Aerobic granular sludge treating anaerobically pretreated brewery wastewater at different loading rates

• Published in: Water science and technology 2020-10, Vol.82 (8), p.1523-1534
• Main Authors: di Biase, Alessandro, Corsino, Fabio Santo, Devlin, Tanner Ryan, Torregrossa, Michele, Munz, Giulio, Oleszkiewicz, Jan A
• Format: Article
• Language: English
• Subjects: Aeration; Aerobiosis; Anaerobic treatment; Biofilms; Bioreactors; Breweries; Brewing industry wastewaters; Chemical oxygen demand; Environmental impact; Granular materials; Granulation; Load distribution; Loading rate; Microbiota; Microorganisms; Nitrogen; Nutrient removal; Organic loading; Phosphorus; Polysaccharides; Ratios; Reaction time; Reactors; Removal; Sewage; Sludge; Sludge treatment; Waste Disposal, Fluid; Waste Water; Wastewater; Wastewater treatment
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2020.433

In this study, three different aerobic granular sludge (AGS) reactors fed with anaerobically pre-treated brewery wastewater were studied. The AGS reactors were operated under different conditions including organic loading rates (OLR) between 0.8 and 4.1 kg COD m d , C:N:P ratios (100:10:1 and 100:6:1) and food to microorganism ratios (F/M) between 0.8 ± 0.6 and 1.2 ± 0.5 and 0.9 ± 0.3 kg-TCOD kg-VSS d . Stable granulation was achieved within two weeks and the size of the granules increased according to the OLR applied. The results indicated that low C:N:P and F/M ratios were favorable to achieve stable aerobic granules in the long term. The carbon removal rate was load-independent in the range examined (TCOD removal >80%), whereas TN removals were inversely proportional to the OLRs. Overall, a longer aeration reaction time with a lower OLR was beneficial to granular structure, which exhibited a compact and defined architecture. Performance results within the other conditions studied further indicated that the microbial community and its complex functionality in nutrient removal was efficient at operational parameters of OLR at 0.8 ± 0.2 kg-TCOD m d and F/M ratio at 0.5 ± 0.2 kg-TCOD VSS d . Moreover, the protein to polysaccharide ratio increased as OLR decreased, leading to a stable granular structure.