(A) User classes. Users of the city wastewater treatment works shall be identified as belonging to one of the following user classes: Residential; Commercial; Industrial; or Governmental. 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 herein.
(B) Operation, maintenance and replacement costs. 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, TSS, and TP being the rate established for concentrations of 300 mg/l BOD, 350 mg/l TSS, and 8 mg/l TP (i.e. normal domestic strength wastewater).
(C) Unit costs for treatment of flow, BOD, TSS, and TP. Unit costs for treatment of flow, BOD, TSS, and TP shall be determined and fixed annually in the sewer service charge system according to the following procedure:
(1) Determine the annual OM&R budget.
(2) Allocate total annual O & M costs to flow, BOD, TSS, and TP proportionately; according to the costs of collection, and of the specific treatment processes required to affect or reduce flow, BOD, TSS, and TP.
(3) Allocate total replacement costs to flow, BOD, TSS, TP, and inflow and infiltration proportionately; according to the replacement costs of the specific facilities required to convey, affect, or reduce flow, BOD, TSS, TP, and inflow and infiltration.
(4) Divide the sum of O & M and replacement costs attributable to flow, BOD, TSS, TP respectively, by the total annual billable volume flow plus inflow and infiltration, and billable loadings of BOD, TSS, and TP to arrive at unit costs.
(5) For purposes of determining user charges, the following definitions of unit costs shall apply:
UF - Unit cost for treatment of flow in $/Kgal.
UBOD - Unit cost for treatment of BOD in $/lb.
UTSS - Unit cost for treatment of TSS in $/lb.
UTP - Unit cost for treatment of TP in $/lb.
(6) Subsequent calculations of unit costs shall be according to the substantive intent of this SSCS.
(D) User charges for normal domestic strength users.
(1) Calculating billable flows and loadings.
(a) The billable amount of flow will be calculated from the volume of metered water usage. For residential users, the monthly billable flow for the billing periods ending in October through May shall be equal to the water usage measured in each of the monthly periods. For residential users, the monthly billable flow for the billing periods ending in June through September shall be equal to the water usage measured in each of the monthly periods or the average of the metered water usage of the monthly billing periods ending in October through May in which usage occurred, whichever is less. For non-residential users discharging NDSW, billable flow shall be equal to monthly water usage measured each month.
(b) Determination of loadings from metered water usage. The billable amounts of BOD, TSS, and TP will be calculated from the volume of metered water usage, as determined above, where the billable quantities will be those attributable to a wastewater concentration of 300 mg/l BOD, 350 mg/l TSS, and 8 mg/l TP (i.e. normal domestic strength wastewater).
(2) Calculating User Charges.
UC(NDS) = (UF x F) + (UBOD x KBOD x F) + (UTSS x KTSS x F) + (UTP x KTP x F)
Where: 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 NDS waste as follows:
KBOD = .00834 X 300 mg/l (BOD concentration of NDS waste)
UTSS = Unit cost for treatment of TSS in $/lb.
KTSS = Constant used to calculate the quantity of TSS in lbs/Kgal of NDS waste as follows:
KTSS = .00834 x 350 mg/l (TSS concentration of NDS waste)
UTP = Unit cost for treatment of TP in $/lb.
KTP = Constant used to calculate the quantity of TP in lbs/Kgal of waste as follows: KTP = .00834 x 8 mg/l
(E) User charges for users contributing wastes 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, TSS, and TP 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 and in accordance with Ordinance No. 744, An Ordinance Establishing Sewer Use Regulations (this Chapter 51).
(2) Calculating user charges.
UC(GNDS) = (UF x F) + (UBOD x QBOD) + (UTSS x QTSS) + (UTP x QTP)
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.
UTP = Unit cost for treatment of TP in $/lb.
QTP = Quantity of TP in lbs.
(F) The city may, at its discretion, require any non-residential user to install wastewater flow meters or such additional water meters as may be necessary to determine wastewater volume. Nonresidential users having a potable water source other than the municipal water system shall install a meter on the water supply to allow determination of monthly water usage unless it is determined by the city that the probable water usage will be less than 2,500 gallons per month in which case the user's usage shall be assumed to equal 2,500 gallons. Residential users having a potable water source other than the municipal water system shall be assumed to have a monthly usage equal to 5,000 gallons unless the user installs a meter on the water supply to allow determination of monthly water usage. Meters installed pursuant to this section shall be of a type approved by the city, equipped with remote registering recorders, and located at an accessible site on the owner's property.
(G) Debt service charge for recovery of treatment plant improvement costs. Unit costs for debt service of capital expenditures attributable to flow, BOD, TSS, and Inflow & Infiltration shall be calculated proportionately; according to the capital costs of the specific facilities required to convey, affect, or reduce Flow, BOD, TSS, and Inflow & Infiltration.
(H) Connection 1 Charge. The cost of billing administration; inflow and infiltrations proportionate share of treatment works operation, maintenance, and replacement costs; and for the costs of inflow and infiltration abatement activities of the city will be recovered through a connection charge based on these costs and the total number of user connections as follows:
K1 = (BA + RII + II + (UF x FII))/(12 x TC)
Where: K1 = Monthly Connection 1 Charge
BA = Annual costs for billing administration
RII = Annual replacement costs allocated to I&I
II = Annual I&I abatement program costs
UF = Unit cost for treatment of flow
FII = Annual volume of I&I flow
TC = Total number of user connections
(I) Connection 2 Charge. Inflow and infiltration's proportionate share of treatment works debt retirement costs will be recovered through a connection charge based on these costs and the total number of user connections as follows:
K2 = (DII + (DF x FII))/(12 x TC)
Where: K2 = Monthly Connection 2 Charge
DII = Annual debt service costs allocated to I&I
DF = Unit cost for debt service of capital costs attributable to flow
FII = Annual volume of I&I flow
TC = Total number of user connections
(J) Connection 3 Charge. The cost of repaying money bonded prior to January 1, 1988 for the construction or improvement of the treatment works; the costs of any improvements made to the wastewater collection system not financed through special assessment proceedings; and for reserve capacity costs are to be recovered through a connection charge based on these costs and the sum of the number of Industrial, Commercial, and Governmental user connections and the number of dwelling units utilizing the wastewater treatment works as follows:
(1) For Residential Users:
K3 = Con3 x DU
(2) For Commercial, Governmental, and Industrial Users:
K3 = Con3 x UC
Where: K3 = Monthly Connection 3 Charge
Con3 = (RC + D87 + CI)/((TCGIC + TDU) x 12)
DU = Number of dwelling units utilizing a residential user connection
UC = Number of user connections
RC = Annual reserve capacity costs
D87 = Annual debt service costs for treatment works improvements completed prior to January 1, 1988
CI = Costs for collection improvements funded through the sewer service fund
TCGIC = Total number of commercial, governmental, and industrial user connections
TDU = Total number of dwelling units utilizing the treatment works
(K) Sewer Service Charge.
SSC = Us + K1 + K2 + K3
Where: SSC = Monthly sewer service charge
Us = Uc + Dc = Monthly usage charge
Uc = Monthly user charge
Dc = Monthly debt service charge
K1 = Monthly Connection 1 Charge
K2 = Monthly Connection 2 Charge
K3 = Monthly Connection 3 Charge
(Ord. 745, passed 11-27-89; Am. Ord. 851, passed 11-24-97; Am. Ord. 928, passed 11-26-01)