Integrated review of resource recovery on aerobic granular sludge systems: Possibilities and challenges for the application of the biorefinery concept.

Aerobic Granular Sludge (AGS) is a biological treatment technology that has been extensively studied in the last decade. The possibility of resource recovery has always been highlighted in these systems, but real-scale applications are still scarce. Therefore, this paper aimed to present a systematic review of resources recovery such as water, energy, chemicals, raw materials, and nutrients from AGS systems, also analyzing aspects of engineering and economic viability.

Evaluation of the production of alginate-like exopolysaccharides (ALE) and tryptophan in aerobic granular sludge systems.

The engineering and microbiological aspects involved in the production of alginate-like exopolysaccharides (ALE) and tryptophan (TRY) in aerobic granular sludge systems were evaluated. The inclusion of short anoxic phase (A/O/A cycle-anaerobic, oxic, and anoxic phase) and the control of sludge retention time (SRT ≈ 10 days) proved to be an important strategy to increase the content of these bioproducts in granules. The substrate concentration also has a relevant impact on the production of ALE and TRY.

Pilot-scale aerobic granular sludge in the treatment of municipal wastewater: Optimizations in the start-up, methodology of sludge discharge, and evaluation of resource recovery.

This work evaluated the formation, maintenance, performance, and microbiology of a pilot-scale aerobic granular sludge reactor treating low-strength municipal wastewater under tropical climate conditions. Additionally, different resource recovery possibilities (phosphorous, tryptophan, and alginate-like exopolysaccharides) were investigated from the produced sludge. Granulation occurred after 35 days without external carbon source supplementation (COD ≈ 461 mg/L; COD/DBO ≈ 3.

Impact of cycle type on aerobic granular sludge formation, stability, removal mechanisms and system performance.

This paper aimed to assess the impact of the cycle type on aerobic granular sludge (AGS) formation, stability and system performance. Six AGS reactors were operated either on A/O cycles (anaerobic followed by oxic phase) or A/O/A cycles (anaerobic, followed by oxic and anoxic phases), changing only the phase time distribution. Reactors with high percentage of aerobic phase (65% of the total cycle time) generated granules with better settleability and resistance, however denitrification was impaired.

Effect of calcium addition on the formation and maintenance of aerobic granular sludge (AGS) in simultaneous fill/draw mode sequencing batch reactors (SBRs).

This work investigated the effect of Ca (100 mg L) addition on the formation and maintenance of aerobic granular sludge in a simultaneous fill/draw mode sequencing batch reactor (SBR), operated with a low liquid upflow velocity (0.92 m h), in order to verify if Ca presence compensates the low selection pressure imposed. Additionally, carbon and nutrients removals, granules characteristics and microbial community were evaluated.

Comparison of the dynamics, biokinetics and microbial diversity between activated sludge flocs and aerobic granular sludge.

This work aimed to compare the dynamics, biokinetics, and microbial diversity between activated sludge flocs (ASF) and aerobic granular sludge (AGS) whose systems were operated under similar experimental conditions in terms of inoculum, feeding, substrate source, etc. Therefore, the kinetic parameters involved in the organic matter removal, nitrification, denitrification, and dephosphatation were determined, as well as the microbial changes were assessed by metagenomics analysis. Regarding the kinetic parameter yield coefficient (Y), values of 0.

Effects of carbon source on the formation, stability, bioactivity and biodiversity of the aerobic granule sludge.

Three aerobic granular sludge systems were operated as sequencing batch reactors (SBR) with acetate, ethanol and glucose as carbon source. The SBR cycle was 6 h, with an anaerobic phase followed by an aerobic phase. The acetate granules (>1.

Aerobic granular sludge: Cultivation parameters and removal mechanisms.

Aerobic granular sludge (AGS) has been the focus of many investigations, and the main parameters responsible for AGS formation are hydrodynamic shear force, short periods and feast-famine cycles. However, some other parameters are associated with AGS maintenance after long periods of operation. This review evaluates the parameters responsible for AGS formation and maintenance and some reference values are proposed.