated by the measurement of these wastes according to a program prescribed by the city in keeping with the latest edition of Standard Methods for the Examination of Water and Wastewater in accordance with the provisions of this chapter.
(2) Calculating user charges.
UC(GNDS) = (UF x F) + (UBOD x QBOD) + (UTSS x QTSS)
Where: UC(GNDS) = User charge for treatment of wastewater that is greater than normal domestic strength
UF = Unit cost for treatment of flow in $ /Kgal
F = Billable flow in Kgal
UBOD = Unit cost for treatment of BOD in $/lb.
QBOD = Quantity of BOD in lbs.
UTSS = Unit cost for treatment of TSS in $/lb.
QTSS = Quantity of TSS in lbs.
(F) The city may, at its discretion, require non-residential users to install wastewater flow meters or such additional water meters as may be necessary to determine wastewater volume. The city may require residential connections to install water meters for the purpose of determining wastewater volume. When so required, such meters shall be of a type approved by the city equipped with remote registering records, and located at an accessible site on the owner's property.
(G) Debit service charge.
(1) Provision for the recovery of local construction costs shall be included in the sewer rate ordinance and accompanying Sewer Service Charge System, in accordance with 40 CFR 35.2104. Federal and state regulations do not require that local construction costs be recovered proportionately, (as is the case with operation, maintenance and replacement costs) but only that the method of recovery be provided for in the sewer rate ordinance. Consequently, the city may employ a variety or methods to recover such costs.
(2) The following alternatives demonstrate provision for such costs in a sewer rate ordinance, and can be employed to assist in the development of a suitable ordinance. These alternatives are offered as suggestions; neither the EPA nor the MPCA endorse a particular approach.
(3) The debt service charge for local capital/construction costs will be recovered through the sewer service charge. The costs are based on the costs found in Appendix, Table 7 at the end of this chapter, estimated federal/state grants and local share costs.
(Ord. 283, passed 5-6-91) Penalty, see § 51.99