“…Biochar, a carbon-abundant product, is produced from pyrolyzing organic materials and has attracted increasing eyes in recent years since it can generate renewable energy, such as biogas and bio-oil, 21 and absorb toxic metals and organic chemicals in soil and water. [22][23][24] Compared with our previous work, 6 the addition of biochar may improve nitrate removal. However, it has not yet been widely studied that biochar and microbes give rise to joint effect on nitrate reduction in water bodies.…”