高钙粉煤灰陶粒对人工湿地强化除磷机制

Phosphorus removal mechanism in constructed wetlands with high calcium fly ash as substrate

为强化人工湿地除磷能力和扩大固体废弃物粉煤灰的利用,选择对磷吸附容量高的高钙粉煤灰陶粒作为人工湿地基质,考察除磷特性,探讨除磷机制。实验结果表明:高钙粉煤灰陶粒具有其巨大的比表面积和孔隙率,相对于传统基质具有较大的磷吸附容量,磷去除率可达90%,出水TP和PO43-质量浓度分别低于0.40 mg/L和0.22mg/L;粉煤灰陶粒吸附Ca-P达到总吸附磷量的90%,强化除磷的机制是陶粒内部的钙元素与水中的磷发生化学反应,造成磷在陶粒表面的沉积,进而达到从水中分离的目的,微生物分解和植物的进一步吸收能维持该过程的可持续性。

In order to strengthen phosphorus removal efficiency of constructed wetlands and expand the reuse of solid waste-fly ash, high calcium fly ash ceramic was applied into constructed wetlands as substrate to treat wastewater. The phosphorus removal characteristics and mechanism were researched. The results show that fly ash has a larger phosphorus adsorption capacity than conventional ceramic substrate, 90% phosphorus removal rate can be obtained and the mass concentrations of TP and PO43- of the effluent are less than 0.40 and 0.22 mg/L, respectively. Experiment of sequential phosphorus extraction attached on wetland substrate reveals that Ca-P is the largest among all kinds of phosphorus, to 90% of the total. The mechanism of fly ash ceramic removal phosphorus in wetlands is that the phosphate of the water reacts with the calcium of the ceramic, which causes phosphorus deposition and separation from the water. The action of microbiology and aquatic plants make the process sustainable.