What Factors Influence The Choice Of Silt Pumps For Dredging Applications
Picking the right silt pump can make all the difference to your dredging work.
The right pump will run more efficiently, be easier to maintain and get the job done without fuss. That’s why it’s worth taking a moment to think through exactly what you need and the demands of your site.
Here we lay out the factors to consider so you can choose a dredging pump that performs well, not one that lets you down when it matters most.
Water Quality
When you’re dredging, inevitably, the water will contain debris of some sort, but not all water pumped during this process is created equal. Even in the same dredging project, the density and solids type can vary widely. Sometimes it could be abrasive material like sand or grit, other times it could be finer silts that tend to settle and block the system.
Some dredged sludge may be highly concentrated, while others are relatively watery. Either way, there is a chance of them damaging a dredging pump not equipped to handle them, forcing you to consider abrasion-resistant pumps, different impellers, or even alternative types of pumps.
In addition, some dredging operations might require the use of dewatering systems, silt filtration and seepage barriers, which can reduce flow and may not be suitable for all pumps. The density and abrasiveness must be taken into consideration when choosing your pump.
Flow Rate Requirements
Think about how much material and water you intend to transfer per hour. Higher rates will require larger dredging pumps, or several pumps used in conjunction. For greater efficiency, it’s important to choose a silt dredge pump that matches your needs throughout the whole process so you’re not over- or underspecifying the equipment.
You also need to calculate your critical flow rate and actual flow rate. The actual flow rate needs to be higher than the critical flow to ensure minimal settlement of sediments, but you need to be careful when selecting the pump you use because a higher flow rate can increase wear and tear.
Distance And Height Of Transfer
How far or how high will your slurry need to travel? It’s an important question to consider because if your pump isn’t strong enough to cope with the distance or elevation, then you risk it struggling to do the job or burning out entirely.
Flooding Risk
Will you use a submersible pump, or will you be able to keep the pump motor dry even after heavy rainfall and rising water levels? It is good practice to keep the distance between the suction head and motor short while allowing for operation at various river-bed depths.
Adding Technology To Improve Efficiency
Efficient system design mandates dewatering the dredged material at the nearest feasible treatment point, allowing the clear water to be returned to its source and the sand or silt to be recovered without excessive energy use.
Many dredging operations can be optimised by deploying a silt removal/sludge dewatering system on the shore, or even on the boat itself. EnviroHub flocculation and laminar settlement tanks can handle 5 - 120 m3/h, depending on the tank size and silt concentration.
Where dredged sand has to be conveyed a distance, problems can occur due to settlement, so it is important to keep the dredged material fluidised and particles in suspension. Atlantic Pumps Sand Transfer Station has been developed to overcome this issue; read our case study on ‘wet quarrying’ sand in Cheshire to find out more.
Environmental Considerations
Some silt removal methods are designed to minimise environmental impact. Rather than dredging and physically disturbing the sea/lake/estuary bed, the “no dig” method uses suction pumps to remove the silt instead. The silt-laden water is then passed through dewatering equipment to separate the solids. It’s a gentler alternative to traditional dredging and a better choice in sensitive environments.
It isn’t always obvious which silt dredge pump will be the best one for your particular needs, and as you can see, there are many factors to consider before you make your choice. The team at Atlantic Pumps is highly experienced and will help you pick the most efficient pump for your operational requirements.
If you would like advice or more information about the types of silt pumps we offer, please contact us.
