937.08 EXTRA STRENGTH SURCHARGES.
In addition to the base user charge applicable pursuant to Section 937.06, users discharging pollutants to the sewage treatment works of the City whose average concentration, as defined in Section 937.02, in one or more classifications exceeds in any month that concentration defined as normal in Section 937.02 in the corresponding classification, shall be subject to surcharges calculated as follows:
(a) Surcharges for each billing period during a calendar year shall be based upon the following values for that calendar year:
(1) Estimated total operation, maintenance and replacement expenses attributed to the sewage treatment plant pursuant to Section 937.06(a)(1)(Cto);
(2) Estimated total pounds of BOD received at the plant (Bt);
(3) Estimated total pounds of suspended solids received at the plant (St); and
(4) Estimated total pounds of ammonia received at the plant (NHt). Data not available shall be estimated in the most practical manner possible.
(b) Surcharge on user charges per pound of BOD in excess of normal equals:
Cto X 0.28
Bt
(c) Surcharge on user charges per pound of suspended solids in excess of normal equals:
Cto X 0.20
St
(d) Surcharge on user charges per pound of ammonia in excess of normal equals:
Cto X 0.09
NHt
(e) Pounds of BOD Per billing period subject to surcharge equals (average concentrations of BOD, calculated pursuant to Section 937.02, in milligrams per liter minus 20 milligrams per liter) times volume of sewage discharged from the user to the sewage treatment works per billing period, in 100 cubic feet, times 0.00624. If average concentrations of BOD are 200 milligrams per liter or less, no surcharge for BOD shall apply.
(f) Pounds of suspended solids per billing period subject to surcharge equals (average concentrations of suspended solids, calculated pursuant to Section 937.02, in milligrams per liter minus 240 milligrams per liter) times volume of sewage discharged from the user to the sewage treatment works per billing period, in 100 cubic feet, times 0.00624. If average concentrations of suspended solids are 240 milligrams per liter or less, no surcharge for suspended solids shall apply.
(g) Pounds of ammonia per billing period subject to surcharge equals (average concentrations of ammonia, calculated pursuant to Section 937.02, in milligrams per liter minus 20 milligrams per liter) times volume of sewage discharged from the user to the sewage treatment works per billing period, in 100 cubic feet, times 0.00624. If average concentrations of ammonia are 20 milligrams per liter or less, no surcharge for ammonia shall apply.
(h) Surcharge on user charges equals (pounds of BOD calculated pursuant to subsection (e)) times (surcharge per pound calculated to subsection (b)) plus (pounds of suspended solids calculated pursuant to subsection (f)) times (surcharge per pound calculated pursuant to subsection (c)) plus (pounds of ammonia calculated pursuant to subsection (g)) times (surcharge per pound calculated pursuant to subsection (d)).
(i) Formulas as contained in subsections (b), (c) and (d) hereof shall be subject to adjustment as necessary based upon a biennial audit of sewer revenue fund expenses. Examples for calculating the rate based on formulas set forth herein are attached as Exhibit A to Ordinance 82-039. Surcharges may also be established for pollutants other than those provided for in this paragraph which are permitted to be discharged to the sewage treatment works by the City, after pretreatment, or without pretreatment.
(Ord. 92-008. Passed 1-7-92.)