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
Primary30−40≤904−10
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

Comments

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 manager@sludgeprocessing.com to remove or edit a comment.

References

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 https://www.youtube.com/channel/UCtJwTN2sMu1kUGOef1OSoVg

About this page

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

This page was last updated on 22 January 2021

Disclaimer

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. SludgeProcessing.com 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