中文关键词潜流人工湿地生物炭有机污染物去除脱氮N₂O排放 英文关键词subsurface flow constructed wetlandbiocharorganic matter removalnitrogen removalN₂O emission

作者	单位	E-mail
邓朝仁	西南大学资源环境学院, 重庆 400715 农村清洁工程重庆市工程研究中心, 重庆 400716	d1372189044@email.swu.edu.cn
梁银坤	西南大学资源环境学院, 重庆 400715 农村清洁工程重庆市工程研究中心, 重庆 400716
黄磊	西南大学资源环境学院, 重庆 400715 农村清洁工程重庆市工程研究中心, 重庆 400716	leihuang@swu.edu.cn
方丹丹	西南大学资源环境学院, 重庆 400715 农村清洁工程重庆市工程研究中心, 重庆 400716
陈玉成	西南大学资源环境学院, 重庆 400715 农村清洁工程重庆市工程研究中心, 重庆 400716
杜刚	重庆大学城市建设与环境工程学院, 重庆 400045

中文摘要 生物炭作为一种生物质废弃物的热解产物，逐渐被应用于受污染水体治理.生物炭具有提高孔隙、吸附氮磷、控制温室气体排放等作用.通过在温室内构建生物炭投加比为40%、30%、20%、10%和0%的微型潜流湿地系统（分别命名为BW-40、BW-30、BW-20、BW-10和CW-K），探究生物炭投加对湿地污染物去除及N₂O排放的影响.结果表明，投加生物炭可以提高出水氧化还原电位（oxidation-reduction potential，ORP），降低电导率（conductivity，Cond），但影响均不显著（P>0.05）.5组湿地系统中化学需氧量（COD）去除率均达到90%，但随着生物炭投加比的增加，氨氮（NH₄⁺-N）和总氮（TN）的去除效果显著提高（P<0.05）.湿地NH₄⁺-N平均去除率为（34.76±14.16）%~（57.96±10.63）%，TN平均去除率为（70.92±5.68）%~（80.21±10.63）%.各湿地系统N₂O的平均释放通量在13.53~45.30 mg·（m²·d）^-1之间，生物炭投加可以通过减少亚硝态氮（NO₂^--N）累积浓度和积累时间，实现N₂O减排，并显著减少湿地中N₂O排放占TN去除的百分比（P<0.05）.40%的生物炭投加比可以实现70.13%的N₂O减排效果. 英文摘要 Biochar, pyrolyzed from agricultural biomass wastes, has been widely used as an improver in wastewater treatment to regulate the oxygen distributions and microbial communities because of its extended surface area and porous structure. In addition, biochar has been shown to play a role in enhancing the porosity, adsorbing ammonium (NH₄⁺-N), and reducing nitrous oxide (N₂O) emissions. In this paper, five groups of constructed microcosm wetlands (CW) were built in a greenhouse with different biochar doses of 40%, 30%, 20%, 10%, and 0% (named as BW-40, BW-30, BW-20, BW-10, and CW-K, respectively) to investigate the influences of biochar on pollutant removal efficiencies and N₂O emissions. The results showed that the concentration of effluent dissolved oxygen (DO) was less than 0.5 mg·L^-1, and the pH was stable at around 7.2 in every CW. Additionally, the effluent oxidation-reduction potential (ORP) was found to have moderately increased with the increases in the quantity of biochar, and the conductivity (Cond) test results showed the opposite trend. However, the effects of biochar on DO, pH, ORP, and Cond were not significant (P>0.05). The chemical oxygen demand (COD) removal rates were up to 90% in all CWs. On the other hand, significantly higher removal efficiencies for NH₄⁺-N and total nitrogen (TN) were found in CWs filled with biochar (P<0.05). The average NH₄⁺-N removal rates were (57.96±10.63)%, (51.12±11.74)%, (48.55±8.75)%, (43.95±9.74)%, and (34.76±14.16)% in BW-40, BW-30, BW-20, BW-10, and CW-K, respectively, while the total nitrogen (TN) average removal rates were (80.21±10.63)%, (78.48±5.73)%, (76.80±4.20)%, (75.88±5.85)%, and (70.92±5.68)%, respectively. Nitrate (NO₃^--N) was not detected in the CWs for there were sufficient carbon sources and suitable denitrification environments. Moreover, the average fluxes of N₂O ranged from 13.53 mg·(m²·d)^-1 to 45.30 mg·(m²·d)^-1 in the experimental systems. Compared with the control, the reduction rates of N₂O in the BW-40, BW30, BW20, and BW10 were 70.13%, 68.26%, 50.83%, and 37.90%, respectively, and the ratios of N₂O emissions to the removed nitrogen in CWs with biochar were significantly lower than those in the CW without biochar. Positive correlations were observed between the N₂O fluxes and nitrite (NO₂^--N) concentrations, and the lower N₂O emissions could be attributed to the higher oxygen transfer and lower NO₂^--N accumulation rates in response to the biochar addition. These results demonstrate that biochar could be used as an amendment to strengthen the nitrogen removal and reduce the N₂O emissions in CWs.

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