Novel Oxidation Strategies for the In Situ Remediation of Chlorinated Solvents from Groundwater—A Bench-Scale Study

Industrial chlorinated solvents continue to be among the most significant issues in groundwater (GW) pollution worldwide. This study assesses the effectiveness of eight novel oxidation treatments, including persulfate (PS), ferrous sulfate, sulfidated nano-zero valent iron (S-nZVI), and potassium ferrate, along with their combinations, for the potential in situ remediation of GW polluted with chlorinated solvents (1,2-dichloroethylene, trichloroethylene, and tetrachloroethylene). Our bench-scale results reveal that the combined addition of PS and S-nZVI can effectively eliminate trichloroethylene (10 µg/L), achieving removal rates of up to 80% and 92% within 1 h, respectively, when using synthetic GW. In the case of real GW, this combination achieved removal rates of 69, 99, and 92% for cis-1,2-dichloroethylene, trichloroethylene, and tetrachloroethylene, respectively, within 24 h. Therefore, this proposed remediation solution resulted in a significant reduction in the environmental risk quotient, shifting it from a high-risk (1.1) to a low-risk (0.2) scenario. Furthermore, the absence of transformation products, such as vinyl chloride, suggests the suitability of employing this solution for the in situ remediation of GW polluted with chlorinated solvents.This research was funded by the European Union’s Horizon 2020 research and innovation program, grant number 101036449.Peer reviewe

The impacts of ozonation on oil sands process-affected water biodegradability and biofilm formation characteristics in bioreactors

To examine the effects of the ozonation process (as an oxidation treatment for water and wastewater treatment applications) on microbial biofilm formation and biodegradability of organic compounds present in oil sands process-affected water (OSPW), biofilm reactors were operated continuously for 6. weeks. Two types of biofilm substrate materials: polyethylene (PE) and polyvinylchloride (PVC), and two types of OSPW-fresh and ozonated OSPWs-were tested. Endogenous microorganisms, in OSPW, quickly formed biofilms in the reactors. Without ozonation, the bioreactor (using endogenous microorganisms) removed 13.8% of the total acid-extractable organics (TAO) and 18.5% of the parent naphthenic acids (NAs) from fresh OSPW. The combined ozonation and biodegradation process removed 87.2% of the OSPW TAO and over 99% of the OSPW parent NAs. Further UPLC/HRMS analysis showed that NA biodegradability decreased as the NA cyclization number increased. Microbial biofilm formation was found to depend on the biofilm substrate type.</p

Novel Oxidation Strategies for the In Situ Remediation of Chlorinated Solvents from Groundwater&mdash;A Bench-Scale Study

Industrial chlorinated solvents continue to be among the most significant issues in groundwater (GW) pollution worldwide. This study assesses the effectiveness of eight novel oxidation treatments, including persulfate (PS), ferrous sulfate, sulfidated nano-zero valent iron (S-nZVI), and potassium ferrate, along with their combinations, for the potential in situ remediation of GW polluted with chlorinated solvents (1,2-dichloroethylene, trichloroethylene, and tetrachloroethylene). Our bench-scale results reveal that the combined addition of PS and S-nZVI can effectively eliminate trichloroethylene (10 &micro;g/L), achieving removal rates of up to 80% and 92% within 1 h, respectively, when using synthetic GW. In the case of real GW, this combination achieved removal rates of 69, 99, and 92% for cis-1,2-dichloroethylene, trichloroethylene, and tetrachloroethylene, respectively, within 24 h. Therefore, this proposed remediation solution resulted in a significant reduction in the environmental risk quotient, shifting it from a high-risk (1.1) to a low-risk (0.2) scenario. Furthermore, the absence of transformation products, such as vinyl chloride, suggests the suitability of employing this solution for the in situ remediation of GW polluted with chlorinated solvents