Simultaneous Removal of Perchlorate and Nitrate Using Biodegradable Polymers Bioreactor Concept

Abstract

Simultaneous perchlorate and nitrate removal from contaminated groundwater in one reactor has been realized with different methods in the past. The usage of biodegradable polymers as biofilm carriers and carbon source is new. Polymer in this paper was designed out of the copolymer of starch and polyvinyl alcohol. Under polluted water with 2 mg/L of perchlorate and 20 mg/L of NO3-N, it was possible to produce completely denitrification only for 5 h and below the detection limit to perchlorate within 9 h. Results indicating a significant impact of liquor pH on the biodegradation of but slight effect on nitrate reduction. Packed-bed reactor filled with polymer granules could remove 2 mg/L perchlorate and 25 mg/L NO3-N completely with influent flow rate of 1.17 mL/min. Morphological observation indicated the developed biofilm coverage on the outer surfaces of the carriers was dense and primarily composed of bacillus and coccus. The microbes in biofilm decomposed polymer, the chink and filament structure on the carrier surface developed, through metabolism and provided carbon source for them by releasing small organic molecules.