Removals of cryptosporidium parvum oocysts and cryptosporidium-sized polystyrene microspheres from swimming pool water by diatomaceous earth filtration and perlite-sand filtration

J Water Health. 2017 Jun;15(3):374-384. doi: 10.2166/wh.2017.221.


Removal of Cryptosporidium-sized microspheres and Cryptosporidium parvum oocysts from swimming pools was investigated using diatomaceous earth (DE) precoat filtration and perlite-sand filtration. In pilot-scale experiments, microsphere removals of up to 2 log were obtained with 0.7 kg·DE/m2 at a filtration rate of 5 m/h. A slightly higher microsphere removal (2.3 log) was obtained for these DE-precoated filters when the filtration rate was 3.6 m/h. Additionally, pilot-scale perlite-sand filters achieved greater than 2 log removal when at least 0.37 kg/m2 of perlite was used compared to 0.1-0.4 log removal without perlite both at a surface loading rate of 37 m/h. Full-scale testing achieved 2.7 log of microspheres and oocysts removal when 0.7 kg·DE/m2 was used at 3.6 m/h. Removals were significantly decreased by a 15-minute interruption of the flow (without any mechanical agitation) to the DE filter in pilot-scale studies, which was not observed in full-scale filters. Microsphere removals were 2.7 log by perlite-sand filtration in a full-scale swimming pool filter operated at 34 m/h with 0.5 kg/m2 of perlite. The results demonstrate that either a DE precoat filter or a perlite-sand filter can improve the efficiency of removal of microspheres and oocysts from swimming pools over a standard sand filter under the conditions studied.

MeSH terms

  • Aluminum Oxide / chemistry
  • Cryptosporidium parvum / growth & development
  • Cryptosporidium parvum / isolation & purification*
  • Diatomaceous Earth / chemistry
  • Filtration / methods*
  • Microspheres*
  • Oocysts
  • Polystyrenes / analysis
  • Public Health / instrumentation
  • Public Health / methods*
  • Silicon Dioxide / chemistry
  • Swimming Pools*
  • Water Purification / instrumentation
  • Water Purification / methods*


  • Polystyrenes
  • Perlite
  • Diatomaceous Earth
  • Silicon Dioxide
  • Aluminum Oxide