Tertiary Filtration with Rotating Discs Unit for Effluent from Urban or Industrial Wastewater Treatment Plants: Hydraulic Study and Granulometric Distribution Influence

Abstract

Continuous tertiary filtration with rotating polymeric discs were studied as post treatment of effluent urban wastewater in real plant (10,000 PE) and of landfill leachate or zootechnical wastes in laboratory scale. For the urban flow, different TSS and hydraulic loads were tested to determine the performances of the device. The particle size distribution, the microscope analysis and the filamentous count for the treated flows was executed to better understand the effect of the bulking sludge characteristics in terms of solids removals and of number of performed backwashing cycles. The average TSS removals were found equal to 89%±12% (11 micron) and the TSS effluent concentrations were always lower than 5 mg/l. Bimodality granulometric distribution and filamentous bacteria presence increase the performances of the filtration phase. The not applicability of this treatment for the tested industrial wastes was demonstrated in laboratory scale.