Aerobic granular sludge (AGS) was rapidly cultivated in an integrated oxidation ditch with two-zone clarifiers by using a novel external sludge treatment and return mode to treat low concentrations of actual domestic sewage. The selective pressure created by the two-zone clarifiers can retain the well-settling granules and discharge light flocs with poor settleability. The granules stayed in the reactor, which induced bacterial attachment to the granules that acted as nuclei, while the discharged flocs can stimulate microorganisms to secrete large amounts of extracellular polymeric substances (EPS) under the external conditioning of CaCl₂ and natural air drying. Then, this surplus sludge was returned to the reactor to create more small granules that combined with each other through the action of hydraulic shear forces to achieve rapid granulation. The results showed that AGS was formed successfully in the reactor on day 18, and after 51 days of continuous operation, the biomass concentration and settling ability were further improved (the mixed liquor suspended solids (MLSS) and sludge volume index at 5 min (SVI₅) were stable at approximately 3500 mg/L and 40.0 mL/g, respectively). During the whole experimental period, the biological sludge activity was greatly improved, and the EPS and microbial community changed significantly, including an enrichment of microbes with EPS secretion and granule stabilization functions. The study results reveal that the pollutant removal efficiency improved after granulation. Furthermore, this approach required less energy and is eco-friendly for potential full-scale implementation.

通过使用新型的外部污泥处理和回流模式来处理低浓度的实际生活污水，在带有两区净化器的集成氧化沟中快速培养好氧颗粒污泥（AGS）。两区澄清池产生的选择性压力会保留沉降良好的颗粒，并排出沉降性较差的轻絮状物。颗粒留在反应器中，该反应器诱导细菌附着在充当核的颗粒上，而排出的絮凝物可以刺激微生物在CaCl ₂的外部条件下分泌大量细胞外聚合物（EPS）。和自然风干。然后，这些多余的污泥返回到反应器中，以产生更多的小颗粒，这些颗粒通过水力剪切力的作用相互结合，从而实现快速制粒。结果表明，反应器在第18天成功形成AGS，连续运行51天后，生物质浓度和沉降能力得到进一步提高（混合液悬浮固体（MLSS）和5分钟污泥体积指数（SVI）₅）分别稳定在约3500 mg / L和40.0 mL / g）。在整个实验期间，生物污泥的活性得到了极大的改善，EPS和微生物群落发生了显着变化，其中包括具有EPS分泌和颗粒稳定功能的微生物的富集。研究结果表明，造粒后污染物去除效率提高。此外，这种方法所需的能源更少，并且对于潜在的全面实施是环保的。