外加碳源对生物炭基潜流人工湿地净化污水处理厂尾水效能的影响

刘勇超; 陈启斌; 王朝旭; 王加勇; 孙兆森; 张业国; 魏阳

doi:10.12153/j.issn.1674-991X.20220733

外加碳源对生物炭基潜流人工湿地净化污水处理厂尾水效能的影响

doi: 10.12153/j.issn.1674-991X.20220733

1.
太原理工大学环境科学与工程学院
2.
中电建市政建设集团北方国际工程有限公司

基金项目: 山西省自然科学基金项目（201901D111066）；校企合作项目

详细信息

作者简介:
刘勇超(1997—)，男，硕士研究生，主要从事水污染控制与水质安全保障研究，2211719826@qq.com

通讯作者:
王朝旭(1981—)，男，副教授，主要从事生物质炭的水土环境效应研究，cxwang127@126.com

中图分类号: X703
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出版历程
- 收稿日期: 2022-07-21
- 网络出版日期: 2023-07-19

Effect of external carbon addition on pollutants removal from the tail water of a sewage treatment plant by biochar-based subsurface flow constructed wetland

1.
College of Environmental Science and Engineering, Taiyuan University of Technology
2.
Stecol Corporation North International Engineering Co., Ltd.

摘要

摘要:
生物炭作为一种多功能生态环保材料，近年来被广泛应用于人工湿地污水处理中，其可为异养反硝化提供碳源，从而提高人工湿地的脱氮能力。通过室内构建石英砂/杏仁壳生物炭基质（体积比7∶3）人工湿地，同时以石英砂基质人工湿地为对照，运行后期通过外加碳源设计不同碳氮比（C/N），且分别采用连续流和间歇流的运行方式，探究外加碳源对生物炭基水平潜流人工湿地深度净化实际污水处理厂尾水效果的影响。结果表明：外加碳源前，人工湿地的化学需氧量（COD）去除率为负，总氮（TN）和硝氮（NO₃ ⁻-N）去除率在41 d内持续降低；而外加碳源后，石英砂单元和石英砂/生物炭单元的COD去除率分别增至37.88%~90.44%和73.60%~97.90%，TN和NO₃ ⁻-N去除率也明显提高。在外加碳源使进水C/N为8且间歇流运行时，石英砂/生物炭单元的TN和NO₃ ⁻-N去除率最高，分别达65.61%和74.20%。生物炭添加提高了湿地微生物生物量，同时创造了有利于反硝化作用发生的氧化还原环境，使石英砂/生物炭单元的COD、TN和NO₃ ⁻-N去除率分别提高了5.66%~130.35%、9.34%~54.03%和8.71%~63.04%。外加碳源与生物炭添加可作为一种有效手段强化实际污水处理厂尾水人工湿地系统的脱氮效能。
- 外加碳源 /
- 生物炭 /
- 潜流人工湿地 /
- 污水处理厂尾水 /
- 硝态氮
Abstract:
As a kind of multifunctional eco-friendly material, biochar has been widely used in sewage treatment by constructed wetlands in recent years, which can provide carbon source for heterotrophic denitrification and enhance nitrogen removal capacity of constructed wetland. To explore the effect of external carbon addition on deep purification of the tail water of a sewage treatment plant by biochar-based horizontal subsurface flow constructed wetland, two parallel indoor experimental units were set with quartz sand/almond shell biochar (volume ratio 7∶3) and quartz sand (the control) as the constructed wetland matrix, respectively. Moreover, in the later phase of operation, different C/N ratios were designed by external carbon addition and the operation modes of continuous flow and intermittent flow were adopted, respectively. Results showed that before external carbon addition, chemical oxygen demand (COD) removal rate of constructed wetland was negative, and total nitrogen (TN) and nitrate nitrogen (NO₃ ⁻-N) removal rates continued to decrease during 41 days. However, COD removal rates of quartz sand and quartz sand/almond shell biochar units increased to 37.88%-90.44% and 73.60%-97.90%, respectively, and TN and NO₃ ⁻-N removal rates also significantly increased after external carbon addition. The maximum removal rates of TN and NO₃ ⁻-N in quartz sand/biochar unit were 65.61% and 74.20%, respectively, as the influent C/N ratio was increased to 8 by external carbon addition and the intermittent flow mode was running. Biochar addition increased the microbial biomass of the constructed wetland, and created the appropriate redox environment facilitating denitrification. Therefore, the removal rates of COD, TN, and NO₃ ⁻-N of the wetland unit set with quartz sand/almond shell biochar increased by 5.66%-130.35%, 9.34%-54.03%, and 8.71%-63.04%, respectively, compared with the control. The external carbon addition and biochar application could be an effective measure to strengthen the denitrogenation efficiency of constructed wetland for tail water purification of sewage treatment plants.
- external carbon addition /
- biochar /
- subsurface flow constructed wetland /
- tail water of sewage treatment plant /
- nitrate nitrogen (NO₃ ⁻-N)

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图 1 人工湿地装置正视图和采样杆布设

Figure 1. Front view of the constructed wetland device and the schematic diagram of the sampling rod layout

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图 2 挂膜前的生物炭与挂膜后湿地基质表面的SEM图（2 000倍）

Figure 2. SEM images of the biochar before biofilm colonization and the wetland substrates after biofilm colonization (2000×)

下载: 全尺寸图片幻灯片

图 3 不同运行阶段人工湿地COD及其去除率的动态变化

Figure 3. Dynamic change of COD and its removal efficiency in constructed wetland during different operating stages

下载: 全尺寸图片幻灯片

图 4 不同运行阶段人工湿地TN和NO₃ ⁻-N浓度及去除率的动态变化

Figure 4. Dynamic changes of TN and NO₃ ⁻-N concentrations and their removal efficiencies in constructed wetland during different operating stages

下载: 全尺寸图片幻灯片

图 5 不同运行阶段人工湿地NO₂ ⁻-N和NH₄ ⁺-N浓度及去除率的动态变化

Figure 5. Dynamic changes of NO₂ ⁻-N and NH₄ ⁺-N concentrations and their removal efficiencies in constructed wetland during different operating stages

下载: 全尺寸图片幻灯片

图 6 不同运行阶段人工湿地基质区DO浓度和ORP的动态变化

Figure 6. Dynamic changes of DO concentration and ORP in the matrix region of constructed wetland during different operating stages

下载: 全尺寸图片幻灯片

表 1 试验用水水质

Table 1. Water quality of the influent water mg/L　

COD	TN浓度	NH₄ ⁺-N浓度	NO₃ ⁻-N浓度	NO₂ ⁻-N浓度	TP浓度	pH^1）	BOD₅/ COD^1）
20~40	8.27~12.57	0.19~0.59	7.16~11.23	0.004~0.090	0.043~0.650	7.5~8.5	0.195~ 0.283
1）pH和BOD₅/COD无量纲。

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表 2 人工湿地运行C/N和运行方式

Table 2. C/N ratio and the operation pattern of the constructed wetland

试验阶段	运行 C/N	外加碳源类型	运行方式	水样采集位置	水力停留时间/d	运行天数/d
第1~ 41天（未外加碳源）	2~3（污水处理厂尾水）	无	连续流	出水区	2	41
第42~ 71天（外加碳源）	4	乙酸钠	连续流	出水区	2	6
	8	乙酸钠	连续流	出水区	2	6
	6	乙酸钠	间歇流	基质区	2	6
	8	乙酸钠	间歇流	基质区	2	12

下载: 导出CSV

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