Treating wastewater under zero waste principle using wetland mesocosms

• Smart wetland was designed to treat wastewater according to zero waste principle. • The system included a dynamic roughing filter, Cyperus papyrus (L.) and zeolite. • It removed 98.8 and 99.8% of chemical and bacterial pollutants in 3 days. • The effluent reused to irrigate a landscape and the sludge recycled as fertilizer. • The plant biomass is a profitable resource for antibacterial and antioxidants. The present investigation demonstrates the synergistic action of using a sedimentation unit together with Cyperus papyrus (L.) wetland enriched with zeolite mineral in one-year round experiment for treating wastewater. The system was designed to support a horizontal surface flow pattern and showed satisfactory removal efficiencies for both physicochemical and bacteriological contaminants within 3 days of residence time. The removal efficiencies ranged between 76.3% and 98.8% for total suspended solids, turbidity, iron, biological oxygen demand, and ammonia. The bacterial indicators (total and fecal coliforms, as well as fecal streptococci) and the potential pathogens (Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa) showed removal efficiencies ranged between 96.9% and 99.8%. We expect the system to offer a smart management for every component according to zero waste principle. The treated effluent was reused to irrigate the landscape of pilot area, and the excess sludge was recycled as fertilizer and soil conditioner. The zeolite mineral did not require regeneration for almost 36 weeks of operation, and enhanced the density of shoots (14.11%) and the height of shoots (15.88%). The harvested plant biomass could be a profitable resource for potent antibacterial and antioxidant bioactive compounds. This could certainly offset part of the operation and maintenance costs and optimize the system implementation feasibility. Although the experiment was designed under local conditions, its results could provide insights to upgrade and optimize the performance of other analogous large-scale constructed wetlands.     

城市污水厂二级处理出水深度处理组合工艺研究

为了研究臭氧-曝气生物滤池二级处理出水深度处理组合工艺的处理效果,采用臭氧-曝气生物滤池(biological aerated filter, BAF)组合工艺对城市污水处理厂二级生化处理出水进行深度处理。结果表明,组合工艺对造成水中色度的主要物质腐植酸和富里酸类有机物和嗅味物质中的二甲基三硫和二甲基异莰醇(MIB)能够进行有效去除。臭氧氧化能够显著提高后续BAF单元对COD_Mn的去除。在进水COD_Mn6~8 mg/L、色度为25~30度、浊度约为8 NTU的条件下,当臭氧投加量为5~6 mg/L、BAF的水力停留时间为1~1.5 h时,出水COD_Mn< 5 mg/L、色度<5度、浊度<1 NTU,出水水质可满足生产工艺对回用水的水质要求。     

粉状活性焦在双层滤料颗粒床中的脱硫试验研究

在双层滤料颗粒床模型试验台上对粒径为300～400目的粉状活性焦进行了脱硫试验,研究了温度、O2和水蒸气体积分数、气体流速、再生次数对脱硫效果的影响.试验结果表明.温度为120℃、O2体积分数为8%、水蒸气体积分数为10%条件下,脱硫效果最好;粉状活性焦在双层滤料颗粒床中经过7次重复吸附.达到硫饱和吸附量为66.2 mg/g.粉状活性焦再生试验表明,随着再生次数的增加.粉状活性焦的脱硫性能呈下降趋势.     

高温烟气除尘滤料过滤性能检测及对比分析

对3大类不同过滤方式的高温烟气除尘滤料的压力损失、过滤速度、分级效率等性能指标进行测试对比分析,得到滤料在清洁和集尘条件下压力损失随过滤时间、粉尘负荷的变化规律.从过滤机理综合分析,集尘滤料的过滤分级效率明显高于清洁滤料过滤效率,为滤料选用提供理论依据.     

空气过滤技术研究综述

文章分别从空气过滤材料、空气过滤器、空气过滤理论及空气过滤技术的应用等四个方面,对空气过滤技术进行了详细阐述.总结了空气过滤材料、空气过滤器的分类及研究进展、空气过滤器的过滤机理及过滤理论的发展.介绍了空气过滤技术的主要应用,并指出了空气过滤技术的发展动向和市场趋势.     

生物接触氧化-滴滤工艺处理水产养殖废水的效能研究

为了高效处理水产养殖废水,采用了生物接触氧化-滴滤(以陶粒为滤料)组合工艺,并对该组合工艺的处理效果进行考察。以生物接触氧化池中组合填料的密度、停留时间以及滴滤的水力负荷作为研究对象,通过对CODMn、氨氮、TN等参数的分析,得到了该组合工艺的处理效果。研究表明:当工艺中组合填料密度(组合填料与废水的体积比)为9.24%,生物接触氧化水力停留时间为0.85 h,滴滤的水力负荷为27.2 m3/(m2·d)时,CODMn、氨氮、TN、TP的去除率可分别高达55.31%、34.31%、57.64%和20.25%。证明采用该组合工艺净化水产养殖废水具有可行性。     

Comparative study of microbial community structure in di erent filter media of constructed wetland

Comparisons of microbial community structure, in eight filter media of zeolites, anthracite, shale, vermiculite, ceramic filter media, gravel, steel slag and bio-ceramic, were undertaken by analyzing the phospholipid fatty acid (PLFA) composition. A total of 20 fatty acids in the range of C11 to C20 were determined but only 13 PLFAs were detected in steel slag. They consist of saturated fatty acids, branched fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. The variation of fatty acids was revealed in the relative proportions of these fatty acids in di erent media. The aerobic prokaryotes were the predominant group in all media. The PLFA composition showed significant di erences among the eight di erent media by Tukey’s honestly test. It was found that steel slag was significantly di erent in the microbial community as compared to other filter media, probably due to its alkaline e uent. Steel slag alone is probably not a good choice of substratum in constructed wetlands. The principle components analysis (PCA) showed that zeolites, bio-ceramic, shale and vermiculite had a similar microbial community structure while steel slag and ceramic filter media were distinct from other media.     

生物滴滤塔装置脱硝效率优化改进实验

针对生物滴滤塔系统脱硝效率偏低的问题,在原实验室装置基础上,对滴滤塔系统进行改进,并模拟燃煤烟气的特性,考察了重金属离子、氧气含量以及强化剂对净化效果的影响,并探究了生物滴滤塔系统对锅炉非稳定运行工况的适应性。结果显示:烟气内的重金属离子对微生物具有较强的抑制作用,其中As离子和Pb离子对体系微生物组成的毒性影响最大,Zn离子的影响最小;氧气含量对脱硝效率影响的研究结果表明,系统含氧量越低,脱硝效率降低幅度越大;强化剂组合结果表明,亚硝酸钠+Fe(II)EDTA的组合,强化效果最为明显;生物滴滤塔脱硝系统对锅炉非稳定运行工况适应能力较差,系统停运再启动,停运1周之内,系统经过10 d可以恢复至原来的性能,如果停运12 d以上,系统恢复则长达30 d。根据研究结果,为中试研究提出优化及研究方向建议。     

AF+BAF深度处理PCB生产废水的试验研究

针对PCB废水难降解及含重金属铜的特点,在经过一系列的物化处理的基础上,采用AF+BAF组合工艺对其进行深度处理。试验研究中,通过控制污水在反应器中的停留时间,使得废水在AF中水解酸化,以增加废水的可生化性,在此基础上利用BAF的生物膜来去除污水中剩余的有机物。试验结果表明,试验系统对PCB废水中的COD、Cu2+去除效果良好,出水COD、Cu2+的含量分别稳定在10~50mg/L和0.02~0.1mg/L,达到排放标准。     

滤料粒径对BAF小尺度下流场形态及挂膜速度的影响

为探讨颗粒粒径对曝气生物滤池(BAF)运行效果的影响,采用数值模拟和实验研究方法分析了滤料粒径对曝气生物滤池流场形态及挂膜速度的作用机理.选用5个颗粒尺寸结构空间作为计算区域,利用Fluent软件对相同颗粒间隙、不同颗粒粒径下BAF小尺度下的流场形态进行模拟分析,并通过对3种粒径下流线图、速度矢量图、压力分布及湍流强度变化的对比分析,发现颗粒粒径为3 mm时流场形态最好,最有利于气水混合及氧传质的进行.同时,为验证模拟结果的正确性,对同种材质、相同运行条件下3种不同颗粒粒径进行挂膜速度对比,通过考察挂膜启动28 d的COD去除率变化及污泥生物量的对比分析,发现颗粒粒径为3 mm时,运行最为稳定,系统运行第16 d时就达到了80%的COD去除效率.