Groundwater Treatment From Hexavalent Chromiumusing in Situ Technology

The article reflects results of groundwater treatment from hexavalent chromium on ilek industrial site,aktobe,kazakhstan. this study describes specific techniques,practices and methodologies currently being employed on sites with so-called “historical contamination” in kazakhstan using in situ technology. the goal of this technology is to reduce cr (vi) in groundwater and contaminated soil to the more thermodynamically stable cr (iii) by creation reactive zones in the aquifer where migrating contaminants are intercepted and permanently immobilized or degraded into harmless end products. all work performed by injecting reagent in a contaminated groundwater plume and allowing them to “react” with the contaminants. the main difference from the standard in situ treatment technology was in creating so-called hydrocycles when after a period of reagent injection started phase of water injection for pressurization and enlargement the area of reagent delivery and after that period of pumping and reinjecting for the further intensification of treatment process. the process of treatment controlled on a numerical model to add or exclude injection wells from the pumping net.results from chemical reduction experiments on contaminated zone shown a considerable decrease of hexavalent chromium from 53 mg/l to 0.05 mg/l,indicating that in situ treatment using hydrocycles may be an effective approach when deployed at the field scale. the results of successful treatment are proved by the absence of secondary contamination during three-year monitoring on a site after a period of work performed.totally injected 1875 tons of ferrous sulfate.proved high efficiency of treatment using in situ technology. © national academy of sciences of the republic of kazakhstan,2017.