SW 91404 Dalles

STORMWATER TREATMENT

The Dalles Lock and Dam on the Columbia River

Background

The Fifth floor of the US Department of Agriculture in Beltsville, MD has been retrofitted to hold its special collection. This space is used to store invaluable manuscripts, documents, and works of art. This 24,000 sq. ft. area is highly secured and isolated from all other building mechanical systems. This floor is also equipped with a very sophisticated computer-controlled “clean room” air conveyance system.

The problem

Despite a specially designed air supply and return distribution system and the most advanced air filtration system available, black soot and oil deposits were being found in the HVAC system’s duct-work as well as on documents and exhibit surfaces near the supply vents. Air samples were found to contain significant hydrocarbon levels. Surface sampling revealed traces of carbon deposits which were eventually traced back to bearing grease, motor lubricants and belt drive compounds within the air handling unit.

The Solution

It was suggested that the problem could be resolved by retrofitting the air handling unit from a “pull-through” to a “push-through” design. However, due to the high cost, inconvenience and timeframes that would be required, USDA called for alternative solutions. Air Tech International Corp. proposed to install Mycelx OilArrest filters and CPS membranes inside the blower compartment of the main supply plenum openings and the supply registers. After cleaning the entire air conveyance system, the Mycelx filters were installed overnight, at a fraction of the retrofit cost.

The Results

All hydrocarbons were removed from the air, leaving no trace within 3 minutesfrom the system re-start. No soot or oil deposits have been found outside the air handling unit in the four months since the filters were installed. Although the life of the Oil-Arrest filters and CPS membranes was projected at 6 months, replacement has been synchronized with the blower fan belt drives change-out schedule.