A/O process
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- Issue Time
- Mar 13,2025
Summary
The A/O process was produced in the 1970s. Because it has the functions of degrading organic matter and denitrification at the same time, and is easy to operate and manage, it has been widely used. Since the sewage treatment process is determined based on many factors such as the amount of sewage, water quality, effluent requirements and local actual conditions, small and medium-sized urban domestic sewage treatment stations generally use A/O and other processes.
A/O process
Introduction:
The A/O process was produced in the 1970s. Because it has the functions of degrading organic matter and denitrification at the same time, and is easy to operate and manage, it has been widely used. Since the sewage treatment process is determined based on many factors such as the amount of sewage, water quality, effluent requirements and local actual conditions, small and medium-sized urban domestic sewage treatment stations generally use A/O and other processes.
Process characteristics:
1. Advantages:
High efficiency: This process has a high removal effect on organic matter, ammonia nitrogen, etc. in wastewater. When the total residence time is greater than 54h, the effluent after biological denitrification is coagulated and precipitated, and the COD value can be reduced to below 100mg/L, and other indicators also meet the discharge standards, and the total nitrogen removal rate is above 70%. The process is simple, the investment is low, and the operating cost is low. This process uses organic matter in the wastewater as the carbon source for denitrification, so there is no need to add expensive carbon sources such as methanol.
2. Disadvantages:
Since there is no independent sludge return system, sludge with unique functions cannot be cultivated, and the degradation rate of difficult-to-degrade substances is low. If the denitrification efficiency is to be improved, the internal circulation ratio must be increased, thereby increasing the operating cost. In addition, the internal circulation liquid comes from the aeration tank and contains a certain amount of DO, which makes it difficult for section A to maintain an ideal anoxic state, affecting the denitrification effect, and the denitrification rate is difficult to reach 90%.
