According to the Global Cement and Concrete Association, concrete is the most used man-made material on the planet. This should come as no surprise. Its strength, durability, resilience, safety and affordability have contributed to its use in much of the world that surrounds us, from the roads and bridges that we travel to homes, offices, residential and commercial buildings. These attributes have also made concrete a key and quite ubiquitous component of water infrastructure, from water storage tanks to water and wastewater treatment plants.

Successfully maintaining concrete assets requires not only a lot of experience with this material but also a keen understanding of its unique nature and the factors that can impact its performance. It is made up of many different components: cement, water, aggregates such as sand, gravel, crushed stone, etc., and often, admixtures used for various functions such as reducing the required water content for a concrete mixture, modifying the setting rate of concrete, or inhibiting corrosion. This makes concrete a remarkably interesting and specialized construction material.

SUEZ has maintained concrete assets for hundreds of clients over the years. Because of this market’s distinctive nature, we provide dedicated Concrete Plant and Pipeline Services (CPPS) focused on rehabilitating and managing a comprehensive array of structures including concrete water storage tanks, wastewater treatment assets, and many pipeline applications.

Our asset management programs can involve performing a complete rehabilitation of an entire concrete structure, but also the internal steel mechanisms. This requires a special skillset and comprehensive approach; in many ways, this work is one part art and execution, and another part involves choreographing work on various assets within a plant with minimal disruption.

Concrete storage tank pre renovation. Courtesy of SUEZ.

Concrete storage tank post renovation. Courtesy of SUEZ.

No matter how large or small the engagement, we have found that the first step in implementing a concrete asset management program is overcoming the common misconception that concrete requires little or no maintenance.

Nothing could be further from the truth. Concrete is a very porous material, and this makes it susceptible to leaks and cracks. There is a saying, “there are two types of concrete: concrete that has cracked, and concrete that is going to crack.” Cracks in a concrete storage tank could result in the leakage of thousands of gallons of water per day and contribute to an increase in the utility’s non-revenue generating water loss. Repairing and properly maintaining concrete tanks can prevent leaking cracks and the subsequent loss of non-revenue generating water.

In addition, the surface inside storage tanks can become coated with biofilm over time. This situation can lead to deteriorating water quality, bad taste and odor. These issues can be averted with preventative maintenance and the use of high-performance coatings.

Wastewater treatment plants present some of the most challenging environments due to the aggressive nature of the material treated. Steel and concrete in these facilities are subject to harsh conditions. Organic matter, bacteria, suspended solids, and aggressive gases pose difficult challenges for these facilities, pipelines and pumping stations. Gases “eat away” the concrete over time, and when concrete starts to break down, that impacts the rebar inside, potentially leading to integrity issues.

Aging water treatment plants, too, face their own challenges. During typical granular filtration processes, chemical reactions and microscopic bacteria create deposits that affect water quality and can increase operational expenses.

The bottom line is that concrete assets need to be regularly maintained in order to extend their service life and protect the client’s investment, reduce the need for expensive major repairs, and prevent possible service disruption or worse still, failure.

Prior to the initiation of an asset management program, SUEZ conducts a thorough condition assessment of the asset or assets in question. In the case of concrete water storage tanks, SUEZ reviews and reports on the safety, sanitary, security, substrates and coatings condition of each tank to determine its rehabilitation or maintenance needs and prepare project specifications. The services are custom-designed to meet the specifications and conditions of each specific tank and are executed by experienced field crews in compliance with all OSHA regulations.

In terms of wastewater treatment plants, assets are restored to their design specifications and protected with high-performance coating and lining systems for long-term viability. Each step – evaluation, repair, application of coating protection, cleaning and rehabilitation solutions – is customized to the chemical and mechanical aggressiveness of each system’s process. Services include:

Ongoing services for water treatment plants typically include annual treatment plant condition assessments with detailed reports; and chemical cleanings, filter media replacement, concrete and steel rehabilitation, underdrains and filter equipment repair, and upgrades as needed.

Just as these asset management programs are customized, so are the contracts for their execution. There is no single game plan because each customer and each asset are different. All contracts are unique based on the number of structures and required scope of services.

After an initial inspection of the asset(s) to determine of the scope of work for rehabilitation, we present the scope to the customer and discuss their expectations.

While we do not have a single “set” program, the financial model typically follows one of three paths. It can be a negotiated sale, where we perform work and then move on. SUEZ also offers a contract for services, where the company will perform work annually for a given contract length at the prescription of the customer.

SUEZ also provides robust asset management programs. This is the level at which we will work with the client to spread the cost of rehabilitation and maintenance over time – usually a number of years to best accommodate the customer’s budget. We typically begin the engagement with upfront renovation of the designated assets. We are then responsible for maintaining the assets for as long as the customer wants to keep the program in place.

Located in South Burlington, Vermont, the Champlain Water District (CWD) is a nationally recognized leader for excellence in drinking water treatment. The district operates as a wholesale water supplier of water to 12 municipal water systems located in eight communities covering approximately 70 square miles in northwestern Vermont. These systems account for approximately 24,000 connections with 75,000 customers.

Asset management has become a cornerstone of Champlain’s approach to proactively manage key assets in its treatment and distribution system, starting with a program to keep its 15 tanks in top condition. While it considered managing these assets in-house, the district looked at projected capital costs and its staffing levels and realized that committing the resources required to care for the 15 tanks would be a significant challenge.

Champlain Water District’s filter maintenance program increased filter capacity, extended media life, improved bed porosity, reduced particle cohesion and more. Courtesy of SUEZ.

The district also wanted to have a single-source responsibility for maintaining the condition and reliability of its assets. It found the answer in the water tank asset management program provided by SUEZ. The tank asset management program keeps these critical water assets in excellent operating condition and fully compliant with all applicable regulations, while minimizing maintenance and future renovation costs. The success of the tank asset management program encouraged the district to apply that model to the eight filters and three adsorption clarifiers in their water treatment plant. The filter and clarifier maintenance program restores the filtration system to “like new” conditions, improving the return on these large capital investments while lowering related long-term operation and maintenance costs. It entails:

Benefits of this filter maintenance program include increased filter capacity and extended media life, improved bed porosity, reduced particle cohesion and reduction of effects of biofilm and inorganic deposits. The program also maintains regulatory compliance.

“We strongly recommend looking at this model,” says Joseph Duncan, general manager of the Champlain Water District. “The volatility of the market and the ability to know that something is going to be serviced is challenging. And putting aside money for future repairs doesn’t always work, as the money that’s been put away might be diverted to other needs. I believe this model has extreme value, because you know that once you’re in the program, maintenance and repairs will move forward.”

Edward Faust is a senior vice president of SUEZ Advanced Solutions with responsibility for the Concrete, Plant and Pipeline Services (CPPS) Business Unit as well as North Region and sales and marketing. He has more than 30 years of experience working in the municipal infrastructure market.

Ross Smith, P.E., is a product engineer for SUEZ Advanced Solutions, where he manages and develops concrete and plant rehabilitation services. He also provides training for clients and water systems consultants in the water/wastewater industry for concrete rehabilitation and coatings.

Joseph Greiner is service center manager at SUEZ and heads up the delivery arm of its CPPS business throughout the United States. He has more than 17 years of experience as a project manager on more than 250 projects with a focus on protecting concrete assets in the water/wastewater industry.

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