Treatment of thickened sludge from industrial wastewater

The aim of the thesis is to present the problem of industrial sludge treatment and to identify and implement in laboratory conditions a suitable technology for the treatment of a specific industrial sludge, which is already partially thickened fermentation residues from the operation of biogas plants (BPS). Based on the research developed on available technologies for the treatment of waste sludge, the mixed evaporator was selected as a suitable technology. The advantage is the possibility of using the low potential heat from BPS CHP units under reduced pressure, which is often thwarted. The agitator in the evaporator ensures homogenization while increasing densification. The use of the technology results in a reduction in the volume of fermentation residues. The main part of the thesis deals with the design and implementation of a stirred evaporator for production. Experimental The plant was constructed on the premises of the LENP (Laboratory of Energy-Intensive Processes) at the Brno University of Technology. During operation, the functionality of the device and its applicability to several types of waste sludge were verified. The experimental results are mainly focused on the properties and behaviour of the fugate, or liquid fraction, of the fermentation residues. The fugate was concentrated from a raw state of 5.4 % dryness to a value of 20.9 % dryness, at which point it becomes a highly viscous and poorly flowing material. In an industrial plant where waste heat is wasted, a stirred evaporator may be a suitable device for sludge treatment or volume reduction. This leads to lower costs for storage, transport, and application as fertilizer to fields. With a suitable evaporator and agitator design, the evaporation principle can be used for less and more concentrated waste sludge. The resulting thickened product can then be fed to the finishing operations, allowing the distillate to be finished