Roto-Sieve rotating drum screens: screening and pretreatment system for wastewater and process water

Screening technology for wastewater, process water and liquids

Mechanical pretreatment with internally fed rotating drum screens

Mechanical pretreatment is an important step in any wastewater treatment process (mechanical screening, fine screening, septic screening, sludge screening, sludge thickening, process water screening, screenings of all kinds of liquids). Roto-Sieve® rotating drum screens are used for high performance particle separation out of wastewater, process waters or any other liquids. Läckeby Roto-Sieve® is an internally fed, self cleaning, inclined drum screen, with round drum perforations.

Why choosing Roto-Sieve® rotating drum screens?

When high performance, low costs and simplicity are the priorities.

Save time and money! The Roto-Sieve® drum screens are self cleaning and low maintenance. With low energy consumption. The Läckeby Roto-Sieve® drum screens are well known for their unequalled quality, performance, durability and reliability.

Roto-Sieve on film

Have a quick look inside the Roto-Sieve.

Projects

An overview of our Läckeby Roto-Sieve® drum screen projects worldwide. We are constantly completing our case studies, some are realized by Läckeby, some by our colleagues worldwide and some by Task. Each picture is hiding more (project descriptions, films, pictures). Take a look on a regular basis for updates!

Roto-Sieve rotating drum screen: water screening system for wastewater and process water treatment – screening technology for particle separation :

Benefits using Roto-Sieve® rotating drum screens in wastewater treatment applications

There are many advantages using Roto-Sieve® rotating drum screens in wastewater treatment applications, especially in the preliminary treatment traject. Also for fine screening, septic screening, sludge screening, sludge thickening, process water screening.

Roto-Sieve rotating drum screens main assets

  • self-cleaning, so minimal maintenance
  • high operational reliability
  • high degree of separation
  • extended life-time
  • small footprint
  • entirely closed system, no odor nuisance
  • easy to install, easy to operate
  • low energy consumption
  • simple design: very few moving parts – wear parts and spareparts are easy to replace
  • good utility in many applications
  • improved performance of water treatment processes
  • wide range of drum screens for capacities of 5 up to 1.000 m³/h/drum screen

Roto-Sieve drum screen : a short description

A rotating drum screen separates solid particles and fibres from liquids by screening. The drums screens are based on proven technology, with a self-cleaning function, offering excellent results with minimal maintenance. With high operational reliability, a long service life and low energy consumption, Roto-Sieve drum screens are a proven good investment. Due to its internal feed and circular perforations, Roto-Sieve offers the best separation that can be achieved mechanically. It has been shown in practice that a fibre or hair has a very small chance of orienting itself at a right angle and against the water current, so that it would be able to pass through a round hole.

Roto-Sieve rotating drum screen : operating principle

Roto-Sieve drum screens consist of a perforated drum (1) with internally fixed screw (2), which transports the separated particles out of the drum. The drum is driven by drive belts (3) and a cog gear motor (4). Incoming liquid is internally fed in the drum through an inlet pipe (5), distributing the water over a large area of the drum’s interior. During passage through the drum, the liquid is screened through the drum’s perforations and collected in the receptacle (6) underneath. Separated particles are transported out of the drum through the screenings outlet cone(7). Dewatering continues throughout transport in the drum. To prevent clogging of the unit’s perforations, all drum screens are fitted with a rotating brush (8) and a spray header with spray nozzles (9). Roto-Sieve drum screens are completely encased in removable splash guards (10) and equipped with a ventilation exhaust (11) to adapt to all industrial environments (installation inside or outside). Reduces the operational cost for the ulterior process stages. It goes without saying that Task is guiding you through the implementation and installation process of your Roto-Sieve.RotoSieve design simplicity

Roto-Sieve rotating drum screen design

Roto-Sieve® drum screens come in five standard models for various flows, in stainless steel or acid-proof steel. All models are equipped with lightweight fiberglass covers. Brushes are manufactured in heat resistant material. Standard drum perforations are 0.8-1.0-1.5–2.0-3.0 mm, the smallest available perforation is 0.6 mm. All models (RS11 excepted) are supplied with standard overflow system.

  • Roto-Sieve is the rotating drum screen with the lowest number of moving parts available on the market
  • the advanced polychain carbon drive system eliminates the need for trunnion wheels under the drum. The trunnion wheels used to be the most common wear parts on the old Roto-Sieves. This significantly lowers required maintenance and improves reliability.
  • few moving wear parts which are quickly and easily accessible. No need for cranes or other lifting devices, 1 single technician can easily do the job in no time.
  • no chains of any kind results in less maintenance issues. No need for automatic oilers.
  • easy and quick access to the drum for visual inspection, thanks to the leightweight fiberglass covers.

Roto-Sieve® rotating drum screen : process benefits

  • enhances process efficiency, for instance in wastewater treatment plants
  • reduces need for cleaning
  • easy maintenance
  • reduces operating cost of the subsequent stages in the wastewater treatment process
  • gravity feeding as well as pump feeding are possible for the Roto-Sieve drum screen

References

Worldwide several thousands of Roto-Sieve rotating drum screens have been installed, enhancing the wastewater treatment process in production plants as well as in municipal wastewater treatment installations. Roto-Sieve rotating drum screens have been succesfully implemented in all kinds of industries, such as:

  • breweries
  • municipal wastewater treatment plants
  • drinking water preparation
  • vegetable and fruit processing industry
  • potatoe processing industry
  • bottling plants
  • malteries
  • coffee-roasting industry
  • animal feed industry, petfoods
  • slaughter houses, chicken slaughter houses, rendering
  • shipping industry and shipyards
  • textile industry
  • sugar industry
  • pulp and paper
  • fish industry
  • dairy industry
  • food industry and semi-finished food products
  • plastic processing industry and plastic recycling
  • dredging works
  • pump stations
  • fat melting plants
  • tanneries
  • chemical industry
  • recycling industry, etc.

Contact

Your Benelux (Belgium, Grand Duchy of Luxembourg, the Netherlands) distributor : Task Environmental Engineering.

Curved Sieve or Roto-Sieve rotating drum screen?

Why choosing a rotating drum screen rather than a curved sieve for the separation of solids from wastewater? In theory, both are doing the same thing, don’t they?
Correct, in theory, they do, but in practice, there are some substantial differences. An internally fed rotating drum screens allows to treat larges flows, without having to claim too much valuable factory space. A rotating drum screen is compact, requiring only a minimal footprint. The maintenance need of a Roto-Sieve rotating drum screen is minimal: all Roto-Sieve drum screens, from the largest model up to the tiniest one, all have a standard custom made roller brush and spraying bar. By this self cleaning function, the Roto-Sieve rotating drum screen can also deal with sticky and greasy materials (convince yourself and have a look at the case studies, higher on this page, at the projects section). Our internally fed Roto-Sieve rotating drum screen is featuring a high separation performance, compared to a curved seeve with round perforations. With the internally fed Roto-Sieve rotating drum screens, flooding belongs to the past. Roto-Sieve drum screens have a standard overflow system, with overflow detection and connection. The Roto-Sieve rotating drum screens are completely closed (with ventilation), avoiding odor nuisance. The self cleaning function and sophisticated design have led to extremely low maintenance drum screens. The design is simple, but most carefully considered for quick and efficient replacement of the occasional spare part. Did you know, by the way, that all spare parts (also for Roto-Sieve older than 30 years!) are always availible from stock in Sweden? Durable design is saving many working hours and contributes to a circular economy. Task/Läckeby is at you disposal for any question you might have. We don’t just stick to the standard, we think along with our customers, small adaptations for a custom made design are always possible for better performance. Submit your problem. Our years of experience in the area of water treatment are at your disposal.

Static screen versus drum screen: comparative table

A Roto-Sieve rotating drum screen with an 0,75 mm perforation is removing twice as much suspended solids compared to a 0,5 mm static screen.Roto-Sieve versus static screen comparative chart

In channel perforated screen versus rotating drum screen: looking for the best wastewater screening technology?

What’s the best wastewater screening technique? Following considerations have to be made:

  • performance of the screening technology
  • flexibility of the system
  • maintenance and inspection

Performance: considered per time unit, a Roto-Sieve rotating drum screen is separating the biggest quantity of suspended solids, compared to in channel screens, channel grids, step screens, etc.

Performance: screening technology without static pressure. The Roto-Sieve rotating drum screen is not under pressure, meaning that the solids and fibers do not get pressed through the screen’s perforations by the pressure. This gentle treatment guarantees that only particles smaller (in any direction) than the perforation will get through.Roto-Sieve rotating drum screen without static pressurePerformance: 100 % guaranteed separation. The Roto-Sieve rotating drum screen with standard overflow detection offer 100 % certainty that all incoming water will get through the perforated zone. With in channel sieves everything depends on how well the edges of the unit are sealed off.Roto-Sieve versus channel screen

The disadvantage of a in channel screen is that a bigger water pressure at certain points is pushing particles and fibers through the perforations. Whenever the perforated plate is moving, all the water condensates on a smaller free section, the higher flow at that particular section, coming along with a higher pressure is leading to this unwanted push through effect. 

Performance and backflow of screening material: the internal spiral on the inside of a Roto-Sieve drum screen is gently and gradually pushing the screening material to the outlet. Many in channel screens are pushing the screening material to the outlet, where a brush is installed. It’s often this brush which is pushing back the screening material through the perforated plate and back into the channelChannel screen push back of screening material
Easy inspection of your Roto-Sieve drum screen: the lightweight fiberglass covers ensure a quick visual inspection of the drum and easy access to all other parts. This is possible during operation: the entire production or wastewater treatment process doesn’t need to be stopped.Roto-Sieve Fiberglass covers for quick inspectionIn channel screens are constantly under water during operation, meaning that there is no control on the sealing of the edges of the screen or on good functioning. As a consequence, visual checks will only happen when problems occur. All too often, the entire unit has to be lifted out of the water.

Maintenance: just remove some lightweight fiberglass covers and your Roto-Sieve drum screen is well accessible from all sides for quick inspection and the occasional replacement of spare parts. Maintenance on an in channel sieve means that the covers are to be removed, the entire screen has to be lifted out of the water for inspection and/or maintenance. The covers need to be replaced quickly to prevent odour nuisance and the entire procedure is to be restarted the other way round to put the screen back in place. So quite some actions to be taken in a time consuming process.

Spareparts

It goes without saying that you can always obtain spareparts for your existing Roto-Sieve rotating drum screen (eg purchased in the past from Roto-Sieve Belgium in Vilvoorde). Also for Roto-Sieve rotating drum screens from the eighties and nineties, spareparts remain available directly from stock. Calculated in total life cycle cost, your Roto-Sieve will turn out to be the most economic screening solution.

Most spareparts are easy to replace. However, our technician is always at your disposal for a thorough checkup of your Roto-Sieve or replacement of spareparts. The Roto-Sieve rotating drum screens have an extended life-time. A good maintenance inspection of your Roto-Sieve will even increase the expected life-time of the drum screen. Your distributor for new Roto-Sieve drum screens as well as for Roto-Sieve spareparts in the Benelux (Belgium, Grand Duchy of Luxembourg, the Netherlands) : Task Environmental Engineering. Contact us (preferably with your machine’s serial number at hand: 10-xxxx) : we take care of the rest. Not in the Benelux area? Find our colleagues worldwide here.

Roto-Sieve ®: registered trademark

Make sure you have the original Roto-Sieve drum screen. Roto-Sieve is a registered trademark, property of Läckeby Products located in Kalmar, Sweden. Every authentic Roto-Sieve drum screen has a nameplate, fully identifying the machine (unique serial number – type – construction year and original drum perforation). The manufacturer is either Roto-Sieve AB or Läckeby Products AB from Sweden, depending on the year the machine was built. Every genuine Roto-Sieve drum screen has its own track record, spareparts remain available from the central stock in Kalmar, Sweden. Your Läckeby/Roto-Sieve drum screen can always remain operational at any moment. You can either install the spareparts yourself or our specialized technician takes care of this job, anywhere in the Benelux area. Authentic Roto-Sieves are built to last a lifetime. A simple and quick replacement of all spareparts is one of the main assets of our Roto-Sieve drum screens. Our Läckeby/Roto-Sieve network is always at your disposal for assistance whenever needed. Of course, the internal stainless steel drum can be repaired or replaced as well, even with another screen perforation, allowing the drum screen to adapt to any new application you had in mind. The internal stainless steel drum is always made to measure: please take into account a production lead time of 4 tot 6 weeks in general. Läckeby AB (owner of Roto-Sieve) is a stable and well established Swedish family business. The company was founded in 1935, and is led today by the third generation, Magnus Axelsson.

Roto-Sieve screening technology. Have a look inside

You need more information? Have a look a the Roto-Sieve information brochure. You have questions? Not sure this is the best solution for you? Don’t hesitate and contact us.