The 2 Volumes

Chapter 18 - Liquid sludge treatment (98 pages)

chapter 18: page example


A sludge treatment system can only be properly designed if we know the answers to the following three questions:

Sludge quality depends on the pollutants contained in the wastewater entering the plant but mainly on the treatments carried out (see chap. 2 § 6.1.) and will have a major effect on the forecast performance of the various processes: impact on dry solids content, on the type of reagents and amounts used, on the choice of equipment. For instance, if the sludge is hydrophilic (presence of biological sludge, of hydroxide sludge, of organic matter, etc.), this will have an adverse effect on dewatering performance (relatively low final dry solids content). On the other hand, if the sludge is hydrophobic (presence of crystalline sludge, of heavy mineral sludge, of primary settled sludge...), dry solids content performance will tend to be quite good.

The quantities (suspended solids) set equipment investment levels and impose certain financial options. Additionally, any rational wastewater treatment plant design must address a major concern: it must attempt to significantly reduce the mass of waste products created by the treatment process. This reduction can be addressed within the water system itself by using organic and non-mineral reagents or very low loaded biological treatment, or even using processes such as Biolysis. Clearly, this reduction can also be dealt with in the sludge system (anaerobic digestion, OM incineration, using an organic conditioner...).

The final disposal of sludge (see chap. 2 § 6.3.) will have a significant influence on the equipment selected:

and even, when selecting the water line, for instance, by aiming for sludge that has a high organic matter content and a high dry solids content so that it can be incinerated...
Therefore, any study concerning sludge end usage must include:

© 2007