How can an operator increase the degree of nitrification in an activated sludge plant?

Increasing the degree of nitrification in an activated sludge plant involves optimizing conditions that favor the growth of nitrifying bacteria, which are responsible for the conversion of ammonia to nitrate. One of the key factors influencing nitrification is the dissolved oxygen (DO) level in the treatment process.

By increasing the DO, you create an aerobic environment that is conducive to the growth of nitrifying bacteria. These bacteria require significant amounts of oxygen to carry out their metabolic processes effectively. A higher level of DO supports their activity, enhancing the nitrification process.

Additionally, increasing sludge age allows for a greater retention time of the microorganisms within the system. This longer retention period means that nitrifying bacteria, which typically grow slower than other types of bacteria, have more time to establish themselves and flourish within the activated sludge system. This balance helps to ensure that sufficient nitrifying populations are present to handle the ammonia load coming into the plant.

Therefore, the combination of increased DO and sludge age provides optimal conditions for nitrification to occur, making this option the most effective choice for enhancing this process in an activated sludge plant.