UC(t) = UC(n) + UC(an)
| |||
Where:
| |||
UC(t)
|
=
|
Total user charge for POTW operation and maintenance.
| |
UC(n)
|
=
|
User charge associated with normal sewage.
| |
UC(an)
|
=
|
User charge associated with abnormal sewage.
|
UC(n)
|
=
|
OM (QIA/QA)
|
UC(an)
|
=
|
OM/100 {[OBx(BIA-Bn)/BA] + [OS x (SIA-Sn)/SA] + [OP x (PIA-Pn)/PA)/PA]
+ [ONH x (NHIA-NHn)/NHA] + [OTK x (TKIA-TKn)/TKA]}
|
Where:
| |||
OM
|
=
|
Total annual POTW operation and maintenance costs.
| |
OQ
|
=
|
Percentage of OM attributable to flow (Q).
| |
OB
|
=
|
Percentage of OM attributable to BOD5.
| |
OS
|
=
|
Percentage of OM attributable to suspended solids.
| |
OP
|
=
|
Percentage of OM attributable to total phosphorus.
| |
ONH
|
=
|
Percentage of OM attributable to ammonia.
| |
OTK
|
=
|
Percentage of OM attributable to total Kjeldahl nitrogen.
| |
QIA
|
=
|
Average daily flow rate (mgd) from discharger.
| |
BIA
|
=
|
Average daily BOD5 loading (lb/day) from
discharger.
| |
SIA
|
=
|
Average daily suspended solids loading (lb/day) from discharger.
| |
PIA
|
=
|
Average daily total phosphorus loading (lb/day) from discharger.
| |
NHIA
|
=
|
Average daily ammonia loading (lb n/day) from discharger.
| |
TKIA
|
=
|
Average daily total Kjeldahl nitrogen loading (lb n/day) from
discharger.
| |
QA
|
=
|
Average daily flow rate (mgd) at the POTW treatment plant.
| |
BA
|
=
|
Average daily BOD5 loading (lb/day) at
the POTW treatment plant.
| |
SA
|
=
|
Average daily suspended solids loading (lb/day) at the POTW
treatment plant.
| |
PA
|
=
|
Average daily total phosphorus loading (lb/day) at the POTW
treatment plant.
| |
NHA
|
=
|
Average daily total ammonia loading (lb n/day) at the POTW treatment
plant.
| |
TKA
|
=
|
Average daily total Kjeldahl nitrogen loading (lb n/day) at
the POTW treatment plant.
| |
Bn
|
=
|
BOD5 loading (lb/day) in discharge if
it were normal sewage.
| |
Sn
|
=
|
Suspended solids loading (lb/day) in discharge if it were normal
sewage.
| |
Pn
|
=
|
Total phosphorus loading (lb/day) in discharge if it were normal
sewage.
| |
NHn
|
=
|
Ammonia loading (lb n/day) in discharge if it were normal sewage.
| |
TKn
|
=
|
Total Kjeldahl nitrogen loading (lb n/day) in discharge if it
were normal sewage.
|
NOTES:
|
If any difference term in the equation above is negative, then
that portion of the equation shall not be used; that is, the difference
shall be set to zero when it is negative.
|
All averages are arithmetic averages determined from available
data during the billing period.
|
User
|
Units
| |
---|---|---|
Single-family house
|
1
| |
Multiple residence
|
1 per apartment
|
User
|
Units
| ||
---|---|---|---|
Food and drink establishments
|
1 per 8 seats or fraction
| ||
Mercantile establishments, unless otherwise listed
|
1 per 4 employees or fraction
| ||
Beauty parlors
|
1 per chair
| ||
Factories
|
1 for each 5 employees or fraction, plus 1 additional for each
100,000 gallons per year of process water or fraction, "process water"
being defined as water used for other than employee drinking or sanitary
purposes
| ||
Service stations and repair garages
| |||
Without car wash
|
2
| ||
With car wash
|
3, plus 1 for each employee or fraction
| ||
General office space
|
1 per 2 offices or fraction thereof
| ||
Laundromats
|
1 per machine
| ||
Dental offices
|
1 per chair
| ||
Undertakers
|
1, plus house unit
| ||
Meat-processing plant
|
1
| ||
Car wash
|
3 per bay
| ||
Utilities
|
1 per office
|
User
|
Units
| |
---|---|---|
Churches and synagogues
|
2
| |
Correctional institution(s)
|
1 per each 2 inmates
| |
Firehouse
|
1
| |
Schools
|
1 per each 30 students or teachers
|