Concrete Waterproofing Solution Helps Indiana Town of Paoli Lift Environmental Sanctions


The principal concrete structures of the new wastewater treatment plant in Paoli, Indiana, were completed in January 2023. Once commissioned later this year, the new facility will enable the town to meet state environmental regulations – and lift the previous sanctions. PENETRON ADMIX SB, a crystalline waterproofing concrete admixture, was used to protect the plant’s concrete tanks and treatment structures from the aggressive environment of the effluent – and substantially extend the service life of the plant.

A rural town of 4,400 people in southern Indiana (USA), Paoli was notable in the 19th century as a Quaker town that played a role in the Underground Railroad by transporting enslaved people from the South to Canada.

More recently, the town has worked on a plan to bring its wastewater collection system and treatment plant into compliance with the Indiana Department of Environmental Management (IDEM) and National Pollutant Discharge Elimination System regulations. Thanks to over $15.4 million in funding through the USDA’s Water & Waste Disposal Loan and Grant Program, construction of a new wastewater treatment plant and upgrades to the collection system began in June 2022.

“The substandard performance and insufficient capacity of the town’s previous plant led to sanctions by the IDEM. Once funding was secured, work on a new wastewater treatment plant could begin,” adds Christopher Chen, Director of The Penetron Group. “Penetron partnered with imi, the project’s ready-mix concrete supplier, to provide around 3,000 yds3 of PENETRON ADMIX-treated concrete for the nighttime pours.”

Designed by Commonwealth Engineers of Indianapolis, IN, the new 1.75 million gallon per day (MGD) wastewater treatment plant (WWTP) in Paoli comprises a new influent lift station, screening, sequence batch reactor (SBR), UV disinfectant tank, cascade aeration tank, sludge holding tank, a bag dewatering system, chemical phosphorus removal system, electrical and controls, and effluent sewer and outfall.

The concrete structures of a wastewater treatment plant are continually exposed to chlorides, sulfates, nitrates, disinfectants, and an array of corrosive compounds and various chemicals added during the plant’s treatment processes. This aggressive environment requires an especially robust waterproofing solution to ensure a long service life for the concrete matrix.

Delivered in pre-measured soluble bags to simplify the batching process, PENETRON ADMIX SB is added to the concrete mix, which reduces concrete permeability, increases chemical resistance, and enables the self-sealing of any new or future hairline cracks – enhancing durability and extending the service life of the WWTP’s treated concrete structures.

“The ready-mix supplier appreciated the ease of use of Penetron’s soluble bag packaging, and Reynolds Midwest, the project contractor, looked for the visual confirmation of the non-toxic, non-staining green tracer found in the bleed water of the PENETRON ADMIX SB-treated concrete,” concludes Christopher Chen.

The Penetron Group is a leading manufacturer of specialty construction products for concrete waterproofing, concrete repairs, and floor preparation systems. The Group operates through a global network, offering support to the design and construction community through its regional offices, representatives, and distribution channels.

For more information on Commonwealth Engineers design of the Paoli, IN Wastewater Treatment Plant, contact Eric Parsley, PE