Location and chemical composition of microbially induced phosphorus precipitates in anaerobic and aerobic granular sludge

Angela Manas (1) , Mathieu Sperandio (1) , François Decker (2) , Béatrice Biscans (3)

1 LISBP - Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés
2 Valbio Toulouse
3 LGC - Laboratoire de Génie Chimique

This work focuses on combined scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX) applied to granular sludge used for biological treatment of high-strength wastewater effluents. Mineral precipitation is shown to occur in the core of microbial granules under different operating conditions. Three dairy wastewater effluents, from three different upflow anaerobic sludge blanket (UASB) reactors and two aerobic granular sequenced batch reactors (GSBR) were evaluated. The relationship between the solid phase precipitation and the chemical composition of the wastewater was investigated with PHREEQC software (calculation of saturation indexes). Results showed that pH, Ca:P ratios and biological reactions played a major role in controlling the biomineralization phenomena. Thermodynamics calculations can be used to foresee the nature of bio-precipitates, but the location of the mineral concretions will need further investigation as it is certainly due to local microbial activity.

Mots clés: Anaerobic granules; Aerobic granules; UASB; Dairy wastewater; Biomineralization; Microbially induced precipitation

Domaines: Génie chimique

Angela Manas, Mathieu Sperandio, François Decker, Béatrice Biscans. Location and chemical composition of microbially induced phosphorus precipitates in anaerobic and aerobic granular sludge. Environmental Technology, 2012, vol. 33 (19), pp.2195-2209. ⟨10.1080/09593330.2012.696719⟩. ⟨hal-00762274⟩