Digesting Odor Control

By Anna Simet | July 11, 2014

No matter what industry you’re involved in, it’s almost a certainty that somebody, somewhere, isn’t going to like what you’re doing. This might be for a number of reasons, including competitive interests, misinformation, or disproval for a legitimate reason.

In the biomass industry, we’re no stranger to criticism and accusations. So many truly believe in biomass energy and all of its positives and strive for perfection, but we’re not immune to mistakes or failure.

I bring this up because over the last couple of months, we’ve received emails from a very upset gentleman, I’ll call him Upset Digester Man, who told us about horrible smells coming from an anaerobic digester sited near his community. He wanted to know why we hadn’t run a story on how bad this digester smelled, as we ran a story a couple of years ago when it began construction. We usually respond to these emails (most of them sound like they are angry at us, as if we have involvement in these projects) and politely explain that we are a trade journal—we support the industry and serve to provide it with useful information—and while we’re a great source of information for the general public, that’s not who we cater to. On top of that, while we cover an enormous amount of industry news, as much as we possibly can, we don’t have the bandwidth to cover every single story in this rapidly expanding and broad industry.

Anyway, between Upset Digester Man’s first and second emails, it was discovered that this digester was, in fact, in violation of state air quality violations.

According to the digester’s state department of environmental management’s office of air quality, during an inspection it was observed that the facility failed to install the biofilter system for odor control on the exhaust for the substrate tanks, manure tank , blend tank and effluent storage tank, as specified in the permit.

So backtracking to what I said about the fact that we cater to the industry, sometimes it is members of the general public like Upset Digester Man who bring up issues that the industry does need to address, ones that cannot just be swept under the rug. Who wants an incredibly nauseating-smelling digester next to their home?

This reminded me of a conversation I had with Dan Goymerac of Miron Construction some while back, about the Potawtami digester located near downtown Milwaukee. He emphasized that the facility added a state-of-the-art odor control system to ensure there was no objectionable odor beyond property borders. That issue was really important, due to the project’s location.

Building a digester is no easy feat. It takes time, money, patience, careful planning, and they aren’t generally extremely lucrative. Most who are successful do it because they truly believe it’s the right thing to do for the environment, and they want to do it right.

But you’re always going to have examples like I mentioned above that rub people—outside of the industry—the wrong way. And as you all know, that can have incredible ripple effects, including on government and regulatory levels.  It is up to the industry as a whole to prove to people that it isn’t the norm.

I’ve stood right next to a digester and know what it smells like being that close. However, this was an onfarm digester, which are typically located away from the community and serve to actually improve odors at sites that have been using traditional liquid manure storage systems.

But what about these new digesters using food waste and other nontraditional feedstocks, which must be located closer to substrate sources—and communities— to ensure project economics?

You’re the experts, so tell me, as more of these kinds of digesters are launched in the U.S., is odor control a growing issue? Or are most facilities installing adequate technologies to prevent negative scenarios/perceptions? What’s the scenario overseas, where many more of these exist?