The role of microbial electrogenesis in regulating methane and nitrous oxide emissions from constructed wetland-microbial fuel cell

This study assesses a sustainable solution to greenhouse gases (GHGs) mitigation using constructed wetland-microbial fuel cells (CW-MFC). Roots of wetland plant Acorus Calamus L. are placed in biological anode to better enable anode microorganisms to obtain rhizosphere secretion for power improvement. Three selected cathode materials have a large difference in GHG emissions, and among them, carbon fiber felt (CFF) shows the lowest emissions of methane and nitrous oxide, which are 0.77 ± 0.04 mg/(m²·h) and 130.78 ± 13.08 μg/(m²·h), respectively. The CFF CW-MFC achieves the maximum power density of 2.99 W/m³. As the influent pH value is adjusted from acidic to alkaline, the GHGs emissions are reduced. The addition of Ni inhibits GHGs emission but decreases the electricity, the power density is reduced to 1.09 W/m³, and the methane and nitrous oxide emission fluxes decline to 0.20 ± 0.04 mg/(m²·h) and 15.49 ± 1.86 μg/(m²·h), respectively. Low C/N ratio reduces methane emission, while high C/N ratio effectively inhibits nitrous oxide emission. At the influent pH 8 and C/N = 5:1, the methane emission flux is approximately 10.60 ± 0.27 mg/(m²·h), and the nitrous oxide emission flux is only 10.90 ± 1.10 μg/(m²·h). Based on the above experimental results by controlling variable factors, it is proposed that CW-MFC offers an environment-friendly solution to regulate GHG emissions.     

Design Methodology and Area Sensitivity Analysis of Horizontal Subsurface Flow Constructed Wetlands

An approach is presented to satisfy the demand for simple criteria, guidelines and models for the preliminary sizing of horizontal subsurface flow (SF) constructed wetland systems. This approach eliminates time-consuming calculations and iterations by providing graphical solutions for wetland system sizing. Therefore, it can be used for the preliminary assessment of new or performance evaluation of existing subsurface flow constructed wetland systems. The validity of this methodology is checked with data from existing systems and is found to be quite satisfactory. This methodology is combined with simple equations predicting the maximum wetland capacity in summer, so as to assist designers in sizing installations in tourist areas with increased summer populations. Furthermore, based on this methodology, a sensitivity analysis is performed of the area requirements for wastewaters of various strengths and various design conditions and performance criteria. The results provide a useful overview to engineers and further simplify the design methodology of new subsurface flow constructed wetland systems.     

基于ANSYS有限元分析深水墩施工技术研究

介绍了丹江口二桥深水墩基础施工平台的设计，重点介绍利用ANSYS通用有限元程序对施工平台的施工过模拟分析，以及对分析结果的总结。     

Geospatial technology applied to spatiotemporal assessment of Harike Wetland,Punjab

The Harike Wetland situated in Punjab is a Ramsar site and a wetland of national importance. The present study was undertaken to assess the spatiotemporal dynamics of the wetland on the basis of geospatial technology and ground‐based studies. Landsat images for the years 2002 and 2014 were acquired from the United States Geological Survey and classified digitally to generate landuse/land cover maps involving four classes (water, grassland (including water hyacinth), agriculture, built‐up (settlement), barren land). The total area of the Harike Wetland was found to be 8023.68 ha. Water sampling at eleven sites was carried out and evaluated for physicochemical parameters. The water quality at several sampling points was found to be severely degraded. Change detection analysis revealed the submerged area (area under water) and grassland (including water hyacinth) had decreased over the past 12 years, whereas that area under agriculture and built‐up land has increased, indicating a shrinkage in the total wetland area. The present study also indicated that the near‐infrared band is a good indicator of water quality parameters, as indicated by the significant positive correlation between the near‐infrared band and relevant water parameters. Because the wetland is important from both an ecological perspective and economic perspective, regular monitoring is recommended, for which geospatial technology has proven to be very useful.     

重金属在宽叶香蒲人工湿地系统中的分布与积累

本文通过对广东韶关凡口宽叶香蒲（Typha latifolia)人工湿地系统的进出水口，土壤剖面及四种优势植物体各部分器官中Pb,Zn,Cu和Cd含量进行分析。结果表明；重金属主要库存于土壤中。从水平上看，全量的重金属含量从进水口到出水口呈上升趋势，而有效态则相反；从土壤剖面的垂直分布上看，全量和有效态重金属含量都随土壤深度的增加而递减，四种植物都具有较强的吸收和富集重金属的能力，且主要富集在植物的地下部分。     

山东南四湖湿地生物多样性及保护措施

南四湖湿地由湖泊、沼泽湿地和人工湿地构成,生物多样性十分丰富。其湿地生态系统具有生境脆弱性、物种多样性、生物稀有性、生态自然性等特点,是我国华北平原最大的具有良好湿地植被的天然湿地生态系统,同时也是众多候鸟的越冬地、繁殖区及迁徙必经的中转站。分析了湿地生物多样性现状及保护中存在的主要问题,提出了相应的湿地保护措施。     

大庆及周边地区湿地萎缩及地下水现状分析

大庆及周边地区的湿地主要分布在齐齐哈尔市区、大庆市区、杜蒙县、肇源县、肇东市、安达市等,现呈逐年萎缩的趋势,其中有其自然因素和人为因素的影响。仅2005~2007年就有5.96×104hm2湿地退化,并且湿地内的地下水也呈现出相应的变化。论述了大庆及周边地区湿地的萎缩情况,并且以3个典型湿地为例进行了湿地内地下水现状分析。     

基于多季相Sentinel-2影像的白洋淀湿地信息提取

白洋淀湿地是华北平原上重要的浅水湖泊湿地,对雄安新区绿色发展具有重要的生态价值。对白洋淀高度异质化的景观格局进行分类,能够为白洋淀湿地资源的遥感监测提供指导意义。针对湿地季节变化的特点,对白洋淀每个季节选取一期具有代表性的Sentinel-2影像,采用分类与回归树（CART）、支持向量机（SVM）、随机森林（RF）3种常用的机器学习分类器对15种季相组合实验方案进行分类,分析不同季相遥感影像及其组合对白洋淀湿地信息提取的优劣。结果表明：相较于使用单一季相影像分类,多季相影像的组合能够显著提高分类精度,春&夏季相组合能够得到最优的分类效果,相对单季影像总体分类精度提高了10.9%~25.5%,Kappa系数提高了0.09~0.29;SVM分类器的分类表现较为稳定,能够得到最高的平均分类精度,CART分类器在处理高维特征的能力不如随机森林和SVM;不同特征类型对湿地信息提取的贡献度从高到底依次是红边光谱特征、传统光谱特征、缨帽变换特征、主成分分析特征、纹理特征。实验成果能为湿地信息的遥感识别提供依据。     

跌水式人工湿地处理溢流雨污水的效能

为改善汉江水电站库区水质,考察了跌水式人工湿地应用于合流制排水系统雨季溢流污染的治理情况,以维护附近生态环境平衡.通过与普通湿地的比较,发现3级跌水式湿地对COD、氨氮、总氮及总磷的去除率均高于普通湿地,分别高13.1%、7.9%、6.1%和6.0%.跌水型湿地具有较好的溶解氧梯度,而普通湿地末端容易形成厌氧环境.Biolog微平板试验的结果表明,跌水型湿地中的微生物对糖类及其衍生物、氨基酸及其衍生物、脂肪酸及脂类、代谢中间产物及次生代谢物的利用程度更高.PCR-DGGE分子图谱技术分析表明,跌水型湿地的微生物种群普遍比普通湿地的微生物群落结构组成丰富,且特有的功能微生物与污染物去除相关.     

湿地水质监测技术与方法

湿地是水陆相互作用形成的特殊自然综合体.具有巨大的水文和元素循环功能,是生物多样性的“基因库”.但由于人类活动和自然因素,使其受到不同程度的污染,特别是水质污染令人担忧.文章对湿地水质监测技术、因子及方法,作了介绍.