The lack of carbon source in the denitrification process with low C/N wastewater is the main factor limiting the denitrification efficiency in constructed wetlands (CWs). However, the traditional method of adding liquid carbon source is often costly and facing the risk of secondary pollution. This study attempted to solve this problem by adding woodchips sustained-release carbon sources as part of the substrate, together with the dewatered alum sludge as the main wetland substrate to the baffle subsurface flow constructed wetland (BSFCW). The effects of woodchips on denitrification capacity, effluent COD and nitrogen transfer and transformation were studied. Results showed that the removal rates of ammonia nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃^--N), total nitrogen (TN) and total phosphorus (TP) were 19.0%-75.3%, 63.6%-96.1%, 61.94%-74.4%, 75.0%-98.8%, respectively, when the C/N ratio varies between 0.93 and 1.87. The two-dimensional contour simulation of pollutants concentration in the system indicated that: i) the release rate of COD by woodchips decreased with the time; ii) woodchips reduced the oxidation reduction potential (ORP) of CW system, creating favorable conditions for the denitrification; iii) the closer the woodchips filling position to the inlet, the higher the denitrification efficiency of the system. The combination of dewatered alum sludge and woodchips substrates realized the simultaneous denitrification and dephosphorization of the BSFCW system. This study is of great significance for the treatment of low C/N wastewater containing considerable even high strength P.

低C / N废水的反硝化过程中缺乏碳源是限制人工湿地（CWs）的反硝化效率的主要因素。但是，传统的添加液态碳源的方法通常成本高昂，并且面临二次污染的风险。这项研究试图通过将木屑缓释碳源作为基质的一部分，以及将脱水明矾污泥作为主要的湿地基质，添加到挡板式地下流人工湿地（BSFCW）中来解决此问题。研究了木片对反硝化能力，废水化学需氧量和氮转移和转化的影响。结果表明，氨氮的去除率（NH ₄ ⁺ -N），硝酸态氮（NO ₃ ^--N），总氮（TN）和总磷（TP）分别在C / N比在10％到25％之间变化时分别为19.0％-75.3％，63.6％-96.1％，61.94％-74.4％，75.0％-98.8％。 0.93和1.87。系统中污染物浓度的二维轮廓模拟表明：i）木片释放的COD随时间降低；ii）木片降低了连续水系统的氧化还原电位（ORP），为反硝化创造了有利条件；iii）木屑填充位置越靠近入口，系统的反硝化效率越高。脱水明矾污泥和木屑基材的组合实现了BSFCW系统的同时反硝化和脱磷。这项研究对于处理含有相当高强度P的低C / N废水具有重要意义。