title: Effect of salinity variations on the performance of activated sludge system.
abstract: OBJECTIVE
  To investigate the influence of salinity variations on the performance of activated sludge systems, treating domestic wastewater.
  
  
  METHODS
  The completely mixed reactor was used and operated in a batch-wise mode. The activated sludge taken from the Gaobeidian Wastewater Treatment Plant was used as a seeding sludge. Total organic carbon (TOC), oxygen uptake rate (OUR) and suspended solids (SS) were used as parameters to characterize the performance of the treatment systems. TOC was measured using a TOC-analyzer (TOC-5000, Japan). The OUR value was measured with a dissolved oxygen meter (YSI model-58). SS was measured gravimetrically.
  
  
  RESULTS
  The TOC removal efficiency and the OUR value of activated sludge were not deteriorated when the NaCl shock concentration was less than 0.5 g/L. However, when the NaCl shock concentrations were up to 10g/L and 20 g/L, the OUR of activated sludge was reduced by 35% and TOC removal efficiency was dropped by 30%, compared with the control experiment without NaCl shock loading.
  
  
  CONCLUSIONS
  The effect of NaCl shock loading on the activated sludge wastewater treatment system is dependant upon the NaCl concentrations and the degree of influence can be inferred through the change of substrate utilization rate at different shock NaCl loadings.
authors.affiliation: Laboratory of Environmental Technology, INET Tsinghua University, Beijing 100084, China. wangjl@tsinghua.edu.cn
authors.forename: Jian-Long
authors.initials: JL
authors.lastname: Wang
authors.forename: Xin-Min
authors.initials: XM
authors.lastname: Zhan
authors.forename: Ye-Cheng
authors.initials: YC
authors.lastname: Feng
authors.forename: Yi
authors.initials: Y
authors.lastname: Qian
mesh_terms: D019149:Bioreactors; D002244:Carbon / Q000032:analysis; D010100:Oxygen / Q000378:metabolism; D012722:Sewage / Q000737:chemistry*; D012965:Sodium Chloride; D014865:Waste Disposal, Fluid
chemical_list: D012722:Sewage; D012965:Sodium Chloride; D002244:Carbon; D010100:Oxygen