When the solid particles in the suspension are large and the particle size is uniform, the pores of the filtrate layer are smooth, and the filtrate passes through the filtrate layer at a higher speed. The application of coagulant to aggregate the fine particles into larger clumps is beneficial to improve the filtration speed.

For the suspension with fast settling rate of solid particles, the filter used in the upper part of the filter medium is used to make the filtering direction consistent with the gravity direction, and the coarse particles settle first, which can reduce the blockage of the filter medium and filter slag layer. Coarse solid particles such as diatomite and expanded perlite can be mixed into the difficult to filter suspension (such as colloids), which can make the filter slag layer become loose; When the viscosity of the filtrate is high, the suspension can be heated to reduce the viscosity. These measures can speed up filtration.