Mechanical Sludge Disintegration: Providing an Alternative Carbon Source for Nutrient Removal

Abstract

The primary driver for efficient biological nutrient removal (BNR) in activated sludge treatment is the sufficient supply of soluble carbon. Several methods have been proposed to increase available carbon sources and enhance BNR. This study examines the effect of ultrasonic equipment and mechanical disintegration technologies on surplus activated sludge (SAS), to release additional soluble chemical oxygen demand (SCOD) and volatile fattty acids (VFA), as a carbon food source for BNR. A laboratory sonicator with a maximum power of 550W, a 3KW SONIX radial horn and a deflaker declared to be used in the paper industry were investigated. All caused significant release of SCOD, up to 48 fold. The maximum concentration of VFA reached (from 0-1 mg 1(-1)), was 530 mg 1(-1). To assess the likely impact to BNR, batch (21) anaerobic lab tests examining the use of disintegrated sludge on phosphorus and nitrogen removal were completed. Phosphorus removal was estimated by observing the phosphate release under anaerobic conditions and up to 460% more release was observed relative to controls. In addition, denitrification rates were improved by over 106%. Ultrasonic and mechanical disintegration technologies have been shown to release soluble carbon for BNR, with subsequent laboratory nitrogen and phosphorus removal efficiencies observed to be comparable to acetate.

Comparison between disintegrated and fermented sewage sludge for production of a carbon source suitable for biological nutrient removal

“…This has been demonstrated to increase the soluble chemical oxygen demand (SCOD) and VFAs content by disrupting microbial flocs and cells using pressure and friction forces [16,17]. However, there is little information about the application of the disintegrated sludge to BNR in order to improve P and N removal [18] and how it compares with primary sludge fermentation.…”

The Impact of Oxone on Disintegration and Dewaterability of Waste Activated Sludge

“…Beneficial outcomes were shown for thermal pretreatment (Camacho et al, 2005;Phothilangka et al, 2008;Tunçal, 2011), addition of enzymes (Barjenbruch and Kopplow, 2003;Roman et al, 2006), ozonation (Song et al, 2003;Carballa et al, 2007), chemical solubilization by acidification (Chen et al, 2007), alkaline hydrolysis (Grübel et al, 2013;Mukherjee and Levine, 1992;Vlyssides and Karlis, 2004), alkaline addition and sonication (Jean et al, 2000;Zhang et al, 2007) as well as mechanical and ultrasonic sludge disintegration (Coelho et al, 2014;Grübel and Machnicka, 2009;Kampas et al, 2007;Kumar et al, 2000;Wang et al, 2006).…”