title: High-rate denitrification using polyethylene glycol gel carriers entrapping heterotrophic denitrifying bacteria.
abstract: This study evaluated the nitrogen removal performance of polyethylene glycol (PEG) gel carriers containing entrapped heterotrophic denitrifying bacteria. A laboratory-scale denitrification reactor was operated for treatment of synthetic nitrate wastewater. The nitrogen removal activity gradually increased in continuous feed experiments, reaching 4.4 kg N m(-3) d(-1) on day 16 (30 °C). A maximum nitrogen removal rate of 5.1 kg N m(-3) d(-1) was observed. A high nitrogen removal efficiency of 92% on average was observed at a high loading rate. In batch experiments, the denitrifying gel carriers were characterized by temperature. Nitrate and total nitrogen removal activities both increased with increasing temperature, reaching a maximum at 37 and 43 °C, respectively. Apparent activation energies for nitrate and nitrite reduction were 52.1 and 71.9 kJ mol(-1), respectively. Clone library analysis performed on the basis of the 16S rRNA gene revealed that Hyphomicrobium was mainly involved in denitrification in the methanol-fed denitrification reactors.
authors: Hitachi Plant Technologies, Ltd., Kami-Hongo 537, Matsudo-shi, Chiba 271-0064, Japan. k-isaka@hitachiplant.co.jp
authors: Kazuichi
authors: K
authors: Isaka
authors: Yuya
authors: Y
authors: Kimura
authors: Toshifumi
authors: T
authors: Osaka
authors: Satoshi
authors: S
authors: Tsuneda
mesh_terms: D001483:Base Sequence; D019149:Bioreactors; D016000:Cluster Analysis; D019295:Computational Biology; D017931:DNA Primers / Q000235:genetics; D058440:Denitrification / Q000502:physiology*; D005782:Gels / Q000737:chemistry*; D052836:Heterotrophic Processes / Q000502:physiology; D020582:Hyphomicrobium / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011092:Polyethylene Glycols / Q000737:chemistry*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013696:Temperature; D018508:Water Purification / Q000379:methods*
chemical_list: D017931:DNA Primers; D005782:Gels; D012336:RNA, Ribosomal, 16S; D011092:Polyethylene Glycols