title: Differences in soluble COD and ammonium when applying inverted phase fermentation to primary, secondary and mixed sludge.
abstract: Primary, secondary and mixed sludge were treated by inverted phase fermentation. This treatment results in solid-liquid separation of sludge after endogenous enzymatic hydrolysis (anaerobic conditions: 42°C, 48 hours). The soluble chemical oxygen demand (sCOD) was increased in the solid phase up to 1,800%, 21,300% and 260% in primary, secondary and mixed sludge, respectively. The corresponding increase in sCOD in the liquid phase accordingly reached values of up to 440%, 5,100% and 140%. Phase separation led to an enrichment of volatile solids in the solid phase (89-358% primary sludge, 80-102% secondary sludge and 29-133% mixed sludge). The NH4+-N values increased notably after the endogenous enzymatic hydrolysis itself. To investigate the short-term evolution following the treatment, the variation in sCOD, NH4+-N and solids was also monitored after keeping the hydrolysate at 37°C under anaerobic conditions for 24 hours. This stage showed no generalized pattern in terms of sCOD.
authors.affiliation: Department of Chemical and Environmental Engineering, University Institute of Industrial Technology of Asturias, Campus of Gijón, University of Oviedo, 33203 Gijón, Spain E-mail: negralluis@uniovi.es.
authors.forename: L
authors.initials: L
authors.lastname: Negral
authors.affiliation: Department of Chemical and Environmental Engineering, University Institute of Industrial Technology of Asturias, Campus of Gijón, University of Oviedo, 33203 Gijón, Spain E-mail: negralluis@uniovi.es.
authors.forename: E
authors.initials: E
authors.lastname: Marañón
authors.affiliation: Department of Chemical and Environmental Engineering, University Institute of Industrial Technology of Asturias, Campus of Gijón, University of Oviedo, 33203 Gijón, Spain E-mail: negralluis@uniovi.es.
authors.forename: L
authors.initials: L
authors.lastname: Castrillón
authors.affiliation: Department of Chemical and Environmental Engineering, University Institute of Industrial Technology of Asturias, Campus of Gijón, University of Oviedo, 33203 Gijón, Spain E-mail: negralluis@uniovi.es.
authors.forename: Y
authors.initials: Y
authors.lastname: Fernández-Nava
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism*; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D005285:Fermentation; D006868:Hydrolysis; D012722:Sewage; D018505:Waste Management / Q000379:methods*
chemical_list: D064751:Ammonium Compounds; D012722:Sewage