Remediation of trichloroethylene-contaminated groundwater: Performance evaluation at a case study site

• Main Authors: Chia-Yuan Chang, 張嘉原
• Other Authors: Chih-Ming Kao
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/9u3ds3

碩士 === 國立中山大學 === 環境工程研究所 === 106 === TCE contamination was discovered in 2011 at the research site, and the remediation has been processed since then. After applying KMnO4 for ISCO between 2013 and 2015, TCE concentration reduced under maximum contaminant level (MCL). However, after stopping injecting substrate, concentration has found bounce back at 4.0 mg/L. To avoid TCE spreading, ground water diffusion control action had been applied between 2009 and 2011 to stopping TCE spreading out of research site. However, the effect to low contamination concentration is limited. Therefore, between 2012 and 2014, two high contamination concentration sites had been selected to apply bioremediation method. Substrate injection can stimulate Dehalococcoides to perform reductive dechlorination of chlorinated ethenes. In that case, concentration will decrease. Objectives of this research included the following (1) Using hydraulic control method to stop contamination from spreading outer research site. (2) Bioremediation: focusing on south of research site at GW1 well to assess long term remediation plan to improve the effective of remediation. (3) Contaminated area monitoring: in conjunction with groundwater contaminated improvement program. Selecting appropriate and existing monitoring wells to exam groundwater quality regularly to develop long term monitoring plan to assess the changes of contamination coverage. The study applied bioremediation method in the entire research site, adopting phased substrate injection with groundwater contamination control. Result on September 2017 showed the TCE contamination concentration were under MCL. GW1 which showed TCE concentration at 0.107 mg/L on February 2016 examine none TCE concentration on September 2017 and last 18 months. Additionally, the changes of contamination coverage had been calculated. Between 2016 and 2017, TCE contamination were lower than 0.05 mg/L. in contamination coverage, TCE contamination volume decreased from 349~702 m3 to 0 m3 indicated the contamination concentration and volume were reduced and under MCL. Consequently, effective of reducing concentration TCE contamination and control contamination coverage were successful in this study. The results indicate that after performing bioremediation process in contaminated source area, the growth of Dehalococcoides can be enhanced, the diffusion of target contaminants in groundwater can be controlled, and the development of bioremediation system to improve the efficiency of TCE reductive dechlorination can be achieved.