| 玉米芯和稻草秸秆强化潜流人工湿地对低C/N污水的处理效果 |
| 摘要点击 4802 全文点击 519 投稿时间：2021-12-23 修订日期：2022-01-05 |
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| 中文关键词 潜流人工湿地 低碳氮比 脱氮 玉米芯 稻草秸秆 |
| 英文关键词 subsurface flow constructed wetland low carbon/nitrogen ratio denitrification corncob straw |
| 作者 | 单位 | E-mail | | 胡曼利 | 西南大学资源环境学院, 三峡库区生态环境教育部重点实验室, 重庆 400715 | 1104963891@qq.com | | 郝庆菊 | 西南大学资源环境学院, 三峡库区生态环境教育部重点实验室, 重庆 400715
重庆市农业资源与环境研究重点实验室, 重庆 400716 | | | 马容真 | 西南大学资源环境学院, 三峡库区生态环境教育部重点实验室, 重庆 400715 | | | 陈柯沁 | 西南大学资源环境学院, 三峡库区生态环境教育部重点实验室, 重庆 400715 | | | 罗师旭 | 西南大学资源环境学院, 三峡库区生态环境教育部重点实验室, 重庆 400715 | | | 江长胜 | 西南大学资源环境学院, 三峡库区生态环境教育部重点实验室, 重庆 400715
重庆市农业资源与环境研究重点实验室, 重庆 400716 | jiangcs@126.com |
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| 中文摘要 |
| 人工湿地在处理低C/N污水时存在碳源缺乏而严重限制反硝化进行的问题.为了补充反硝化需要的碳源，选择了玉米芯和稻草秸秆作为外加碳源引入湿地系统，对比两种碳源对湿地脱氮的强化效果.结果表明，通过11 d的纯水浸提释放实验发现，碳素累积释放量：稻草秸秆［（145.17±9.44） mg·g-1］>玉米芯［（57.41±5.04） mg·g-1］；氮素累积释放量：稻草秸秆［（2.31±0.09） mg·g-1］>玉米芯［（0.66±0.08） mg·g-1］.在观测的时间内，玉米芯和稻草秸秆累积释放碳氮比平均值分别为94.78和63.64.相比于稻草秸秆，玉米芯更适合作为外加碳源.在为期58 d的潜流人工湿地实验中，发现除了第8~12 d，添加玉米芯和稻草秸秆人工湿地出水中ρ（COD）超过50 mg·L-1外，其它时间都低于50 mg·L-1.在观测期间，添加玉米芯人工湿地的NO3--N去除率为93%~99%，具有良好的反硝化性能.而添加稻草秸秆人工湿地在运行后期NO3--N去除率最低只有76.8%，反硝化速率明显下降.对照组NO3--N去除率只有76.2%~77.7%，出现了明显碳源不足的现象.碳源不足还造成了NO2--N的蓄积.添加稻草秸秆和对照组人工湿地中NO2--N的出水质量浓度分别是玉米芯人工湿地的2.5~6倍和6~26倍.与添加稻草秸秆比，添加玉米芯可以使人工湿地中NO2--N出水质量浓度得到更显著地降低（P<0.05）.玉米芯、稻草秸秆和对照组人工湿地TN去除率分别为83.75%~93.49%、76.59%~78.85%和67.85%~72.56%，三者之间存在显著性差异（P<0.01）.最后，通过对玉米芯进行了稀碱加热预处理，使玉米芯的碳素累积释放量提高到（93.73±17.49） mg·g-1，累积释放的碳氮比提高至175.8，进一步提高了玉米芯的释碳性能，表现为更合适的外加碳源. |
| 英文摘要 |
| The lack of carbon sources severely inhibits denitrification in wastewater with a low C/N ratio. Corncob and rice straw were chosen as supplementary carbon sources to bring into the wetland system to supplement the carbon sources needed for denitrification, and the enhancing effects of the two carbon sources on nitrogen removal from the wetland were studied. The cumulative release of carbon was in the order of rice straw[(145.17±9.44) mg·g-1]>corncob[(57.41±5.04) mg·g-1] based on the 11-day pure water extraction and release experiment, whereas the cumulative release of nitrogen was in the order of rice straw[(2.31±0.09) mg·g-1]>corncob[(0.66±0.08) mg·g-1]. The average carbon/nitrogen ratios released and accumulated by corncob and rice straw during the observation period were 94.78 and 63.64, respectively. Corncob was more suited as an additional carbon source than rice straw. COD concentrations in the effluent from the corncob and straw constructed wetlands were found to be below 50 mg·L-1 for the 58-day pilot test of subsurface flow constructed wetlands, except on days 8 to 12. The NO3--N removal rates of the corncob-added built wetlands were 93%-99% over the observation period, with good denitrification performance. In comparison, the lowest NO3--N removal rate of the constructed wetland with the addition of rice straw was only 76.8% at the late stage of operation, and the denitrification rate dropped dramatically. The control group removal rates of NO3--N were only 76.2%-77.7%, indicating a clear lack of carbon sources. The accumulation of NO2--N was also induced by a lack of carbon supply. NO2--N effluent concentrations were 2.5-6 times and 6-26 times higher in the constructed wetlands with rice straw and the control groups, respectively, than those in the wetlands constructed with corncob. The addition of corncob resulted in a more substantial reduction in NO2--N content in the constructed wetland than the addition of rice straw (P<0.05). The TN removal rates of wetlands constructed with corncob and rice straw and the control group were 83.75%-93.49%, 76.59%-78.85%, and 67.85%-72.56%, respectively, with significant differences among the three (P<0.01). Finally, pretreatment with dilute alkali heating raised the cumulative carbon release of corncob to (93.73±17.49) mg·g-1 and the carbon/nitrogen ratio to 175.8, significantly improving the carbon release performance of corncob and demonstrating that it is a suitable source of extra carbon. |
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