BELT PRESS, CENTRIFUGE, SCREW PRESS OR OTHER ALTERNATE DEWATERING DEVICE – WHAT IS BEST FOR YOUR PLANT?

Municipal and industrial wastewater treatment plants at one time or another are all faced with deciding what is the best dewatering technology for their sludge or biosolids. Several dewatering technologies such as gravity belt thickener, belt filter press, decanter centrifuge, and screw press are available in the market. Screw press dewatering technology is often used for the industrial wastewater treatment applications while the belt filter press and decanter centrifuge are often used for the municipal wastewater treatment.This paper briefly describes the various dewatering technologies and focuses on belt filter press and decanter centrifuge technologies. The decision of whether to utilize belt filter press or centrifuge technology can be difficult and there are many variables to be considered that will influence the selection process.Results of side-by side tests where a full-scale centrifuge was tested next to a full-scale belt press are presented. Variables associated with operator and manufacturer bias can be eliminated if both technologies are available from the same supplier.A comparison of equipment performance parameters such as cake dryness, throughput capacities, polymer dosage, and solids capture rates is presented. Results of these evaluations and the factors affecting the decision-making processes associated with them are presented in order to aid the design engineer or plant engineer in the decision-making process for his or her specific situation.