[Survival of salmonellas and ascaris eggs during sludge utilization in forestry (author's transl)]

Salmonella senftenberg survived in sewage sludge after a single application in summer in experimental plots of 11 different forest stands between 424 and 820 days. After application of infected sludge in winter the survival times were between 104 and 350 days. Salmonelles adsorbed to germ carriers located on or below the sludge layers survived for a shorter time than those germs which were suspended into the sludge. Ascaris eggs survived not longer than between 78 and 107 days. It is therefore recommended to prohibit the utilization of infectious sewage sludges in forests and at their edges as it is handled in Switzerland. If this cannot be achieved the permission for utilization of sludge in forests should only be given if the sludge is tilled into the soil.