ABSTRACT
The process of removing enough water from a liquid biosolids to change its consistency to that of damp solid is called biosolids dewatering. The particular types of dewatering techniques/devices used best describe the actual processes used to remove water from biosolids and change their form from a liquid to damp solid. The commonly used techniques/devices include the following: filter presses, vacuum filtration and sand drying beds. Filter press calculations typically used in wastewater solids handling operations include solids loading rate, net filter yield, hydraulic loading rate, biosolids feed rate, solids loading rate, flocculant feed rate, flocculant dosage, total suspended solids, and percent solids recovery. Land application of biosolids requires precise control to avoid problems. Use of process control calculations is part of the overall control process. Calculations include determining disposal cost, plant available nitrogen (PAN), application rate, metals loading rates, maximum allowable applications based upon metals loading, and site life based on metals loading.
