title: Use low direct current electric field to augment nitrification and structural stability of aerobic granular sludge when treating low COD/NH4-N wastewater.
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.
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Wenli
authors.initials: W
authors.lastname: Huang
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Wenlong
authors.initials: W
authors.lastname: Wang
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Wansheng
authors.initials: W
authors.lastname: Shi
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Zhongfang
authors.initials: Z
authors.lastname: Lei
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan. Electronic address: zhang.zhenya.fu@u.tsukuba.ac.jp.
authors.forename: Zhenya
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Rongzhi
authors.initials: R
authors.lastname: Chen
authors.affiliation: Shanghai Biotechnology Corporation, 121 Libing Road, Shanghai 201203, China.
authors.forename: Beibei
authors.initials: B
authors.lastname: Zhou
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D057919:Biological Oxygen Demand Analysis; D017931:DNA Primers / Q000235:genetics; D004574:Electromagnetic Fields; D059014:High-Throughput Nucleotide Sequencing; D019216:Metals, Heavy / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D058465:Nitrification; D017672:Nitrogen Compounds / Q000737:chemistry; D010316:Particle Size; D011134:Polysaccharides / Q000032:analysis; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry*
chemical_list: D017931:DNA Primers; D019216:Metals, Heavy; D017672:Nitrogen Compounds; D011134:Polysaccharides; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D062065:Wastewater
keywords: Aerobic granules; Electric field; Extracellular polymeric substances (EPS); Free ammonia; Nitrification