Screens and compact pretreatment
Wastewater pretreatment equipment
A complete range of pretreatment equipment is offered for municipal and industrial waste water. The range includes coarse bar screens, fine step or drum screens, compactors for screenings, sand classifiers and washers and comact pretreatment units performing in a single tank screening, sand and grease removal.
Meva Rotoscreen RS
The Meva Rotoscreen is a self-cleaning fine step screen for the separation of solid particles from water. The screen has a very low flow resistance that provides a low head loss and the highest relative capacity of all screen types on the market, which is an advantage for open-channel installation.
The Meva Rotoscreen is suitable for installation in incoming channels to municipal waste water treatment plants and process industries where a separation of around 1-6 mm is required.Since the mid-eighties the Meva Rotoscreen has been continuously developed to meet the demands of the future for functional screens. The Meva Rotoscreen fine screen is a product of long experience, which has proven performance in all over the world.
This is how it works
The Meva Rotoscreen has an exact slot width even during operation. This is ensured by a robust bar fixing and and replaceable plastic spacers. The screen has an automatic anti-blockage protection and sealing gap at the channel bottom, which makes the screen completely resistant to sand, gravel, etc. There is very good accessibility for maintenance and cleaning as the screen can be pivoted out of the channel without the combined equipment, such as screw and press, needing to be moved or dismantled. The above mentioned advantages, together with a high hydraulic capacity and a very robust design, ensure that the Meva Rotoscreen is a very efficient and robust screen.
The Meva Rotoscreen is available in various sizes that are distinguished mainly by unloading height. The sizes are available in different width versions adapted to regular channel widths. The Meva Rotoscreen is fully enclosed and provided with a ventilation sleeve coupling for venting.
SWP screw wash press
Due to the increasing use of fine screens, the amount of screenings separated from waste water is continuously growing, leading to increased odor problems and disposal costs.
Using Meva SWP to wash the fecal content and reducing the screenings volume is advantageous for environmental as well as for economical reasons. Meva SWP is well suited for both small and large waste water treatment plants. It is a compact, cost efficient and robust unit, which has proven good functionality due to its simple and functional design.
Meva SWP allows for both the return of washed-out organics to the treatment process and an increased DS content of the screenings. The combination of Meva Screw Wash Press and Meva Counter Pressure Screw results in a product optimal for incineration.
Combined with a Meva fine screen, the result is an optimal screenings unit. Meva SWP can also be used directly after coarse screens, sieves or transportation equipment such as spiral or belt conveyors.
Meva SWP is designed with double troughs making it very “torque resistant”, which is important in heavy operations where screenings have high DS content. The high “torque resistance” also enables the SWP to be delivered with a large inlet opening. Further, the double trough allows for the inner pipe to be fully perforated and, thereby, allowing maximal dewatering. A robust axial bearing and a worm gear absorb the forces from the press. The press zone is easily accessible through a hatch.
Meva Channel Screen (drum sieve) MCS
Meva Channel Sieve is a compact and simple solution for screenings separation and handling at a waste water treatment plant or industry. Meva MCS combines separation, washing and
pressing in one unit. The screenings are shredded into pieces at the discharge in order to eliminate large compact screenings that can cause problems at incineration.
This is how it works
Waste water is screened through the lower separating part of the unit inside a channel or a tank. The separation can be done with a perforated plate or a wedge wire. The sieving element is shaped as a trough (drum), in which a spiral with a smaller diameter transports the separated screenings out of the water. The spiral is fitted with a brush inside the sieving trough to prevent clogging. From the sieving trough the unit transforms to a shafted spiral fully capsulated in octagonally bent stainless steel. This contributes to a good working environment and the octagonal form gives a good transport capability. The screenings is washed in the screw and transported to the discharge. The water used to wash the organics from the screenings is added in the opposite direction to the spiral movement. The screenings are pressed to a DS of up to 45% before the discharge and is then shredded into smaller pieces. In the press zone a large amount of water is removed. With effective flushing without spray nozzles the Meva Channel Sieve requires a minimum of maintenance.
Sand washers SWA and sand classifiers
Meva Sand Washer SWA is designed to dewater and wash sand from sedimentation tanks.
In traditional sedimentation tanks there is no separation of organic or inorganic materials. As a result, the organic part of the material caught in the sedimentation tank often totals up to 30-80%. Meva SWA reduces the organic content in the sand to an end product with an ignition loss of 1-5%. This level is prescribed internationally.
The operation-related advantages are, apart from substantially smaller amounts of sand, a better working environment and decreased transportation and disposal costs.
Sand classifiers SA are simpler in design and provide sand separation on the sedimentation principle. An inclined screw removes and dewaters the collected sand.
MEVA compact pretreatment units MCU
The Meva combi-unit MCU can be used for the mechanical pre-treatment of municipal and industrial waste water. All treatment steps are integrated and performed in the same steel container. The Meva MCU is supplied in sizes from 10 l/s to 300 l/s. The combi-unit consists of the well known and proven Meva products Meva Rotoscreen, Meva Monoscreen and screw wash press (SWP).
This is how it works
The waste water, which can be delivered by gravity or pumping, is led to a fine screen and purified from solid particles. In the screw wash press the screened material is washed, dewatered and compacted. The washed and dewatered screened material is delivered via a pipe system or CPS back-pressure screw to a container. Sand separation occurs in the subsequent sand trap that can be fitted with aeration and a surface scraper for grease removal. The sand is ejected by means of screw conveyors, with associated dewatering. If you want to or need to wash the sand, the unit can be supplemented with sand wash. The combi-unit can be used with the installation for both outdoor and indoor environments.