Stockage et stabilité à long terme de boues d’épuration municipales décontaminées et stabilisées par voie chimique ou biologique

The objective of this research was to evaluate the effects of sewage sludge storage on biological and physico-chemical parameters of sludge treated by different stabilization and decontamination processes. Three sludge storage methods were tested: inside at stable temperature (21 ± 2 °C), outside during summer (May–October), and inside at different temperatures to simulate the winter season. An increase of the sludge pH (approximately 8.0–8.5) and an odour removal process were measured following a 5-month storage period, and this, for all conditions of sludge treatments and storage options. The sanitary conditions of the sludge improved, because the fecal coliforms were completely eliminated, and fecal streptococci and salmonella were significantly reduced. The results also revealed that the pH adjustment, near neutrality, of sludge treated by acid processes (Stabiox and Metix-AC) is preferable before a long storage period. This allows a better biodegradation of the organic matter and the production of le...