Devic-Bassaget, B. and J.-Y. Richard.
NORDROCS 2018: 7th Joint Nordic Meeting on Remediation of Contaminated Sites: Poster.

A new biofiltration process has been developed for treating perchlorate-contaminated groundwater. The extensive biofilter comprises a thin granular bed completely saturated with water. The contribution of a carbon source in the effluent and the presence of organic matter in the upper layer of the biofilter allow passage and maintenance in an anoxic condition, which is favorable for the desired biodegradation. A deep layer supports the purifying biomass. Initial lab tests validated the system's feasibility and main operating parameters. A semi-industrial pilot (10 m x 10 m) was carried out on site to test the hydraulics of the system and the efficiency of the reed declogging device. A first industrial application was conducted to treat heavily impacted groundwater from a source containing ammonium perchlorate. The biofilter achieved perchlorate biodegradation up to 15 kg/d. Under optimal conditions, the system yielded residual perchlorate concentrations of a few µg/L (ppb) from input at >100 mg/L.