Biological recovery of phosphorus (BioP‐Rec) from wastewater streams using brewer's yeast on pilot‐scale

Abstract

Most recent advances for phosphorus (P) recovery using brewery yeast on laboratory scale were used to scale up to a pilot‐scale process (BioP‐Rec module) and applied in a full‐scale wastewater treatment plant (WWTP). A P balance was established for WWTP Markranstädt according to two thresholds: (1) the economic feasibility threshold for P recovery of 0.05 kg/m3 of free P, and (2) the German Sewage Sludge Ordinance (GSSO) threshold, which demands that all WWTPs with a P content in dry matter (DM) of biosolids of 20 gP/kgDM or higher in the coming years must perform mandatory P recovery. In terms of defined thresholds, return and excess sludges were identified as the most feasible WWTP process streams for P recovery. In a 1 m3 BioP‐Rec module a 3 stage process was established. From the P‐rich water‐phase of the return sludge produced in stage 1, which contained 0.051 kg/m3 of free P, 77.56% was taken up by P‐depleted brewer's yeast Saccharomyces pastorianus in 3 h in stage 2. In stage 3, the yeast was concentrated in 1 h to produce yeast sludge as a fertilizer product. We demonstrated a novel pilot‐scale process for the production of bio‐based P‐rich fertilizer.