Efficient dewatering of polymer-rich aerobic granular sludge with cationic polymer containing hydrocarbons

Abstract

This study compared the dewatering properties of aerobic granular and activated sludge from full-scale wastewater treatment plants, and determined how polymer dose and type affect granular sludge dewatering efficiency. At the same dose, granular sludge filtration cake had about 4% lower humidity than activated sludge cake. Aerobic stabilization improved only activated sludge dewatering. The granular sludge reactor had over 1.5 times more extracellular polymeric substances (1.8 times more alginate) per reactor volume than the activated sludge reactor, but the high polymer content did not decrease granular sludge dewatering. Granular sludge dewatered best with FLOPAM EM 840MEB, due to its composition (n-alkanes, isoalkanes, cyclic/aromatic hydrocarbons). With this polymer, sludge cake moisture was lowest (84.7 ± 0.4%) at 1.6 g polymer/ kg MLSS. With all tested polymers, the lowest dose (0.2 g/kg MLSS) ensured low cake humidities; this dose was far lower than typical doses for activated sludge dewatering. Upgrading from activated to granular sludge technology significantly facilitates excess sludge management.

Alginate-like polymers from full-scale aerobic granular sludge: content, recovery, characterization, and application for cadmium adsorption

“…3 a). These values were slightly higher than the ALP-AGS content reported in another study conducted in a full-scale WWTP 30 and similar to values observed in lab-scale reactors, which are usually higher than in full-scale systems 23 . For example, in lab-scale reactors fed with primary effluent from municipal wastewater, AGS contained 184 ± 18 mg VS ALP/g VSS 9 .…”

Aerobic Granular Sludge: Perspectives for Excess Sludge Management and Resource Recovery

“…In contrast, it was reported that the Ps content is positively associated with dewaterability [69]. So, a lower PN/Ps ratio means a higher dewaterability [4,61]. Zhang et al [70] and Jahn et al [24] indicated that the presence of tightbound EPS significantly limits granules dewaterability since it contains the majority of PN content.…”

“…[ [86][87][88][89][90][91] It can be injected as bio-flocculants in combination with multivalent cations for sludge dewatering. [4,82,83] EPS can be used as bio-absorbent for metal removal from industrial wastes. [94][95][96][97] Removal of toxic organic compounds.…”

“…In addition to the role of granular size, the PN in EPS content is also positively correlated with the water-holding capacity of granules [24]. Cydzik-Kwiatkowska et al [4] showed that a higher PN content induces a lower hydration rate. In contrast, it was reported that the Ps content is positively associated with dewaterability [69].…”

Biopolymers in Aerobic Granular Sludge—Their Role in Wastewater Treatment and Possibilities of Re-Use in Line with Circular Economy

“…Extractable ALE can comprise up to 25% of AGS [37]; extraction of ALE can, therefore, decrease the solids content of AGS and contribute to sludge management [49]. In a study by Cydzik-Kwiatkowska et al [50], the content of ALE was about 184 mg/L of excess activated sludge, whereas the amount of ALE in granular sludge was over three times higher. The amount of ALE per g unit of biomass was over twofold higher in AGS (86.0 ± 11.2 mg/g MLSS) than in activated sludge (49.0 ± 9.0 mg/g MLSS).…”