III. SANITARY SEWER RESULTS

The Laboratory’s sanitary sewer system is based on gravity flow and discharges through one of two monitoring stations: Hearst or Strawberry (see Figure 7-1):

• Hearst Station, located at the head of Hearst Avenue below Berkeley Lab, monitors discharges from the western and northern portion of the site. The monitoring site is located just before the Laboratory’s sanitary sewer system connects to the City of Berkeley sewer main.
  
• Strawberry Station is located next to Centennial Drive in Strawberry Canyon and monitors discharges from the eastern and southern parts of the Laboratory. Beyond the monitoring station, this section of the discharge system first ties into University-owned piping and then into the City of Berkeley system. Because of the design of the network, Strawberry monitoring station also receives effluent from several UC Berkeley campus facilities, which are located above the Laboratory and are separate from the main UC Berkeley campus (i.e., Lawrence Hall of Science, Space Sciences Laboratory, Mathematical Sciences Research Institute, Animal Research Facility, and the Botanical Gardens).

Figure 7-1     Sanitary Sewer System

Self-monitoring of wastewater discharge within Berkeley Lab also occurs at Buildings 25 and 77 and at groundwater treatment units (see Table 6-6), according to the terms of their respective East Bay Municipal Utility District (EBMUD) permits.¹

Berkeley Lab currently has four wastewater discharge permits issued by EBMUD: one for general sitewide discharges, two for the metal finishing operations found in Buildings 25 and 77, and one for the discharge of treated groundwater from hydraugers. EBMUD renews the site’s wastewater discharge permits annually in September, except for the treated groundwater permit, which is granted for two years. EBMUD is the local Publicly Owned Treatment Works that regulates all industrial discharges to its treatment facilities.

As in previous years, the Laboratory’s 1998–1999 permit required monitoring of wastewater discharge four times per year and metals analysis once per year at times specified in the permit. EBMUD continues to perform unannounced monitoring four times per year. There were no changes in discharge limits or other permit requirements. All sampling results are presented in volume II.

Sanitary sewer discharge monitoring is divided into two major types: nonradiological and radiological. Nonradiological monitoring is generally termed "self-monitoring" and is mandated in the wastewater discharge permits granted to Berkeley Lab by EBMUD. Sitewide samples are always analyzed for pH, methylene chloride, total suspended solids, and chemical oxygen demand, with additional analyses for metals required once during the permit year.

Radiological monitoring is required by Department of Energy guidance² and orders,³ but it also ensures compliance with the radiological limits given in the California Code of Regulations.⁴ California regulations now incorporate by reference the applicable federal regulations⁵ and associated discharge limits.

Analysis is performed by a state-certified outside contract laboratory. Results are compared against the discharge limits for each parameter given in the permits, and self-monitoring reports are submitted to EBMUD following permit requirements.

Four nonradiological self-monitoring samples were taken from the Hearst and Strawberry outfalls during 1998. All results were well within discharge limits, as were all measurements made by EBMUD in its independent samplings. Analysis for metals was required for only one of the four samples and was carried out at the November sampling. Most metals were not detected above detection limits in either Hearst or Strawberry outfalls.

Although no specific limit for iron is given in the permit, an EBMUD sampling showed an elevated level with respect to the thresholds given in Ordinance 311 (EBMUD Wastewater Control Ordinance). In voluntary response, in the July sampling Berkeley Lab analyzed for iron and found levels at about 2% of the ordinance limits. Figure 7-2 shows the metals results for the 1998 sampling as a percentage of permit discharge limits.

Figure 7-2     Concentration of Metals in Hearst and Strawberry Sewer Water Samples

Methylene chloride was not detected at either Hearst or Strawberry Station during the four samplings conducted this year. According to the permit, the pH level must remain at no less than 5.5; all results for 1998 were above 8.0. Total suspended solids and chemical oxygen demand are measured to determine wastewater strength, which forms the basis for EBMUD’s charges to the Laboratory for wastewater treatment. Starting with the 1997–1998 permit, Berkeley Lab is expected to estimate the average and maximum wastewater strength for the coming year in its permit application, and these then become the permit limits. The estimates for 1998 met EBMUD’s standard.

The Hearst and Strawberry sewer outfalls are sampled continuously by automatic equipment that collects samples at half-hour intervals. The composite samples are collected biweekly for subsequent analysis of gross alpha, gross beta, iodine-125, and tritium by a state-certified laboratory. Some split samples were occasionally analyzed by a third laboratory for additional quality control purposes.

The federal⁵ and state⁴ regulatory limits are based on total amounts released per year. For tritium, this amount is 1.9 × 10¹¹ Bq (5 curies) per year. The limit for all other radioisotopes is a combined 3.7 × 10¹⁰ Bq (1 curie) per year. Total amounts of monitored radioisotopes in Berkeley Lab’s sewer wastewater for 1998 are summarized in Figure 7-3.

Alpha emitters, which can potentially come from transuranic and heavy-element research, were never seen at either Hearst or Strawberry Station. Beta emitters, including iodine-125 from biomedical research, were detected in both sewers at low levels, generally with less at Strawberry than at Hearst. The highest readings for the year appear to have occurred at Hearst at the beginning of November and toward the end of December. For individual results, see the data tables in the appendix.

Tritium was generally below the minimum detectable activity at Hearst but was usually seen at Strawberry. The total yearly discharge of tritium in wastewater was 1.7 × 10¹⁰ Bq (0.46 Ci), and the total for other radioisotopes was 4.0 × 10⁸ Bq (0.011 Ci). Tritium was slightly above last year’s values, while the total for other radioisotopes remained about the same. All values, however, were well below allowable limits. For example, tritium was only 9% of the allowable federal and state limit, while all other isotopes together were less than 2% of their limit.

Figure 7-4 trends the total amount of tritium released to Berkeley Lab’s sewers over the last five years. Results vary from 4.4 × 10⁹ to 1.7 × 10¹⁰ Bq, which is about 2% to 9% of the permitted level.

Figure 7-4     Annual Releases of Tritium to Sewers (1994–1998)

The Photo Fabrication Shop in Building 25 manufactures electronic printed circuit boards and screen print nomenclature on panels to support the needs of Berkeley Lab research and operations. Wastewaters containing metals and other hazardous materials from these operations are routed to a fixed treatment unit (FTU) before discharge to the sanitary sewer. The Building 25 FTU treats wastewater in batch mode.

All sampling performed by Berkeley Lab and EBMUD during two monitoring efforts each yielded daily maximum results well within EBMUD discharge limits.¹ One self-monitoring measured a level of copper (2.4 mg/L) slightly above the monthly average limit (2.07 mg/L), but further sampling measured a much lower level, which brought the monthly average down to a level that was below the compliance threshold.

In 1997, the Photo Fabrication Shop obtained a filter, which first became operable in 1998. This filter was used to remove copper particles from wastewater generated by a mechanical scrubber and a surface deburring machine. This wastewater stream previously was required to be treated through the FTU. Using the filter, the Laboratory can recycle 19,000 liters (5,000 gallons) of water per year and reclaim the copper particles deposited on the filter cloth.

The Ultra-High Vacuum Cleaning Facility (UHVCF) at Building 77 cleans various types of metal parts used in research and support operations at Berkeley Lab. Cleaning operations include passivating, acid and alkaline cleaning, and ultrasonic cleaning. Vapor degreasing was phased out during 1998, replaced by a recently installed ultrasonic cleaning system.

Acid and alkaline rinsewaters containing metals from UHVCF operations are routed to a nearby 227-liter (60-gallon) per minute fixed treatment unit, designated FTU 006. During 1998, FTU 001 was officially closed and dismantled. DTSC, the City of Berkeley, and EBMUD were formally notified of the closure.

Three self-monitoring samples were taken from the Building 77 FTU during 1998. For two of them, all parameters analyzed were well within permit limits.¹ An unplanned chromium release to the sewer was detected by the July 9 sampling. This environmental incident was reported to EBMUD and investigated. For details on this incident, see §3.26.

Since 1993, EBMUD has permitted Berkeley Lab to discharge treated groundwater to the sanitary sewer. The treatment process consists of passing the contaminated groundwater through a double-filtered carbon adsorption system.

The EBMUD permit allows for discharge of treated groundwater from certain hydrauger treatment systems and extraction wells, plus well samplings and developments. All treated groundwater discharged under the permit is routed through the Hearst sewer. One of the conditions for this discharge is a quarterly report on the volumes treated and discharged and any contaminants found.

Tests using US/EPA-approved methodologies are run quarterly on treated groundwater to determine levels of volatile organic compounds. Most results have been "nondetect." Occasional detections of certain chlorinated hydrocarbons have been extremely low (parts per billion) and do not exceed allowable limits. As a precautionary measure, a sample is taken from between the two drums of carbon in each system to assist in determining when the first drum should be changed out. This prevents contaminated groundwater from being discharged to the sanitary sewer. For further discussion of groundwater monitoring and treatment, see chapter 6.