County of Sacramento - Waste Management & Recycling

As part of the effort to maintain this closed facility, the County is required to continually monitor groundwater and air quality in the vicinity of the landfill. In summer 2001, four new monitoring wells were installed in the following locations:

During the week of May 20, 2002 two new monitoring wells were installed in the Sheriff’s parking lot and a third monitoring well was installed on the southwest side of the landfill in the field east of Laguna Creek. The continued testing of those wells will determine the next step in the remediation project.

The Elk Grove Landfill has impacted local groundwater as we reported in October 2001. Significant progress has been achieved with remediation efforts. While progress to date has been substantial, there remains some work to do to enhance the effectiveness of the remediation system, and some changes have been made to the original concept due to identification of a groundwater “hotspot” beneath the Sheriff’s station.

Ongoing testing still shows very low levels of chemical contamination from the Elk Grove Landfill in wells operated by the Elk Grove Water Service. Residents and businesses in the area south of Bond Road, east of Elk Grove -Florin Road, west of Waterman Road and north of Dino Drive and Emerald Park Drive receive water from these wells. The water still meets drinking water standards set by the State Department of Health Services and does not pose any immediate health threat. Nonetheless, Sacramento County, in cooperation with the Elk Grove Water Service, is committed to containing and cleaning up this contamination as quickly as possible.

The chemical detected in the wells is tetrachloroethene (PCE), a solvent commonly used in dry cleaning. It is suspected that PCE has leached from the landfill into the groundwater.

Yes. The water meets all of the public health standards for drinking supplies set by the State Department of Health Services. That standard for tetrachloroethene in drinking water is 5 ug/L (micrograms per liter). The concentrations measured near the Elk Grove Water Service wells are approximately 1/10th of that safe drinking water standard.

In addition, the standard is intended to prevent health problems caused by a 70-year, lifetime exposure to this chemical. Investigations in late summer of 2001 revealed that the tetrachloroethene we found had only been in the water for a few months.

If the water meets public health standards, why is Sacramento County acting to take this chemical out of the water?

Even though the water provided by the Elk Grove Water Service meets all safe drinking standards, Sacramento County is committed to containing the contamination and cleaning it up before it creates a health problem. The clean-up is technically feasible and addressing this problem immediately will reduce clean-up costs and is in keeping with Sacramento County’s policy of preventing environmental problems rather than having to clean them up after the fact.

The landfill gas flare at the Sheriff’s station has been running 24 hours a day since last fall. This has resulted in significant reductions in volatile organic compounds (VOCs) in groundwater monitoring wells on the south side of the landfill. Gas vapors in the soil above the water table has also shown significant declines, such that methane gas has not been observed at all in the perimeter gas probes for months. The other component of landfill gas, carbon dioxide, is also declining rapidly in the south area.

The County continues to work closely with the Elk Grove Water Service on this problem and have kept them informed of all our findings. The most significant finding has been the identification of higher concentration VOCs in shallow groundwater beneath the Sheriff’s station. This higher concentration was discovered during construction of treatment wells in the station parking lot. This well has basically struck at the heart of the problem, and will be supported by additional monitoring wells and treatment wells, if needed, to isolate the contamination from the Fallbrook supply well, and to finally remove the contaminants.

Compared to other types of chemicals that contaminate water, tetrachloroethene is easy to treat and eliminate from water supplies. Sacramento County continues to work closely with the State Departments of Health Services and Water Resources, who have agreed to expedite any permits to insure that the cleanup can begin as quickly as possible.

Due to recent developments with the hot spot being located in the Sheriff’s station, the remediation effort is being concentrated on the west side of Laguna Creek. The first two groundwater treatment wells, EW-5 located on the bike trail at the end of Pelham Way and EW-6 in the Sheriff’s parking lot, became operational in early April 2002. A third treatment well, EW-4 is located on the bike trail off Ringe Circle. Initial results reported as non-detect. If contamination is detected the well can be used as a treatment well.

The treatment processes use compressed air to strip the contamination from extracted groundwater. The treated clean water is then reinjected back into the well in a shallower zone. These processes generate a hissing and bubbling sound that you may have heard as you pass over the well on the bike trail. Testing of air emissions from the off gas to the atmosphere over the vault lid has shown that there is no need for air treatment in the extraction wells. Should future conditions warrant, the extraction wells can be equipped with carbon filtration.

Two new monitoring wells have been drilled in the Sheriff’s station parking lot. Initial results show that our extraction wells are operating near the hot spot of the groundwater contamination. Continued testing of the monitoring wells in the Sheriff’s station will determine whether additional extraction wells are needed in the future. The most likely location of those wells would be in the Sheriff’s station and/or at the end of Ellery Place or Summer Tea Way. All of Sacramento County’s efforts on this project will be approved and supervised by the State, to insure that all drinking water and environmental standards are met.

To insure that the water in this area continues to meet safety standards, Sacramento County continues to monitor water quality in the Fallbrook water supply well on a weekly basis. This is far more often than the State’s requirement for monitoring every three months.

The County will continue to work with Elk Grove Water Service to provide residents with ongoing information regarding continued monitoring, project scheduling and progress of the remediation plan.

Please feel free to contact the following agencies for additional information:

Elk Grove Landfill Related Issues:
Chris Richgels, Manager, Engineering and Planning
Sacramento County, Department of Waste Management & Recycling
Phone: 916-875-7011
Fax: 916-875-6767
E-mail: Richgelsc@SacCounty.net

Water Supply Issues:
Tony Ouellette, Operations Manager, Elk Grove Water Service
9257 Elk Grove Blvd., Elk Grove, CA 95624
Phone: 916-685-3556
Fax: 916-685-5376