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The role of extracellular polymeric substances on aerobic granulation with stepwise increase of salinity
- Publication Year :
- 2018
- Publisher :
- Elsevier B.V., 2018.
-
Abstract
- A granular sequencing batch reactor (GSBR) worked for 164 days to study the effect of salinity on aerobic granulation. The feeding had an organic loading rate (OLR) of 1.6 kg COD⋅m −3 ⋅d −1 and a gradual increase of salinity (from 0.30 to 38 g NaCl − ⋅L −1 ) to promote a biological salt-adaptation. First aggregates (average diameter ≈ 0.4 mm) appeared after 14 days. Extracellular polymeric substances (EPSs) analyses revealed that proteins were mainly higher than polysaccharides, and microorganisms metabolized EPSs as additional carbon source, mostly in feast phase, to face the energy demand for salinity adaptation. No significant worsening of organic matter removal was observed. The initial decrease of nitrification (from 58% to 15%) and the subsequent increase (up to 25%), confirmed the acclimation of AOBs to saline environment, while the accumulation of nitrites suggested NOBs inhibition. The nitrogen removal initially decreased from 58% to 15%, due to the inhibitory effect of salinity, and subsequently increased up to 29% denoting a simultaneous nitrification–denitrification. The dimensions of mature granules (higher than 1 mm) probably involved PAOs growth in the inner anaerobic layers. Nitrites caused a temporary deterioration of phosphorous removal (from 60% to almost zero), that increased up to 25% when nitrites were depleted.
- Subjects :
- 0208 environmental biotechnology
Hydrophobicity
Sequencing batch reactor
Filtration and Separation
02 engineering and technology
010501 environmental sciences
01 natural sciences
Acclimatization
Nutrients removal
Analytical Chemistry
Aerobic granular sludge
EPS
Extracellular polymeric substances
Saline wastewater
Extracellular polymeric substance
Organic matter
Food science
0105 earth and related environmental sciences
chemistry.chemical_classification
Settore ICAR/03 - Ingegneria Sanitaria-Ambientale
020801 environmental engineering
Salinity
chemistry
Aerobic granulation
Nitrification
Anaerobic exercise
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....652bdb95301be27eba77ea51ead621f7