Many communities in the United States have experienced substantial growth in the past 50 years, and a new generation of treatment plants is currently being built (both new plants and expansions and reconstruction of existing plants).
Dallas/Fort Worth metroplex has had a boom in treatment plant construction. Unlike some areas of the construction industry that have been slowed by the economy, treatment plants are typically funded by revenue bonds, which are less sensitive to market conditions.
In Dallas/Fort Worth, Oscar Renda Contracting has recently completed work on two large-scale treatment plant jobs, the Eagle Mountain Water Treatment Plant Expansion (Phase III), and the Tom Harpool Regional Water Treatment Plant. Construction costs for the Harpool project were in excess of $35 million.
During construction Oscar Renda built a new plant from scratch, including a building for pretreatment operations and for administration, bulk storage tanks, and a clearwell with a capacity of 4 million gal. (15 million L), built of pre-stressed concrete. In addition, thousands of linear feet of raw water inflow lines and treated effluent distribution lines must be built to deliver water to the surrounding distribution network. In the case of the Eagle Mountain plant, Oscar Renda built approximately 35,000 linear ft. (10,670 m) of pipe, ranging from as small as 4 in. (10 cm) to as large as 72 in. (182 cm).
In essence, a job as major as a new plant can be broken down into a number of simple construction operations. For building a clearwell, the first step is a large excavation, which requires a fleet of excavators, led by the John Deere 850 LC, which has an engine power of 532 hp (397 kW).
Wastewater treatment plant construction has many of the same challenges as water treatment plant construction, but there are some unique traits to the wastewater industry. While water treatment plants and wastewater treatment plants have a number of hazardous chemicals, such as chlorine on hand, wastewater treatment plants are notorious for having to deal with corrosion. Structural elements, facilities, and just about every aspect of the plant is subject to corrosion, which leads to construction jobs to replace aging, corroded parts of the plant. Corrosion can occur on structural components of tanks, or can happen to amenities such as hand rails.
Another side of wastewater treatment plant construction is odor control. Wastewater contractors often engage in work to cover tanks to control the release of odors to surrounding neighborhoods, which in the case of Dallas/Fort Worth have expanded around the treatment plant due to suburban growth. One such project of this nature was Walsh Group’s recent $39 million expansion to the Wilson Creek Wastewater Treatment Plant. The project included a number of improvements, including ultraviolet treatment basins, two primary clarifiers (for settling out larger particles in the wastewater influent), a sludge pumping station, and odor control measures.
To cover a tank for odor control, a builder needs a crane, such as the Terex RT 1120. This crane is designed for rough terrain, which is conducive to operating on a project with large-scale earthwork such as a new treatment plant. The RT 1120 has a 120 ton (109 t) lifting capacity, with a boom height of 155 ft. (47.2 m). It has a maximum tipping height of 271 ft. (82.6 m), and a maximum shipping weight of 142,000 lbs. (64,410 kg).
The heavy equipment used in the water treatment industry continues to build a new generation of plants, as a new generation of facilities rises to replace and expand on the older generation of plants. In the years to come, business is expected not just to be steady, but to grow at a rapid rate, to keep up with growth in the population of the United States. While many of the jobs are large-scale, there are also thousands of smaller municipal utility districts across the country. These utility operators are in need of projects as small as single lift stations, booster pumps, and utility lines, and general construction site work to handle administrative offices and equipment storage.