Product Information
A screw press is a common sludge dewatering unit, often called a screw extrusion dewatering machine. It relies on the squeezing action between an internal rotating screw shaft and external fixed stacked rings to achieve efficient solid-liquid separation. As a compact piece of solid-liquid separation screw equipment, its biggest feature is its self-cleaning ability. It doesn't clog easily, making it an excellent fit for oily or low-concentration sludge. It also uses noticeably less energy than traditional centrifuges or belt filter presses.
Get a QuoteScrew Press | Screw Press for Sludge Dewatering | Solid-Liquid Separation Screw Equipment
Working Principle
Sludge is first mixed with flocculant and enters the flocculation tank. It then flows into the filtering body, which is made of alternating fixed and moving rings stacked together. The screw shaft rotates slowly inside, pushing the sludge forward continuously. As the pitch gets smaller, pressure inside the chamber increases, forcing the water out through the tiny gaps between the moving rings. The rotation of the screw shaft also constantly clears the gaps between the rings to prevent clogging. The dewatered cake is discharged from the end, while the filtrate flows out through the collection tank below.
Application Fields
1.Municipal wastewater: dewatering of excess sludge in small to medium wastewater plants or pumping stations.
2.Food processing: treating oily or high-organic sludge from slaughterhouses, breweries, and beverage plants.
3.Chemical and printing: dewatering chemical and biological sludge from fine chemicals and printing/dyeing wastewater.
4.Livestock and slaughter: solid-liquid separation of manure for easier composting downstream.
FAQ
Q1: Does a screw press clog easily?
A: No, it doesn't. That's one of its biggest advantages. The moving rings inside the unit continuously self-clean as the screw shaft rotates. So, when handling oily sludge or activated sludge prone to bulking, the filter gaps rarely get clogged. That's a key reason why it's becoming more and more popular.
Q2: What is the typical cake moisture content from a screw press?
A: Depending on the material, usually around 75%–85%. If you need a drier cake, a simple press or drying unit can be added downstream. For municipal sludge, it typically achieves around 80% moisture content.
Q3: Why is a screw press relatively energy-efficient?
A: Its core principle relies on slow screw extrusion. It rotates very slowly (usually just 2–3 rpm), unlike centrifuges that require extremely high speeds or belt presses that need high-power squeeze rollers. Its drive motor is small, which means both energy consumption and noise levels during operation are relatively low.