Calculation of Radius of Influence and Evaluation of Applicability of Air Sparging/Soil Vapor Extraction system for the Remediation of Petroleum Contaminated Rail Site

Abstract

The objectives of this study were to calculate the radius of influence (ROI) of well for an air-sparging (AS)/soil vapor extraction (SVE) system and to evaluate the applicability of the system applied for the remediation of the petroleum contaminated rail site. For air permeability test, three monitoring wells were installed at a location of 1.3 m, 2.3 m, 3.0 m from the extraction well. And the pressure of each monitoring well was measured by extracting air from the extraction well with the pressure and flow of (−)2,600 mmH 2 O and 1.58 m 3 /min. The ROI for an extraction well was calculated as 4.31 m. Air was injected into the injection well with the pressure and flow of 3,500 mmH 2 O and 0.6 m 3 /min to estimate the radius of influence for oxygen transfer. Oxygen concentrations of air from three monitoring wells were measured. The ROI of an injection well for oxygen transfer was calculated as 3.46 m. The 28 extraction wells and 19 injection wells were installed according to the ROI calculated. The AS/SVE system was operated eight hours a day for five months. The rail site was contaminated with the petroleum and concentrations of benzene, toluene, and xylene were over the 'Worrisome Standard' of the 'Soil Environment Conservation Act'. The contaminated area was estimated as 732 m 2 and contaminants were dispersed up to (−)3 m from the ground. During the operation period, soil samples were collected from 5 points and analyzed periodically. With the AS/SVE system operation, concentrations of benzene, toluene, and xylene were decreased from 7.5 mg/kg to 2.0 mg/kg, from 32.0 mg/kg to 23.0 mg/kg, from 35.5 mg/kg to 23.0 mg/kg, respectively. The combined AS/SVE system applied to the rail site contaminated with volatile organic compounds (VOCs) exhibited a high applicability. But the concentration of contaminants in soil were fluctuated due to the heterogeneous of soil condition. Also the effect of the remediation mechanisms was not clearly identified.

Remediation of Petroleum-Contaminated Gas Station Soil Using High-Pressure Soil Washing Technology

“…[9][10][11] 열탈착법은 적정한 수준의 열을 가해 토양 내 유류 오염물질을 증발시키는 토양정화 기술로 단기간 에 높은 정화 효율을 보여줄 수 있지만, 운영비가 높아 경제성 이 낮다. 12,13) 토양증기추출법은 오염토양 내에 공기를 주입한 후 진공조건에서 VOC를 휘발시켜 제거하는 기술로 초기 건 설 비용은 저렴한 편이나 장기간 운영 시 경제성이 떨어진다 는 단점이 있으며, 경유로 오염된 토양에는 효과적인 정화 효 율을 기대하기 어렵다. [14][15][16] 토양세척법은 대표적인 Ex-situ 정 화기술로 물리적 선별(Physical separation)과 화학적 세척 (Chemical extraction)이 결합되어 있는 기술이다.…”