Enhanced biological phosphorus removal (EBPR) is often applied by wastewater treatment plants (WWTPs) whereby phosphorus (P) is accumulated in the activated sludge (AS) biomass. The German Sewage Sludge Ordinance demands that large WWTPs recycle P from their process streams by 2029. This study aimed at evaluating the potential of an acetate-mediated P re-dissolution from non-acclimated AS of three full-scale WWTPs. All AS exhibited enhanced P re-dissolution during acetate uptake and followed kinetics typical of EBPR systems. Re-dissolution efficiency differed depending on the WWTP operation mode. The highest P re-dissolution yield (56% of total P) was obtained for pure EBPR sludge. Lower re-dissolution rates of 19-22% were observed in the AS from WWTPs that employed additional chemical P removal, probably due to shortage of intracellular polyphosphate. Pure EBPR systems may be suited for the implementation of a re-dissolution based strategy for P recycling from AS where P depleted AS could potentially be returned to the biological treatment stage.

污水处理厂 (WWTP) 通常采用强化生物除磷 (EBPR)，其中磷 (P) 在活性污泥 (AS) 生物质中积累。德国污水污泥条例要求大型污水处理厂在 2029 年之前从其工艺流中回收 P。本研究旨在评估醋酸盐介导的 P 从三个全规模污水处理厂的未驯化 AS 中重新溶解的潜力。所有 AS 在醋酸盐吸收过程中都表现出增强的预溶解，并遵循 EBPR 系统的典型动力学。再溶解效率因污水处理厂运行模式而异。纯 EBPR 污泥获得了最高的 P 再溶解产率（总 P 的 56%）。在来自采用额外化学除磷的污水处理厂的 AS 中观察到的再溶解率较低，为 19-22%，可能是由于细胞内多磷酸盐短缺。纯 EBPR 系统可能适用于从 AS 回收 P 再溶解的策略，其中 P 耗尽的 AS 可能返回到生物处理阶段。