Overview of Dewatering Technologies

Belt filter presses are common dewatering choices in Europe and the United States. They can dewater sediment rapidly and do not take as large an area as the air drying processes. Belt filter presses are, thus, often used in confined locations (such as cities) and where large volumes of sediment must be dewatered. They do not dewater as completely as air drying processes, however, and may be limited by the percent solid demands of the treatment to be used. Furthermore, if the sludge is very gritty, the belts may wear out rapidly. 

Technique AppUcations limitations Secondary Impacts Relative Cost 

Belt Filter Press Used to dewater fine grained sediments. Capable of obtaining relatively dry filter cake obtaining up to 45 - 70 % solids able to achieve solids capture of 85 - 95%. Generally best suited of filtration methods for mobile treatment systems. Performance is very sensitive to incoming feed characteristics and diemical conditions. Belts can deteriorate quickly in presence or abrasive material. Generates a substantial amount of waste water that must be treated. Medium 

Chamber Filtration Used to dewater fine grained sediments. Capable of obtainii a relatively dry filter cake with a solids content up to 50 - 80 % able to achieve a high solids capture rate of up to 98%. Costly atsl energy intensive. Replacement of filter media is tiiiK consummg. Generates a wash water dut must subsequently be treated. HG  

Vacuum Rotary Filtration Used to dewater fine grained sediments capable of obtaining a filter cake of up to 35 - 40% solids and a solids capture rate of 88 - 95%. Least effective of tlie filtration metliods of dewatering. Energy intensive. Generates a wash water that must be treated. High 

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