Your web browser is out of date.

Update your browser for better security, speed and to get the best experience on this website.

Update your browser

Screw presses for sludge dewatering

Posted on
Mud splashes on a white background

How screw presses work

A screw press (SP) provides sludge dewatering by conveying the sludge along the inside of a permeable cylinder. It is based on a slowly-rotating (~5 RPM) Archimedean screw within a cylindrical screen (otherwise termed drum filter/screen or basket). It is normally inclined by ~20° to the horizontal to assist with the draining of water into the sump. The screen generally has an aperture rating below 0.5 mm and is based on wedge-wire or occasionally perforated metal.

The screens are less susceptible to clogging than the filter media used for other thickening and dewatering processes. Consequently, spray-cleaning is applied only intermittently for around 2−4% of the operating time.

As with all thickening and dewatering processes, the product solids (or cake) content is dependent on the feedwater sludge quality. The cake solids content has been shown to be inversely proportional to the volatile solids (VS) of the feed sludge.

Screw press Credit: Judd Water & Wastewater Consultants
Screw press
Screw press containing and inclined screw which transports the sludge along a porous cylindrical channel though which the water drains as the sludge travels up the cylinderCredit: Judd Water & Wastewater Consultants

Huber Q-PRESS® screw press

Huber Q-PRESS® screw press Source: HUBER SE / YouTube

Sign up to our newsletter

Table 1. Screw press dewatering DS concentration of dewatered sludge (cake), solids recovered and polymer dose (Metcalf & Eddy, 2014; Andreoli et al, 2007)
Sludge origin % cake solids % solids capture Polymer dose − g/kg DS
Waste activated sludge (WAS)15−2288−958.5−11
Anaerobically-digested (AD) primary22−28≤9010−17.5
Anaerobically-digested WAS15−2588−958.5−17.5
Aerobically-digested, WAS15−2088−958.5−17.5
Mixed, primary + WAS25−35≤905−10
Mixed, AD primary + WAS17−25≤9010−17.5


All comments are moderated and may be edited or deleted at any time. You must not post anything that is defamatory, illegal, offensive or which contravenes our privacy policy guidelines. Email addresses are only used for comments purposes. Contact to remove or edit a comment.

Eve Mitchell

It's good to know that these can help prevent the pipe from clogging. It seems like a screw press might be really beneficial in agriculture. I'll make sure to keep this in mind in case I find someone who would use it!


Can it use for sludge from wastewater from coffee roaster processing?

Simon JuddPakpoom

I think you'd have to ask the individual suppliers to see of they have any reference installations.

Kristy Stiers

Good Morning,
We are in the market for a screw press for our distillery. Could we please get more information on the presses.


Claire JuddKristy Stiers

Hi Kristy
Unfortunately, we don't supply equipment or recommend companies but we are aware that, for example, Huber sells screw presses -
You may wish to contact them? Hope this helps,

Best wishes

Claire (Website Manager)

XyanKristy Stiers

I also know a manufacturer of sludge dewatering equipment,Hope this helps,


Thanks above is my e-mail address ManagerVíctor

Hello Victor - your email address is not visible - please either reply to Kevin below his comment, or you can send me your email address on and I will forward it to Kevin for you.

Victor Romero

Dear Sirs,
We are looking a sludge dewatering equipment.
Our flow is 2 liter/sec, solid in the mix between 5 and 10%
Please could you send me price and lead time.
Thank you very much

Kevin BoakesVictor Romero

Dear Victor,
Could you please provide your email address so I can send over more detailed information to you.
Should you have any queries or questions, just let me know?


Andreoli, C.V., von Sperling, M., & Fernandes. F. (2007). Sludge treatment and disposal, IWA Publishing (Lon, NY)

Metcalf & Eddy (2014). Wastewater engineering, treatment and resource recovery, 5th ed. Eds. Tchobanoglous, G., Stensel, D., Tsuchihashi, R., and Burton, F., McGraw-Hill (NY)

YouTube channel, HUBER SE

About this page

'Screw presses for sludge dewatering' was written by Simon Judd

This page was last updated on 19 April 2021


Information on this page may have been supplied by third parties. You are reminded to contact any third parties to confirm information is accurate, up to date and complete before acting upon it. accepts no liability for information provided by third parties, actions taken on the basis of this information or information held on third-party websites.

© Text copyright Judd & Judd Ltd unless otherwise indicated on this page