(A) (1) Users of the wastewater treatment works shall be identified as belonging to one of the following user classes:
(a) Residential;
(b) Commercial;
(c) Industrial;
(d) Institutional; and
(e) 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 Clerk/Treasurer. Allocation of users to user classes shall be based on the substantive intent of the definitions of these classes contained herein.
(B) (1) 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.
(2) The minimum rate for loadings of BOD and of TSS being the rate established for normal domestic wastewater (such as concentrations of 265 mg/l BOD and 310 mg/l TSS).
(C) (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 proportionately, according to the costs of collection, and of the specific treatment processes required to affect or reduce flow, BOD and TSS; and
(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 the purposes of determining user charges, the following definitions of unit costs shall apply:
(a) UF equals the unit cost for treatment of flow in $/1,000 gallons.
(b) UBOD equals the unit cost for treatment of BOD in $/lb.
(c) UTSS equals the unit cost for treatment of TSS in $/lb.
(D) (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 per quarter billable flow shall be equal to quarterly metered water usage as averaged between the first and last quarters of the calendar year. For nonresidential users discharging normal domestic strength wastewater, billable flow shall be equal, to quarterly water usage averaged throughout the year.
(b) All residential sewer users served by the city water utility shall have meters for measuring water usage. All nonresidential users shall have meters for measuring flow. Residential sewer users not served by the water utility shall have an estimated water usage assigned annually by City Council resolution. Water usage shall be estimated as outlined in § 52.29.
(c) The billable amounts of BOD and TSS 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 265 mg/l BOD and 310 mg/l TSS (such as “normal domestic strength wastewater”).
(2) Calculating user charges.
UC(NDS) = (UF X F) + (UBOD X KBOD X F) + (UTSS X KTSS X F )
(a) UC(NDS) equals the user charge for treatment of normal domestic strength wastewater.
(b) UF equals the unit cost for treatment of flow in $/Kgal.
(c) F equals the billable flow in Kgal.
(d) UBOD equals the unit cost for treatment of BOD in $/lb.
(e) KBOD equals the constant used to calculate the quantity of BOD in lbs./Kgal. of normal domestic strength (NDS) waste (265 mg/l BOD) as follows:
KBOD = .00834 x 265 mg/l (BOD concentration of NDS waste)
(f) UTSS equals the unit cost for treatment of TSS in $/lb.
(g) KTSS equals constant used to calculate the quantity of TSS in lbs./Kgal. of NDS waste (310 mg/l TSS) as follows:
KTSS = .00834 x 310 mg/l (TSS concentration of NDS waste)
(E) (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 and in accordance with other applicable ordinances and regulations of the city.
(2) Calculating user charges.
UC (GNDS) = (UF X F) + (UBOD X QBOD) + (UTSS X QTSS)
(a) UC(GNDS) equals the user charge for treatment of wastewater that is greater than normal domestic strength.
(b) UF equals the unit cost for treatment of flow in $/Kgal.
(c) F equals billable flow in Kgal.
(d) UBOD equals the unit cost for treatment of BOD in $/lbs.
(e) QBOD equals the quantity of BOD in lbs.
(f) UTSS equals the unit cost for treatment of TSS in $/lb.
(g) QTSS equals the quantity of TSS in lbs.
(F) The city may, at its discretion require nonresidential users to install wastewater flow meters or 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, the meters 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) (1) Local construction cost for the wastewater treatment facility will be recovered by ad valorum taxes and special assessment. The portion of the local construction cost attributable to reserve capacity will be paid by the “ad valorum” tax, and the remainder will be paid by special assessments of users.
(2) As new users are added to the system, each new user will be assessed the amount of this special assessment and the “ad valorum” tax will be reduced a proportional amount. The amount of assessment shall be computed based on equivalent residential units (ERUs). Each single-family residential user shall be considered one ERU be assigned a number of ERUs based on water usage (actual or estimated), and estimated wastewater strength. The assessment shall be calculated as follows:
AC = AT X ERU
Total ERU's
Total ERU's
(a) AC equals the amount of the assessment.
(b) AT equals the total amount to be specially assessed.
(c) ERU equals the number of ERUs for the unit.
(d) Total ERUs equals the total number of ERUs connected to the treatment facility.
(3) The number of ERUs will be computed according to the following formula:
ERUs = (0.50) Quarterly Flow + (0.25) Quarterly BOD Load + (0.25) Quarterly TSS Load
20,500 45.3 lbs BOD 53.0 lbs. TSS
20,500 45.3 lbs BOD 53.0 lbs. TSS
(4) Flows, BOD load and TSS load will be based on actual loadings for the previous eight quarters if available. If data is not available, a best estimate of loadings shall be used.
(Ord. 10.03, passed 6-28-88)