Dewatering containers continue to rise in popularity as guidelines become stricter and the cost of steel increases. They would certainly be worth considering as your next roll-off purchase.
By Meagan Daugherty
A dewatering style roll-off is a unique container commonly used within the water and wastewater industries to separate liquids from solids. Let’s explore how this separation process is possible with a roll-off container.
How They Are Used
The separation process of a dewatering container occurs using the perforated steel basket. The liquid is filtered to the bottom while the sludge material remains on top. Depending on the application, the operator will either take the container filled with the separated materials to a secondary location or drain the liquid back to its original source before taking the rest of the material to the landfill. While most dewatering containers are used to drain the liquids from sludge, grease trap waste, septic waste and similar waste applications, they have also taken over markets into clean water to assist in separating the unwanted sediments from drinking water, ocean
water, and other filtration and cleanout processes. Popular applications for a dewatering container include:
• Oil and Gas
• Construction
• Municipalities
• Environmental Remediation
• Wastewater Treatment Plants
• Water Filtration
• Rental Fleets
When used in the waste applications, the operator will drain the excess liquid before going to the landfill. This process decreases the container payload and saves money. The growth in water applications is due to the stricter guidelines within the Clean Water Act (CWA). There have been several initiatives within the CWA to continue to provide sustainable drinking water distribution and wastewater collection systems after seeing a growth in aging wastewater equipment and infrastructures (epa.gov). Therefore, dewatering containers are becoming more popular in the water and wastewater industries.
Middle: A Dewatering Basket removed from the Dewatering Container. A Dewatering Basket, also known as a shell, is manufactured with perforated steel. This Bucks Fabricating customer requested liner hooks and fork pockets.
Right: Some operators will select to add a Dewatering basket to a Vacuum Tank. This pairing will quicken the dewatering process.
How They Are Built
Dewatering containers, designed by roll-off manufacturers, are custom-built to the specifications requested by each buyer. They can range from a small 10-yard container to as big as 60 yards. Depending on the manufacturer, there may be a difference in steel gauge on the build. For example, one may use 10GA steel sides and 3/16″ floor sheet, while another will use 7GA steel sides and 1/4″ floor sheet. The buyer has a choice of cable, hooklift or combo style hookup, as well as a variety of options available to fit the needs of their business.
Standard dewatering containers have a perforated steel basket, sometimes known as a shell, built on 6″ channel, that raises the basket 6″ from the floor sheet of the container. This gives plenty of space for the liquid once separated from the sludge material. They feature heavy-duty slider style hinges and a sealed latch lift handle that help pull the tailgate tight to the container to give it a watertight seal.
Another unique feature of dewatering container is the fittings. The buyer chooses which style is used. Here are common fittings and caps available and how they work with the roll-off container:
• Pipe and Nipple Caps are the most common fittings for a dewatering container. They are mostly placed on the bottom of the tailgate specifically at the level where the liquid can be easily drained from the container.
• Brass Lever Valves are used in wastewater applications for quick and efficient draining and pressurizing.
• Blind Flanges are used to seal up a pipe when not in use.
• Dust Caps, also known as a Type DC, are used to seal off Type A cam and groove pipes when not in use.
• Threaded Flanges can be used instead of welded on flanges on containers that transport and store more hard-to-handle materials.
• Butterfly Valves help to regulate the flow of liquids.
Along with the fitting style, the buyer can also select different options to further customize their container:
• Splash Plates—Additional sheets of steel added to the front and/or rear tops to reduce spill over when the material is getting dumped in or sloshing during transport.
• Tarps—The buyer can choose to add a tarp at the time of purchase or order one afterwards. Different tarp styles include side roll tarp system, throw tarps or a roll tarp system that is attached to the roll-off truck.
• Full Pivoting Lid System—Designed to fully cover a roll-off container. The adjustable system will fit most roll-off sizes, making it easy to abide by federal and state regulations for roll-off businesses. The system allows a single operator to manually open and close the system with ease.
• Double Rolling Roof—Added as a more permanent coverage for the dewatering container. When dumping materials into the container, the operator will have the roof in the open position giving an opening of 84″ x 131″ for dumping materials. When ready to store or transport, the operator can close the roof giving it a watertight seal.
• Sight Glass—If an operator has chosen to add a lid to their dewatering container, they may add sight glass that will allow them to see the contents of the container.
• Liner Hooks—Located around the dewatering basket that allows the operator to loop a liner on for easy placement and removability.
• Liners—Available in knit mesh, screen mesh, and cloth, dewatering liners fit in roll-off containers and assist in the separation of liquids and solids, as well as increase your container’s longevity. Furthermore, using a dewatering liner provides onsite waste minimization and avoids additional weight and cost of solidification agents.
• Epoxy Coating—Provides additional protection against materials and temperatures.
• Rectangle or Round Bottom—Some manufacturers can manufacture a round bottom design. Operators will select this option to avoid material buildup in the corners of the roll-off container.
• Vacuum Tank—Adding a dewatering basket to a vacuum tank makes the dewatering process faster.
Depending on the options selected, the buyer may receive a drawing from the manufacturer to approve. This ensures that the container will be correctly built. Once completed, the dewatering container and basket are primed and painted to the buyer’s selected color. After the curing process is complete, the basket is placed within the container, bolted in, and it is ready to be put to work by the customer.
raising the basket 6″ from the bottom of the roll-off container, leaving plenty of space for the liquid to be stored when separating. With the container tailgate open, you can see the water draining.
Middle: A Bucks Fabricating Dewatering container being drained after passing the watertight seal test.
Right: A rounded bottom Dewatering container
featuring a double rolling roof. This design
offers a leak-proof method for transportation and storage.
Image courtesy of Mobile Mini Tank + Pump Solutions.
A Good Investment
A dewatering roll-off container is an investment. They are more costly than a standard roll-off container and can range from $15,000 to close to $50,000 depending on the features added. However, this is a container that will last many years if maintained properly. It is recommended that they be cleaned between each use, allowing the container to be used again and again for several years. Keep in mind that with a removable basket, the container can be used for even more applications. If an operator is working on a project and does not want to invest in a dewatering container for a single use, they can choose to rent one as well.
Dewatering containers continue to rise in popularity as guidelines become stricter and the cost of steel increases. They would certainly be worth considering as your next roll-off purchase. | WA
Meagan Daugherty is the Communications Specialist for Deist Industries, Inc. (Hadley PA). She is responsible for connecting with end users, dealers and the general public through social media, newsletters, magazines, mailers and more. Meagan can be reached at (724) 253-5055 or e-mail at [email protected].