Research and Engineering Application of Biological Contact Oxidation–Sediment In Situ Remediation Technology for In Situ Treatment of Black Odorous Waterbodies

Abstract

This study involves a comprehensive rectification project for the aquatic environment of a black odorous river in Dongguan City, China. It employs a combined process treatment technology of pollution source control, in situ remediation of sediments, biological contact oxidation, forced aeration–biological agent combination, flowing water circulation, and landscape greening to remediate a heavily polluted river. The project has improved the traditional biological contact oxidation process and built a pond with a daily treatment capacity of $\mathrm{1,200}{\mathrm{m}}^3$ inside the river to perform in situ repair of the polluted water body. The results show that the pond can efficiently degrade ammonia nitrogen (${\mathrm{NH}}_3\text{─}\mathrm{N}$ ) and has a strong resistance to the impact loads of black odorous water. After the in situ remediation of the sediments, the pollutants were greatly reduced, and the average removal rate reached 56.03%. The tracking and monitoring of the combined process showed that the water quality index chemical oxygen demand in the later stage of the project was reduced from 187 to $25\mathrm{mg}/\mathrm{L}$ , ${\mathrm{NH}}_3\text{─}\mathrm{N}$ was reduced from 19.46 to $1.67\mathrm{mg}/\mathrm{L}$ , and total phosphorus (TP) was reduced from 2.51 to $0.32\mathrm{mg}/\mathrm{L}$ . Simultaneously, the dissolved oxygen increased from 0.12 to $6.34\mathrm{mg}/\mathrm{L}$ , and the transparency increased from 4 to 55 cm. This shows that the combined process is practical and effective and can efficiently remove pollutants such as organic matter, ${\mathrm{NH}}_3\text{─}\mathrm{N}$ , and TP from water, providing a reference basis for the in situ treatment of urban black odorous waterbodies.