Respirometry Analysis: Microbial Activity Assessment

The science of probing within microbial communities is called respirometry, meaning we have the ability to monitor microbial metabolic activity by measuring respiration rates. RespirTek employs respirometry to determine the rates of degradation of any organic or biological material that releases or utilizes quantifiable gases.

Illustration of respiration and microorganisms.

RespirTek, Inc. is the only laboratory in the United States with internally developed protocols for treatability and toxicity testing using respirometry on our ISO/IEC 17025: 2017 scope of accreditation. This certification (or “These certified protocols”) supports us in providing reliable testing services across a wide range of applications that are scientifically defensible.

Respirometry propelled our understanding of the impact of contamination, wastewater, or consumer products within their native and/or disposal environments. The advent of automatic respirometers offers significantly higher resolution in answering questions regarding how a bioenvironmental system will respond to the introduction of new compounds or wastes.

What is a Respirometry Test?

Respirometry is the study of oxygen consumption and biogas evolution due to metabolism in living cells. A respirometry test measures oxygen consumption in aerobic studies and biogas evolution in anaerobic studies for a specific consortium of microorganisms to determine its metabolic rate. In wastewater treatment, respirometry is used to assess the state of microorganisms by determining how much oxygen they consume and the rate of consumption, providing comprehensive insights into metabolic activity.

There are many different types of respirometry tests available, and testing can also be customized based on the specific type of microorganism and your broader wastewater treatment goals. A respirometer can measure aerobic and anaerobic processes, which are both normal chemical processes for cells and are an important part of mitochondrial function. Aerobic respiration occurs when oxygen is present and produces water and carbon dioxide, whereas anaerobic respiration occurs when oxygen is not present and results in carbon dioxide production along with the production of methane and other biogases.

Why Respirometry Matters

Respirometry helps wastewater treatment plants improve their processes and operate in a more environmentally friendly way. Part of the wastewater treatment process utilizes activated sludge, which contains a large consortium of microorganisms, to break down and remove the organic matter that is naturally present in sewage. By assessing how the microorganisms present in the activated sludge react to various waste streams and wastewater treatment methods, respirometry tests can help determine whether waste streams are helpful or harmful to wastewater treatment and whether current treatment methods are fully effective.

Respirometry testing helps wastewater treatment plants identify which microorganisms to use to supplement existing biomass or re-establish bacteria populations after a toxic or wash-out event. It provides helpful insight into their metabolic demands, allowing plants to find the right temperatures and oxygen levels for efficient processing.

How Respirometry Works

How does a respirometer work? Generally, a respirometry system works by monitoring the amount of oxygen microorganisms in a closed environment consume or the amount of carbon dioxide and other biogases that are produced. These measurements are then used to calculate metabolic rate.

Wastewater treatment plants need to know how to measure cellular respiration effectively and how to apply that knowledge to their testing procedures. There are two main types of respirometry tests: aerobic and anaerobic.

Aerobic  Respirometry

In an aerobic respirometry test, a wastewater sample containing microorganisms is placed in a sealed testing device. The device measures the amount of oxygen consumed by the sample over time. Some respirometers directly measure the oxygen level of the sample. As the oxygen levels decrease, the measurements will indicate the rate of oxygen consumption. Other respirometers measure the amount of oxygen consumed by measuring changes in headspace pressure of the reactor vessels. As oxygen is consumed, it is converted to carbon dioxide, which is subsequently absorbed by a scrubber solution, resulting in a decrease in the headspace pressure.

Aerobic tests are useful in assessing the health, effectiveness, and response effects of activated sludge used in aeration tanks and other aerobic biomass.

Anaerobic  Respirometry

In an anaerobic respirometry test, a wastewater sample containing microorganisms is placed in a sealed testing device without the presence of oxygen. The device measures the amount of biogas produced by the sample over time. As biogas is produced, the headspace pressure of the reactor vessel increases. This increase in headspace pressure is measured by the respirometer as an indication of metabolic activity of the sample. Anaerobic tests are useful in assessing the health, effectiveness, and response effects of wastewater sludge used in anaerobic digesters and other anaerobic biomass.

RespirTek™ is fully equipped to perform both aerobic and anaerobic work projects.

Laboratory table with vials and tubes.

Biological Applications

Groundwater Remediation, Wastewater Treatment, and Consumer Product Biodegradation Studies

The systems primarily under investigation at RespirTek include a range of bioenvironmental microorganisms found in soils, groundwater aquifers, composting systems, anaerobic digesters, and/or wastewater treatment systems. Respirometry enables us to monitor microbes in all types of environments, and we have experience fabricating specialty bioreactors for your special requirements. In many cases, respirometry is used in conjunction with chemical analyses so that correlations can be observed that relate microbial respiration with changes in contaminant or substrate concentrations in a quantitative fashion.

Respirometry Testing for a Brighter Future

Respirometry testing has various benefits, both for wastewater treatment organizations and for the community as a whole. Most importantly, respirometry can help communities operate in a more environmentally sustainable way. Through respirometry testing, organizations can ensure that their wastewater treatment processes are optimized, efficiently removing pollutants from wastewater. This creates a safer environment for everyone.

Respiratory testing can also be used to identify the No Observed Effect Concentration level, or NOEC, of a specific substance or waste stream. This is the highest possible concentration of substance that can be present without changing the respiration levels of the microorganisms in the water or activated sludge. Determining the NOEC of a substance or waste stream can be a critical step in identifying possible hazards to a wastewater treatment process.

Respirometry testing can also help wastewater treatment plants refine their operations, ensuring efficient pollutant removal while consuming fewer resources and complying with environmental regulations.

Finally, respirometry testing can make wastewater treatment more cost-effective. These tests can help identify and correct problems before launching new treatment strategies, potentially saving thousands of dollars. Through respirometry testing, you can also fine-tune your operations for affordability without sacrificing quality or safety.

Why RespirTek?

RespirTek is a leading environmental testing laboratory based in Ocean Springs, Mississippi. Since 2001, we have pioneered respirometry testing, using innovative methods to help clients improve their biological systems. RespirTek, Inc. is also the only laboratory in the United States with internally developed protocols for treatability and toxicity testing using respirometry on their ISO/IEC 17025: 2017 scope of accreditation.

We use internationally recognized accredited testing methods and can help your organization develop a custom respirometry testing plan based on your unique needs. Our advanced respirometric technology allows for real-time monitoring of microbial metabolic activity, providing valuable insights into the effectiveness of wastewater treatment and other biological processes.

Contact us today for more information or to develop a custom respirometry testing plan.