Study on the Flow Patterns Characteristic of Modified Carrousel Oxidation Ditch by Adjusting Working Conditions and Enhanced Nitrogen Removal Technology at Low-Temperature

摘要

In this study, carrousel oxidation ditch was used aiming to solve the common problems in the normal operating conditions, such as sludge deposition, low nitrogen removal rate at low-temperature and considerably huge energy consumption, whose treatment capacity was 10000m /d. Three experimental conditions were designed and such factors as flow profile, treatment effect and energy consumption were analyzed under different conditions in the oxidation ditch. The results showed that: in the optimal working conditions, with three aeration wheels in operation, the indicators for effluent quality namely COD and NH3-N can meet the first level of B criteria, which could ensure the dissolved oxygen environment about simultaneous nitrification and denitrification in the main ditch of oxidation ditch, consequently the nitrogen removal capacity of the system can be enhanced. After optimization, the effluent quality can meet the first level B criteria steadily. Additionally, with the area of sludge deposition zone reduced, energy consumption required for the safe operation of oxidation ditch was also reduced, with the power density being reduced from 29.61 W/m3 to 18.87W/m3.