P recovery from wastewater treatment plants (WWTPs) as struvite fertiliser is a recognised method of
improving P use efficiency and reducing P losses into the environment. The main driver for P recovery
from the water industry viewpoint is the reduction in the nuisance of struvite clogging inside pumps
and pipes. Struvite recovery leads to an average P recovery rate of 72 ± 7% from centrifuge centrate,
with 8.8 ± 0.7% total P and 20.5 ± 3.2% PO4-P removed from the WWTP influent as struvite. This reduces
the potential for struvite precipitation, moderates P loads on biological nutrient removal processes and
lowers P concentration in the final effluent. Totalling revenue from sale of struvite and operational site
savings, P recovery becomes an attractive option for water companies. The implementation of P recovery
technologies to produce struvite fertiliser in all UK WWTPs could produce a national P fertiliser source
of 7.05 ± 2.01 kt P/year. In addition, sludge produced at WWTPs could be diverted to advanced energy
recovery (AER) processes and P recovered from AER residues; up to 21.71 ± 0.95 kt P/year could be recovered
in this way in the UK. Combining the two methods of P recovery, UK imports of P fertiliser could be
reduced by 36.2 ± 1.1%. P recovery on a large scale has the further benefit of protecting against eutrophication
by reducing P emissions to water bodies by 21.7 ± 1.9%. The protection of the environment and
reduction in reliance on imported P are major national motivations to legislate P recovery from waste.
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