Farrant, L1, Le, M.S.1, Phipps, D1 and Alkhaddar, R.1, 1Liverpool John Moores University, 2United Utilities PLC(free)
Enhanced biological phosphorus removal (EBPR) is regarded as more sustainable than chemical dosing for the removal of phosphorus from wastewater. However, successful operation of EBPR requires that the process influent contains a sufficient concentration of a suitable carbon source, preferably in the form of volatile fatty acids (VFA). Traditionally, this is provided by a fermentor or by the direct addition of an external carbon source making EBPR an expensive option.
Inverted Phase Fermentation (IPF), a novel sludge thickening process has provided a convenient means for VFA production from un-thickened sludge. If phosphate accumulating organisms (PAOs) can utilise IPF liquor as a sustainable VFA carbon source, which can be produced on demand, onsite, it would eliminate the need for an external carbon source or a costly fermentor. The IPF liquor would therefore provide a new carbon source from sludge to make EBPR a more viable option.
Initial results using the fermented VFA indicated that the IPF liquor was a suitable carbon source for EBPR. The bacteria were able to release polyphosphate under anaerobic condition indicating that they were able to store Poly-β-hydroxyalkanotes (PHA). PAO cycling experiments illustrated the longer term effects of process parameters such as cycle aeration period on the PAO population. However, further work needs to be carried out to investigate the long term effect of regenerated carbon source on EBPR performance.
EBPR; carbon source; Fermentation; VFA production; Inverted Phase Fermentation
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