The outbreak of cryptosporidiosis in Ogose in 1996 forced the wastewater treatment authorities to rethink the level of contamination by Cryptosporidium of wastewater and waters in the watersheds and counter-measures in wastewater treatment plants. A survey of Cryptosporidium concentrations in wastewater and treated wastewater conducted nationwide showed relatively low levels. Also, evaluation of wastewater treatment showed a 2 log oocyst removal with an activated sludge process and an additional 1 log removal with coagulant dosing.

This content is only available as a PDF.