Clean-water plants increasingly rely on controls to limit odors to surrounding neighborhoods and limit nuisance complaints.

Chemical and biological controls are proven effective against common gases such as hydrogen sulfide, but air streams containing odorous organic compounds can be more challenging to treat. Now, BioAir Solutions has created a Mobile Research Center (MRC) that it will deploy on treatment plant sites to test new biological odor-control technologies and help provide customers with treatments tailored to their own applications.

The laboratory, constructed in an over-the-road trailer, enables testing of biofilter technologies under operating conditions that can be varied and closely controlled. Biological media can be tested under different process conditions and treatment performance can be quantified under each scenario.  

Louis le Roux, company president, says the MRC will also help the company develop next-generation, sustainable biological solutions for treating air streams from municipal and industrial wastewater facilities. He talked about the mobile facility in an interview with Treatment Plant Operator.

TPO: Why did you develop the Mobile Research Center?

le Roux: Since our founding in 2006, we have made our mark with biological trickling filter technology for control of hydrogen sulfide odor. But we also want to be able to treat all odors coming from wastewater facilities, municipal or industrial, with biological technology.
Air streams can contain a lot of organic odorous compounds, and there are many unknowns about how well these can be treated by biological means. So about a year ago we decided to further the science of how to remove these compounds.

TPO: Why did you decide to create a mobile research facility instead of studying the removal processes in a laboratory?

le Roux: To get real-life data, it is preferable to take research to the field instead of trying to simulate things in small cylinders in the lab. A full-scale research trailer lets us experiment with many media types, biological processes and process parameters, with a goal to develop biological odor control that targets volatile organic compounds, and in particular organic sulfur compounds. It will help us bring to market technologies that set the standard for what is achievable. The goal is to have systems that can treat the whole cocktail of odors biologically.

TPO: Where odor removal is concerned, what are the limitations of lab-based research?

le Roux: The problem with lab testing is that it’s very controlled. You might find something that works in the lab, but then you take it to the field and find out there are interferences between the various odor compounds, so it may not actually work under field conditions. We decided to venture into new and somewhat virgin territory and discover what will work in live situations. That way we know the solutions we develop will work and are not just theoretical concepts.

TPO: How do the agencies that host the mobile lab benefit from the research?

le Roux: They get access to a proven biological technology that meets the specific needs of their application. That could mean they now have a technology to replace chemical scrubbers or carbon treatment with a biological technology that is very low in operating expense and has a compact footprint, and so is extremely cost-effective.

TPO: How long will the MRC stay at any given host site?

le Roux: Six months to one year. When you deal with a biological process, you don’t get reliable results overnight. We would never rely on a short-term study for developing processes. It’s essential to see what happens in the longer term.

TPO: What equipment does the MRC contain?

le Roux: The MRC is a 53-foot-long semi-trailer that we converted to a laboratory. It has eight reactor vessels that enable us to treat the same air stream in different ways. We can add different biological media types, and we can operate each reactor independently but on the same air so we don’t add another variable. We can also test different operating parameters and process conditions in each reactor. By having control over the process, the media and the microbiology, we can truly optimize the biological process for the application.

TPO: What are some examples of the ways in which you can control the process parameters in the different reactors?

le Roux: We can control the moisture going into each vessel. We can vary the biochemical additives – the nutrients we use boost the system’s performance. We can run the airflow with or counter to the water flow. We can also regulate the pH. The biological oxidation of many compounds leads to acid production. We can manipulate the pH so we don’t have a self-destructive process where the pH becomes too low and bacterial growth is hindered.

TPO: How is this research facility staffed?

le Roux: Dr. Ashraf Hassan, our senior process engineer, is responsible for the MRC and will spearhead the development of the biological processes. He has a Ph.D. from the University of Cincinnati in the biological odor-control field. Working with him is Timur Dunaev, senior technologist, who has a master’s degree in environmental engineering from Villanova University, with a focus on biotechnology. I will also assist. I have a Ph.D. in engineering from the University of Illinois at Urbana-Champaign and will monitor the development work.

TPO: Does this research facility have applications on the industrial as well as the municipal side?

le Roux: Yes. There is potential to bring it, for example, to industrial customers whose production capacity is being limited by air emissions. If we can help them limit their discharges, we can enable them to add capacity. So then we’re in a different realm where we add value to production by reducing emissions.

TPO: How do you measure the effectiveness of approaches developed in the MRC?

le Roux: There are different ways to quantify and qualify odors. There is speciation analysis in which we collect and analyze bag samples of untreated and treated air from various operating conditions. This helps us determine how well we remove particular odorous compounds like methyl mercaptan, dimethyl sulfide and dimethyl disulfide.

This form of analysis is most applicable in the industrial market, where specific compounds are regulated according to concentration. In municipalities, odors are more often a nuisance issue rather than a regulatory concern. So here we send bag samples to an olfactometry lab where they perform smell tests and express results in terms of odor units.