SF
|
=
|
a(BOD - 300)
300
|
+
|
b(SS - 300)
300
|
+
|
c(CLD - 25)
25
|
+
|
d(P - 30)
30
|
Where:
| |||
SF
|
=
|
Surcharge factor.
| |
BOD
|
=
|
Milligrams per liter of biochemical oxygen demand, as defined in § 113-14.
| |
SS
|
=
|
Milligrams per liter of suspended solids, as defined in § 113-14.
| |
CLD
|
=
|
Milligrams per liter of chlorine demand, as defined in § 113-14.
| |
P
|
=
|
Milligrams per liter of phosphorus, as defined in § 113-14.
| |
a
|
=
|
Proportion of operation and maintenance cost to treat a pound
of biochemical oxygen demand (BOD).
| |
b
|
=
|
Proportion of operation and maintenance cost to treat a pound
of suspended solids (SS).
| |
c
|
=
|
Proportion of operation and maintenance cost to treat a pound
of chlorine demand (CLD).
| |
d
|
=
|
Proportion of operation and maintenance cost to treat a pound
of phosphorus (P).
|
NOTES:
| |
1.
|
Items a, b, c and d are decimal portions of the total operation
and maintenance cost for the sewerage system. The values shall be
determined by the Administrator on a yearly basis from data accumulated
during each preceding year from the actual operation and maintenance
costs.
|
2.
|
If any of the values for BOD, SS, CLD or P as determined by laboratory analysis are less than the respective normal values stated in § 113-14, the factor for the pollutant shall be eliminated from the formula.
|
Example 1. Treatment charge based on volume.
| ||
An industry discharges into the public sewer system wastes which
have been found to contain the following:
| ||
BOD: 630 milligrams per liter; normal value 300 milligrams per
liter
| ||
SS: 280 milligrams per liter; normal value 300 milligrams per
liter
| ||
CLD: 50 milligrams per liter; normal value 25 milligrams per
liter
| ||
P: 45 milligrams per liter; normal value 30 milligrams per liter
| ||
Monthly volume of discharge = 100,000 gallons
| ||
Normal operation and maintenance sewer charge = $0.70/1,000
gallons
| ||
Values for a, b, c and d are, respectively: 0.53, 0.35, 0.08
and 0.04
|
SF
|
=
|
0.53(630 - 300)
300
|
+
|
0.08(50-25)
25
|
+
|
0.04 (45 - 30)
30
|
SF
|
=
|
0.53 (1.1) + 0.08 (1.0) + 0.04 (0.5)
|
SF
|
=
|
0.68
|
NOTES:
| ||
1.
|
The factor for SS is dropped because SS is less than 300 milligrams
per liter.
| |
2.
|
Surcharge factors are rounded off to two decimal places.
| |
Normal sanitary sewer operation and maintenance charge =
| ||
100,000 x 0.70
1,000 gallons
| ||
= $70.00 per month maintenance charge
| ||
Surcharge = (0.68) ($70.00) = $47.60
| ||
Total sewerage treatment charge = $70.00 + $47.60 = $117.60
per month
|
This example illustrates sewer use by large commercial or industrial
establishments and not average residential users with normal sewage.
|
Example 2. Treatment charge based on unit rates.
| |||
A commercial establishment discharging wastes into the public
sewer system is rated at 20 equivalent units. (One unit is equivalent
to a dwelling unit or lot or 60,000 gallons per year of water consumption.)
The unit charge is $45 per unit per year. The establishment discharges
wastes into the public sewer system which has been found to contain
the following concentrations of pollutants:
| |||
BOD
|
=
|
450 MG/L
| |
SS
|
=
|
200 MG/L
| |
CLD
|
=
|
15 MG/L
| |
P
|
=
|
60 mg/l
| |
Values for a, b, c and d are, respectively: 0.3, 0.3, 0.1 and
0.2
| |||
Normal sanitary sewer charge = (20 units x $45.00)) + $1.00;
fixed district parcel charge = $901.00 per year.
| |||
SF
|
=
|
0.3 (450 - 300) + 0.2 (60 - 30) 300 30
|
NOTE: The factors for SS and CLD are dropped because values
are below normal limits.
| ||
SF = (0.3)(0.5) + (0.2)(1) = 0.35
| ||
Portion of unit charge which is cost of treatment =
| ||
$27.55
$45.00
|
= $0.61
| |
Surcharge = (0.35) ($0.61) ($901.00) = $192.36
| ||
Total sewer charge = $901.00 + $192.36 = $1,093.36
|
Both of these examples illustrate sewer use by large commercial
or industrial establishments and not average residential users with
normal sewage.
| ||
The sewer surcharge for unpolluted water discharge into the
Village of Webster sewerage system or tributary public sewer shall
be:
| ||
A.
|
In the case of a volume charge as in Example 1, double the normal
sanitary sewer treatment charge based on the volume of metered water;
and/or
| |
B
|
In the case of unit charge, the product of the following:
| |
(1)
|
Unit charge portion due to treatment cost.
| |
(2)
|
Pollutant surcharge factor, if any, as computed by formula.
| |
(3)
|
Normal sewer charge (see Example 2).
| |
NOTE: When excessive volumes of water (stormwater, surface water,
groundwater, etc.) enter the Village of Webster sewerage system directly
or by inflow or infiltration of the local sewage collection systems,
the Village shall take the following actions:
| ||
(1)
|
Notice shall be given to the property owner or local governmental
unit responsible for the sewage collection system contributing excessive
volumes of water into the Village of Webster sewerage system.
| |
(2)
|
Within 30 days after notification to the property owner or local
governmental unit, an informal timetable for the elimination and/or
control of the excessive water infiltration shall be filed with the
Village.
| |
(3)
|
A property owner or local governmental unit failing to provide
said timetable or not substantially complying with the scheduled abatement
of excessive inflow or infiltration to the timetable filed with Village
shall be surcharged for the excessive water.
| |
(4)
|
The surcharge shall be based in proportion to the determined
excess volume of water entering the Village of Webster sewerage system.
|