Experimental study on aeration process optimization of A2/O domestic sewage treatment by static spiral cutting

Abstract

A2/O is a common domestic sewage treatment process.The aeration method of aerobic section is usually the traditional bottom aeration, which has low oxygen dissolution efficiency. In order to achieve high quality and efficient treatment of sewage, a static spiral cutter without power drive was developed based on gas-liquid mass transfer enhancement and fluid mechanics theory. Large bubbles in gas-liquid mixture could be cut into micro-nanometer scale small bubbles, which can improve dissolved oxygen in a short time, and control gas flow to achieve the adjustment of dissolved oxygen. Experiments with no aeration, traditional bottom aeration, and static spiral cutting were carried out. The results showed that compared with the traditional bottom aeration process, with the static spiral cutting, the removal rate of solid suspended solids(SS) increased by 12.3%,the removal rate of COD by 5.6%, the removal rates of ammonia nitrogen (NH3-N) and total phosphorus (TP) were increased by 8.1% and 8.5% respectively, and the concentration of saturated dissolved oxygen (DO) was increased by 48.2%. Overall,static spiral cutter has advantages of simple structure and good economy, it has a promising application for the optimization of sewage treatment aeration.

Keywords

• domestic sewage treatment
• static spiral cutter
• optimize aeration process