In this video, I will demonstrate how to put the treatment plant into an anoxic zone. An anoxic zone is where the Aeration basin is depleted of dissolved oxygen (DO). If the air isn't being supplied for sometime, eventually denitrification will occur. This will help to breakdown the nitrates, nitrites, and nitrogen forming compounds providing for better pollutant removal in the end. It also helps to save a little energy but in this particular video, this isn't happening. There are 3 PD blowers that can supply air to 3 basins but only 1 is running. What I did in the video is just divert the air flow from the aeration basin to the equalization tank. This method is one way to control the amount of DO in the aeration basin. Wastewater textbooks say that 2.5 mg/l of DO is necessary in order to achieve good nitrification which helps get rid of ammonia compounds but results in the conversion of Nitrate compounds. Also, too much DO or over-aeration could potentially cause a bacteria's outer cell wall to become less "sticky" and that could result in a poor floc formation with the "food". If the floc is poor, the microorganisms won't settle to the bottom of the clarifier when they reach it. This will result in pin floc or lots of little bits of pieces of scattered sludge to overflow the weirs with the clear water.
