An innovative wood-chip-framework substrate used as slow-release carbon source to treat high-strength nitrogen wastewater

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• 作者：Huai Li¹ ; ^{lihuai@iga.ac.cn} ; Zifang Chi² ; ³ ; Baixing Yan¹ ; Long Cheng¹ ; Jianzheng Li² ; ^{envhit@aliyun.com}
• 关键词：Baffled constructed wetland ; Combined substrate ; Wood-chip ; Nitrogen ; Removal
• 刊名：Journal of Environmental Sciences
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：51
• 期：Complete
• 页码：275-283
• 全文大小：1103 K
• 卷排序：51

文摘

Removal of nitrogen in wastewater before discharge into receiving water courses is an important consideration in treatment systems. However, nitrogen removal efficiency is usually limited due to the low carbon/nitrogen (C/N) ratio. A common solution is to add external carbon sources, but amount of liquid is difficult to determine. Therefore, a combined wood-chip-framework substrate (with wood, slag and gravel) as a slow-release carbon source was constructed in baffled subsurface-flow constructed wetlands to overcome the problem. Results show that the removal rate of ammonia nitrogen (NH4+-N), total nitrogen (TN) and chemical oxygen demand (COD) could reach 37.5%–85%, 57.4%–86%, 32.4%–78%, respectively, indicating the combined substrate could diffuse sufficient oxygen for the nitrification process (slag and gravel zone) and provide carbon source for denitrification process (wood-chip zone). The nitrification and denitrification were determined according to the location of slag/gravel and wood-chip, respectively. Nitrogen removal was efficient at the steady phase before a shock loading using slag-wood-gravel combined substrate because of nitrification–denitrification process, while nitrogen removal was efficient under a shock loading with wood-slag-gravel combined substrate because of ANAMMOX process. This study provides a new idea for wetland treatment of high-strength nitrogen wastewater.