title: Identifying an interfering factor on chemical oxygen demand (COD) determination in piggery wastewater and eliminating the factor by an indigenous Pseudomonas stutzeri strain.
abstract: OBJECTIVE
  This study attempted to demonstrate nitrite interference on chemical oxygen demand (COD) determination in piggery wastewater, and the capability of aerobic denitrification of the SU2 strain which is capable of promoting the efficiency of nitrogen and COD removal from piggery wastewater.
  
  
  RESULTS
  This study was performed in a 17-litre reactor with a 30% packing ratio, with a ratio of immobilized SU2 cells to sludge of 100:1. The ratio of aeration to nonaeration was 4 : 1.5. Removal efficiency of COD was 86.8%. Removal efficiency of BOD and SS was higher than 90%, and removal efficiency of NH4+-N and TKN was almost 100%.
  
  
  CONCLUSIONS
  NO2- -N interference is significant when its concentration in piggery wastewater exceeds 100 mg l-1. COD in piggery wastewater can be indirectly reduced following nitrite reduction by SU2 strain.
  
  
  CONCLUSIONS
  Utilizing immobilized SU2 cells in coordination with an SBR system simultaneously reduces nitrite and COD concentrations.
authors.affiliation: Division of Applied Biology, Animal Technology Institute Taiwan, PO Box 23, Chunan, Miaoli, Taiwan, R.O.C. 35099. jjs01@ms9.hinet.net
authors.forename: J J
authors.initials: JJ
authors.lastname: Su
authors.forename: B Y
authors.initials: BY
authors.lastname: Liu
authors.forename: Y C
authors.initials: YC
authors.lastname: Chang
mesh_terms: D000332:Aerobiosis; D000822:Animal Husbandry; D000818:Animals; D019149:Bioreactors; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D011549:Pseudomonas / Q000254:growth & development / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*; D013552:Swine; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D009566:Nitrates; D009573:Nitrites; D012722:Sewage; D010100:Oxygen