title: [Investigation on the phenomena of bacteria exceeding standards in rural pit water treated by ultrafiltration membrane].
abstract: OBJECTIVE
  To investigate the phenomenon of bacteria exceeding standards in rural pit water, which was intermittently operated by water pump equipped with ultrafiltration membrane, and to explore the solutions.
  
  
  METHODS
  Polyvinyl chloride (PVC) alloy capillary membranes combined with UV, disinfectant, one-way valve, water-seal, high water level-water tank and direct outlet were tested. The operation on water treatment was intermittent, simulating the ways of treating pit water in the rural.
  
  
  RESULTS
  The combination modes of ultrafiltration membrane with UV, disinfectant and high water level-water tank are valid in solving the problem of high turbidity and microorganism of pit water stored in cellars, the quality of effluents was consistent with the requirements of the national standards. While the combination modes of ultrafiltration membrane with one-way valve or water-seal were less desirable, more bacteria in treated water than raw water were observed because of bacteria breeding on the membrane component.
  
  
  CONCLUSIONS
  In order to avoid excessive bacteria in filtered pit water caused by intermittent operation, it is recommended that for the pit water in high water level water tanks, the ultrafiltration membranes should be cleaned with disinfectants on a regular basis. The effluent pit water from underground cellars should be disinfected with UV after ultrafiltration.
authors.affiliation: Institute of Environmental Health and Related Product Safety, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
authors.forename: Yinling
authors.initials: Y
authors.lastname: Yue
authors.forename: Lan
authors.initials: L
authors.lastname: Zhang
authors.forename: Bo
authors.initials: B
authors.lastname: Ling
mesh_terms: D002681:China; D008567:Membranes, Artificial; D014462:Ultrafiltration / Q000379:methods; D014871:Water Microbiology; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*; D014881:Water Supply
chemical_list: D008567:Membranes, Artificial