National Engineering Laboratory for Industrial Waste-water Treatment, East China University of Science and Technology, Shanghai 200237, PR China.
National Engineering Laboratory for Industrial Waste-water Treatment, East China University of Science and Technology, Shanghai 200237, PR China.
Sci Total Environ. 2019 Dec 10;695:133825. doi: 10.1016/j.scitotenv.2019.133825. Epub 2019 Aug 6.
The settleability performance of activated sludge (AS) is a very important indicator in the biological treatment of wastewater. In this paper, we investigated the influence of hydrocyclone treatment on sludge settleability and explored the influence mechanism by sorting the excess sludge (ES) with a hydrocyclone. A lateral-line test of the treatment process of the campus wastewater treatment plant (WWTP) at East China University of Science and Technology (ECUST) was carried out by using a sequencing batch reactor (SBR) AS process equipped with a hydrocyclone. The results showed that the sludge flocs rotate and revolve in the hydrocyclone; the resulting shear and centrifugal stress cause the flocs to crack into smaller pieces and can break the extracellular polymeric substances (EPS) on the floc surface, thus changing the floc structure and density. After density sorting by the hydrocyclone, the particle size of the sludge floc returned to the bioreactor decreased, the compactness increased, the settleability performance improved, the sludge volume index (SVI) decreased by 6.1%, and the effluent suspended solid (SS) concentration decreased by 6.1%. Meanwhile, the broken EPS caused organic carbon sources, such as polysaccharides and proteins, in the floc channels to be released into the water phase, supplementing the carbon source for denitrification and improving the effluent water quality: the removal rates of soluble chemical oxygen demand (SCOD), total nitrogen (TN), and NH-N increased by 6.9%, 8.9%, and 8.4%, respectively.
活性污泥（AS）的沉降性能是废水生物处理的一个非常重要的指标。本文研究了水力旋流器处理对污泥沉降性能的影响，并通过水力旋流器对剩余污泥（ES）进行分类，探讨了其影响机制。华东理工大学（ECUST）的校园污水处理厂（WWTP）采用配备水力旋流器的序批式反应器（SBR）AS 工艺进行了侧向线测试。结果表明，污泥絮体在水力旋流器中旋转和旋转；产生的剪切和离心应力导致絮体破裂成更小的碎片，并可以破坏絮体表面的胞外聚合物（EPS），从而改变絮体结构和密度。经过水力旋流器的密度分类后，返回生物反应器的污泥絮体粒径减小，密实度增加，沉降性能得到改善，污泥体积指数（SVI）降低了 6.1%，出水悬浮物（SS）浓度降低了 6.1%。同时，破碎的 EPS 导致絮体通道中的有机碳源，如多糖和蛋白质，释放到水相中，补充反硝化的碳源，提高了出水水质：可溶解性化学需氧量（SCOD）、总氮（TN）和 NH-N 的去除率分别提高了 6.9%、8.9%和 8.4%。
