Nitrification is the biological removal of ammonia in lagoons of wastewater. The process involves the treatment of ammonia with bacteria that are present in the water. These bacteria enable the release of nitrogen gas to the atmosphere through the breakdown of ammonia present in the wastewater—leading to the nitrification of ammonia in the wastewater lagoon and thus, lowering the levels of ammonia in the effluent. Here are steps followed to remove ammonia during the industrial wastewater treatment:
1. Ensure that you have healthy levels dissolved oxygen in your lagoon
Nitrification of wastewater lagoon utilizes a high amount of oxygen. About 1.5lb of oxygen is required to oxidize each pound of biochemical oxygen demand or BOD, while every pound of ammonia oxidized uses up to 4.57 lb of oxygen. So in order for nitrification can take place in wastewater treatment systems, you will require a minimum of 2.0 mg/L dissolved oxygen and a maximum of 5mg/L DO (dissolved oxygen).
2. BOD to be removed first
Heterotrophic bacteria that are responsible for BOD removal usually competes with the nitrifying bacteria. For nitrification to occur, the level of BOD should be adequately reduced so that competition can be removed. Normally, a BOD level of 20-30 mg/l is necessary before ammonia removal in wastewater treatment systems can start taking place.
3. The lagoon PH needs to be in the range of 7.5-8.0
Lagoon nitrification is considered to be PH-specific, and the treatment of ammonia rate greatly declines at PH of below 6.8. The optimal lagoon nitrification takes place at PH in the range of 7.5-8.0. Many wastewater treatment companies ensure that their PH is in the mentioned range. But, industrial wastewater treatment lagoons may keep changing, so it’s necessary to keep monitoring the levels.
4. Enough lagoon water temperature
The decrease in temperature results to the slowing down of the nitrification process. Wastewater treatment companies should, therefore, ensure that their nitrification temperature ranges between 82 to 97 degrees F. For the majority of wastewater lagoons this is obviously impractical, but the suitable rates of lagoon nitrification can be attained above or at 68 degrees F.
5. Mix adequately to reduce sludge levels
Allowing the sludge to buildup in the wastewater system can lead to the release of ammonia. If there is no adequate lagoon mixing, the sludge levels will increase. This finally leads to higher levels of ammonia in the effluent compared to the influent.
6. Lack of toxins that hinder the process
Heavy metals and other toxins easily hinder nitrifying bacteria and not the BOD reducing bacteria. Always be sure that your wastewater has no toxic substances that can inhibit lagoon nitrification.
Ammonia removal can be a complicated process, and with the new ammonia effluent requirements, it makes it even a harder problem to deal with. But proper industrial wastewater treatment of ammonia requires that you invest in an efficient treatment method, infrastructure as well as regular monitoring of the required constituents. There is a great source of information available on the JNE Environmental website.