Landfill and transfer station operators are combating a common problem with their transfer trailers—leachate. No one wants to receive a call from a concerned or angry citizen about the liquid leaking from the back of a trailer. Moving floor trailers have been used for decades in the waste industry, and one concern has been how to keep the leachate from under the trailer.
Leachate is the water content that percolates through municipal solid waste (MSW). The source of leachate from a transfer trailer comes from the compression of MSW within the trailer either through compactor insertion, top loading via a loader with high-moisture MSW, or from a transfer trailer being left loaded during precipitation uncovered or with a permeable tarp. This excessive moisture settles into the bottom of the trailer and leaks through the trailer tailgate or worn moving floor slat seals. Leachate contains biological agents, water-soluble chemicals, and suspended particulate matter. It is an odorous dark brown liquid which causes frustrations for vehicles following a trailer which is leaking and poses a potential environmental hazard.
Justin Wagner from Delaware Solid Waste says, “In our area, regulators have been focusing heavily on leaking containers and trailers on the roadways. While we’re not in the transportation business, we do utilize moving floor transfer trailers at our facility. Since we were in the market for replacing one of the trailers, we took a hard look at the leak resistant options and came across the Hallco Leakproof ‘W’ floor and Brute drive unit. We were impressed with the design of a leakproof trailer without sacrificing on performance.”
The seals used in moving floor trailers wear over time. The aluminum slats, which take the brunt of the load every time the trailers are loading and unloading, are a consumable part needing proper maintenance and regular inspection. However, explaining this to an angry constituent on the phone is difficult.
To contain leachate from a trailer, one of two approaches must be taken: a containment pan under the full length of the trailer, or a specific built leak-proof live floor, needs to be installed. A full-length containment pan is mostly an option for retrofitting older trailers when required by law. The cost of welding a full-length pan under a new trailer adds significant costs to the purchase price of the trailer and reduces the accessibility to the floor drive systems for cleaning and maintenance. Building a trailer with a specifically built leak-proof floor is a much more economical approach which, when designed and properly built, increases access to the hydraulic drive for cleaning and maintenance.
Working with industry OEMs and end-users, Hallco engineers have designed a Live Floors system specifically to address this problem. The raised subdeck allows OEMs and dealers to have a continuous floor pan from sidewall to sidewall within the trailer’s walls. The raised subdeck is installed on top of the floor pan without penetrating the leak-proof pan within the trailer. Combined with the Hallco “W” floor, the system is one of the most robust moving floors in the waste hauling industry. The raised subdeck also creates channels between the deck slats. These channels allow the liquids and sediments to easily run out when the floor is unloading and for cleaning. This system, combined with an OEM’s sealed single rear door, creates one of the most effective deterrents to combat the leachate problem in transfer trailers.
The raised subdeck utilizes 9-foot continuous bearings which interlock with the subdeck, creating a stable and robust base for which the floor will operate. The raised subdeck can be installed on a new trailer or added to an existing tipper trailer with a good tipper floor.
The biggest challenge with making a moving floor trailer leak-proof is the traditional position of the hydraulic drive unit. Most moving floor systems utilize an under-mount drive system which is located under the trailer floor and bolted to the floor slats from underneath. Maintenance and cleaning must be accessed from under the trailer. This location eliminates the options of a solid floor pan and relies on the floor slat seals to mitigate leaking, some of which are leak resistant.
To combat the under-mount drive vulnerabilities to leaking, Hallco Industries built a Front-Mount Brute Drive. The system is mounted to the front of the trailer, tied into the trailer’s 5th wheel plates, and utilizes shafts moving through the front wall of the trailer. These shafts are sealed against the wall of the trailer to prevent leachate from leaking through the drive mounting area. Slats are bolted to cross drives under a hinged or bolted slope sheet for easy cleaning and maintenance of the cross drives.
By providing a hydraulic drive system outside the trailer and mounted on the top side of the floor, OEMs can create a floor system which, when combined with a single hinge tailgate, dramatically reduces the potential for leachate making it to the ground. The front-mount drive makes cleaning and routine maintenance much simpler for employees, reducing the need to crawl under the trailer.