This document discusses glycogen accumulating organisms (GAOs) which play an important role in enhanced biological phosphorus removal (EBPR) in wastewater treatment. GAOs, like polyphosphate accumulating organisms (PAOs), can uptake volatile fatty acids anaerobically and convert them to polyhydroxyalkanoates. However, unlike PAOs, GAOs do not release or take up phosphorus. While GAOs do not contribute directly to phosphorus removal, they can support the anoxic activity of PAOs by reducing nitrate to nitrite. The document also provides information on common types of GAOs and optimal operating conditions for EBPR.

1. GLYCOGEN ACCUMULATING
ORGANISMS
AMAN GANGWAR
18mscest01

2. In Enhanced Biological Phosphorus Removal (EBPR)
specific bacteria are used for accumulation of
phosphorus within their cell in the form of
Polyphosphate (Poly-P).
These bacteria are called as Polyphosphate
Accumulating Bacteria.
GAO contributed to the reduction of nitrate to nitrite
thereby supporting the anoxic activity of PAO.
Accumulate large quantity of phosphorus within their
cell up to 20% of their mass.
Biosolids from treated waste have a high fertilizer
value.

3. COOPERATION DURING ANAEROBIC CONDITIONS
•Glycogen accumulating organisms (GAOs), are also capable of anaerobic VFA uptake
and conversion to PHA.
•But difference is that GAOs do not release P anaerobically, nor do they take up P
aerobically, hence they do not contribute to P removal.
Oehmen et.al.,(2006)

4. •PAO I culture did not perform a significant anoxic P-uptake
using nitrate.
• PAO I-GAO culture showed a higher anoxic P-removal
activity on nitrate.
•GAO contributed to the reduction of nitrate to nitrite
thereby supporting the anoxic activity of PAO.

5. Anaerobic phase of PAOs
Tarayre et.al.,(2016)

6. Aerobic phase of PAOs
Tarayre et.al.,(2016)

7. Candidatus Accumulibacter phosphatis (PAO) blue
Candidatus Competibacter phosphatis (GAO) red
Bacteria which play important role in EBPR
Oehmen et.al.,(2006)

8. Operating conditions
pH not below than 6.5
Temperature- 22-25 ⁰C
DO - 3 to 5 mg/l
SRT- 8.0 to 10.5 days
Stephens, H., & Stensel, H. (1998).
Effect of Operating Conditions on
Biological Phosphorus Removal. Water
Environment Research, 70(3), 362-369.
Retrieved March 3, 2020, from
www.jstor.org/stable/25045051
Glycogen accumulating
organisms
1 Sphingomonadales
2 Defluviicoccus
3 Candidatus propionivibrio
aalborgensis
Pisco, A. R., Bengtsson, S., Werker, A.,
Reis, M. A., & Lemos, P. C. (2009).
Community structure evolution and
enrichment of glycogen-accumulating
organisms producing
polyhydroxyalkanoates from
fermented molasses. Appl. Environ.
Microbiol., 75(14), 4676-4686.

9. Conclusion
Phosphate minerals are used for the production of
phosphorus based chemicals. These resources are not
renewable and the natural phosphates stocks are
decreasing. So, the need for new phosphate sources has
arisen.
The waste water has appropriate phosphorus value which
we can extract by the help of Polyphosphate Accumulating
Organisms (PAOs) biologically and used as the phosphate
fertilizers because of high fertilizer value after the extracting
the phosphate material except heavy metals in them.

10. Crocetti, G. R., Banfield, J. F., Keller, J., Bond, P. L., & Blackall, L. L. (2002). Glycogen-
accumulating organisms in laboratory-scale and full-scale wastewater treatment
processesbbThe GenBank accession numbers for the sequences reported in this
paper are given in Methods. Microbiology, 148(11), 3353-3364.
Oehmen, A., Saunders, A. M., Vives, M. T., Yuan, Z., & Keller, J. (2006). Competition
between polyphosphate and glycogen accumulating organisms in enhanced
biological phosphorus removal systems with acetate and propionate as carbon
sources. Journal of Biotechnology, 123(1), 22–32.
doi:10.1016/j.jbiotec.2005.10.009
Tarayre, C., Nguyen, H. T., Brognaux, A., Delepierre, A., De Clercq, L., Charlier, R., ...
& Delvigne, F. (2016). Characterisation of phosphate accumulating organisms and
techniques for polyphosphate detection: a review. Sensors, 16(6), 797.
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