Pharmaceutical contaminants present in wastewaters cause severe health hazards among chronically exposed population. Emerging pharmaceutically active contaminants pose a serious challenge to conventional treatment technologies. Employing advanced treatment technologies for the abatement of such contaminants is usually energy-intensive. In this study, a complex pharmaceutical wastewater from a pharmaceutical industry in California, USA, was treated by employing a novel bio-electrochemical treatment train system. Labeled "Bio-electroperoxone," our proposed system comprises (i) an electrically bound biofilm reactor (EBBR) that accelerates bacterial adhesion for the removal of biodegradable and persistent organics and (ii) an electroperoxone reactor that removes recalcitrant organics with minimal energy uptake. The EBBR comprises a platinum-coated titanium cathode and a conductive nematic liquid crystal display electrode (NLCE) obtained from electronic waste that serves as the anode. Characterization of functional groups, morphology, and elemental mapping of NLCE were carried out to explain mechanisms for rapid biofilm attachment. The concomitant electroperoxone reactor comprises a platinum-coated titanium (Pt-Ti) anode and a reticulated vitreous carbon (RVC) cathode that catalyzes the two-electron reduction of oxygen to form in situ H2O2. The bio-electroperoxone system (i) inactivated 99.99% of the micro-organisms, removed (ii) 92.20% of the color, (iii) 84.72% of the total suspended solids, and (iv) 89% of the total organic carbon (TOC). Possible mechanisms for the degradation of organic contaminants are elucidated. Bio-electroperoxone thus paves the way for an efficient and sustainable approach for the efficient removal of both biodegradable and recalcitrant, persistent organic contaminants from pharmaceutical and possibly other complex wastewaters.
Keywords: Advanced oxidation process; Bio-electroperoxone; Biodegradation; E-waste; Nematic liquid crystal electrode; Pharmaceutical wastewater treatment; Reticulated vitreous carbon electrode.