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Extraction of Structural Extracellular Polymeric Substances from Aerobic Granular Sludge
Published on: September 26, 2016
Use low direct current electric field to augment nitrification and structural stability of aerobic granular sludge
Wenli Huang1, Wenlong Wang1, Wansheng Shi1
1Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
Abstract:
This study explored the effect of low direct current (DC, ⩽5 V) electric field on aerobic granules by using two identical square sequencing batch reactors (SBRs) when influent chemical oxygen demand to ammonia nitrogen (COD/NH4-N) ratio decreased from 6 to 1.2 (with COD fixed at 600 mg/L). Results showed that the granules from the electro-augmentation SBR had a more compact and dense microbial structure with enriched Actinobacteria, Bacteroidia, Betaproteobacteria, and Nitrospira. Compared to the control, these granules produced 17.4% and 21.5% more proteins and polysaccharides respectively in the extracellular polymeric substances (EPS), with their integrity coefficient stabilized at 3.3-5.2% during 120 days' operation. Interestingly, more di- and tri-valent metals were accumulated in the electro-augmented granules. In addition, greater than 99% nitrification especially with stably high nitratation efficiency was realized in this new system.
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