While cleaning wastewater, biological wastewater treatment processes such as membrane bioreactors (MBR) produce a significant amount of sludge that requires costly management. In the oxic-settling-anoxic (OSA) process, sludge is retained for a temporary period in side-stream reactors with low oxygen and substrate, and then it is recirculated to the main reactor. In this way, excess sludge production is reduced. We studied the influence of the rate of sludge exchange between MBR and side-stream anoxic reactors on sludge yield reduction within MBR. Two MBRs, namely, MBR_OSA and MBR_control, each coupled with separate external anoxic side-stream reactors, were run in parallel for 350 days. Unlike MBR_control, MBR_OSA had sludge exchange with the external reactors connected to it. During the investigation over a sludge interchange rate (SIR) range of 0–22%, an SIR of 11% achieved the highest sludge reduction (58%). Greater volatile solids destruction i.e., bacterial cell lysis and extracellular polymeric substance (EPS) destruction occurred at the SIR of 11%, which helped to achieve the highest sludge reduction. The enhanced volatile solids destruction was evident by the release of nutrients in the external anoxic reactors. It was confirmed that the sludge yield reduction was achieved without compromising the wastewater treatment quality, sludge settleability and hydraulic performance of the membrane in MBR.

在清洁废水时，诸如膜生物反应器（MBR）之类的生物废水处理过程会产生大量污泥，需要进行昂贵的管理。在有氧-沉降-缺氧（OSA）过程中，污泥会在侧流反应器中的氧气和底物含量低的情况下暂时保留，然后循环到主反应器中。这样，减少了过多的污泥产生。我们研究了MBR和侧流缺氧反应器之间的污泥交换速率对MBR内污泥产率降低的影响。两个MBR，即MBR _OSA和MBR _control，分别与独立的外部缺氧侧流反应器结合，并行运行350天。与MBR_控制不同，MBR _OSA与与其相连的外部反应器进行了污泥交换。在调查范围为0-22％的污泥交换率（SIR）期间，SIR为11％达到了最高的污泥减少率（58％）。SIR为11％时，发生了较大的挥发性固体破坏，即细菌细胞裂解和细胞外聚合物质（EPS）破坏，这有助于实现最大程度的污泥减少。通过外部缺氧反应器中养分的释放，可以明显提高挥发性固体的破坏能力。证实了在不损害MBR膜的废水处理质量，污泥沉降性和膜的水力性能的情况下实现了污泥产率的降低。