Dewatering frees up the capacity of your retention ponds, cuts hauling and disposal costs, and keeps your projects on schedule.
Dewatering is the process of removing water from one location and moving it to another. It’s accomplished by using water permeable tubes and bags to separate the liquid from the solid in soils, slurries, and sludge, allowing them to settle for ease of collection and disposal. Dewatering is performed for two general purposes: to pump water out of a construction site and to increase the capacity of a body of water, such as a retention pond, lake, lagoon, or river.
For municipalities and state or federal agencies, flows are collected from sumps, trenches, or wellpoints and routed through approved controls—such as geotextile dewatering tubes and bags and sediment tanks—before discharge in accordance with permit conditions. Where authorized, polymers (flocculants) may be introduced to enhance settling and improve clarity. Dewatering projects can also clean up contaminated sediment and effluent waters, helping keep your site in compliance with National Pollutant Discharge Elimination System (NPDES) permits.
Construction & Civil Engineering: For construction or excavation projects, the process of dewatering is extremely straightforward. Water is pumped from one part of the site to the other through the use of discharge tubes. These tubes then feed into a filter, so that the outflow of sediments can be controlled. This ensures that the work site area is kept dry, and the discharge is in compliance with state and federal permits keeping you from violating the Clean Water Act (CWA).
The two most common tools for construction dewatering projects are dewatering bags, and dewatering filter socks, or pipe socks. A dewatering bag is a large square pad that retains any muck or excess sediment pumped into it, and slowly allows water to flow out of it, trapping the sediments inside for easy removal. A pipe sock slips over a single discharge pipe and filters the outflow. The amount of water and sediment being discharged from the dewatered area generally governs which product is used.
Municipal: Municipal dewatering revolves around one concept: increasing the capacity of a body of water. The largest use-case for dewatering is retention ponds for wastewater treatment plants (WWTPs). As the pond gathers sediment over time, it decreases the total amount of water it can hold. To solve this, either a new pond must be built—a costly and often infeasible solution—or a dewatering solution is used, like a dewatering tube. Cities and municipalities may also dredge through lakes, rivers, and lagoons to free up waterways for travel, which may have been disrupted by the buildup of muck over the year.
These projects are accomplished by the use of geotextile dewatering tubes. These tubes are pumped with effluent water and designed to capture solid waste and sediment while discharging liquids. Combined with polymer injections, this process reduces the cost of hauling by compacting the waste for disposal.
Due to the time it takes for the dewatering process to work, dewatering and hauling efforts could be split between fiscal periods, giving cities some flexibility with their budget and timelines.
Dewatering tools depend really on the prior application use; are you reclaiming capacity in a pond or body of water, or are you managing discharge from a construction site? Aside from municipal and construction use, dewatering is an important component of quite a few industrial processes. Power plants deploy it to remove coal ash and other by-products from slurry, reducing their environmental impact. Pulp & paper facilities use it for fiber recovery, while the agricultural industry uses it to separate manure and other products for composting.
A geotextile dewatering tube is a large woven fabric sleeve for retention ponds and other water bodies. Filled with pond-dredged sludge, it captures sediment and solids, producing consolidated material that is easier to transport, thereby reducing hauling time and cost.
Dewatering silt bags are big rectangular pouches, and handle wastewater removal for a single construction site. Once filled with sludge, the silt bags drain on their own. This means they can be left out on-site, don't require supervision, and keep your site within compliance.
Dewatering socks offer dependable filtration for a single stormwater pipe or discharge hose. These are meant for sensitive construction or environmental projects, allowing you to stay within compliance of your Stormwater Pollution Prevention Plan (SWPPP), and reducing risks of harmful discharge.
Talk with a specialist for practical guidance and equipment recommendations.
*Always confirm requirements with your authority having jurisdiction and your site safety team before design or purchase*
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Whether it’s a pond that needs to be dredged, keeping up local permits, or something custom, our team can help you compare available solutions.
