硫碳比对芦苇碳源-硫耦合表面流湿地脱氮的影响

针对农田退水中NO₃--N占比高、碳氮比低的问题，提出PS-SFW（Phragmites australis and sulfur combined surface flow constructed wetland，芦苇碳源-硫耦合表面流人工湿地），对其强化农田退水脱氮的可行性进行了研究，并与SFW₀（无芦苇碳源-硫填充的常规表面流湿地）进行对比，重点研究了HRT（水力停留时间）为3、2、4 d条件下S/C（质量比，分别为0.32、0.56）对PS-SFW脱氮效能的影响.结果表明，HRT为3 d（第29~40天）时，PS-SFW_0.32（S/C比为0.32）、PS-SFW_0.56（S/C比为0.56）和SFW₀的w（NO₃--N）分别为55.9%±11.0%、66.0%±10.0%和7.0%±3.0%，w（TN）分别为36.9%±1.0%、40.3%±3.0%和4.5%±2.0%，PS-SFW_0.56对TN和NO₃--N去除效能高于PS-SFW_0.32，远高于SFW₀；HRT为4 d时（第41~81天）及HRT为3 d（第130~149天）时，PS-SFW_0.32、PS-SFW_0.56、SFW₀的w（NO₃--N）为66.3%±5.0%、90.5%±4.0%、14.4±4.0%和53.4%±3.0%、62.9%±10.0%、48.5%±5.0%，w（TN）为55.5%±5.0%、75.4%±5.0%、14.4%±3.0%和48.8%±2.0%、57.5%±6.0%、44.1%±5.0%，PS-SFW_0.56对NO₃--N和TN的去除效能均优于PS-SFW_0.32，并且优于SFW₀.HRT为2 d（第82~129天）时，PS-SFW_0.32、PS-SFW_0.56、SFW₀的w（NO₃--N）为47.7%±7.0%、46.6%±6.0%和26.8%±4.0%，w（TN）为37%±6.0%、36.6%±6.0%和24.0%±3.0%，PS-SFW_0.32、PS-SFW_0.56对氮的去除效能接近，但仍优于SFW₀.研究显示，PS-SFW运行条件应优选S/C为0.56、HRT为4 d. 

Influence of Sulfur-to-Carbon Ratio on Nitrogen Removal by Phragmites australis and Sulfur Combined Surface Flow Construction Wetland

A Phragmites australis and Sulfur Combined Surface Flow Constructed Wetland (PS-SFW) were put forward for treatment of high-Nitrate and low COD/TN (C/N) ratio agricultural runoff, and their feasibility for advanced nitrogen removal of agricultural runoff was extensively studied and compared with a conventional surface flow constructed wetland without P.australis pieces and sulfur packing (SFW₀). The study focused on the influence of sulfur/carbon ratio (S/C) on PS-SFW nitrogen removal under 2, 3 and 4 d hydraulic retention time (HRT). The results showed that under 3 d HRT (29-40 d), w(NO₃^--N) removal of PS-SFW_0.32 (0.32 S/C ratio), PS-SFW_0.56 (0.56 S/C ratio) and SFW₀ were 55.9%±11.0%, 66%±10.0% and 7.0%±3.0%, and w(TN) were 36.9%±1.0%, 40.3%±3.0% and 4.5%±2.0%, respectively. The NO₃^--N and TN removals of PS-SFW_0.56 were higher than those of PS-SFW_0.32, and they were both much higher than SFW₀. Under 4 d HRT during 41-81 d operation (3 d HRT during 130-149 d operation), w(NO₃^--N) of PS-SFW_0.32, PS-SFW_0.56 and SFW₀ were 66.3%±5.0%, 90.5%±4.0% and 14.4%±4.0% (53.4%±3.0%, 62.9%±10.0% and 48.5%±5.0%), and w(TN) were 55.5%±5.0%, 75.4%±5.0% and 4.4%±3.0% (48.8%±2.0%, 57.5%±6.0% and 44.1%±5.0%), respectively. Both NO₃^--N and TN removal of PS-SFW_0.56 were higher than those of PS-SFW_0.32, and both were much higher than those of SFW₀. Under 2 d HRT (82-129 d), w(NO₃^--N) of PS-SFW_0.32, PS-SFW_0.56 and SFW₀ were 47.7%±7.0%, 46.6%±6.0% and 26.8%±4.0%, and w(TN) were 37%±6.0%, 36.6%±6.0% and 24.0%±3.0%, respectively. The nitrogen removal at 0.56 and 0.32 S/C were similar and much higher than SFW₀. Considering the above results, 0.56 S/C and 4 d HRT were selected as the optimal conditions for PS-SFW operation.