Floating covers are the most popular, although it is possible to use a cover supported by cables above the stored liquid. Researchers conducted scentometer evaluations on a pit before and after a synthetic cover was installed. In that evaluation, the cover greatly reduced the odor from the pit, Figure 1. Synthetic covers, unlike biocovers, should last for several years. Iowa State University's covers have been in place for eight years.
Producers can reduce the cost by installing the covers themselves.
Three cooperators are demonstrating biocovers as part of the Iowa Odor Control Demonstration Project.