The EcoFilter biological air treatment system from BioAir Solutions offers a sustainable, nontoxic way to treat odors at municipal wastewater treatment plants. The system uses biotrickling filter technology and a structured synthetic media that removes more than 99.5 percent of hydrogen sulfide and 95 percent of all odors without chemicals or carbon adsorbents.

The system’s uniform airflow, optimized mass transfer and controlled microenvironment facilitate proliferation of specific odor-removing bacteria. The filter is available in a range of sizes and configurations and can treat airstreams from 75 cfm to more than 100,000 cfm.

The system is not a bioscrubber, says Louis D. le Roux, company president. “A bioscrubber is basically a tower containing media that is irrigated with recirculated water,” he says. “Much of the biology resides in the liquid, rather than on the media. In the biotrickling filter, you don’t recirculate water — it’s a once-through system. The bacteria adhere to the media inside the reactor, so it’s a fixed-film reactor that allows for stratification of different types of bacteria. This enables removal of inorganic and organic odors in a single reactor vessel.”

With an estimated lifespan of more than 10 years, the low-maintenance filtering system includes a blower that moves air through the bioreactor, a control panel, and a programmable logic controller that can be connected to a SCADA system for remote viewing. “It’s a low-operating-cost system,” le Roux says. “The bacteria don’t charge you anything to do the work.”

BioAir has collaborated with North Carolina State University on the use of molecular biology tools using gene probing and DNA extraction to identify bacteria inside the reactor for optimum performance. Through further research, the company reduced residence time to about three seconds, similar to that of a chemical scrubber.

For plants not ready to abandon their existing technology, the filter unit can be installed in series before a chemical scrubber or carbon system to reduce operating costs. The modular system also can be rented, leased to purchase, and customized. 856/258-6969; www.bioairsolutions.com.