Dredging is a way to recover resources from the bottom of a sea, river, lake, or any other body of water that has depth and presence of moving water. Dredging can be done by dredge cutters and dredge vacuum equipment.
Dredge dewatering is the process that happens after dredging, where the sediment is removed from underwater land.
Dewatering can happen in few ways:
Drying Dredged Material (DMD)
A common byproduct of water recovery is a dirty liquid that's often referred to as “dewatering slurry.” This substance can take on many forms, including mud and sand - but all you have left after it dries out are these tiny particles
Drying Dredged Material (DMD) is one of the most commonly used ways to dewater dredge material. DMD uses metal carriers that act like a sponge, with water (dewatering slurry) in its pores.
DMD works through heat and air - DMD carriers are heated up by burners, which draw water inside the carrier into the air stream. As it heats up, DMD's process causes the liquid to turn into steam; this steam then reaches dryers (inside DMD), where additional water is removed through condensation.
Dense Media Separation (DMS)
Another way to dewater dredge material is Dense Media Separation (DMS).
DMS is done by using gravity and density differences between the fine particles and the fluid to separate them. DMS does not allow for oil removal and can be time-consuming and expensive if lots of DMD is required; DMS requires several recycles in order to obtain 100% dryness. DMS makes use of a Dredge Drying Beds which is filled with steel balls as large as 2 mm.
In this scenario, the dredging slurry enters at the top and flows downward through Dredge Drying Bed, taking on additional water from inside these large spheres as it passes through them. Because of their size, the heavier minerals stay behind in the dredge drying bed while lighter particles flow over the top and pass out to a conveyor belt for further processing.
DMS processes can create up to 95% dry solids from dredging slurry with minimal oversize material remaining – materials that contain recoverable minerals which can be processed into marketable high-value commodities such as stone or gravel.
Dredge dewatering refers to the process of extracting water from dried material after dredging. This process is an important part of dewatering because it has a high overall cost of all processes (DMD and DMS).
Dredge Dewatering takes place right after Dense Media Separation (DMS) or another technique of dry solids separation. This process generally uses decanter centrifuges - decanter centrifuges separate dewatered materials by applying what's known as “the sedimentation principle.”
A real working example involves placing mixed solids into the machine, turning on the machine's generator, and allowing the liquid to settle in slurry tanks while rotating at high speed. The dried material is then recovered in the slurry tanks after separation, while clean water flows out of the system's outlet on its way to a drain or holding tank.
A Dredge Dewatering System has several benefits that make it the most sought after dredging equipment:
- Flexibility - It can handle slurry, sludge, and mud. No need to have separate equipment for each flow because this solution provides you with efficiency in all types of flows. Dredge Dewatering Systems can be used with any dredging operation or waterway that needs dredged material dewatered.
- Ease of use - Dredge dewatering equipment is fully automated and compact, making it easy to install at your site; no cranes are needed. Dredge Dewatering Systems are typically installed on-site using cranes but can also be factory-built, especially if they will be used widely across multiple sites.
- Energy efficiency - The dredge dewatering vacuum pump consumes less power than traditional dredges pumps (8% - 12% less).
- Reliability and safety - Dredge Dewatering System does not need a lot of maintenance, and it is easy to repair in case of break down.
- Affordable solutions - DMS Dredge Dewatering Systems are more affordable, efficient, and reliable than DMD systems, but they require large land areas for DMS Dewatering Dredge Material.
Dredge Dewatering Applications
Dredge Dewatering Systems can be used to dewater dredge materials from any waterway or dredging operation. These dewatering systems are mostly used for:
- Dredging material removal
- Dredged material treatment and transportation
However, the applications are endless when we think about how much this tool could improve our lives:
- Building rehabilitation projects
- Removing shoreline pollutants (like PCBs) through dredging operations at grade stakes, like rivers estuaries
- Cleaning dirty runoff after heavy rains...the list goes on forever!
Dewatering by Dredge Drying Beds
Dredge Drying Beds are specially designed for dredging dewatering - they can be installed both overland and overseas. Dredge Drying Beds are used as a final step of drying wet solids that come from dense media separation (DMS) or other dry solids methods.
The unique design allows bulk solid/sludge to be easily discharged from an alternative to settling basins, digging pits, pumping units, and truck loading stations.
Some benefits of using Dredge Drying Beds include:
- They have a distinct advantage, as they do not require any excavation or infrastructure.
- They are installed above the ground on specially designed platforms and positioned in a dry location free from water and other environmental contaminants.
- Dredge Drying Beds have a low total cost of ownership (TCO), as compared to alternative methods.
- Dredge dewatering has less risk - there's no need for pumps or sludge storage tanks, as water simply flows through Dredge Drying Beds with no additional treatments needed.
Do you need to dewater your dredge?
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About U.S. Aqua Services
U.S. Aqua Services was created to support the dredging process in advancing commerce and responding to its many challenges. To accomplish this, our dredging company assembled an exceptional group of experienced individuals and a diverse inventory of dredge equipment and excavator dredge pumps.
We offer dredging equipment rental services so you can have access to the latest and greatest in dredging technology without having to pay to maintain it, transport, and store it, along with dewatering services.
With an emphasis on mobility, dependability, durability, diversity, efficiency, and safety, our dredging rental company can ensure that our different types of dredging systems are easy to move through any terrain and can work in the most rugged and remote environments. Our multi-function hydraulic systems are built with jetting and mechanical options that can efficiently move loose sediment or stiff layers of clay.
US Aqua services also and maintains a ready fleet of Amphibious Marsh Equipment capable of completing projects in some of the harshest and most remote environments. U.S Aqua is also the dealer for Louisiana of the amphibious vehicle Fat Truck. No matter the size or scope of the job or the remoteness of your work location, you can rely on Fat Truck’s industrial off-road utility vehicles to get the job done right.
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