Potable water treatment
Potable water treatment

This free course is available to start right now. Review the full course description and key learning outcomes and create an account and enrol if you want a free statement of participation.

Free course

Potable water treatment

5.12 Sludge treatment and disposal

The sludge collected in any sedimentation tank in the water treatment process has to be disposed of. In some instances the wet sludge is transported to the nearest sewage works where it is discharged into the raw sewage inlet channel. The presence of the added chemicals can help in the primary sedimentation of the crude sewage. Alternatively, the sludge can be sent to a landfill site after it has been concentrated into a cake by dewatering.

The dewatering is carried out by pressure filtration, vacuum filtration or centrifugation. In pressure filtration, the sludge is pressed at high pressure between filter cloths. Vacuum filters are popular in the USA but few treatment works in the UK employ them. A slowly revolving drum, partly immersed in the sludge, carries a filter cloth through which water is sucked from the sludge under vacuum. In centrifuging, chemically or biologically conditioned sludge falls onto the centre of a rapidly rotating bowl. The solids are thrown to the outer edge of the bowl where they are removed by a scraper. With chemical-conditioned sludge, 80–98% of the solids can be separated this way. These solids would contain typically 10–35% water.


Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to university level study, find out more about the types of qualifications we offer, including our entry level Access courses and Certificates.

Not ready for University study then browse over 900 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus