Demonstration research project of a new three-stage bio-oxidation pond for purifying black smelly water bodies

This is a comprehensive improvement project for the water environment of black smelly rivers. The project aims to carry out in-situ remediation of black smelly water bodies based on technologies including pollutant source control, in-situ remediation of substrate, biological contact oxidation tank - artificial aeration, ecological floating bed. The treatment effect has been analyzed. The project has improved the traditional biological contact oxidation pond by installing a tertiary biological contact oxidation pond with a daily treatment capacity of 300 m3 in the river. The result indicated that the biological contact oxidation tank combined with artificial aeration could efficiently reduce ammonia nitrogen in the water body. The concentration of ammonia nitrogen (NH3−N) has been reduced from 18.29 mg/L to 1.6 mg/L, with a removal rate of 91.3%. The water body has been purified from worse than Grade V to Grade V water. Meanwhile, and the water transparency has been increased from 2.5 cm to 21 cm. The concentration of dissolved oxygen (DO) has been increased from 0.19 mg/L to 2.1 mg/L. The concentration of dichromate oxidizability (CODCr) has been reduced from 191 mg/L to 23 mg/L. And the concentration of total phosphorous (TP) has been reduced from 2.72 mg/L to 0.27 mg/L. This process has a fast and stable effect on the treatment of black and smelly water, which is highly feasible in engineering application, and can also provide reference for in-situ treatment of urban black smelly rivers.