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Phagotrophic microalgae production from waste activated sludge under non-sterile conditions
- Source :
- Water research. 145
- Publication Year :
- 2018
-
Abstract
- In this study waste activated sludge (WAS) was sonicated to release bacteria-sized volatile solids (VS) from flocs, after initial pH adjustment to 10 for higher energy efficiency. The released VS supported growth of phagotrophic alga Ochromonas danica. Initial-rate growth experiments confirmed the Monod-type kinetics but the specific cell growth rate, μ, correlated with the prey-to-predator ratio, i.e., the ratio of (fed VS concentration)-to-(initial O. danica concentration), significantly better than with the VS alone, as the typical Monod dependency on soluble substrates. The best-fit kinetics had the following parameters: μmax = 0.198 h−1 and KM = 1.056 (g-VS/g-algae). Post-sonication reflocculation could render particles too large to ingest by O. danica; therefore, pH and VS effects on reflocculation were investigated. Batch cultivations were then conducted in fermentors at pH 5, under nonsterile conditions. Algae number reached 8.86 × 1010 L−1 after 20 h, corresponding to ∼2.3 g/L dry-weight and volumetric algae productivity of 2.8 g/L-day. VS reduction was 38%, giving an O. danica VS yield of 44.5%. The ultrasonication-algae process can be used to produce algae while achieving at least partial WAS treatment.
- Subjects :
- Environmental Engineering
020209 energy
Sonication
Kinetics
02 engineering and technology
010501 environmental sciences
01 natural sciences
Ochromonas
Waste Disposal, Fluid
Ochromonas danica
Bioreactors
Algae
0202 electrical engineering, electronic engineering, information engineering
Microalgae
Growth rate
Food science
Waste Management and Disposal
0105 earth and related environmental sciences
Water Science and Technology
Civil and Structural Engineering
Cell specific
biology
Bacteria
Sewage
Chemistry
Ecological Modeling
biology.organism_classification
Pollution
Activated sludge
Yield (chemistry)
Subjects
Details
- ISSN :
- 18792448
- Volume :
- 145
- Database :
- OpenAIRE
- Journal :
- Water research
- Accession number :
- edsair.doi.dedup.....ef370d071afc0765d31440f7a9472295