Pictured are two aluminum covers, installed at a Greater Cincinnati area Wastewater Treatment Facility, sold by Chesley Associates, Inc. and manufactured and installed by Hallsten Corporation. The covers are substantially air tight, chemical resistant and designed to withstand loads of up to 400 lbs./sq.ft. over the entire surface without deflection. Hallsten aluminum covers can be configured in any shape or size to replace concrete, fiberglass and other bent sheet metal covers and are specifically intended for environmental applications. The aluminum panels shown are intended to help control odor at the site.