(a)
Often, the wastewater discharged from businesses contains solids
and organic matter at higher concentrations in comparison to concentrations
found in residential wastewater. Wastewater is considered to be “normal
strength” if it meets the wastewater quality standards established
for typical residential wastewater (see “normal values”
in the table below). Wastewater that exceeds these standards is considered
to be “extra strength.” Much of the cost associated with
treating wastewater is related to the amount of solids that must be
removed and the amount of oxygen that is required to stabilize and
digest that organic matter in the wastewater. As such, the treatment
of wastewater from some businesses is significantly more expensive
than the treatment of typical residential wastewater.
(b)
Relying on the periodic collection and analyses of wastewater samples
from each permitted source of industrial waste, the surcharge program
enables the city to recover the extra costs associated with the treatment
of extra strength wastewater. Designated individualized surcharges
are determined for each industrial source. These surcharges are based
on site-specific sample results for biochemical oxygen demand (BOD),
chemical oxygen demand (COD) and total suspended solids (TSS).
(d)
All users subject to a surcharge are notified by letter, and the
monthly surcharge fees are applied to the user’s monthly utility
bill.
(Ordinance 05-0503-2 adopted 5/3/05)
(a)
For industrial wastes having a COD concentration of 2.25 or more
times that of the BOD concentration, the surcharge will be based on
Formula 2 below. Computations of surcharges shall be based on the
following formulas:
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Formula 1
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S = [(BOD - 250) + (TSS - 250) + (4 x O&G - 200)] x 0.001
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Formula 2
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S = [(0.44 x COD - 250) + (TSS - 250) + (4 x O&G - 200)]
x 0.001
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Where:
|
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S = Surcharge factor applied to wastewater charge.
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(b)
The surcharge is computed by multiplying the monthly wastewater charge
for the facility by S.
(c)
BOD, TSS, O&G, and COD refer to the annual average concentrations
of those parameters measured in mg/l as reported by the permit holder
or as measured by the director. If the concentration of any of these
pollutants is less than the concentration of normal wastewater, then
the term in the equation for that parameter will be deleted.
(d)
(1)
All flow rates, BOD, COD, O&G and TSS values used in determination
of the surcharge of major wastewater customers shall be reevaluated
on an annual basis and shall be adjusted to reflect any increase or
decrease in wastewater treatment costs based on the previous year’s
experience. However, if there is a major change in the operation to
cause changes in value, the values may be increased or decreased during
the calendar year based on a study of changes or actual measurements.
(2)
The permit holder may request an adjustment of surcharge after submittal
of any self-monitoring report.
(Ordinance 05-0503-2 adopted 5/3/05)
