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PURPOSE AND SCOPE
Effective April 1, 1991, the County Sanitation Districts of Los Angeles County (Sanitation Districts) implemented a program to recover the costs of controlling benzene emissions as its Joint Water Pollution Control Plant (JWPCP) in Carson. The JWPCP, which receives and treats industrial wastewater, must control air emissions of benzene from its treatment process to meet South Coast Air Quality Management District (SCAQMD) requirements. Activated carbon adsorption units, previously used for odor control were retrofitted and their operation dramatically changed to provide benzene removal. These units must be regularly monitored and maintained to ensure that the public health and environment are protected. Section 423 of the Sanitation Districts’ Wastewater Ordinance ‑ Special Charges for Nonconventional Industrial Wastewater Constituents - allows the Sanitation Districts’ Chief Engineer and General Manager to bill dischargers for the cost of providing collection, treatment, and disposal services in connection with nonconventional wastewater constituents including volatile organic compounds.
In order to recover the costs of controlling benzene emissions at the JWPCP, the Sanitation Districts instituted a monitoring and charge program for the significant dischargers of benzene to its Joint Outfall System. Petroleum refineries, oil and gas producers, and petroleum handling facilities have been found to be significant dischargers of benzene. Companies subject to this program are required to pay for the costs of controlling benzene emissions at the JWPCP based on the mass of benzene the company discharges relative to the total mass of benzene discharged to the system. Each company is granted an exemption from payment for the first one half pound of benzene discharged per day or 45.5 pounds per quarter. The benzene charge calculation is outlined below. If a company can demonstrate that it consistently discharges less than the exemption amount of benzene, it may request to be removed from the benzene charge program, thus eliminating benzene sampling and reporting requirements. Benzene charges are billed to each company quarterly. Remittance of the payment is required 30 days from the date of billing. The charge is currently running in the range of $25.00 to $50.00 per pound of benzene discharged.
Benzene Charge Calculation
Quarterly charge = ( Q (i) – 45.5 ) * ( O&M ) / Q (t)
Where Q (i) = pounds of benzene discharged by company (i) in the quarter
45.5 = 0.5 pound/day exemption cumulated for the quarter
O&M = Sanitation Districts’ benzene control costs for the billing period
Q (t) = Total pounds of non-exempt benzene discharged to system in the period
To verify the amount of benzene being discharged to the Sanitation Districts’ sewerage system, each company in the program is required to obtain grab samples of their wastewater and have the samples analyzed for benzene. Sample frequencies are outlined below. Samples must be taken in accordance with approved methods for wastewater containing volatile organic compounds as outlined in the Handbook for Sampling and Sample Preservation of Water and Wastewater, (EPA 600/4-82 029). Analysis must be performed by a laboratory certified by the state or the Sanitation Districts using either EPA method 602 or 624. Benzene monitoring reports must be typewritten using a copy of the “Industrial Waste Self-Monitoring Report for Benzene” form and must include copies of all lab reports and wastewater flow records for the reporting period. Lab results must be reported by recording the date that the sample was taken and the corresponding benzene concentration in micrograms per liter in the spaces provided. The total wastewater discharged in thousands of gallons must be reported for each month of the quarter. If the flow data were obtained from a Sanitation Districts approved and properly calibrated wastewater flow meter, the company must check the first box on the Source of Flow Data section of the report. If the flow was estimated or measured in some other way, the company must check the appropriate box and attach a sheet, which explains in detail the method used. The company must also attach any other documentation that supports the flow data provided such as flow metering logs, batch discharge records, or monthly Department of Oil and Gas Reports. The benzene monitoring report must be signed and dated by a responsible company official and submitted to the Sanitation Districts Industrial Waste Section no later than 21 days after the end of each quarter.
Minimum Benzene Monitoring Requirements
DISCHARGER TYPE FLOW RATE TEST FREQUENCY*
Non-Refiners 30,000 or less 1 per 4 weeks
Non-Refiners More than 30,000 1 per 2 weeks
Oil Refiners 1 million or less 1 per 1 week
Oil Refiners More than 1 million 2 per 1 week
*Dischargers with benzene discharges less than 100 pounds per quarter may request amended test frequencies.