Evaluation of the effectiveness of bioaugmentation and biostimulation in atrazine removal in a polluted matrix using degradation kinetics

The objective of the present study was the restoration of sterilized soil contaminated with atrazine (5.52 mg kg(-1)) using atrazine-degrading bacteria, biochar, and poultry manure amendments. The atrazine-degrading bacterium was purified from a mixed culture isolated from a long-history atrazine soil, and identified as Alcaligenes sp. strain AZUHUB-A31-CH52 ND4 based on the 16S rRNA sequence. After 35-day bioremediation, the sterile soil inoculated with Alcaligenes sp. and amended with biochar or poultry manure improved atrazine removal efficiency (98-99%) while the soil containing only atrazine degraders resulted in the lowest atrazine removal (78%). The atrazine degradation kinetics in the amended and unamended soils adequately fit the double first-order in parallel (DFOP) model given the goodness of fit parameters (high r(2) (0.9703-0.9997) and low AICc (-106.30 to -28.92) values. The DFOP model also predicted that DT50 (half-life) in all treatments was < 1 day (0.03-0.13 day) at a fast dissipation rate k(1) (5.422-20). The DT90 (90% atrazine removal) estimated by DFOP ranged between 23-94 days. The results demonstrated that low-cost bio-waste could offer a sustainable and eco-friendly approach for the reclamation of soils contaminated with atrazine.