In addition to the base user charges applicable pursuant to Section 929.06, users discharging pollutants to the wastewater treatment works of the City, whose average concentration, as defined in Section 929.02, in one or more classifications exceeds in any month that concentration defined as normal in Section 929.02 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 and maintenance expenses pursuant to Section 929.06(a)(1)(C);
(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 phosphorus received at the plant (Pt).
Data not available shall be estimated in the most practical manner possible.
(b) Surcharges on user charges per pound of BOD in excess of normal equals:
C x 0.25 to Bt |
(c) Surcharge on user charges per pound of suspended solids in excess of normal equals:
C x 0.18 to St |
(d) Surcharge on user charges per pound of phosphorus in excess of normal equals:
C x 0.05 to Pt |
(e) Pounds of BOD per billing period subject to surcharge equals: [ (average concentration of BOD, calculated pursuant to Section 929.02, in milligrams per liter minus, 200 milligrams per liter) times volume of wastewater discharged from the user to the wastewater treatment works per billing period, in 1,000 cubic feet ] times 0.06238. If average concentration of BOD is 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 concentration of suspended solids, calculated pursuant to Section 929.02
, in milligrams per liter minus 240 milligrams per liter) times volume of wastewater discharged from the user to the wastewater treatment works per billing period, in 1,000 cubic feet ] times 0.06238. If average concentration of suspended solids is 240 milligrams per liter, or less, no surcharge for suspensed solids shall apply.
(g) Pounds of phosphorus per billing period subject to surcharge equals: [ (average concentration of phosphorus, calculated pursuant to Section 929.02
, in milligrams per liter minus 10 milligrams per liter) times volume of wastewater discharged from the user to the wastewater treatment works per billing period in 1,000 cubic feet] times 0.06238. If average concentration of phosphorus is 10 milligrams per liter, or less, no surcharge for phosphorus shall apply.
(h) Surcharge on user charges equals: pounds of BOD calculated pursuant to subsection (e) hereof times surcharge per pound calculated pursuant 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 phosphorus calculated pursuant to subsection (g) times surcharge per pound calculated pursuant to subsection (d).
(i) Formulas contained in subsections (b) to (d) hereof shall be subject to adjustment as necessary based upon biennial audits of sewer revenue fund expenses.
Surcharges may also be established for pollutants other than those provided for in this paragraph which are permitted to be discharged to the wastewater treatment works by the City, after pretreatment, or without pretreatment.