A. The city or its engineer, shall determine each customer's average volume of wastewater, which has been discharged to the wastewater system, which shall then be divided by the average daily volume of all wastewater discharged to the wastewater system, to determine each customer's volume contribution percentage. The amount contributed as the total average daily volume of wastewater shall exclude infiltration and inflow.
B. The city or its engineer, shall determine each customer's average daily poundage of five (5) day twenty degree centigrade (20°C) biochemical oxygen demand (BOD) which has been discharged to the wastewater system which shall then be divided by the average daily poundage of all five (5) day BOD discharged to the wastewater system to determine each customer's BOD contribution percentage.
C. The city or its engineer, shall determine each customer's average suspended solids (SS) poundage which has been discharged to the wastewater system which shall then be divided by the average daily poundage of all suspended solids discharged to the wastewater system, to determine the customer's suspended solids contribution percentage.
D. Each customer's volume contribution percentage, BOD contribution percentage and suspended solids contribution percentage shall be multiplied by the annual operation and maintenance costs for wastewater treatment of the total volume flow, of the total five (5) day twenty degree centigrade (20°C) BOD and of the suspended solids, respectively. (Ord. 219, 8-15-2000)