title: Reducing sludge production and the domination of Comamonadaceae by reducing the oxygen supply in the wastewater treatment procedure of a food-processing factory.
abstract: Sludge production was reduced remarkably by reducing the dissolved oxygen supply to less than 1 mg/l in the conventional wastewater treatment procedure of a food-processing factory that produced 180 m(3) of wastewater of biochemical oxygen demand (BOD) of about 1,000 mg/l daily. DNA was extracted from the sludge and subjected to PCR amplification. The PCR product was cloned into a plasmid and sequenced. Estimation of the resident bacterial distribution by 16S rDNA sequences before and after improvement of the system suggested a remarkable gradual change in the major bacterial population from Anaerolinaeceae (15.6%) to Comamonadaceae (52.3%), members of denitrifying bacteria of Proteobacteria. Although we did not directly confirm the ability of denitrification of the resulting sludge, a change in the major final electron acceptors from oxygen to nitrate might explain the reduction in sludge production in a conventional activated sludge process when the oxygen supply was limitted.
authors.affiliation: Clarus Environment Co., Ltd., Shinjuku, Tokyo, Japan.
authors.forename: Tamiko
authors.initials: T
authors.lastname: Sadaie
authors.forename: Aya
authors.initials: A
authors.lastname: Sadaie
authors.forename: Masao
authors.initials: M
authors.lastname: Takada
authors.forename: Keiichi
authors.initials: K
authors.lastname: Hamano
authors.forename: Junichi
authors.initials: J
authors.lastname: Ohnishi
authors.forename: Niji
authors.initials: N
authors.lastname: Ohta
authors.forename: Kouji
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Sadaie
mesh_terms: D042621:Comamonadaceae / Q000254:growth & development* / Q000378:metabolism; D004269:DNA, Bacterial / Q000032:analysis; D005525:Food-Processing Industry; D010100:Oxygen / Q000378:metabolism*; D020560:Proteobacteria / Q000254:growth & development* / Q000378:metabolism; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D004269:DNA, Bacterial; D012722:Sewage; D010100:Oxygen