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Diagnosing Nitrification Problems

Nitrification is a critical step in many wastewater treatment systems.

Environmental Business Specialists, LLC (EBS) is a recognized authority in the area of biological wastewater troubleshooting, training, and optimization. With clients throughout North America, EBS has worked with some of the largest industrial wastewater systems in the world. A staff of twenty-five dedicated wastewater specialists, including engineers, microbiologists, and chemists are available to assist you in all aspects of system assessment and optimization.

One area of particular specialty is nitrification. Nitrification is a critical step in many wastewater treatment systems and becoming more important as regulations tighten regarding nutrients in industrial effluents. Nitrification is the biological oxidation of ammonia, first to nitrite and then to nitrate. It is carried out in activated sludge systems by two unique types of bacteria – Nitrobacter and Nitrosomonas. These bacteria are much more sensitive to environmental conditions than their heartier carbonaceous cousins.

Periodic loss of nitrification can be a puzzling and serious problem for operators of municipal and industrial wastewater systems. EBS offers a full menu of products and services to help you solve a wide variety of nitrification related issues. While a site visit is sometimes required, it is often possible for the EBS staff to assist you in returning your system to peak performance by evaluating plant performance parameters and utilizing respirometry to simulate the performance of your biomass under varying conditions. EBS has conducted numerous studies to determine the nitrifying capacity of the biomass under various conditions, such as temperature or alkalinity. Respirometry has also been used to evaluate the potential toxic impact of streams or compounds on the nitrifiers. This information is invaluable in determining the root cause of loss of nitrification or evaluating the potential benefits of adding commercial nitrifiers or nitrifying bacteria.

By conducting a comprehensive nitrification evaluation via respirometry, EBS can determine the current “state of the system” in terms of nitrifier health and evaluate the influent for toxicity/inhibition.

A typical project of this type consists of:

1.       Review of performance data for at least the past one to two years to evaluate trends and investigate any underlying relationships that may be affecting performance.

2.       Ammonia uptake on the plant’s biomass by adding ammonia under controlled conditions. This will give us an idea of the nitrifying capacity. This is combined with other testing such as microscopic examination to provide a general assessment of the system biology.

3.       Testing the impact of the influent and effluent on standard commercial nitrifier cultures to measure toxicity/inhibition.

Testing typically takes a couple of days with results available a few days later. The cost for this time of work depends on the number of samples and the complexity of the test protocol and can range from as low as $800 for a single sample to several thousand dollars for a complex study.

Based on the findings from this work, we will make formal recommendations that may include process changes, application of NitriStar 750 nitrifying bacteria, or a site visit by one of EBS’s wastewater specialists. Figure 1 below shows the results from a client study where nitrification was lost and high temperature was suspected. As the test results showed, even at temperatures of 110 F, the samples seeded with commercial nitrifiers were able to show a significant increase in ammonia removal.

impact of nitrifiers addition on ammonia removal

As winter approaches, nitrification is often the first aspect of your treatment that suffers. For more information about how EBS can help you now and in the future with nitrification issues CONTACT US.