| Summary: | This research was initiated with the purpose to remove and recover phosphorus
simultaneously, by coupling a sidestream for phosphorus recovery to an enhanced biological
phosphorus removal (EBPR) process. Sidestream process comprised of a phosphorus release
unit along with a clarifier connected to the MAP (magnesium ammonium phosphate)
crystallizer. To understand the sidestream process and to investigate the optimum operating
conditions, the configuration was simulated using ASM2-Delft metabolic bio-P model on
AQUASIM platform. The simulation exercise revealed that anoxic is the best zone to take
sidestream when taken individually and anoxic/anaerobic when taken in combination. In
both the cases N: P molar ratio of the supernatant was more than 1:1 which is essential for
the recovery of phosphorus as struvite. The minimum hydraulic retention time required in the
phosphate release unit was found to be around one to two hours, above which there was no
considerable amount of phosphate released. Potentially, up to 78% of the incoming
phosphorus is estimated to be recovered by implementing sidestream technology.
Based on the simulation results, sidestream process was successfully implemented at UBC
pilot plant for both membrane and conventional enhanced biological phosphorous removal
processes (MEBPR and CEBPR). The MAP crystallizer was used to recover phosphorus as
struvite. Although, the recovery efficiency obtained was not very high (approximately 60%),
the refined conditions as suggested should yield better results.
Sidestream wasting method to control the solid retention time of the process indicated
selective increase of phosphorus accumulating organisms in the main EBPR process.
Sidestream wasting also reduced the phosphorus rich sludge wasting from the aerobic zone
of the EBPR process. Magnesium (Mg) was added to the influent of the process to increase
the Mg²⁺ concentration in the sidestream supernatant to provide better conditions for struvite
formation. The CEBPR and MEBPR processes experienced poor phosphorus removal after
Mg addition was started. More detailed investigation is suggested to look in to the effects of
magnesium on the EBPR process along with potassium. === Applied Science, Faculty of === Civil Engineering, Department of === Graduate
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