The screens are suitable to retain the floating solids from wastewaters. They are usually mounted in open channels, before sand catchers, in mechanical level of wastewater treatment process.
The scope of these equipments is to retain the floating solids from wastewaters, keeping away from other mechanical equipments, preventing their breakdown.
The various type of screen can be classified by: the distance of the bars, the mounting place and the construction type.
Taking in consideration their efficiency, their low cost exploitation, and their low cost we categories as follow:
Screens with manual cleaning system
These types of screens are usually mounted in open channels; their cleaning is made by the operator manually by the help of a rake and are used in small wastewater treatment plants, where the automated screens are not economic.
In case of big wastewater treatment plants are mounted on the by-pass channels of automated screens.
Automatic cleaning screens
These types of screens consist of two parts. The fix part is the screens body and the moving part is the rake system (the cleaning system of the screen). The cleaning of this type of screen is made automatically. The level switches mounted in front and in back of the screens, in case of a big level difference will send a signal and this will start the cleaning of the screen. The cleaning can also start by the help of a countdown timer or manually. Their function can be continuous or intermittent.
The most frequently used screens are: plan screens/ multi-rake screens, multi-rake chain screens, stepping screens etc.
Multi-rake chain screens
These types of screens are the most frequently used screens. They have a large high liability; can be mounted against the water race. Applicable for large water flows.
Dimension of the screens are determined by the width and height of channels where it will be mounted, but also the water flow.
The retained material is transported to washing and compacting equipment.
Construction material: SS 1.4301, optional SS 1.4401
The distance between bars:
Rotating fine screen
They are used to retain floating solids from wastewater as bar screens. The difference is its shape and functioning.
Filtering fines is determined by the plate perforation, which can be 2, 3, 5, 6, 10 mm (or other dimensions on request). The wastewater flows into the open end of the inclined screen basket and then through the screen, the floating solids bigger then the perforations of the plate will be retained, while the water will flow thru the equipment. The conveyor will transport the retained solids to the washing and compacting part.
This type of screen can be mounted in an open channel, or it can be delivered in a compact version. The compact version it is used for small or medium water flows.
This type of screen is endower with a washing and compacting system. There is no need to use another conveyor to transport the retained materials, which gives the equipment an advantage, reducing significantly the economic aspect.
Construction material: SS 1.4301, optional SS 1.4401
For an automatic functioning the equipment can be delivered with control panel.
Rotary drum fine screen
The rotary drum fine screens are used just like the other screens in wastewater treatment plants, in the mechanical process. The rotary drum fine screens are endower with a screening, transporting, washing and compacting zone.
Construction material: SS 1.4301, optional SS 1.4401
For an automatic functioning the equipment can be delivered with control panel.
Curved bar screens
Curved bar screens are used in mechanical process of wastewater treatment plants as other screens.
The equipment has a compact construction. The wastewater flows in the tanks of the screen, from where the solids bigger then the perforation of the plate (3- 5- 6 mm or other dimensions on request) are being retained. The perforated plate is being cleaned by the brushes. The cleaning brushes are fixed to a shaft, which is being operated by geared motor.
The equipment it’s made of SS 1.4301, optional SS 1.4401, and the brushes are polyamide.
The compact construction of equipment retains any odors.
The capacity of this equipment is 110 m3/h. If higher capacity is needed it can be used more equipments with parallel coupling.
Receiving stations for discharged wastewater
These stations are used in communal wastewater treatment plants for reception of discharged wastewater.
Construction:
The composition of equipment it is detailed in offer, depending on customer’s request.
The function of installation is fully automated, no need any operating staff.
