Predicting pollutant removal in constructed wetlands using artificial neural networks(ANNs)

Growth in urban population,urbanisation,and economic development has increased the demand for water,especially in water-scarce regions.Therefore,sustainable approaches to water management are needed to cope with the effects of the urbanisation on the water environment.This study aimed to design novel configurations of tidal-flow vertical subsurface flow constructed wetlands(VFCWs) for treating urban stormwater.A series of laboratory experiments were conducted with semi-synthetic influent stormwater to examine the effects of the design and operation variables on the performance of the VFCWs and to identify optimal design and operational strategies,as well as maintenance requirements.The results show that the VFCWs can significantly reduce pollutants in urban stormwater,and that pollutant removal was related to specific VFCW designs.Models based on the artificial neural network(ANN) method were built using inputs derived from data exploratory techniques,such as analysis of variance(ANOVA) and principal component analysis(PCA).It was found that PCA reduced the dimensionality of input variables obtained from different experimental design conditions.The results show a satisfactory generalisation for predicting nitrogen and phosphorus removal with fewer variable inputs,indicating that monitoring costs and time can be reduced.     

镁矿渣酸溶释出镁离子的特征及影响因素研究

为评估镁矿渣用于人工湿地填料回收磷的潜力,分析了镁矿渣酸溶释出镁离子的特征及影响因素。结果表明:当镁矿渣颗粒直径 <150 μm(100目)时,颗粒浓度为5 g/L时,随着浸出时间的延长,浸出液中镁离子浓度逐渐增加,浸提5 h后镁矿渣中镁离子达到浸出平衡,浸出量不再发生变化;浸出溶液中镁离子的浓度随着浸提液中盐酸浓度的降低而逐渐下降。当镁矿渣颗粒直径 <150 μm时,盐酸浓度为1 mol/L,浸出时间为5 h时,增大浸出液中镁矿渣浓度,镁离子的浸提效率反而降低。当浸提盐酸浓度为1 mol/L,浸出液中镁矿渣浓度为5 g/L时,镁离子的浸出量达到最大值,为117.70 mg/kg。通过对比浸出前后镁矿渣中镁形态发现,在最佳浸提条件下,浸出的镁几乎全部为酸可溶态(占比达92.00%)。浸提后镁矿渣粒径减小,比表面积增大,其矿物晶格受到破坏,对溶液中的磷吸附能力得到强化。理论上对污水中磷的去除能力可达810 mg/kg,是一种极具潜力的磷回收材料。     

三江平原水资源可持续利用与保护

介绍了三江平原的基本自然条件,论述了三江平原水资源利用的现状及存在的地下水超采、湿地萎缩等生态环境问题,针对若干问题提出了三江平原水资源合理开发的几点建议,以期促进三江平原水资源的可持续利用和保护。     

Towards (dis)continuity of agricultural wetlands: Latvia’s polder landscapes after Soviet productivism

The concepts of agricultural regimes in advanced economies, such as productivism or non/neo/post-productivism, have been critically debated over the last decades to understand the transition and diversity of modern agriculture. We explore these concepts to understand the environmentally vulnerable landscape of agricultural wetlands in Latvia that, during the era of Soviet high modernism (productivist agricultural regime), have been converted into polders as part of a mass drainage movement. Today, these post-Soviet agro-polders can be characterised as antipodes in relation to integrity of heritage, ecology and the socio-economics of agricultural concerns. Building on case studies, wider political contexts and current debates on agricultural transitions, the paper traces the transition of wetlands through agricultural regimes and unfolds the various pathways for current polder landscapes. This paper concludes with critical notes on the contemporary co-existence of different agro-polder use of which the most incoherent are the non-productivist actions producing landscapes of mere agricultural appearance.     

人工湿地在水质净化中的应用及研究进展

污染物在人工湿地中的去除机理包括了物理、化学及生物学过程,人工湿地能同时去除多种污染物质正源于其中的协同机制。影响人工湿地水质净化的主要因素包括:植物、碳源、基质、溶解氧和微生物。探讨了人工湿地对氮、磷和有机物的去除机理,同时论述了影响人工湿地去污的主要因素,并对今后的相关研究方向进行了展望。     

复合垂直流人工湿地去除混合有机化合物现场试验

以苯、1,4-二氯苯、硝基苯和邻苯二甲酸二丁酯(DBP)为目标有机化合物,开展人工湿地去除混合溶液中有机化合物的现场试验。结果表明,人工湿地系统对苯的平均去除率为88%左右,对1,4-二氯苯的平均去除率在92%左右,对硝基苯的平均去除率为46.85%~61.13%,对DBP的平均去除率为65.75%~80.96%。冲击负荷试验表明,在一次性高浓度进水条件下,页岩陶粒人工湿地能拦截90.4%的苯;砾石人工湿地能拦截83.3%的1,4-二氯苯;黄沙人工湿地对苯和1,4-二氯苯的拦截能力相当,拦截率分别为91.4%和90.0%,对硝基苯和DBP的拦截能力相当,拦截率分别为60.5%和61.3%。     

A/O—SBBR—氧化塘—人工湿地处理猪场沼液

针对猪场沼液氮磷浓度高、有机物含量大且可生化性差等特点,采用A/O—序批式生物膜反应器—氧化塘—人工湿地组合工艺对沼液进行深度处理。处理规模400 m~3/d,工程总投资117.5万,运行费用1.46元/(m~3·d)。运行结果表明,经过该组合工艺处理后COD_(Cr)、BOD_5、SS、NH_3-N、TP去除率分别为85.93%、79.84%、89.86%、94.78%、88.67%,出水指标均符合《畜禽养殖业污染物排放标准》(GB 18596—2001)要求。     

胛⑾讣际踅逃恐氐闶笛槭?上海交通大学

200030,上海200030磁悬浮;;微陀螺;;电容检测为了实现磁悬浮转子微陀螺的电容检测,使用数值积分方法计算了新型磁悬浮转子微陀螺的电容值与转子倾斜角度的关系。计算确定了电容极板尺寸,电容的连接采用了差动电容的连接方式。通过电容检测电路,检测到了小角度输入范围内的陀螺输出信号。检测结果表明:该电容结构对于静态角度输入具有较好的线性响应,该微陀螺原形的电容结构能够检测到的转子倾斜角度可达到0.1°,对应的电容变化约为1 000 aF,满足了微陀螺对电容检测的要求。Design of capacitance structure of micro gyroscope with electromagnetically levitated rotorHUANG Xiao-gang,LIU Wu,SHAO Shi-yi,CHEN Wen-yuan,ZHANG Wei     

复合垂直流人工湿地对氮的净化效果

采用复合垂直流人工湿地处理武汉东湖污染水的中试结果表明 ,出水中NH+ 4-N、NO- 2 -N和凯氏氮 (KN)浓度均显著降低 ,而NO- 3-N含量有所上升 ;系统最佳运行水力负荷为 80 0mm/d ,超过此负荷后系统净化效果随负荷增加而下降 ;在东湖现有的污染负荷下 ,处理系统仍呈现出继续承载污染量的潜力 ;就基质中KN的分布而言 ,水平方向为下行流池含量高于上行流池 ,垂直方向为上层 >中层 >下层 ,而在植物体内的分布则为叶片中含量最高。