During the drying process, the ejection shafts swirl the sewage sludge into a constant cloud of material and the 300°C (572°F) hot air circulates around, acting on all the sludge material. The sewage sludge is completely sanitized by the high temperature. Microbiological investigations even confirm extensive sterilization of the dried sewage sludge.
Pathogens which exist in the sewage sludge through viruses, bacterial endotoxins, fungi, protozoa and worms, are completely destroyed by the drying procedure. During subsequent use as a fertilizer, there is no risk that pathogens can re-enter the human cycle.
Any health risk for humans coming into contact with sewage sludge is considerably reduced through sanitization.