Advanced Filtration Technology Has Changed The Design Of Vacuum Excavation Systems

It’s difficult to remember a time before the existence of the 811 system, but the Common Ground Alliance was no more than an idea just 20 short years ago. It was 1998 when the U.S. Department of Transportation began the process of identifying the “best practices” for minimizing damage to underground infrastructure caused by excavation activities. During a year-long study that was initiated to find a system that would enhance safety and prevent damages, the CGS (Common Ground Study) developed a number of best practices; the process of vacuum excavation was identified as the most appropriate “soft excavation” method for exposing or “daylighting” underground utilities.


In the years leading up to the existence of the CGA, two types of vacuum excavation systems were available to perform the soft excavation process. Hydro-excavators came into existence in the early 1970s in the form of “water jetting” trucks that were originally designed to clean the inside of sewers and storm drains. These trucks were modified to support the excavation process by adding a handheld water wand to liquify the soil that covered underground utilities. At the same time, rudimentary dry excavation systems that used compressed air to break up the soil were being developed for digging small 12-inch diameter holes or 1-foot by 2-foot slot excavations over gas utilities to repair leaks and perform standard maintenance procedures on gas distribution systems. As with any new technology, the leaders of each excavation method began to develop a vision for their preferred equipment configuration by implementing additions and modifications to their existing product offerings.

If we examine the vacuum excavation systems that have evolved over the past 20 years, it is reasonable to believe that the manufacturers of both wet and dry vacuum excavation systems have designed their product offerings to meet the perceived needs of their market segment. Recent years have demonstrated that many of the providers of hydro-excavation systems have focused their resources on the development of huge truck-mounted systems that are suited for large excavations or trailer-mounted systems designed to support the process of directional drilling. During this same timeframe, many of the manufacturers of dry excavation systems have focused their resources on development of systems designed to support small hole excavation methods which has become known as “keyhole technology.” This technology relies on core cutting a small round opening in the pavement, excavating to the underground utility lines to perform repairs using long handle tools, and then restoring the excavation by back-filling the dirt in the excavation and grouting the core back into the pavement.

Looking back on the dry excavation systems of the 1990s and early 2000s, it is apparent that all of these systems were handicapped with an Achilles heel. The process of dry excavation demanded filtration equipment that would have an ability to remove gigantic quantities of dirt from the systems’ high velocity airstream. The filtration equipment that was available at that time clogged often and required extensive maintenance to keep these dry excavation systems running at any satisfactory level of performance. Recently, filtration technology has been developed that can keep dry excavation systems running at 100 % efficiency without interruption. These computer-controlled filtration systems have the ability to clean themselves while the machine is excavating and will run for years on a single set of filters. These revolutionary filtration systems not only have the ability to clean themselves, but they can purify the air that is flowing through the system to a staggering cleanliness level of 1 micron (0.000039 inches).

The Changing Landscape of Vacuum Excavation Systems for Daylighting

While it is true that large hydro-excavation systems are still well suited for creating large excavations, the excavated mud generated by the hydro-excavation process can never be used for restoration of the excavation. It is also true that the size of these trucks is directly proportional to the quantity of soil to be removed from the excavation site and the amount of water necessary to excavate this soil. Conversely, the size of dry excavation systems is simply a function of the equipment necessary to perform the excavation process, giving them the ability to daylight utilities at the excavation site indefinitely. The soil that is removed from the excavation can usually be used for site restoration and there is no need to carry a large quantity of water to support the excavation process. These advanced dry excavation systems, fitted with the revolutionary filtration technology described above, can be mounted on 4-wheel-drive trucks as small as 19,500 lb. Gross Vehicle Weight (F-550 or 5500) or trailers as small as 10,000 lb. GVW.

“Rightsizing” equipment to match the demands of the task at hand is critical to the development of a good business strategy. Vacuum truck manufacturers have a vested interest in convincing you that “bigger is better.” Their interests tend to skew their recommendations toward bigger and more expensive systems, pointing out factors such as your need to consider speed of excavation or future growth requirements as key factors in your decision process. Oversizing your truck will likely result in outcomes that may not have been considered. Larger capital outlays may result in wasted capital that could be invested elsewhere. Also, operating expenses, an integral part of the larger equipment, will be higher than necessary.

In the world of business, there is a saying about the effect of new technology on market participants: “Once technology rolls over your market, if you are not part of the steamroller you will become part of the road.” As you search for growth in any business sector, your opportunities will be defined by your ability to identify technologies that will improve the product or service you provide. When technology advancements deliver capital and operating costs that are substantially lower than costs provided by the prior technology, it becomes important to develop a full understanding of the effects this technology will have on your marketplace. Some innovative companies that offer Subsurface Utility Engineering services have identified the cost advantages provided by the latest dry vacuum excavation systems and have restructured their business strategy to reflect their new cost and capabilities structure. Those who choose to not take advantage of this opportunity will likely find it necessary to identify other opportunities or new technologies if they want to continue to participate in this market.

Frank Russo is vice-president of Tellus Underground Technology, Inc. He can be reached at

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