2种BDPs固相反硝化的脱氮效果对比

利用批量和连续流填充床试验对比了2种BDPs(可生物降解聚合物)——PBS(聚丁二酸丁二醇酯)和PCL(聚ε-己内酯)的反硝化效果. 批量试验结果表明,在脱氮稳定阶段,B1(PCL)和B2(PBS)对TN的平均去除率和反硝化速率分别为97.4%、67.0%和7.5、1.8 mg/(L·h),B2均明显优于B1. 连续流试验中,在进水ρ(NO₃--N)为16.8～18.8 mg/L、HRT(水力停留时间)为4.0 h的条件下,L1(PCL填充床)的反硝化速率大于L2(PBS填充床). 但是随着HRT的减小,L1呈现出比L2更快的反硝化速率. L2和L1分别在HRT为2.0和1.5 h时获得最大反硝化速率,分别为7.7和9.3 mg/(L·h). ESEM(环境扫描电子显微镜)观察结果表明,生物膜剥离后,PCL和PBS颗粒表面均出现大量的坑洞,并且PCL颗粒表面坑洞的密集程度远大于PBS. 三维荧光光谱(3D-EEM)分析结果表明,L2和L1出水中的溶解性有机物主要为类色氨酸这类简单的蛋白质和SMP(溶解性微生物代谢产物),并且L1水中SMP的荧光峰强度明显高于L2. 

Comparison of Two Biodegradable Polymers in SPD System for Nitrogen Removal

Nitrogen removal performance using two different BDP carrier materials, poly butylene succinate (PBS) and polycaprolactone (PCL), by batch and continuous fixed-bed tests were compared. When the batch tests were stable, the nitrogen removal and dinitrification performance of reactor B1 (97.4% and 7.5 mg/(L·h)) filled with PCL carrier was superior to that of reactor B2 filled with PBS carrier (67.0% and 1.8 mg/(L·h)). The results of continuous fixed-bed experimentation indicated that the denitrification rate of L1 filled with PCL carrier was higher than that of L2 filled with PBS carrier, under the conditions of influent nitrate around 16.8-18.8 mg/L and flow rate 5 mL/min (HRT=4.0). However, with the decreasing of HRT, L2 showed a higher denitrifiction rate. The denitrificaiton rates of L1 and L2 reached maximum values of 7.7 and 9.3 mg/(L·h) when the HRTs were 2.0 h and 1.5 h, respectively. ESEM observation revealed that many cavities appeared on the surfaces of the PCL and PBS carriers due to corrosion by microorganisms. Furthermore, the cavities on the PCL surface were denser than those of PBS. Finally, the results showed that the effluent from L1 and L2 contained mainly protein-like and soluble microbial product-like substances, and the fluorescence intensity of SMP from the effluent of L1 was significantly stronger than that from the effluent of L2, as shown through 3D-EEM investigation.