Of Course foul odors are unacceptable! And, for composters who are truly committed to excellence, eliminating foul odors is simple, a standard practice. Bio-filters have been in use for decades. We've improved on the technology a bit, with our "Dynamic Bio-Filters", which have demonstrated themselves to be delightfully effective, while also being very cost efficient.
Our Compost Research Silos are inside a building, so the air is being re-circulated. We don't ask you to believe our words, that we can compost food residuals with no foul odors. We invite you to bring your nose over to our lab, and let your nose answer that question.
We learned the hard way that early stage compost, even when oxygen is maintained at 18% or above, can give off unacceptable foul odors. That taught us that we had to re-configure our aeration system to provide bio-filtering. Then we learned that for bio-filters, to work effectively, the moisture has to be maintained, high enough to support the micro-organisms that scrub the odors. We also learned that the bio-filter medium has to be turned at least once every six weeks to maintain uniform porosity. The turning also enables us to check the moisture content, and, if necessary, to re-hydrate the material.
Having learned those lessons, since February 16, 2004, we have had no foul odor problems, and we've been composting food residuals, including fish scraps. As said above, our compost research silos are inside a garage, in a confined space. The air being pulled through the early stage compost, is sent through the bio-filters. The air coming out of the bio-filters has a slight earthy odor. Sniffing, at a special port that we designed into the manifold, to enable sampling, the air after it has come through the very active early stage compost, before it goes through the bio-filters... there are foul odors, at that point. And, that is exactly why we use dynamic bio-filters, to eliminate those foul odors. Results are what count, and, we're able to compost food residuals, with no foul odors, outside of our aeration systems.