Influence of Storage Strategies on the Reactivation Characteristics of Shortcut Nitrification Aerobic Granular Sludge

Appropriate storage strategies were helpful in keeping the integrity and activity as well as in promoting the engineering application of granular sludge. The particle size distribution, composition of extracellular polymeric substances (EPSs), and activity of shortcut nitrification aerobic granular sludge (SNAGS) of the different storage strategies (15 °C with intermittent aeration, 4 °C, −20 °C, and −80 °C) were investigated in this study. The results showed that the storage strategies influenced particle size distribution, EPSs, protein (PN), polysaccharide (PS), PN/PS, and the oxidation ability of ammonium nitrogen of SNAGS. However, storage strategies had little effect on nitrite accumulation. The particle size, EPSs, PN, and PS of the SNAGS decreased after storage. The change of EPSs, PN, and PS of SNGS was smaller under the storage condition of −20 °C. The ammonium nitrogen oxidation and denitrification abilities of SNAGS were highest under the storage condition of −80 °C and −20 °C.