A Laboratory Based Method for Predicting Dewaterability

The goal of this research was to develop a lab-scale dewatering method that estimates dewatering characteristics such as polymer demand, cake solids and capture. The method replaces traditional centrifuge tubes with belt filter cups which are fitted with circular belt filter press fabric. Digestate is conditioned and then portions of the conditioned sludge is placed in the centrifuge cups and centrifuged at a set g-force for a defined time. The essential parameters defining the method were: (1) mixing the cake during centrifugation, (2) the time of centrifugation, and, (3) dry solids loading onto the belt filter cups. Mixing the cake during the centrifugation increased the final cake solids as did increasing the centrifugation time. However, cake solids decreases as solids loading increases. Using appropriate parameters, the method could accurately predict full scale belt filter press cake solids with only 0.15% difference relative to full scale. Overall, the method is well suited for use in the laboratory because it demands less equipment and also produces cake which can be further tested for other dewatering parameters such as odors.