Patil Sagar, Chakraborty Saswati
a Department of Civil Engineering , Indian Institute of Technology Guwahati , Assam , India.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2017 Mar 21;52(4):403-412. doi: 10.1080/10934529.2016.1262608. Epub 2016 Dec 14.
The effect of step feed strategy and intermittent aeration on removal of chemical oxygen demand (COD) and nitrogen was investigated in a laboratory scale horizontal subsurface flow constructed wetland (HSSFCW). Wetland was divided into four zones along the length (zone I to IV), and influent was introduced into first and third zones by step feeding. Continuous study was carried out in four phases. In phases I to III, 30% of influent was bypassed to zone III for denitrification along with organics removal. Intermittent aeration was provided only in zone II at 2.5 L/min for 4 h/day, during phases II, III and IV. In phase I, 87% COD and 43% NH-N (ammonia-nitrogen) removal were obtained from influents of 331 and 30 mg/L, respectively. In phase II study, external aeration resulted in 97% COD and 71% NH-N removal in the wetland. In phase IV, 40% of feed was delivered to zone III. Higher supply of organic in zone III resulted in higher denitrification, and total nitrogen removal rate increased to 70% from 56%. In the final effluent, concentration of NO-N was 9-11 mg/L in phase I to III and decreased to 4 mg/L in phase IV. Batch study showed that COD and NH-N removal followed first order kinetics in different zones of wetland.
在实验室规模的水平潜流人工湿地（HSSFCW）中，研究了分段进水策略和间歇曝气对化学需氧量（COD）和氮去除的影响。湿地沿长度方向分为四个区（I区至IV区），进水通过分段进水引入到第一区和第三区。连续研究分四个阶段进行。在第一阶段至第三阶段，30%的进水被旁路到第三区进行反硝化，同时去除有机物。在第二阶段、第三阶段和第四阶段，仅在II区提供间歇曝气，曝气流量为2.5 L/min，每天曝气4小时。在第一阶段，进水COD浓度为331 mg/L，NH-N（氨氮）浓度为30 mg/L时，COD去除率为87%，NH-N去除率为43%。在第二阶段研究中，外部曝气使湿地中COD去除率达到97%，NH-N去除率达到71%。在第四阶段，40%的进水输送到第三区。第三区较高的有机负荷供应导致了更高的反硝化效果，总氮去除率从56%提高到70%。在最终出水中，第一阶段至第三阶段的NO-N浓度为9-11 mg/L，第四阶段降至4 mg/L。批次研究表明，湿地不同区域的COD和NH-N去除遵循一级动力学。
