Research on the treatment of black and odorous water bodies in rural areas under the background of rural revitalization

Abstract

This research addresses the excessive presence of pollutants, such as total nitrogen (TN), total phosphorus (TP), ammonia nitrogen (NH3-N), and chemical oxygen demand (COD), among others, in rural water bodies that are heavily contaminated and emit a foul odor. The base substrate used in this research consists of nano-particles of ferric chloride. Subsequently, these particles undergo chemical modifications using various agents, such as hydroxybenzoic acid, sodium hydroxide, chitosan, acrylamide, sodium polyacrylate, and zinc sulfate. To alleviate the contamination and foul odor in rural water bodies, the resulting composite material was combined with microbial effective microorganisms (EM) agents and subjected to an aeration process. The findings of this study indicate a significant reduction in the chemical oxygen demand (COD) value over a 70-day experimental period. The COD concentration in the water decreased significantly from 80 mg/L to a mere 15 mg/L, resulting in a reduction percentage of approximately 68.56%. Additionally, the water quality improved from a fifth-class rating, indicating inferior quality, to a third-class rating, denoting a higher quality. The oxidation-reduction potential (ORP) value remained stable at levels below 50 mV, while the redox potential increased fivefold, effectively eliminating black and smelly water. Moreover, the levels of TN and TP also improved from inferior fifth-class to third-class water quality. This research highlights the capacity of using a combination of flocculants and microbial treatments, in aerated environments, to significantly enhance the water quality in heavily contaminated and foul-smelling rural water bodies. The proposed method exhibits the potential to efficiently remediate heavily contaminated and foul-smelling water bodies in small-scale rural regions, indicating its robust scope for future application.