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 {[OB x (BIA-Bn)/BA] + [OS x (SIA-Sn)/SA] + [OP x (PIA-Pn)/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 (million gallons per day) from discharger
| |
BIA
|
=
|
Average daily BOD5, loading (pounds per
day) from discharger
| |
SIA
|
=
|
Average daily suspended solids loading (pounds per day) from
discharger
| |
PIA
|
=
|
Average daily total phosphorus loading (pounds per day) from
discharger
| |
NHIA
|
=
|
Average daily ammonia loading (pounds per day) from discharger
| |
TKIA
|
=
|
Average daily total Kjeldahl nitrogen loading (pounds per day)
from discharger
| |
QA
|
=
|
Average daily flow rate (million gallons per day) at the POTW
treatment plant
| |
BA
|
=
|
Average daily BOD5, loading (pounds per
day) at the POTW treatment plant
| |
SA
|
=
|
Average daily suspended solids loading (pounds per day) at the
POTW treatment plant
| |
PA
|
=
|
Average daily total phosphorus loading (pounds per 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 (pounds per day) in discharge
if it were normal sewage
| |
Sn
|
=
|
Suspended solids loading (pounds per day) in discharge if it
were normal sewage
| |
Pn
|
=
|
Total phosphorus loading (pounds per 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 load (LB N/DAY) in discharge if it were
normal sewage
|