QINFENG Custom FIBC manufacturer since 2001
Water Treatment & Environmental Remediation Application brief
Dredged spoil, channel sediment and lagoon or settlement-pond silt dewatered in filter bags: filled by pump or excavator, drained in batches on a prepared pad, and lifted out once drained.
Dredging contractors, canal, marina and harbour operators, treatment works with settlement ponds, and environmental remediation firms. The buyer is normally a site or project engineer who has a dredge volume, a solids figure and a limited area on the bank to lay bags out.
Sludge & Sediment and other dry bulk solids, typically 0.8–1.6 t/m³.
Handling chain
Bags are laid out empty on a prepared pad, sometimes lined, and filled by pump from the dredge or by excavator from the bank. They drain on the pad for days or weeks, then are lifted out by plant and taken to a drying or disposal area. Bags are worked in batches: one group fills while another drains. Where the fill point has to be kept clear, bags can be filled in a frame and lifted out of it.
Filled on automated spouts or semi-manual toll lines. High-speed de-aeration shapes the square footprint before the bag leaves the fill station.
Stacked two to three tiers high in transit warehouses. A baffle construction that does not bulge keeps the stack square instead of leaning into the aisle.
Lifted three to five separate times by port stevedores. Reinforced loop anchoring and cross-corner loops resist fork abrasion and tine punctures.
Has to fit inside the container wall, at roughly 2,350 mm internal width. A square footprint uses the cube without the bag dragging on the wall.
What fails in this chain
Dewatering performance controls the job, and it depends on sediment that varies along the dredge, so a fabric that suits one stretch may blind on the next. Grit and shell fragments abrade the fabric as they are pumped in and again when the drained bag is dragged. The water that leaves the bag is not clean water: anything dissolved in the sediment leaves with it, so on contaminated dredgings the water has to be handled as the site's permit and waste classification require. The fill weight is unknown until the bag is full of water, so the pad, the frame and the lifting plan have to assume a heavy, wet, variable load. Bags that stand outside for weeks to months need UV-stabilised fabric.
Hazard: A standard tubular bag rounds out as it fills, wasting container volume and leaning in a warehouse stack.
QINFENG defense: Internal perforated ultrasonic baffles hold a square profile after fill, which is what makes three-high stacking in a shed predictable.
Hazard: Repeated lifting by rough tines tears side seams or frays loop attachment bases at transhipment hubs.
QINFENG defense: Heavier coated fabric with reinforced corner perimeter wraps and extra loop reinforcement backing, specified from the number of relifts.
Hazard: Faded printing or a torn document pouch causes customs delays and rejected cargo at the destination port.
QINFENG defense: Flexographic printing with UV-cured inks and a reinforced document pocket sewn onto the body seam, agreed before production.
Hazard: Unsheltered storage while awaiting vessel arrival degrades untreated polypropylene yarn within weeks.
QINFENG defense: UV-stabilised masterbatch in the tape, selected for how long the consignment actually waits on the quay rather than for the total storage period.
What we would quote
Start from the solids content and the particle size range, not from a bag size. Coarse sand and gravel drain quickly and suit a tighter fabric; silt and clay drain slowly and usually mean more bags at a smaller size, because the area available to drain on is the limiting factor and not the bag. Where the water returns to the channel or goes to treatment, agree the condition it has to meet before the bags are ordered, because that sets how fine the fabric can be. A trial bag filled with the actual dredgings is the normal way to confirm drainage and retention before an order.
Bag families we would send for this application
Before we can quote
Bag dimensions, baffle spacing and the safety margin all follow from these. Answer the ones you can and leave the rest; the missing details can be settled with our engineers.
Pump or excavator, the volume one bag takes per fill, and how often a bag is filled.
Percentage solids and whether the spoil is sandy, silty or clay-rich, which sets the fabric opening size.
The area that can be given to bags and the surface they sit on, because draining takes area and time.
Return to the channel, to a treatment plant, or to a discharge point under your permit, and the condition it has to meet.
pH and any known contamination, which affects the fabric choice and how the drained water has to be handled.
How the drained bag is lifted out and where it goes, since the bag leaves with its contents.
This page covers filter and dewatering bags for dredged spoil and for channel, lagoon and settlement-pond sediment. It does not design the dredge, the drainage pad or the discharge route, does not set discharge or consent limits, and does not replace the site's own permit, waste classification and water-quality duties. Drainage, retention and drained weight are confirmed per project against the customer's own material.
Talk to the applications team
We will come back with the construction we would build, the safety factor it carries and the dimensions that fit your loading plan — with drawings and a prototype before any bulk run.