This study aims at exploring the prospect of recovering phosphorus from sludge which results from biological nutrient removal. As the first part of a year long thesis, the main focus of this report is to provide backgrounds of P removal technologies, to conduct a thorough literature review on biological P removal, and to develop a methodology that would allow P release from the BNR sludge. In addition, two experiments had also been carried out as pioneer studies on P release from BNR sludge.
It was found that with granular sludge, a 60% recovery of P recovery is possible, while biological P release from floccular sludge did not happen at all. Further studies will be carried out to investigate the strange behaviour of floccular sludge, and to boost the amount of P release from granular sludge to a higher level, possibly 80 to 90%.
Apart from trying to increase the percentage yield of P from the BNR sludge, the crucial factors that affect P release will also be identified. This will be the major focus of the second report.