(A) (1) The unit cost for users of the sewage works and facilities shall be determined by adding the total annual cost of Categories A and B and dividing by billable flow to determine a unit charge per 1,000 gallons of billable flow.
(2) Billable flow will be determined annually by the sum of the following:
(a) Measured industrial flow discharged to the sewer system;
(b) Flow discharged to sewer system as determined by metered water, minus metered water to measured industries;
(c) Flow discharged to sewer system as determined by meters or estimates of well water supplies, minus well water from measured industries.
(3) The formula for this calculation of unit cost is as follows:
Sum of cost in § 52.088 ÷ estimated billable flow in 1,000 gallons = dollars per 1,000 gallons |
(B) The charges to users of the sewage works and facilities shall be the product of the unit cost determined in accordance with division (A) above and that portion of the billable flow attributed to each domestic, commercial, institutional, governmental and industrial user. The formula for this calculation is as follows:
Unit cost per 1,000 gallons x users billable flow in gallons = user charge |
(C) (1) The users surcharges for BOD and SS loading discharged to the sewage works and facilities in excess of those concentrations defined in § 52.087 shall be determined as follows: unit costs for BOD and SS shall be calculated by apportioning the total Category A and B cost associated with that year, 30% to BOD and 20% to SS and then dividing each cost so apportioned by the total estimated BOD and SS to be received at the sewage treatment plant in that year.
BOD: Category A and B cost x .30 ÷ estimated annual BOD in 100 lbs. |
SS: Category A and B cost x .20 ÷ estimated annual SS in 100 lbs. |
(2) The BOD and SS loads in excess of the allowable concentrations shall be utilized to determine the surcharge. The excess BOD and SS load shall be calculated by subtracting the allowable BOD and SS concentrations from the actual concentration discharged and then determining the excess pounds of BOD and SS. The formula for this calculation is as follows:
Excess BOD: (Actual mg/l - 212 mg/l BOD) x (users billable flow in mg) x 8.34 lbs. BOD |
Excess SS: (Actual mg/l - 210 mg/l SS) x (users billable flow in mg) x 8.34 lbs. SS |
(3) The surcharge shall be calculated by multiplying the excess pounds of BOD and SS by the appropriate unit cost. The formula for this calculation is as follows:
BOD: ($ per 100 lbs. BOD) x (excess BOD per billing period in 100 lbs.) = $$ |
SS: ($ per 100 lbs. SS) x (excess SS per billing period in 100 lbs.) = $$ |
(1999 Code, § 99.05) Penalty, see § 52.999