Media Release

Penetron Concrete Treatment Stops Microbially Induced Corrosion in Missouri Wastewater Treatment Plant


The May 2023 commissioning of the new City of Perryville Wastewater Treatment Plant completes an effort to enhance treatment capacity and quality. Penetron’s antimicrobial concrete admixture provides permanent protection for the plant’s key concrete structures exposed to potential microbially-induced corrosion (MIC), which can rapidly compromise and disable concrete structures.

A city of approximately 8,500 people, Perryville is located in southeastern Missouri, about seven miles from the Mississippi River and just north of the Cinque Hommes Creek, which flows past the south side of the city.

“In order to improve water quality and enable Perryville to meet future environmental regulations, a new treatment facility was needed. The completed expansion of the city’s wastewater treatment infrastructure increased treatment capacity from 2.5 million gallons per day (MGD) to peak throughput of 9 MGD,” explains Patrick O’Brien, Regional Sales Manager for Penetron USA.

HDR, the project’s engineering consultant, worked with the Missouri Department of Natural Resources to establish water-quality levels. The new $30 million plant meets guidelines for biological oxygen demand, ammonia and total suspended solids removal, and nitrification and phosphorus removal.

“The general contractor, Robinson Industrial, Heavy & Commercial Contracting (RIHC Contracting), required a robust solution to prevent microbially induced corrosion (MIC) in the concrete structures of the new wastewater treatment plant,” adds Patrick O’Brien. “We suggested Penetron’s antimicrobial concrete admixture as a solution to the problem.”

A growing issue within the construction industry, MIC is an increasingly widespread problem that causes billions of dollars in damage to wastewater and sewage related concrete structures every year. Concrete sewage systems can deteriorate rapidly when exposed to thiobacillus bacteria that convert hydrogen sulfide gas (H2S), found in raw sewage, into biogenic sulfuric acid (H2SO4), which
eats away the cement paste of the concrete matrix, potentially exposing the embedded steel reinforcement to corrosion when exposed to water, oxygen, possibly CO2 , and chlorides.

“This process can rapidly lead to the severe concrete deterioration known as MIC, which is often the cause of catastrophic corrosion failures in concrete structures,” says Patrick O’Brien.

Penetron’s antimicrobial admixture prevents microbial-induced corrosion (MIC) by using an electro-physical mechanism to destroy the cell-walls of the acid-producing bacteria. Eliminating the bacterial growth on and in concrete consistently stops the formation of biogenic sulfuric acid, preventing damagecaused by MIC.

Penetron worked with RMC, the ready-mix concrete supplier, to add Penetron’s antimicrobial admixture to the concrete mix during batching, much like the well-known PENETRON ADMIX crystalline waterproofing admixture. The Penetron antimicrobial admixture is permanent. It becomes an integral part of the concrete matrix and is leach resistant, i.e., repeated contact with bacteria does not lessen the effectiveness of the admixture.

“Thanks to ease of use and attractive cost, Penetron’s antimicrobial concrete admixture provides the Perryville plant with long-term protection from MIC that the general contractor needed,” concludes Patrick O’Brien. “With our new admixture, the concrete will have the needed durability – and only minimal need for any future repairs of the treated concrete structures.”