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Physical Enrichment of Polyphosphate‐Accumulating Organisms in Activated Sludge
Two methods that physically separate polyphosphate‐accumulating organisms (PAO) from other organisms in activated sludge were developed. The first method used 4'6‐diamidino‐2‐phenylindole dihydrochloride (DAPI) to selectively stain PAO. When excited with light at 340 nm, polyphosphate granules in DAPI‐stained cells fluoresce yellow while cells without polyphosphate fluoresce blue. This difference in fluorescent response was used to separate PAO from non‐PAO using flow cytometry. The second method consisted of a simple gradient centrifugation to physically separate PAO from non‐PAO based on their density differences. Both methods produced cell suspensions with an increased PAO concentration. From an average PAO concentration of approximately 14% in a full‐scale process, the DAPI–flow cytometry method produced sorted samples with PAO representing more than 70% of the total cells, while the density gradient method produced an approximate 43 to 48% PAO enrichment. The physical enrichment methods described herein should facilitate the identification and study of PAO that are relevant in full‐scale enhanced biological phosphorus removal processes.
Physical Enrichment of Polyphosphate‐Accumulating Organisms in Activated Sludge
Two methods that physically separate polyphosphate‐accumulating organisms (PAO) from other organisms in activated sludge were developed. The first method used 4'6‐diamidino‐2‐phenylindole dihydrochloride (DAPI) to selectively stain PAO. When excited with light at 340 nm, polyphosphate granules in DAPI‐stained cells fluoresce yellow while cells without polyphosphate fluoresce blue. This difference in fluorescent response was used to separate PAO from non‐PAO using flow cytometry. The second method consisted of a simple gradient centrifugation to physically separate PAO from non‐PAO based on their density differences. Both methods produced cell suspensions with an increased PAO concentration. From an average PAO concentration of approximately 14% in a full‐scale process, the DAPI–flow cytometry method produced sorted samples with PAO representing more than 70% of the total cells, while the density gradient method produced an approximate 43 to 48% PAO enrichment. The physical enrichment methods described herein should facilitate the identification and study of PAO that are relevant in full‐scale enhanced biological phosphorus removal processes.
Physical Enrichment of Polyphosphate‐Accumulating Organisms in Activated Sludge
Hung, Chun‐Hsiung (author) / Peccia, Jordan (author) / Zilles, Julie L. (author) / Noguera, Daniel R. (author)
Water Environment Research ; 74 ; 354-361
2002-07-01
8 pages
Article (Journal)
Electronic Resource
English
| UB Braunschweig | 2011