Dewatering Methods | The Dewatering Bag

Dewatering methods include a wide range of practices including settling ponds, basins, filtering rocks, and even dewatering skimmers. Today we will discuss the method known as the dewatering bag.

This Sediment Filtering Bag is designed to connect to outlet hoses or drains and filter water as it flows into the bag. The non-woven bag retains sediment and silt, while allowing only clean water to flow out of the unit.

Dewatering Bag Construction

Fabric: The dewatering bag is typically designed from a type of non-woven geotextile material. This needle-punched fabric has the unique ability to successfully retain several different fine silt and sediment materials, while still allowing water to flow out of the bag. This has allowed it to successfully function as a filtering device for sediment or sludge laden waters.

Sizes:  Choosing a filtering bag size is generally based on the amount of water being pumped through the bag, the rate at which this water is being pumped, and the type of sediment you are looking to retain.

Bag Placement: While bags are made from a reliable geotextile material, it is still important to consider the location in which you will be placing this filtering device.  These dewatering bags have been placed in numerous locations including some of the following:

• 20’ Drop Boxes or Dumpsters: This is a common choice for people who wish to transport the bag or water to a different location.
• Ground: These dewatering filter bags can be placed on ground while operating in a filtering process. Ground cloths are often placed underneath these bags to help support the bottom of the bag and protect it during use.
• Permeable Surfaces: These bags can also be placed on porous surfaces such as hay bales to help decrease the amount of surface area needed for the bags and improve the bags performance.

Discharge Hose: To insert a discharge hose into your sediment filter bag, make a small incision along the edge of your bag. Hoses can be easily placed into these incisions and then sealed to the fabric by devices such as ropes, clamps, ties, and wires.

Dewatering sediment filter bags are a common choice for applications such as construction site dewatering, sediment removal in small ponds, and trench pumping. They are often used to keep your keep areas in compliance with NPDES and other stormwater regulations.