The City of Alexandria in partnership with Virginia Department of Environmental Quality has implemented a program to prevent, mitigate, and remediate (if needed) contaminated lands within the city. The City adopted an Administrative Procedures for the Development of Contaminated Land, which identified certain types of remediation for a variety of contaminants. Since that time, the City has incorporated language into the City's Zoning Ordinance that requires contaminated sites to be remediated as part of the development process. The Zoning Ordinance requires contaminated sites to be identified as part of the preliminary site plan submittal, while the final site plan must include plans indicating how the site will be remediated. In an effort to insure these sites are identified, the City maintains a contaminated land site map, which includes information on old landfills, underground storage tanks, and some former industrial sites.
City's Ongoing Contaminated Land Projects
- Oronoco Outfall - Alexandria Town Gas Site
VDEQ has a Voluntary Remediation Program (VRP) that allows for owners of contaminated sites that are not regulated under any of the programs or predates any regulations, to remediate those sites. The VRP consists of a program consisting of six key elements including: 1) a determination of eligibility; 2) submittal of registration fee; 3) report submittals including a site characterization, documentation of public notice, remedial action work plan and demonstration of completion report; 4) establishment of remediation goals based on current and/or future land use; 5) public participation to provide a forum for affected residents; and 6) a Certification of Satisfactory Completion documenting that the cleanup standards have been achieved.
Several sites in the City have entered into this program some are complete others are on going.
The Underground Storage Tank Program regulates most large underground storage tanks in Virginia and the City. Gas stations are the most common source of these tanks in the City. This program requires that the tanks be maintained so they do not leak and if it has been confirmed that tanks have resulted in a release to the environment, VDEQ requires the site to be remediated. There are cases in the City where tanks have leaked and the VDEQ has required remediation.
The City also has an Environmental Offenses Ordinance prohibiting illegal dumping or discharges to the sewer systems, streams, or on the ground etc. To assist in administering and enforcing this ordinance and to better investigate these type of releases, the City created an Environmental Industrial Unit, which meets monthly with representatives from the Police, Fire, T&ES, Code Enforcement and Recreation, Parks and Cultural Activities.
City's Contaminated Land Projects
Oronoco Outfall – Alexandria Town Gas Site
- The City of Alexandria continues to address environmental concerns associated with the Alexandria Town Gas – Oronoco site (ATG-Oronoco). Since entering the site into Virginia's Voluntary Remediation Program (VRP) in 2000, the City has made considerable progress towards remediating this site.
- Alexandria operated a manufactured gas plant (MGP) near the corner of North Lee and Oronoco Streets between 1851 and 1946. The plant produced a coal-derived gas to provide energy for residents and businesses in the City. From the late 1800's to the mid 1900's, thousands of manufactured gas plants across the United States supplied homes and industry with this manufactured gas for heating, cooking, and lighting.
- The production of manufactured gas created wastes, some of which remain at former MGP sites, long after the MGPs ceased operating. Over the decades during which many of these MGPs operated, coal tar leaked from storage and processing facilities and contaminated surface soils, subsurface soils, and groundwater. Today, municipalities across the country, like Alexandria, are working to remediate sites contaminated by MGPs.
- The City is committed to addressing issues associated with the site by pursuing cleanup under the Virginia's VRP. The Virginia Department of Environmental Quality (VDEQ) oversees the program to ensure that the cleanups achieve a satisfactory level of protection for human health and the environment and is actively involved in monitoring the progress of the ATG-Oronoco site remediation. The City has been pro-active in satisfying all requirements of the VRP to date.
- Coal-tar discharges from the Oronoco Street storm water outfall into the nearby Potomac River were first reported in 1975. The observations took place shortly after the City installed a tributary pipeline next to the former MGP beneath Oronoco Street. The tributary pipeline collects run-off from nearby streets and then discharges that run-off into the Potomac River 500 feet east of the site.
- After closing, most of the MGP was demolished and the remaining buildings were used by various businesses until the mid-1970s. In 1977, the site, including the last two remaining MGP buildings, was redeveloped into a commercial-office townhouse complex.
- In 1999, the City received letters from USEPA and the US Coast Guard notifying the City that it must immediately address the issue of ongoing releases into the Potomac River. The City applied and was accepted into the Virginia's VRP in May 2000.
- Over the last 17 years, the City has taken numerous measures to prevent further discharges of plant-related wastes into the river. However, the extent and complexity of the problem has made the development of an effective and lasting solution a difficult challenge.
Corrective Actions to Date
- Installation and operation of the floating oil containment boom around the outfall discharge area with additional oil absorbent booms installed and replaced periodically on the interior to collect contaminants.
- The City has installed and is currently operating a free product removal system that includes recovery wells installed in the source area. The removal of free product from the subsurface will make future remedial efforts more efficient.
- The City successfully completed the relining of the Oronoco Street storm sewer in 2006. The relining has reduced the amount of oily substances infiltrating into the pipe and subsequently reduced the amount of impacted material being discharged to the Potomac River.
- In 2008, the City's environmental consultant experimented with a treatment scheme that uses air and nutrients to breakdown oily substances near the outfall site, resulting in a significant reduction in contamination levels. Subsequent sampling has confirmed the continuing success of this biodegradation technique.
- Based on the above successful biodegradation technique, in 2013, the City installed a groundwater treatment system beneath Oronoco Street. The system removes coal tar from groundwater before it discharges into the Potomac River. After nearly five years of operation, quarterly groundwater monitoring of wells located downgradient from the system, indicate that the system is functioning properly.
- VDEQ approved the City's Remedial Action Plan (RAP) to dredge and cap the residual coal tar-impacted sediments within the Potomac River. The bulk of affected sediments will be removed and a reactive cap installed over the remaining sediments will eliminate future seepage of coal tar into the river and cut off potential exposure pathways to human and ecological populations. Once in place the cap will not be visible above the waterline. This work is scheduled for January 2018
- In February 2017, the City cleaned and inspected inside the main storm water pipe along Oronoco Street between North Union and North Fairfax Streets. Follow-up work identified and repaired pipe sections to ensure pipe integrity and prevent intrusion of contaminants into the pipe.
- VDEQ also requires the City proceed with an upland investigation. The investigation is intended to build upon data collected in previous years and is aimed at delineating the extent of below ground contaminant spread through the soil and groundwater. The collected data will be modeled to determine if further remedial actions are necessary. The upland investigation plan will take place in two phases. The first phase was completed in June 2017. The second phase was completed in winter 2018.
- The dredge and cap project was completed in April 2018.