Wastewater Nitrification: Everything You Need to Know [QUICK GUIDE]

Wastewater Nitrification

Wastewater nitrification is essential for helping wastewater treatment plants reduce ammonia and meet effluent permit requirements. In this quick guide, we review what nitrification is, why it’s important and how it works.

What Is Nitrification?

Nitrification is the process of oxidizing ammonia to remove nitrogenous compounds from wastewater. Domestic sewage typically contains 20 to 40 mg/L (parts per million) of ammonia nitrogen, and it takes 4.5 mg of oxygen to fully oxidize 1.0 mg of ammonia nitrogen. To bring ammonia nitrogen levels down, industrial and municipal wastewater treatment plants add microbes to the water.

A wastewater treatment plant uses nitrification to:

  • Save time and money
  • Offset toxicity events
  • Meet effluent permit requirements
  • Improve nitrification during the winter
  • Increase plant operation efficiency

Why Wastewater Nitrification Is Important

Organic matter containing nitrogen releases ammonia when it biodegrades. When the ammonia enters receiving streams through wastewater effluent, it poisons the fish and other animals while causing significant oxygen depletion. And if the nitrogen and phosphorous levels are too high, it can lead to an algae bloom, making people sick.

The National Pollutant Discharge Elimination System (NPDES) permit program helps prevent these problems by regulating point sources like industrial and municipal wastewater treatment plants that discharge pollutants into water.

When a wastewater treatment plant gets a permit from the NPDES, the effluent must meet certain levels of reduced contaminants. If the plant doesn’t meet these requirements, the NPDES will issue warnings of non-compliance and then fines.

But how does a wastewater treatment plant know if it needs nitrification? Let’s dive deeper.

When Is Nitrification Necessary?

Most wastewater treatment plants need nitrification to happen all the time in order to keep their nitrogen levels low for permit purposes. Nitrification also helps a plant operate more efficiently.

The natural microbes in wastewater perform better in warmer weather. So in the summer, a treatment plant’s ammonia levels are typically acceptable because the microbes are happy with the climate.

In the winter, the growth rate of natural nitrifying microbial populations tends to slow down. Therefore, facilities perform cold weather nitrification to help reduce the amount of ammonia in the wastewater.

Signs a Wastewater Treatment Plant Needs Nitrification

In general, there are no visible signs a wastewater treatment plant needs nitrification. Foam and odor could be a clue, but those issues can occur for other reasons. Therefore, treatment plants rely on analytical testing to learn the ammonia levels in the water.

When those numbers are high, it’s time to start the nitrification process. That means partnering with a wastewater nitrification expert who can troubleshoot the problem and monitor the solution.

How the Wastewater Nitrification Process Works

Microbes are sensitive. When there are changes to factors like water temperature, pH or alkalinity levels, the wastewater microbiology becomes erratic. The result is high ammonia nitrogen levels, which are bad for the wastewater treatment plant and the environment.

Since maintaining optimal conditions isn’t always cost-effective, treatment plants turn to nitrification experts.

The wastewater nitrification process includes three steps:

  1. Evaluate the wastewater treatment plant
  2. Take and review wastewater samples
  3. Provide a solution

1. Evaluate the Wastewater Treatment Plant

The wastewater nitrification expert will visit your plant or facility to conduct a comprehensive evaluation. Instead of simply resolving the symptoms, they will take a deeper look into your plant’s operations to figure out why it’s not nitrifying. To do this, they need to put your wastewater under a microscope.

2. Take and Review Wastewater Samples

During their visit to your plant, the wastewater nitrification expert will take wastewater samples for laboratory testing. That way, scientists can determine the ammonia nitrogen levels in your wastewater for a baseline. They will also perform nitrification oxygen uptake testing to figure out what’s inhibiting the nitrifiers from doing their job of breaking down the ammonia nitrogen. From there, the nitrification expert can offer solutions for the problem.

3. Provide a Solution

The simplest way to fix your nitrification problem is to add natural microbial products to your wastewater. They are easy to use, safe to handle, environmentally friendly and have proven performance.

The traditional microbes used in the wastewater nitrification process are the Nitrosomonas species (ammonia-oxidizing bacteria) and Nitrobacter species (nitrite-oxidizing bacteria) because they have ideal growing conditions. This simplification makes it easy for the process operator and troubleshooter to work together since they are both familiar with the solution.

Recently, scientists found that another nitrite-oxidizing organism species, called Nitrospira, helps with the nitrification process. So wastewater nitrification experts may use a combination of the three species to get the best results.

Examples of nitrification products include:

In many cases, all you need to do is add the product to your plant’s aeration zone, and the microbes will work their magic.


Wastewater nitrification is complex, but the good news is you’re not alone. When you need a professional to fix your nitrification issue, find a partner who can get to the root cause of the problem and provide an actionable solution.

Monera Technologies offers expert consulting, comprehensive lab services and holistic nitrification solutions for wastewater treatment facilities. Contact us to learn how we can bring a cost-effective approach to your facility’s problems.