Evaluation of the Fate, Transport, and Concentrations ofRadionuclides In Septic Sludge and Leaching Fields

摘要

The Vermont Department of Environmental Conservation (VT DEC) has becomernincreasingly concerned by current practices for disposing drinking water treatment process wastesrncontaining radionuclides. Recently, the Drinking Water Program approved the discharge ofrnwashwater to an onsite dry well from an ion exchange unit used for radionuclide removal at arnmobile home park drinking water source. State wastewater program staff questioned this practicernand as a result, an interim management solution to discharge washwater to the septic system wasrnagreed upon. Solutions for disposal methods were discussed among Vermont agencies and withrnthe New England State Drinking Water Administrators, without conclusion. Of particularrnconcern to Vermont, are the fate, transport, and concentration of radionuclides discharged tornseptic systems and leaching fields and whether concentrated wastes result in health hazards.rnAlthough the same concerns have been expressed by other states nationwide, very few havernchosen to address the issue due to lack of existing data and minimal knowledge on the subject.rnWith implementation of the Radionuclides Rule, this problem will be further exacerbated andrnboth states and systems will be forced to confront it. Following a regional meeting held onrnSeptember 12, 2001, and receipt of EPA Region I funding, the New England states agreed tornwork cooperatively towards a solution. The University of New Hampshire (UNH) is co-fundingrnthe project and will serve as the principal researcher. NEIWPCC will coordinate state efforts.rnThe presentation will outline project objectives and the various issues associated with subsurfacerndisposal of radionuclides.rnThe project objective is threefold: define the problem and current New England practices, collectrndata from existing facilities, and determine the fate, transport, and concentration of radionuclidesrndischarged to septic systems and leaching fields from residential and very small system treatmentrnunits. Samples will be analyzed to determine if radionuclides are bound in the septic solids or ifrnthey pass through the system and are ultimately discharged to the subsurface. Approximately fivernto six sites from several states will be investigated. Preferably, both private homeowner andrnsmall community systems (serving less than 500) discharging to varying on-site wastewaterrnsystems in clay or gravel settings will be included. UNH proposes a study period of 18 months.rnDue to the difficulties of locating suitable sites, it is estimated that monitoring and data collectionrnwill not be initiated until April 2003. A final report will be completed by March 2004.