ABSTRACT
The process of removing enough water from liquid biosolids to change their consistency to that of damp solids is called biosolids dewatering. Although the process is also referred to as biosolids drying, the dry or dewatered biosolids may still contain a significant amount of water, often as much as 70%. But, at moisture contents of 70% or less, the biosolids no longer behave as a liquid and can be handled manually or mechanically. Several methods are available to dewater biosolids. The particular types of dewatering techniques or devices used best describe the actual processes used to remove water from biosolids and change their form from a liquid to damp solids. The commonly used techniques and devices include the following:
• Filter presses • Vacuum filtration • Sand drying beds
An ideal dewatering operation would capture all of the biosolids at minimum cost and the resultant dry biosolids solids or cake would be capable of being handled without causing unnecessary problems. Process reliability, ease of operation, and compatibility with the plant environment would also be optimized.
