View looking down the tank after six months in service (tank cleaned). |
Aulffo Painting of Minotola, N.J., was consulted for its expertise on tank rehabilitation and to perform the tank refurbishment. "We constantly strive to provide long-lasting service and affordability to our customers, and in this unique situation we had to react quickly with a solution to minimize Logan Township MUA's tank downtime," said Jon Lattin of Corrosion Technology Systems. MUA arranged for a separate contractor to weld in new sections of stainless steel in areas that were compromised. The stainless steel was then abrasive- blasted by Aulffo Painting to achieve a 3-4 mil profile (SSPC-5 White Metal blast).
The lining material selected to protect the structure was Sauereisen's SewerGard™ No. 210X, chosen because of its chemical resistance, elongation and abrasion-resistant properties. Aulffo Painting spray-applied the material in two coats, totaling 60 mils, to withstand the corrosion and abrasion from solids and debris in the wastewater. The walls were coated 12 inches below the low waterline up to the top of the tank - the area most susceptible to the corrosive effects of the MIC.
Gary Aulffo, president of Aulffo Painting, stated, "We have been working with Corrosion Technology Systems and Sauereisen for over 10 years, and over the course of countless projects, they have proven to provide the highest quality products, complemented by excellent customer service." Another preventative measure taken by the Logan Township MUA was to replace the closed hatch tops with open grates to minimize the accumulation of destructive hydrogen sulfide gases in the vapor zone.
Spraying epoxy in February and March in the Northeast adds additional challenges for applicators such as keeping the material and substrate at the proper temperatures to insure ease of application and proper cure. Southern New Jersey's late winter temperatures are unpredictable with the average temperatures in the 30˚F – 45˚F range. Aulffo Painting erected a small heated storage area in which to store the materials before application and also piped heated air into the headworks tank during application.
"The entire project team - CTS, Sauereisen and Aulffo Painting - were all very helpful and responsive, resulting in a successful project with no issues," said Christopher Whalen, Logan Township MUA Superintendent. The structure was inspected by Sauereisen and MUA six months and 1.5 years after being returned to service and is exhibiting superior performance. The coating is 100 percent fully intact with no indications of areas of concern. It continues to be washable and serviceable and will be periodically monitored to ensure its longevity.
"The coating looks to be holding up great. We will continue to check it but, to date, we have no issues," Whalen said.WW
About the Authors: Jon C. Lattin, CSI, CCPR, from Corrosion Technology Systems, is an independent manufacturer's representative for Sauereisen. Jon is the current Vice President of the Construction Specifications Institue (CSI)–Allentown Chapter and serves on several committees for the Eastern PA Water Pollution Control Operators Association (EPWPCOA).
John E. Davis is a Marketing Specialist with Sauereisen Inc., a global manufacturer of corrosion-resistant materials. He frequently contributes to professional journals on the topics of specialty materials and the rehabilitation of wastewater infrastructure. John graduated with a bachelor's degree in business management and a minor in marketing from Penn State University with honors.