EFFECTIVENESS OF SECONDARY DIGESTERS AS A PATHOGEN CONTROLLER IN WINTER

It was found that temperature is a key factor in the rate of pathogen de-activation under isothermal conditions. however, in the full scale secondary digester trial under winter conditions it was found that there was a significant difference between the surface temperature and the bulk temperature within the sludge, at the surface the temperature decreased more quickly.There was no significant difference between the performance of two designs of concre-te thanks with respect to wall thichness, cooling rates and E.coli reduction rate.