Lift Station In 13th Year Without Breakdown Of Chemical-Resistant Lining From Sauereisen

Rehabilitation Option with Polymer Lining Produces Long-Term Benefits

A Long History of Proven Performance
Sauereisen, Inc. of Pittsburgh, PA has been developing novel solutions to problems in industry since 1899. From initial High Temperature Bonding Cement to a complete line of corrosionresistant engineered materials for various industries, Sauereisen has remained the leader in providing high-quality products.

An On-Going Concern
Communities across the country continue to encounter challenging problems within their wastewater collection and treatment facilities. The process of Microbiologically Induced Corrosion (MIC) has been studied and documented for years. Of equal concern is the process of Inflow and Infiltration, (I&I) where water not intended for treatment enters the system. Each gallon must be treated, costing communities millions of dollars in additional expense. Sauereisen has engineered products and systems designed to address these problems.

A Case History
When faced with the decision to "repair or replace" degraded concrete structures in wastewater systems, several factors must be considered. Life expectancy versus cost is obviously a major factor. Does it make financial sense to rehabilitate a weakened, chemically attacked structure, or should it simply be replaced?

In 1988, Jefferson Parish, Louisiana chose to rehabilitate a concrete lift station, which was on the verge of disrepair. This particular structure, Lift Station I-10-1, sees a significant amount of turbulent flow, abrasion and hydrogen sulfide gas. The concrete prior to restoration was in extremely poor condition, with exposed reinforcement in much of the area. Meyer Engineering of Metairie, LA was awarded the contract to engineer the project. With the cooperation of Sauereisen's technical sales staff, a specification was prepared, which included the "SewerGard" Epoxy Lining System to restore the structure and to protect it from further chemical attack.

The SewerGard product is ideally suited for the demanding conditions existing in wastewater systems in the Gulf Coast area. In addition to highly corrosive conditions, water infiltration is ever present in southern Louisiana.

Python Corporation, of Slidell, LA was the installing contractor, who did an excellent job in properly preparing the structure prior to applying repair materials. This process entailed the removal of all loose, weak, chemically attacked concrete, followed by a thorough cleaning to remove all oils and contaminants. A fast-setting, cement-based Underlayment was then applied to restore the integrity of the concrete and to provide a uniform surface for application of the protective lining. The selection of the proper underlayment is critical, as many will tend to soften and re-emulsify in immersion conditions. The underlayment must also be compatible with the epoxy lining in order to provide a strong, firmly bonded monolithic structure.

The SewerGard No. 210T – Trowelable Epoxy Lining was then applied to a thickness of 125 mils. SewerGard is a strong, chemically resistant product designed specifically for difficult, corrosive, wastewater environments. As a Quality Assurance measure, the lining was then spark tested. High Voltage Spark Testing reveals any type of breach in the lining, many of which are not visible with the naked eye. Left un-repaired, these defects would allow water and sewerage to undercut the lining, leading to a premature failure. The contractor marked all identified areas, made the necessary repairs and then re-tested the repairs. This process ensures a pinhole-free lining, which means optimum performance of the lining.

In 2001, the lift station was inspected and found to be in excellent condition. The SewerGard Epoxy Lining is still firmly bonded and providing protection to the concrete after more than 13 years service. This structure presented a challenge to all involved parties. By choosing the appropriate materials and rehabilitation methods, the community saved considerable money, avoiding the additional expense and inconvenience required for full replacement.

There are instances where concrete in wastewater systems may be beyond repair, with replacement as the only option. In most cases, however, the proper materials, application methods, and quality assurance measures make rehabilitation not only feasible, but also practical.