Bioremediation of crude oil polluted surface water using specialised alginate-based nanocomposite beads loaded with hydrocarbon-degrading bacteria and inorganic nutrients

Abstract

This study explored the elimination of petroleum from river water using matrix-bound composites of iron oxide nanoparticles (IONPs) decorated on biochar with immobilized hydrocarbon-degrading bacteria (HCB) and monoammonium phosphate (MAP) at 10%v/v pollution levels. The beads containing biochar and IONPs (BCNP) showed better pollutant removal than those with biochar alone (BC). The treatment with beads containing biochar, IONPs, HCB and MAP had the highest removal efficiency for TPH (98.5%) and PAH (93.7%) and the lowest biodegradation half-lives. The removal efficiency for TPH and PAH was greater in the treatment microcosms than in the controls with significant differences (p ≤ 0.05) between the two groups. TPH and PAH elimination levels differed significantly (p ≤ 0.05) between systems with the BC bead and those with the BCNP beads. The study revealed a steady increase in the abundance of the total cultivable heterotrophic bacteria and cultivable hydrocarbon utilizing bacteria in the treatment microcosms after an initial decline, with strong negative correlation between bacterial abundance and TPH and PAH concentrations based on r values (0.5 − 1.0) and shared variances obtained. Bacillus, Pseudomonas and Klebsiella pneumoniae dominated as the drivers of the bioremediation process while organic acids and esters (25.0%) and ketones (14.3%) were the main biodegradation metabolite groups.

Keywords:

• Biochar
• biodegradation
• biodegradation half-life
• biodiversity
• bioremediation
• hydrocarbon pollution
• iron oxide nanoparticles
• monoammonium phosphate
• river water
• water quality

Disclosure statement

The authors declare that they have no known competing interests.

Patents filed

There is a pending patent for the nanobioremediation beads

Additional information

Funding

This study was sponsored by the institution-based research grant from the Tertiary Education Trust Fund (TETFund), Nigeria and a research fellowship from the World Bank Africa Center of Excellence in Oilfield Chemicals Research (ACE-CEFOR).