A_2N-IC工艺诱导结晶柱位置选择及投药量优化

Optimizations of induced crystallization reactor position and calcium dosage in A_2N-IC process

针对传统生物脱氮除磷工艺处理生活污水时碳源不足、聚磷菌与反硝化菌对碳源存在竞争、泥龄矛盾难以协调等问题,提出了双污泥反硝化聚磷-诱导结晶磷回收新工艺.该工艺不仅可以有效提高污水脱氮除磷效率,还可实现磷资源的有效回收.针对该新型工艺,以厌氧释磷的富磷上清液为研究对象,利用对比试验优选结晶柱在生物系统中的位置,并考察结晶柱中钙盐投加量对化学除磷的影响.结果表明:从优化结晶过程p H的角度考虑,诱导结晶化学除磷系统宜放置于厌氧沉淀池后;钙盐投加量的增加并不能显著增加磷回收率,但在增加沉淀过程后,增加钙离子投加量可明显提高化学除磷量;粗糙的晶种表面更容易聚集钙磷结晶物,无定形钙磷化合物可能为结晶产物的主要前驱物.

The conventional biological nitrogen and phosphorus removal processes for sewage treatment have some disadvantages, such as the competition for carbon source between phosphorus re- moval bacteria and nitrogen removal bacteria, the sludge age conflict. To solve these problems the anaerobic-anoxic/nitrifying/induced crystallization （A2N-IC） process is proposed. This new process not only increases the nitrogen and phosphorus removal efficiency, but also effectively recovers phosphorus. In the A2N-IC process, the rich-phosphorus supernatant from the phosphorus release is used for the optimization of IC reactor position. The effect of calcium dosage on the chemical phos- phorus removal is also investigated. The results indicate that IC reactor is more suitable to be placed after the anaerobic tank in consideration of pH value for chemical phosphorus removal. The increment of calcium dosage cannot distinctly increase the phosphorus recovery efficiency. However, af- ter adding sedimentation stage, the increment of calcium dosage can significantly increase the phos- phorus recovery efficiency. The phosphorus recovery product is easier to be maintained on the seeds with rough surface. Amorphous calcium phosphate is possibly the precursor of hydroxyapatite.