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

ABSTRACT

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 r² (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 k₁ (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.

KEYWORDS:

• Atrazine
• biostimulation
• single first order
• double first order in parallel
• indeterminate order rate equation

Acknowledgments

The authors are grateful to Dr. Uchenna Nduka, Department of Statistics, Faculty of Physical Sciences, University of Nigeria, Nsukka, for his input in the statistical analysis of the data.

Disclosure statement

No potential conflict of interest was reported by the author(s).

CRediT author contribution statement

G.O. Aliyu: Data curation, Formal analysis, Investigation, Software, Methodology, Writing – original draft. C.U. Anyanwu: Supervision, Validation, Methodology, Writing - review and editing. C.I. Nnamchi: Supervision, Validation, Methodology, Writing - review and editing. C.O. Onwosi: Software, Validation, Methodology, Writing - review and editing

Declaration of competing of interest

There is no conflict of interest to declare.

Supplementary material

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