Effects of the Feeding Solution Composition on a Reductive/Oxidative Sequential Bioelectrochemical Process for Perchloroethylene Removal

Chlorinated aliphatic hydrocarbons (CAHs) are common groundwater contaminants due to their improper use in several industrial activities. Specialized microorganisms able perform the reductive dechlorination (RD) of high-chlorinated CAHs such as perchloroethylene (PCE), while low-chlorinated ethenes vinyl chloride (VC) more susceptible oxidative mechanisms performed by aerobic dechlorinating microorganisms. Bioelectrochemical systems can be used an effective strategy for stimulation both anaerobic and microbial dechlorination, i.e., a biocathode electron donor RD, bioanode provide oxygen necessary reaction. In this study, sequential bioelectrochemical process constituted two membrane-less electrolysis cells connected series has been, first time, operated with synthetic groundwater, also containing sulphate nitrate, simulate realistic conditions possible establishment competitive processes reducing power, respect previous research made PCE-contaminated mineral medium (with neither nor nitrate). The shift from showed nitrate reduction caused temporary decrease PCE removal efficiency 100% 85%. analysis RD biomarkers (i.e., Dehalococcoides mccartyi 16S rRNA tceA, bvcA, vcrA genes) confirmed decrement performances after introduction characterized lower ionic strength nutrients content. On other hand, system self-adapted flowing current increased demand reduction, so that power was not defect although coulombic less.