Put a sludge and water mixture into a sludge dewatering bag and the separation happens where the material arises. The mixture goes in from the top, water passes out through the filter area, the solids stay behind and build a filter cake over time. There is no pump in the process, no moving part and no power supply. What does the work is the column of water inside the bag.
Sludge dewatering bags from 0.125 to 1.25 m³ · working loads up to 400, 600 or 900 kg · PP geotextile with O90 100 µm · paint sludge nonwoven bags and dewatering box
Our F-BAG range covers small batches as readily as larger dewatering duties in industry, trades, municipal wastewater treatment and on site: usable volumes from 0.125 to 1.25 m³, several working load ratings, and one low-profile version for existing chambers and tanks. For paint and coating sludges there are additionally two lighter, more open nonwoven bags and a compact dewatering box.
Search results for terms like dewatering bags cover several different products, so it is worth being precise about what you are looking at here.
These are open-topped, free-standing gravity dewatering bags. They have no defined pump connection and no hose coupling. Filling is done from above, by hose, pipe, pump, bucket or straight from a collection tank, and that is deliberate, because it means the bags work with whatever equipment is already on site.
They are not geotextile dewatering tubes for dredging work, not FIBC bulk bags with transport certification, and not pressure-fed bag filters in a housing. Where you need one of those, this is not the right category, and we would rather say so on the first page than after the first delivery.
Whether you call it a filter bag for sludge dewatering, a sludge dewatering filter bag or a slurry dewatering bag, the same four questions decide which version you order. Usable volume, the mass of the wet or dewatered sludge, floor area, method of filling and the installation situation have to be considered together. The largest volume is not automatically the right version.
| Version | Usable volume / dimensions | Working load | Sales unit | Where it fits |
|---|---|---|---|---|
| Compact nonwoven bag | 1.19 × 0.55 m; opens to 0.53 m; approx. 0.17 kg | none stated | pack of 25 | consumable bag for smaller quantities and suitable boxes |
| Size M | 0.125 m³; 0.50 × 0.50 m base; 0.50 m high | up to 400 kg | single | small batches, maintenance work, tight floor space |
| Size L | 0.5 m³; 0.90 × 0.80 m base; 0.70 m high | 400 / 600 / 900 kg | single | the standard size for regular quantities |
| Size XL | 0.8 m³; 1.00 × 1.00 m base; 0.80 m high | 400 / 600 / 900 kg | single | larger batches where build height is limited |
| Size XXL | 1.25 m³; 1.00 × 1.00 m base; 1.25 m high | 400 / 600 / 900 kg | single | high capacity, not a blanket replacement for a fixed plant |
| Custom size, low profile | 0.99 × 0.60 m base; 0.40 m high | up to 400 kg | single | existing chambers, tanks and limited build height |
On M, L, XL and XXL the strap loops stand 280 mm proud. The working load applies to the version you select and cannot be derived from the usable volume alone.
This is the point that decides most orders between the two largest sizes, and it is easy to miss in a table. XL and XXL have exactly the same base area of 1.00 by 1.00 metres. The only difference is build height, 0.80 against 1.25 metres.
Where filling height, hook height or clear height are limited, XL is the only version that still gives you a full square metre. Where the height is available, XXL puts around 56 per cent more volume on the same floor area.
Searches for a dewatering container for sludge usually mean one of two things: the container or frame itself, or the filter medium that goes inside it. WINKLER primarily supplies the bags. Whether a standard size fits an existing dewatering container or box has to be checked against the exact internal dimensions, and we are happy to do that from the measurements.
If the box or frame is already there, what you need are filter bags for sludge dewatering boxes rather than another container. A dewatering box filter bag has to match the clear internal size and the rim it rests over, so send us those two figures and we will tell you which version fits.
Sizes M, L, XL and XXL and the current custom version are made from a geotextile based on polypropylene. The material is thermally bonded and has a hydrophilic finish, with a basis weight of 200 g/m², a thickness of 2.0 mm and a characteristic opening size O90 of 100 µm.
For the flat filter material, flow rates of 80 l/s/m² at 50 mm water column and 135 l/s/m² at 100 mm water column are documented. Those figures are not a guaranteed dewatering performance for a filled bag. As the cake builds, throughput falls in service.
The O90 figure is not a sharp separation limit. Depending on the structure of the sludge, finer particles may pass at first, or may be retained only once the filter cake has formed. With a sludge you do not yet know, a trial with a small quantity is worth the time. Why that is so is set out in the process guide.
An industrial sludge filter bag ends up in a fairly narrow set of situations. These are the ones we see most often.
Wash bays and wash water. Vehicle, commercial vehicle and rail vehicle wash installations produce sludge traps that need emptying on a schedule. Wash bay sludge dewatering in a filter bag keeps that job on site, and the same applies to wash water sludge dewatering from other cleaning processes. Both reduce the mass that leaves the site.
Concrete and mineral processing. Water is used for cooling and dust suppression when concrete and stone are drilled, sawn and ground. Slurry dewatering bags are used for the mineral suspensions that result. Confirmed applications include water-cooled drilling in quarries as well as concrete processing and concrete drilling. Other drilling fluids, bentonite mixtures and chemically loaded media are assessed individually beforehand.
Small and decentralised wastewater treatment. The bags are used on municipal sewage sludge and in package treatment plants. Where quantities are small or the plant is decentralised, bag dewatering can be an economical alternative when a centrifuge or filter press does not pay for the quantity involved.
Street cleaning and gully waste. The wet fraction from wet sweeping and gully emptying is heavy and mineral, which makes the working load rather than the volume the limiting factor.
Industrial side streams. Where solids have to come out of a process water before further treatment, wastewater sludge filter bags do the separation and leave the rest of the treatment train as it is.
Paint shops and coagulation systems. Paint sludge behaves differently from mineral sludge and needs a different material, which is why it has its own products in this category.
For paint shops, workshops and coagulation systems there are two PP nonwoven bags with different constructions and a matching dewatering box. Which version fits depends on floc size, consistency, how quickly the water should leave, the mechanical load and the holder you have.
Color Drain, 15 g/m². Very light, hydrophilic, thermally bonded polypropylene spunbond nonwoven, 0.16 mm thick, air permeability 8,900 l/m²/s. For stable flocs where the water should leave quickly.
Nonwoven bag, 30 g/m². Firmer PP spunbond nonwoven, 0.25 mm thick, thermally bonded and hydrophilic, with a documented tensile strength of 50 N/5 cm. Air permeability 4,300 l/m²/s against 8,900 l/m²/s for the lighter material. For finer fractions and mechanical load.
Dewatering box. Compact holder for dewatering paint sludge and coating residues, 60 × 40 × 32 cm externally, with matching nonwoven bags supplied separately.
Dewatering lowers the liquid fraction. How far volume, mass and residual moisture change depends on the starting sludge, on conditioning and on how long the bag stands.
The filtrate that comes out is not automatically suitable for a drain, for ground or for a watercourse. Depending on the original medium, testing, neutralisation, further filtration or controlled disposal may be required. That applies equally to industrial wastewater sludge. A wastewater sludge filter bag carries out solid and liquid separation, nothing beyond it, and wastewater sludge dewatering bags do not replace effluent treatment.
The sludge dewatering bags, the paint sludge nonwoven bags and the light dewatering bags are single-use products. After dewatering, bag and contents are disposed of according to the classification of the sludge and the applicable requirements.
Sludge and process. Type of sludge, origin, solids content, consistency, density, particle or floc size, pH value, additives and temperature.
Quantity and installation. Quantity per batch, space available, existing container, method of filling and the change interval you want.
Load and handling. Expected mass of the wet and dewatered sludge, working load rating, lifting equipment and the intended transport route.
Filtrate and disposal. How the filtrate is collected, what further treatment is needed and the planned disposal route for filtrate, bag and sludge.
Size M with 0.125 m³ is designed for small batches and tight floor space. Size L with 0.5 m³ is the standard size for regular quantities. XL with 0.8 m³ and XXL with 1.25 m³ suit larger batches. Density, working load, floor area and the method of filling all play a part as well.
That depends on the type of sludge, solids content, viscosity, particle size, filter area, cake build-up and ambient conditions. We cannot therefore commit to a general figure. With sludges you have not run before, we recommend a trial.
Yes. The bags are used on municipal sewage sludge and in package treatment plants. For drilling slurry, use is confirmed for water-cooled drilling in quarries and for concrete processing. Other drilling fluids, bentonite mixtures and chemically loaded media are assessed individually beforehand. The right version follows from the process, the quantity, the density and the working load required.
Sludge filter bags, dewatering filter bags, filter bags for dewatering and sludge drainage bags are common names for the same type of product. What matters for the selection is usable volume, working load, dimensions and the type of sludge, not which term you started from.
The bags are open at the top. The sludge and water mixture can go in by hose, pipe, pump, from a collection tank or straight from above, depending on the process. No fixed inlet connection is required.
No. The sludge dewatering bags and both nonwoven bags for paint sludge are single-use products. After dewatering, bag and contents are disposed of according to the classification of the sludge.
Not automatically. Depending on the original medium, the filtrate has to be tested, collected, treated or removed properly. The filter bag does not guarantee that the water may be discharged and it does not replace effluent treatment.
Unsure about usable volume, working load, type of sludge or installation dimensions? Through our filtration product advice we will work out together which standard size or custom version suits your process. It helps to have details of the sludge, the batch quantity, the density, the floor area, how you fill, what happens to the filtrate and how many bags you expect to need.
Praxisbeispiele, Auswahlhilfen und technisches Wissen für die passende Einordnung der Produkte dieser Kategorie.
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