15.64.010 Abnormal sewage surcharge.
A. Any user generating abnormal sewage which exhibits none of the characteristics of waste prohibited in Section 15.48.020, or in excess of limitations stated in Section 15.48.030, but which has:
1. As an average concentration of suspended solids or BOD content in excess of domestic sewage (two hundred fifty mg/L) during a twenty-four-hour period;
2. Oil and grease content in excess of domestic sewage (one hundred mg/L) during a twenty-four-hour period;
3. Other constituents as deemed necessary by the director of public works and utilities may be required to pay a surcharge.
B. Prior to imposition of a surcharge, the user shall be notified in writing that the waste discharge exceeds the abnormal sewage discharge criteria. If after sixty days of the date of notice the abnormal sewage discharge has not been corrected, the user must enter into a surcharge agreement or be disconnected from the city’s sewer system. The surcharge will be adjusted on billings for the billing period following submission of new data. Surcharge values for each industry will be determined by the city using twenty-four-hour composite sampling.
C. Payment of a sewage surcharge in no way relieves the user of the discharge prohibitions set forth in Chapter 15.48.
D. The user may elect to sample the discharge at its own expense. Sampling done by the user shall be under the direction of a registered professional engineer employed by the user and reports submitted to the city shall contain a statement that the samples collected and values determined are based on a twenty-four-hour composite representative of the establishment’s flow.
E. Computation of each surcharge, as applicable, shall be based on the wastewater user charge in $/HCF for "Metered Industrial" or "Non-Residential" as specified in the most current city of Petaluma waste water service rate schedule:
|
S |
= |
V |
x |
8.34 |
x |
A |
x |
(BOD – 250) |
|
S |
= |
V |
x |
8.34 |
x |
B |
x |
(TSS – 250) |
|
S |
= |
V |
x |
8.34 |
x |
C |
x |
(oil and grease – 50) |
|
S |
= |
Surcharge in dollars for the billing period. |
||||||
|
V |
= |
Wastewater flow in millions of gallons during the billing period. |
||||||
|
8.34 |
= |
Weight of water in pounds per gallon. |
||||||
|
A |
= |
Unit charge in dollars per pound for BOD as established in the sewer rate schedule in effect at the time of the billing. |
||||||
|
B |
= |
Unit charge in dollars per pound for TSS as established in the sewer rate schedule in effect at the time of the billing. |
||||||
|
C |
= |
Unit charge in dollars per pound for TSS as established in the sewer rate schedule in effect at the time of the billing. |
||||||
|
D |
= |
Unit charge in dollars per pound for TSS times three. |
||||||
|
BOD |
= |
Five-day biochemical oxygen demand in mg/L. |
||||||
|
TSS |
= |
Total suspended solids in mg/L. |
||||||
|
250 |
= |
Normal BOD and TSS in mg/L in domestic sewage. |
||||||
|
50 |
= |
Normal oil and grease in mg/L in domestic sewage. |
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(Ord. 2472 NCS §2 (part), 2013; Ord. 2282 NCS §3 (part), 2007.)