Brookhaven National Laboratory
Posted on July 1, 2015
Client: Brookhaven National Laboratory
Location: Upton, NY
- Short-Term Monitoring Program
- Quantification & Removal Study
- Mercury Minimization Program
Brookhaven National Laboratory (BNL) is a multiprogram laboratory located on 5,265 acres of land in central Suffolk County, New York. BNL is managed by Brookhaven Science Associates under contract to the United States Department of Energy. The BNL facility contains numerous research and support buildings, including various facility services and research related processes that generate sanitary and process wastewater which is conveyed to BNL’s Sewage Treatment Plant (STP). BNL maintains a State Pollutant Discharge Elimination System (SPDES) Permit for the discharge from the STP, as well as several other outfalls located at the facility.
In total, 16 outfalls are regulated by the Permit. Twelve of the outfalls are groundwater discharges
that consist predominately of storm water, non-contact cooling water and cooling tower blowdown. One of the outfalls is the previously mentioned BNL STP discharge, which is regulated as a surface water discharge, and the remaining three outfalls are internal outfalls that discharge to the sewer system connected to BNL’s STP. The New York State Department of Environmental Conservation (NYSDEC) modified BNL’s SPDES Permit in July 2009 to include very stringent copper, iron, lead, mercury, nickel and zinc water quality based effluent limits on BNL’s STP discharge to the Peconic River. In addition, the modified Permit required a Short-Term Monitoring Program, Quantification & Removal (Q&R) Study for the six metals of concern and development of a Mercury Minimization Program (MMP). Dvirka and Bartilucci Consulting Engineers (D&B) was retained to conduct the studies and develop the required reports to be submitted to the NYSDEC.
Short-Term Monitoring Program
The Short-Term Monitoring Program was performed at the request of NYSDEC to determine whether certain pollutants were present in the BNL outfalls that would require additional monitoring or control to be specified in the SPDES Permit. The program included the collection of samples from 14 outfalls on a weekly basis for a three-month period with the intent of characterizing wastewater quality at each outfall with respect to the pollutants of concern. Some of the pollutants of concern include arsenic, bromide, chloroform, 4,4’-DDD, 4,4’-DDE, 4,4’-DDT, endrin, mercury, phenol and selenium. Grab sampling techniques were utilized at most outfalls. The BNL STP outfall was sampled using BNL’s existing 24-hour flow-paced composite sampler. At two storm water outfalls, “first flush” samples were collected utilizing I-CHEM storm water samplers. These samplers allowed D&B’s sampling technicians to install sample bottles in the field prior to a rain event and retrieve the collected samples for laboratory analysis after the event concluded. This facilitated the collection of storm water samples regardless of the time of the rainfall event, which can occur overnight or on weekends when sampling technicians may not be on-site.
Quantification and Removal Study
The Q&R Study was specifically designed to identify, quantify and control discharges of copper, iron, lead, mercury, nickel and zinc at the BNL facility. The study included a detailed evaluation of processes and operations that may contribute these metals to the BNL STP, including but not limited to, discharges from cafeteria operations, laboratory activities, cooling towers, metal cleaning operations, water treatment plant backwash, boiler blowdown, boiler wash operations, vehicle cleaning and sanitary waste. D&B collected samples from each potential source on a weekly basis for a three-month period to characterize the wastewater quality at each source. The BNL STP’s influent wastewater, effluent wastewater, digester supernatant and treated wastewater to the existing sand filters were also sampled and analyzed during the program. In total, 450 samples were collected at approximately 40 locations during the field program.
Automated composite samplers were utilized at continuous discharges. BNL’s existing 24-hour flow-paced composite samplers were utilized to sample the influent and effluent wastewater at the BNL STP. The STP effluent wastewater samples were lagged behind the influent samples by the approximate hydraulic retention time of the STP to facilitate determination of the existing STP’s ability to remove the metals of concern. D&B supplied automated composite samplers for the remaining continuous discharges, which generally consisted of select locations within the BNL sewer system. At these locations, a time-weighted average sampling algorithm was utilized. Grab sample technique were used for intermittent discharges, such as cooling tower blowdown. All mercury sampling was conducted in accordance with the “clean hands, dirty hands” sampling techniques outlined by USEPA Method 1669. All low-level mercury analyses followed the USEPA Method 1631 which can achieve a detection limit as low as 0.5 nanograms per liter (0.5 parts per trillion).
In addition to the sampling outlined above, D&B collected flow measurements or estimated flow rates for each pollutant source included in the program in order to estimate the mass contribution of each potential source of metals to the BNL STP. Flow measurements were conducted in the wastewater collection system utilizing an ISCO Model 2150 Area Velocity Meter.At these locations, the area velocity sensor was installed within the sewer pipe to be monitored utilizing the manufacturer’s street installation tool with a tension band to hold the sensor in place. This allowed D&B’s technicians to install the flow sensor in below-grade sewers from street level, eliminating safety concerns and additional costs associated with conducting confined space entry. At some locations, where the collection of flow measurements was not feasible, BNL’s process knowledge, operating data or existing flow metering data was utilized to estimate daily flow rates.
Each waste stream was evaluated to determine the various processes that contribute metals of concern to the BNL STP. In addition, historical analytical data was reviewed and analyzed to determine the statistical probability of achieving the proposed water quality based effluent limits. The daily mass load from each source was calculated for each metal to prioritize those sources contributing the most metals, on a mass basis, to the STP. For each significant source, different source control strategies such as source treatment, collection and off-site disposal, and treatment at the STP were evaluated and recommendations were provided to address each significant source. In addition, several alternatives for upgrading BNL’s STP were evaluated. These alternatives included precipitation, ion exchange, granular activated carbon, proprietary adsorption technologies and eliminating the discharge to the Peconic River utilizing groundwater recharge.
A key finding of the Q&R Study was that the existing sand filters at the STP were one of the largest sources of metals, especially mercury, at the entire BNL facility. Another key finding was that sanitary-only sources were found to be a significant source of metals, indicating that source control alone would have only a limited impact on BNL’s STP effluent quality. D&B’s evaluation of the various alternatives identified as part of the study resulted in recommending replacement of the existing sand filters with cloth filtration and redirecting the STP discharge to new recharge basins to be constructed as part of the STP upgrade. Based on the findings of the study, D&B determined that is was more cost effective for BNL to redirect the STP effluent to a series of recharge basins than to install the sophisticated treatment technologies necessary to achieve the new water quality based effluent limits needed to continue discharging to the Peconic River, since the groundwater discharge standards could be
met using conventional wastewater treatment processes.
Mercury Minimization Program
The MMP established that the goal of the program required by the SPDES Permit and outlined by D&B is to reduce the mercury effluent levels in the BNL STP and ultimately achieve the NYSDEC calculated water quality based effluent limit. The MMP summarized BNL’s historical pollution prevention efforts aimed at reducing BNL’s mercury inventory and the use of mercury at the facility. These pollution prevention efforts will be continued as part of the MMP. The most significant mercury sources identified in the Q&R study were the existing sand filters and “legacy mercury” from historical laboratory activities which includes mercury-impacted plumbing components. The elimination of the existing sand filters was recommended as an integral part of any treatment upgrade to the STP to reduce the mercury levels in the effluent. A multi-phased approach was developed to reduce the legacy mercury emanating from the laboratories, including the replacement of key plumbing components (e.g., sink traps) and decontamination of plumbing components with a mercury release compound. The report established key monitoring locations to evaluate the success of each phase of the ongoing program. D&B prepared the first Annual Report required by the modified SPDES Permit which will serve as the basis for future Annual Reports that will document the progress made in implementing D&B’s recommendations.
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