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Monday, 11 February 2019 09:46

New paper on phosphorus recovery in Journal of Cleaner Production

Phosphorus recovery is usually based on the chemical precipitation of struvite in the anaerobic digestion supernatant from wastewater treatment plants sludge. However, the recovery of Phosphorus from the main water line would be very beneficial to the operation of the plant and this work represents a step forward in this challenge. The configuration of a sequencing batch reactor Performing Enhanced Biological Phosphorus Removal was modified to include the extraction of a P‑rich anaerobic supernatant after a settling period. The liquid extracted after the anaerobic phase has the highest phosphorus concentration in all the reactor cycle and is therefore suitable for implementing P-recovery strategies. This system is the first experimental system operated under this configuration and in a long-term basis (more than one year) under different influent COD/P ratios with good performance and stability. This work shows experimentally that up to 60% of the P could be extracted without a deleterious effect on biological phosphorus removal. The system could even operate at very high COD/P ratio (7.5) with high activity. Finally, anaerobic supernatant extraction was linked to anaerobic purging and it was demonstrated that higher methane production (24.3 %) was obtained compared to the default case with the sludge purged at the end of the aerobic phase.