Work

Influence of in situ biochar capping on microbial dynamics and ammonia nitrogen release in sediment

Year: 2024

Type: article

Abstract: To study the influence of in situ biochar (BC) capping technique on the release of ammonia nitrogen (NH 4 + -N) from sediments, a field mesocosm experiment was conducted in Baiyangdian Lake (BYDL), a critical water body often referred to as the "kidney of North China" where sediment pollution poses a significant threat to water quality. This study also assessed the impact of BC on sediment microorganisms. The results showed that the NH 4 + -N concentration in the overlying water of the BC-treated mesocosms was the lowest among four treatments, decreasing to 0.051 mg L −1 by the 60th day. More importantly, the BC treatment showed the least increase in NH 4 + -N concentrations in sediments compared to other treatments. For sediments capped with a 4 cm layer of BC, the potential release flux of NH 4 + -N was reduced from 1.84 mg m −2 d −1 to −0.76 mg m −2 d −1 . This reduction is likely due to the negatively charged surfaces of biochar, which enhance NH 4 + -N adsorption through electrostatic interactions. Additionally, BC modified the physical and chemical properties of the surface sediment, improving pH and increasing both organic content and the carbon/nitrogen (C/N) ratio. These changes influenced the microbial community structure within the sediments, enhancing NH 4 + -N removal. After 60 days, a significant alteration in the microbial community was observed in the BC-treated surface sediments. The addition of BC significantly increased the abundance of Proteobacteria and Firmicutes of the phyla in the sediments. Furthermore, BC enhanced the expression of functional genes including amoA, amoB, nirK, nirS, hzsB, nrfA and ureC , which are likely the primary microbial mechanisms promoting NH 4 + -N conversion in sediments for final removal. • In situ biochar capping technique reduced ammonia nitrogen release from sediment. • Biochar increased the abundance of specific microorganisms in the surface sediments. • Biochar addition enhanced functional genes for nitrogen conversion.

Source: Journal of Environmental Management

DOI: 10.1016/j.jenvman.2024.123524

Authors: Yu Zhao, Yaoyao Zhu, Jianyin Huang, Zhixin Song, Wenzhong Tang

Institutions: Chinese Academy of Sciences, Research Center for Eco-Environmental Sciences, The University of Queensland, University of South Australia, North China University of Water Resources and Electric Power

Language: English

Topic: Wastewater Treatment and Nitrogen Removal

Subfield: Pollution

Field: Environmental Science

Domain: Physical Sciences

SDGs: Clean water and sanitation, Climate action, Life on land

Open Access status: hybrid

Estimated APC paid: $3,850