[미국] 뉴욕 슈퍼펀드 지역에 새로운 처리 기술 적용

환경보호국은 뉴욕 Dewey Loeffel Landfill Superfund 지역의 처리 플랜트에 새로운 기술을 적용한다고 밝혔다. 2014년 1월에 운영을 시작한 플랜트는 오염된 지하수와 쓰레기 매립지의 액상 오염을 처리한다. 새로운 시스템은 1.4 다이옥신의 장기간 처리하고 화장품, 세제, 샴푸의 구성요소인 안전제와 용액을 다루기 위해 설치된다.

1952년부터 1968년까지 Dewey Loeffel Landfill Superfund 지역은 여러 수도지구 회사에서 발생하는 4만6천톤의 폐기 물질을 처리하기 위해 사용됐다. 회사에서 발생한 폐기물에는 산업용액, 폐기오일, 폴리염화비페닐, 폐기물질, 침전물 등을 포함하고 있었다. 휘발성의 유기 화합물과 다른 위험한 물질이 매립지에서 새어나와 지하수를 오염시켰다. 또한 폴리염화비테닐은 하류까지 이동하여 나소 호수주변의 어류와 침전지를 오염시켰다.

The Environmental Protection Agency (EPA) has announced that an additional treatment technology will be added to the existing treatment plant at the Dewey Loeffel Landfill Superfund site in Nassau, Rensselaer County, New York. The plant, which began operating in January 2014, is treating liquids seeping from the landfill, called leachate, as well as contaminated groundwater. The new system is being added to further address the long-term treatment of the chemical 1,4-dioxane, a stabilizer and solvent that is also a component of some cosmetics, detergents and shampoos.

From 1952 until 1968, The Dewey Loeffel Landfill Site was used for the disposal of an estimated 46,000 tons of waste materials generated by several Capital District companies including General Electric, Bendix Corporation (now Honeywell International, Inc.) and Schenectady Chemicals (now SI Group, Inc.). The waste included industrial solvents, waste oils, polychlorinated biphenyls (PCBs), scrap materials, sludge, and solids. Volatile organic compounds and other hazardous substances have seeped out of the landfill and contaminated the groundwater. PCBs have also moved downstream, causing contamination of sediment and several species of fish in and near Nassau Lake.

Since the treatment plant began operating, EPA has required that the treated water be stored in a series of three on-site storage tanks and tested before each individual tank is discharged to the Valatie Kill. This tank-by-tank process will continue until seven to 10 days prior to delivery of the new treatment system, expected in late October. In order for the new system to be installed, the storage tanks at the site will need to be removed. The EPA will approve direct discharge from the plant to the Valatie Kill at that time, provided the sampling data continues to meet the stringent discharge limits set by the New York State Department of Environmental Conservation (NYDEC). It's expected that EPA will have sampling data from about 40 individual tanks by the time it allows any direct discharges from the treatment plant.

Out of an abundance of caution, the rate of groundwater and leachate coming into the plant for treatment, called the flow rate, will be reduced as low as possible while the additional treatment technology is being installed. The plant needs to continue operating during the two- to three-week installation period to ensure that one of the treatment technologies in the plant relying on microorganisms to treat the wastewater can continue to operate effectively. The wastewater and leachate coming into the plant provide the nutrients these microorganisms need to survive. After the new treatment system is installed, the flow rate will be increased. Surface water will be sampled at least three times after direct discharge is approved.

The slow startup phase was intended to gradually bring the plant up to capacity to ensure that it is working effectively and is capable of meeting the discharge limits set by the NYDEC. To date, 26 tanks have been sampled, analyzed and individually discharged to the Valatie Kill. This comprehensive sampling program has demonstrated that the plant is working as intended. The majority of compounds tested in the tanks that were discharged have not been detected in the treated water and all have been below the requirements set by the NYDEC for discharge to the Valatie Kill. The carbon filtration system, a component of the existing treatment plant, has been effectively removing 1,4-dioxane and will continue to be the primary treatment method for 1,4-dioxane until the new treatment technology is in place.

Prior to direct discharge, some modifications will be made to the existing sampling schedule. Sampling will meet and exceed the requirements set by the NYDEC. While there is no discharge limit set for 1,4-dioxane at this time, the state requires quarterly monitoring. Sampling for 1,4-dioxane in the treated water will occur weekly, in excess of the requirement.

[출처 = Water World / 2014년 7월 22일]