Properties of Sludge Produced From the Pressurized Wastewater Treatment Process

Authors: Ali BERKTAY

Abstract: The aim of this study was to investigate the effect of pressure on settleability and filterability of the sludge produced from a pressurized biological wastewater treatment unit in comparison with an equivalent unit held at atmospheric pressure but otherwise operating under identical conditions. The specific sludge volume index (SSVI) and the specific resistance to filtration (r) are described as standard parameters to expresss the sludge settleability and filterability properties. For the sludge from the pressurized unit, the combination of air stripping and mechanical stirring produced SSVI results of as low as 60 ml/g and the specific resistance was discovered to be moderately stable with a mean 51.9\times10^{12} m/kg at 49 kPa. Investigations filterability into sludge settleability and filterability revealed that realistic settlement of the sludge from the pressurized unit could only be achieved following aeration and stirring. The indications from filterability tests suggest that the pressurized unit sludge may be more readily dewatered than that from the unit open to atmosphere.

Keywords: Biological wastewater treatment, Sludge treatment, Settleability, Filterability, Pressure

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