Lower Colorado River Authority
LCRA operates a series of dams along the Colorado river. These dams require periodic maintenance of paint stripping and painting. Because of the location of the work, lead abatement costs for paint stripping where very high and produced significant wastes. A particular site, Wirtz Dam, was scheduled for maintenance. If a conventional abrasive blasting technology was used and a standard two part epoxy had been chosen, approximately 83 tons of hazardous waste (D008) from blasting material would have been generated and 1,180 gallons of paint releasing 4.4 tons of VOCs would have been required.
Two technologies demonstrated in a pilot test showed a way to reduce these wastes. Cavi-Tech, Inc., of Atlanta, Georgia produces a blasting system using a jet stream of water (20,000 psi) to strip paint. The water jet is oscillated and cavitated to produce a series of blips similar to hammer blows whose velocity is increased over that of a standard water jet stream. The result is an increase in the force level which is applied in an aggressive and highly erosive strike pattern. The water is collected and filtered, removing the paint solids, and then the water is continually reused. At the end of a job the non-hazardous water is sent to a POTW and the only hazardous waste is the filter and sludge material. Wasser High-Tech Coatings of Kent, Washington produces a surface tolerent, moisture cured, single component urethane low VOC coating to replace the two part epoxy paint system. This system produces less than 25% of the VOC's of the epoxy paint.
Using these two systems LCRA was able to reduce the volume of hazardous waste generated by 78 tons or 95%. In addition, the wet strip conditions greatly reduced the levels of lead in fine dust in the air to 12-15µg/m3. VOC emissions were reduced by 3.4 tons.
Details of Reductions
Additional Information :
The total cost of the Wirtz project was $437,157. LCRA estimates that the one time savings on this project are $272,000.