The Activated Sludge Process is known to produce significant quantities of sludge, which is thickened, digested and dried to produce conventional biosolids, as shown in the general flowsheet.
Industrial thickeners are widely used in process industries and can routinely produce underflows with a solids concentration of up to 60% solids, Segovia et al (2011).
In the treatment of Municipal Waste Water, however, online civil engineering notes describe different types of sludge digester that produce stabilized sludge of different properties that feed the final sludge dryer, that produces the biosolids for dry stacking.
This project proposal involves building on fluid bed research from the 1980’s that involves the fluidised bed combustion of raw brown coal, which has a moisture content of 61%. This pilot plant study involved feeding fuel into a bubbling fluid bed, see figure below.
There is an extensive research base into high temperature processing in fluidised beds, which can be discussed at length when required as this is the specific area of professional expertise.
A low risk pathway to investigate the combustion of thickened sludge is to construct a similar facility to that shown above to conduct trials using samples collected on site. If the test facility is appropriately sized then heat recovered from the fluid bed combustor could be used to generate electricity in an ORC energy production module, similar to this.
Contact us if you want would like to discuss developing these project ideas further.
