Simultaneous application of CaO2 nanoparticles and microbial consortium in Small Bioreactor Chambers (SBCs) for phenol removal from groundwater

Abstract

Phenols are toxic products derived from a wide range of industrial activities and the entry of these contaminants into the environment is seriously hazardous for both human and aquatic ecosystems. This study presents the use of a phenol-degrading consortium surrounded in an innovative “Small Bioreactor Chambers” (SBCs) along with biostimulation for phenol bioremediation from contaminated groundwater. To investigate the effect of biostimulation, synthesized-calcium peroxide (CaO2) nanoparticles were applied. The phenol-degrading consortium, was successfully isolated from a water well located in Iran. The highest growth rate and phenol degradation of the ph100-consortium were observed at 15 °C and pH 7.5 in the presence of 500 mg·L-1 of powdered CaO2 and 100 mg·L-1 of phenol as a sole source of carbon. Next-generation sequencing (NGS) analysis of the consortium revealed that Proteobacteria and Bacteroidetes with 75.3% and 16.2% relative abundance were the dominant phyla in the ph100-consortium, respectively. Experimental results indicated that 100% of the contaminant (100 mg·L-1) was successfully removed from groundwater using encapsulated CaO2 within 60 days with the negligible negative impacts on the microbial population. Furthermore, the highest biodegradation percentage were achieved during incubation of SBCs in a medium supplemented with 500 mg·L-1 CaO2 powder in 25th days of experiment. These results provide certain evidence for a successful simultaneous application of biostimulation and bioaugmentation processes through SBCs for contaminated water treatment.