石榴石滤料的过滤性能及反冲洗试验研究

石榴石作为一种新型矿物滤料在净水处理方面具有强大的竞争力和广阔的应用前景.通过对石榴石滤料进行过滤及反冲洗试验，研究其截污除浊性能、水头损失变化规律及对有机物的去除效果，并与传统的石英砂滤料做对比，同时探讨了石榴石滤料的适宜反冲洗强度范围及气水反冲洗运行参数.结果表明:在滤速为8 m/h的条件下，与石英砂滤柱的过滤效果相比，石榴石滤柱滤后水的平均浊度下降0.3 NTU，有机物平均质量分数下降5%，但其平均水头损失增长率为1 cm/h；在截污除浊及去除有机物方面，石榴石滤柱在60 cm滤层厚度处与石英砂滤柱在85 cm滤层厚度的去除效果十分接近，因此其能有效减少滤料体积，从而节省滤料及节约设备投资.在不同滤速下，水头损失是限制石榴石滤柱过滤周期的主要因素；石榴石滤料适宜的气反冲洗强度范围为14~16 L/（s·m2），水反冲洗强度范围为5~7 L/（s·m2），其气水反冲洗的最佳运行参数为气洗强度16 L/（s·m2）、水洗强度7 L/（s·m2）、气水联合反冲洗4 min、单独水漂洗7 min.其中，气反冲洗强度对石榴石滤料的反冲洗效果影响最大.研究显示，相较于传统石英砂滤料，石榴石滤料具有高过滤性能、低滤料体积的特点，在水处理滤料的应用方面显示出一定的优势. 

Filtration and Backwashing of Garnet Media

As a new mineral filter material, garnet media shows great competitiveness and broad prospects for water purification applications. In this paper, filtration and backwashing experiments on garnet media were performed to research the turbidity and organic pollutant removal performance and regularity of the variation of head loss. We also investigated the optimum backwashing rate and the optimal backwashing parameters of garnet media. Compared with the performance of quartz sand media, the garnet media shows certain advantages. At filtration a rate of 8 m/h, compared with a quartz sand filter column, the average turbidity and organic content of effluent from garnet filter column were 0.3 NTU and 5% lower than those of the quartz sand media respectively. Moreover, the removal efficiency of a garnet filter column with thickness of 60 cm was very close to that of a quartz sand filter column with thickness of 85 cm, which indicates that the use of garnet media could reduce the volume of the filter, and cut down on investment for equipment. However, the average head loss was 1 cm/h higher than for quartz sand. The head loss was also the main factor restricting the filtration cycle duration of garnet filter column. The optimum air scour and water backwashing range of garnet media was found to be 5-7 and 14-16 L/(s·m²) respectively. The optimal operation parameters of garnet media were determined as follows:air backwashing intensity and water backwashing intensity were 16 and 7 L/(s·m²) respectively, combined backwashing time and single water backwashing were 4 and 7 min respectively. The air backwashing intensity was the most important factor influencing the backwashing efficiency of the garnet filter column. According to our results, the garnet media shows certain advantages for application as a water treatment filter, such as better turbidity removal, smaller size and more efficient volume than the traditional quartz sand media.