TCE and CrVI source zone treatment by innovative formulation of NZVI

Abstract : NANOFREZES collaborative research program aims to develop an optimized formulation of Nanoscopic Zero Valent Iron (NZVI) using an innovative organic coating and preparation. Batch tests shows 99% abatement of TCE in 34 days for coated NZVI in comparaison with 11 days with bare NZVI. However, column test with real soil matrix indicate 67 % transfer of coated NZVI whereas only few percent of bare NZVI migrated through the column. These laboratory results indicate that it could be possible to increase significantly radius of injection (ROI) while high reactivity is maintained. This could limitate treatment wells and thus decreases in situ remediation costs. Complementary tests have also shown total reduction and immobilization of CrVI after coated NZVI addition. The new formulation of NZVI will be tested on a 5m x 5m source zone of TCE and CrVI located on a site in South France. First injection will be carried out on a single well with combined suspension of coated NZVI and bromide tracer. Many downstream wells will be monitored 2 times a month up to the second injection 3 month later for complete source zone treatment. Monitoring is planned up to 3 months after second injection. First injection is planned in July and will be the first official attempt of NZVI in situ injection in France.