摘要
地下渗滤系统(subsurface wastewater infiltration system,SWIS)是一种生态化的污水处理技术模式,在处理小水量、分散污水方面具有较为明显的技术优势,例如管理简单、运行费用低、兼具生态服务功能等。SWIS对污水中氮的去除主要依靠微生物硝化-反硝化作用,脱氮效果受内外部条件因子制约。当基质层内部溶解氧含量不足、NO_2^-积累、氧化亚氮还原酶活性受到抑制时,硝化和反硝化过程均可释放N_2O气体。进水水质、操作条件、温度等因素影响N_2O释放量和转化率。利用原位实验平台,采用静态箱-气相色谱分析方法,以实际生活污水为研究对象,分析了进水氮负荷波动条件下SWIS中N_2O产率、转化率和释放周期的变化规律。研究表明,进水氮负荷显著影响SWIS除污效率、N_2O产率和转化率。随着进水氮负荷由1.6 g·m^(-2)·d^(-1)增至7.2 g·m^(-2)·d^(-1),出水COD、NH_4^+-N、TN质量浓度分别由(9±3)、(0.4±0.1)、(1.5±0.11)mg·L^(-1)升高到(70±7)、(11.0±1.0)、(15.4±0.4)mg·L^(-1);N_2O产率与转化率表现出先升高后降低的趋势,其中,N_2O产率可高达(60.6±2.0)mg·m^(-2)·d^(-1),同时,进水总氮(转化率1.33%±0.03%)转化成N_2O逸出系统;随着系统落干时间的延长,N_2O产率呈下降趋势。综合考虑处理能力、出水水质和N_2O释放量,建议在工程应用中,选用具有一定脱氮能力的前处理工艺,控制SWIS进水氮负荷在4.0~5.6g·m^(-2)·d^(-1)之间,且适当延长SWIS干化周期。此时,出水水质满足城市景观地表水水质标准(GB/T18921—2002),N_2O产率和转化率均维持在较低水平。
Subsurface wastewater infiltration system（SWIS）is considered to be an ecological system for domestic sewage treatment.SWIS has advantages in treating small scale and decentralized wastewater,such as simple management,low operation cost as well as ecological service function.Nitrogen is mainly removed through nitrification followed by denitrification process,being affected by internal and external factors.Insufficient dissolved oxygen concentration,NO_2--accumulation and restricted nitrous oxide reductase activity would encourage N_2O emission from SWIS.Influent quality,operation method and temperature are dominant factors deciding N_2O production and conversion rate.Based on a field experiment,this study focused on the influence of variable nitrogen loading on N_2O production,conversion rate and release cycle.The results suggested that nitrogen loads had significant effect on pollutants removal,N_2O production and conversion rate.With the increase of nitrogen loads from N 1.6 g·m-（-2）·d-（-1） to N 7.2 g·m-（-2）·d-（-1）,effluent concentration for COD,NH_4-＋-N and TN increased from（9±3）,（0.4±0.1） and（1.5±0.11） mg·L-（-1） to（70±7）,（11.0±1.0） and（15.4±0.4） mg·L-（-1）,respectively.The production and conversion rate of N_2O increased first followed by a decrease.The production rate was achieved as high as（60.6±2.0） mg·m-（-2）·d-（-1）,and up to（1.33%±0.03%） of influent nitrogen was converted to N_2O.Taking into consideration of removal efficiency,effluent quality and N_2O release quantity,a pre-treatment process with reliable nitrogen removal ability was highly recommended.The optimal nitrogen loading was recommended with ranges of N 4.0 and N 5.6 g·m-（-2）·d-（-1）,and long drying period would be encouraged.In this case,effluent quality met the surface water quality standard of urban landscape（GB/T18921—2002）.Meanwhile,production and conversion rate of N_2O maintained at low levels.
出处
《生态环境学报》
CSCD
北大核心
2016年第12期1999-2004,共6页
Ecology and Environmental Sciences
基金
国家自然科学基金项目(41571455
51578115)
中央高校基本科研业务费项目(N140105003)
关键词
地下渗滤
生活污水
氮负荷
N_2O
释放
subsurface wastewater infiltration system
domestic wastewater
nitrogen loading
N_2O
release
