北京地区不同湿地植物对生活污水的净化效果研究

选择北京地区芦苇、东方香蒲、水芹、睡菜和蒿柳5种湿地植物,设计6种不同的植物配置方式,研究不同湿地植物单种及其配置对水中pH值、化学需氧量(COD)、总氮(TN)和总磷(TP)的净化效果。通过连续6个月的动态监测,结果表明:湿地植物对污染物有明显的净化效果,且9月份前随着温度的升高和植物的生长逐步提高,9月份后净化效果上升趋势趋于缓和或下降。单种湿地植物中,东方香蒲对pH值净化效果最好,睡菜对COD净化效果最好,芦苇对TN净化效果最好,蒿柳对TP净化效果最好,东方香蒲、蒿柳对上述污染物的综合净化效果最好;从湿地植物单种和植物配置对污染物的净化效果比较来看,植物配置对pH值、TN的净化效果高于单种,而对COD和TP的净化效果低于单种,芦苇和睡菜适合与其他植物配置使用,而东方香蒲、蒿柳和水芹单种使用对污染物的综合净化效果高于与其他植物配置的效果。     

保护生态环境 拯救乌梁素海

乌梁素海位于巴彦淖尔盟乌拉特前旗境内,是1931年形成的黄河遗迹湖。水域面积44万亩,湖中生长着大片芦苇、香蒲和杂草,有47种浮游植物和19种浮游动物,是鸟类栖息繁殖的良好场所,也是候鸟迁徙间歇     

三娘湾滨海旅游对景区水环境的影响

通过对三娘湾风景区游客出入频繁区域海上水域环境因子pH值、PO4-P、NH4-N、NO2-N、NO3-N、COD、漂浮物质进行的调查与检测,探讨了滨海旅游(包括旅游设施及不同种类的旅游活动)对三娘湾水环境的影响。结果表明:研究区域内水环境中pH值、PO4-P、NH4-N、NO2-N、NO3-N、COD均没超过海水Ⅱ类标准,海上没有明显的漂浮物质、无异常色、臭、味。海域旅游环境尚处在安全范围之内。但是,通过营养指数计算表明,采样区域的5个点只有一个点没有达到富营养化,这说明滨海水域存在一定程度的富营养化,值得相关部门关注。     

哈尔滨市9种湿地植物在不同HRT下净污效果研究

选择慈姑、水葱、香蒲、小叶章、菖蒲、泽泻、芦苇、地榆、水莎草9种典型湿地植物,构建小型人工模拟湿地,分析在不同水力停留时间下湿地植物对城市生活污水的净化能力。研究结果表明,最佳的水力停留时间为5 d,植物对COD、TN和TP的平均去除率分别为:55.25%、81.80%、77.51%,均高于对照组;植物对COD的去除能力大小排序为:香蒲>菖蒲>水莎草>水葱>慈姑>小叶章>泽泻>地榆>芦苇;对TN去除能力大小为:香蒲>慈姑>菖蒲>小叶章>水莎草>水葱>泽泻>地榆>芦苇;对TP去除能力的大小依次为:香蒲>小叶章>慈姑>水葱>菖蒲>水莎草>泽泻>地榆>芦苇。综合分析表明,香蒲、菖蒲、水葱和慈姑的净污能力最强,可应用于人工湿地中。     

加州鲈鱼网箱养殖技术

加州鲈鱼是一种纯淡水的温水性鱼类,原产于北美洲的淡水水域,现已在我国推广养殖. 加州鲈鱼最适水温20℃-30℃,生存水温1℃-36℃.喜清新水质,尤喜在缓慢流动的清新水质中.正常生长要求pH值为6至8.5,每升水溶解氧在3毫克以上.     

滇西北高原主要湿地挺水植物净化氮、磷效应研究

实验选取滇西北高原湿地4种典型挺水植物,茭草、菖蒲、香蒲、水葱进行室内净化效率试验,通过对4种植物净化水体中的氮、磷等营养元素的比较研究,为云南省污染湖泊治理的人工湿地构建提供科学依据。在对茭草、菖蒲、香蒲、水葱四种挺水植物的室内净化效率试验研究中发现,茭草对TN的平均去除率为69.3%;TP平均去除率为75.2%;氨氮平均去除率为76.4%;正磷酸盐平均去除率为74.7%;COD平均去除率为69.4%。香蒲对TN的平均去除率为60.1%;TP的平均去除率为66.3%;氨氮平均去除率为69.8%;正磷酸盐平均去除率为64.3%;COD平均去除率为60.3%。菖蒲对TN的平均去除率为56.2%;TP平均去除率为61.7%;氨氮平均去除率为64.7%;正磷酸盐平均去除率为62.4%;COD平均去除率为57.9%。水葱对TN的平均去除率为51.9%;TP平均去除率为57.8%;氨氮平均去除率为60.7%;正磷酸盐平均去除率为57.4%;COD平均去除率为53.8%,表明4种挺水植物具有较好的对生活污水的净化效果,4种主要挺水植物中,茭草对氮、磷的总体净化效率最高、香蒲次之、菖蒲第3、水葱第4。运用湿地植物净化水体中的氮、磷是一项既能处理污染,又能保护环境、美化环境的生态工程,人工湿地构建中植物选择是基础,研究为我国高原污染湖泊湿地的治理、修复、重建以及保护利用提供了科学依据。     

黄鳝养殖技术

一、鳝生活习性黄鳝栖息于河沟、湖泊、水田等浅水域里,白天潜居洞穴中,晚上出来觅食。当水温至10℃以上时,开始活动觅食。生长适温为15至28℃,最适温度为23至28℃,28℃以上时摄食能力减弱。黄鳝的繁殖季节在5至9月份,最盛期在6至7月份。一般体长20厘米左右即达性成熟。成熟亲鱼有     

Water quality of Kaptai reservoir in Chittagong Hill Tracts of Bangladesh

A study was conducted in Kaptai reservoir, one of the largest man-made freshwater lakes of South-east Asia, to determine present status of water quality and its suitability for fishing and other uses. Water samplings were from middle part of the reservoir at 0.2 and 0.8 fractional depths at five different locations from upstream to downstream viz. Burburichara, Maichchari, Subolong, Basanthakum, and Rangamati. Water analyses show that concentrations of NO3-N, K+ and total P, and suspended solid at all the sampling stations were beyond the recommended values for fish culture. Concentrations of Na+, Ca2+, Mg2+, SO42-, Cl-, total dissolved solid (TDS), dissolved oxygen (DO) and chemical oxygen demand (COD) were within the standards for aquaculture. Concentrations of NO3-N, SO42-, K+ and total P showed no definite trend with depths, locations as well as rainy and dry seasons. Water pH, conductivity, Na+ and HCO3- contents were lower in rainy season, and DO and COD higher at almost all the locations in both the depths, compared with dry season. Total solids and concentrations of TDS, DO, COD, Ca2+, Mg2+ and Na+ were higher in upstream and decreased gradually towards downstream in the reservoir. Concentrations of DO and Ca2+ and pH were higher and Mg2+ less at 0.2-fractional depth than those at 0.8-fractional depth at almost all the locations. The reservoir is in mesotrophic condition containing high concentration of NO3-N and total P, in alarming status with the presence of excessive suspended solids from urban pollution around the town. It is necessary to adopt measures for protecting water quality in the reservoir due to such deteriorations.     

兴丰垃圾填埋场渗滤液中pH值、COD和BOD5的变化特征

通过对2005～2011年兴丰垃圾填埋场渗滤液中pH值、COD和BOD5浓度变化分析,结果表明:广州兴丰生活垃圾填埋场已提前进入"老龄化"阶段,自2009年以来渗滤液中pH值稳定在7.73～8.24之间,且有增大的趋势;COD和BOD5均有大幅度下降,但仍保持较高值,两者间有明显的相关性;BOD5/COD的值介于0.48～0.19之间,可生化性差。     

西宁市地表水水质状况研究

于2010～2011年在西宁市主要地表水体设12个断面,对10项水质指标进行了监测和分析。结果表明:氨氮和总硬度严重超标,远高于GB3838-2002《地表水环境质量标准》中Ⅲ类标准;铁、化学需氧量(COD)、挥发酚、总氯、电导率、六价铬、pH值符合GB3838-2002《地表水环境质量标准》中Ⅲ类标准浓度限值;个别断面平水期、枯水期的溶解氧(DO)浓度略低于GB3838-2002《地表水环境质量标准》中Ⅲ类标准浓度限值。     

地表水水生生物指标与水质理化指标相关性研究

本文应用逐步回归分析方法，对岷江水系1993--1999年地表水的水生生物与水质理化同步监测数据进行相关性分析，结果表明，水生生物监测指标与水质理化监测指标之间存在明显的相关性。其中，紫露草平均微核率主要与水质指标中的COD、pH值两个指标相关，不同于污染水体；大型蚤24h死亡率主要与水质指标中的酚、Cr^6 、As^2 |三个指标相关。获得的回归方程具有较好的预测效果。     

水量均衡原理在扎龙湿地生态需水量评价中的应用

湿地的敏感因子——水,已成为扎龙湿地生态环境恶化的最主要因素。通过查阅资料,了解了国内外生态环境需水量的研究进展,采用水量均衡原理,利用系列资料数据计算得出天然状态下扎龙湿地水资源平衡量和受控状态下扎龙湿地的蓄水量,比对分析后得出扎龙湿地的最小生态需水量。建议扎龙湿地应确定合理的补水方式和补水时间,同时提出了今后进一步的研究方向和重点。     

Modelling water absorption in wood

Abstract

A fibre-level model for the longitudinal absorption of liquid water in wood has been developed. The model is primarily intended for simulation of absorption in softwoods. Capillary suction is based on the lumen radius, which is a stochastic parameter. The average lumen volume (and thus radius) is assumed to vary linearly across the annual ring and thus account for the difference in earlywood/latewood. The number of open bordered pits between fibres is also a stochastic parameter. The water flow rate is determined by the capillary suction and the flow resistance between fibres, i.e. the number of unaspirated bordered pits between fibres. The resulting pressure field in the liquid phase is calculated and the calculation has to be updated each time a new fibre has been filled with water. In this way the absorption is determined in a stepwise manner. Some general results are presented and the results resemble those obtained in experiments. It is shown that the model can predict features that a pure diffusion-based model cannot predict. Finally, the model is used for the simulation of an experiment that showed some unexpected results and the model gives a reasonable explanation.     

循环冷却水中微生物的处理

工业循环水是水资源的重复利用,但由于在循环过程中产生的微生物易使管道腐蚀、堵塞,因此循环冷却水应处理。本文介绍了几种防止微生物产生的方法和处理方法。     

Assessing water use and soil water balance of planted native tree species under strong water limitations in Northern Chile

Some forest plantations with native species are established in semiarid central Chile to compensate for industrial activities such as those of mining. Two of those operational forest plantations were monitored from age 1 to 3 years-old (2014–2016). Some plant attributes and soil volumetric water content (VWC) were monitored for eight native tree species (Acacia caven, Schinus polygamus, Porlieria chilensis, Lithraea caustica, Quillaja saponaria, Cryptocarya alba, Drimys winteri and Maytenus boaria), and a water balance model fitted to assess plant water use. Site preparation comprised planting holes of 40 cm?×?40 cm by 50 cm in depth dug with a backhoe. Substrate was removed and mixed with compost in proportion 70:30 before mixing it in the planting hole. Planting holes acted as water reservoirs over the study period with soil VWC generally increasing with soil depth being also less variable deeper than in the upper soil layers. The ratio of adaxial (upper leaf side) to abaxial (lower leaf side) stomatal conductance approximately followed a species gradient from xeric to mesic. Irrigation represented about 26% and 53% of the total water input for the sclerophyll and the D. winteri plantation, respectively. At the plant level (0.4?×?0.4 m), soil evaporation and transpiration of D. winteri (273 and 232 mm year^?1, equivalent to 43.7 and 37.1 L plant^?1, respectively) were about twofold the values for the sclerophyllous/malacophyllous plantation (138 and 128 mm year^?1, 22.1 and 20.5 L plant^?1, respectively). We suggest the water budget for the sclerophyll/malacophyllous plantation was tight but feasible to be adjusted while for D. winteri irrigation was excessive, could be drastically reduced, and suppressed altogether if planted in gullies. We believe water balance models and soil moisture content sensors could be used to better plan and manage irrigation frequency and amounts in compensation forest plantations in semiarid central Chile.     

Growth, leaf morphology, water use and tissue water relations of Eucalyptus globulus clones in response to water deficit

Changes in leaf size, specific leaf area (SLA), transpiration and tissue water relations were studied in leaves of rooted cuttings of selected clones of Eucalyptus globulus Labill. subjected to well-watered or drought conditions in a greenhouse. Significant differences between clones were found in leaf expansion and transpiration. There was a significant clone x treatment interaction on SLA. Water stress significantly reduced osmotic potential at the turgor loss point (Pi0) and at full turgor (Pi100), and significantly increased relative water content at the turgor loss point and maximum bulk elastic modulus. Differences in tissue water relations between clones were significant only in the mild drought treatment. Among clones in the drought treatments, the highest leaf expansion and the highest increase in transpiration during the experiment were measured in those clones that showed an early and large decrease in Pi0 and Pi100.     

保土于山藏水于山--浅论治山治水方略

水灾是中国的心腹大患。治水是安邦兴国的大事，是使环境能与经济社会协调发展的大事。关于治水方法有以工程措施为主，以生物措施为主之争。治水之最高境界应该是以生物措施为主，以工程措施和农业耕作措施为辅，但农业耕作措施不能少。     

Diffusion of bound water in wood

Summary Fick's law states that during steady-state diffusion, moisture flux is proportional to the gradient in moisture concentration, making concentration gradient the driving force for diffusion. Although Fick's law permits convenient comparisons between predicted and measured moisture contents, fundamental and experimental difficulties with it have been reported. In this paper, the dependence of spreading pressure on vapor pressure and temperature is developed. This information is used to show that gradients in spreading pressure and chemical potential are not proportional. Spreading pressure gradient is considered the correct driving force because the associated transport law can be derived from first principles.The author wishes to thank Dr. Christen Skaar for his interest and advice during preparation of this paper for publication     

Diffusion of bound water in wood

Summary Choong's (1963) data for isothermal sorption of water vapor by wood are used to compute pressures, chemical potentials, and entropies of water in the wood specimens of his nonisothermal mass equilibrium experiments. Entropies of both the bound water and water vapor were reasonably constant. A balance existed between thermal diffusion and mass diffusion, as indicated by gradients in temperature and chemical potential. This balance also is suggested by opposing gradients in spreading pressure and vapor pressure. Equal chemical potentials showed that the vapor and bound water were in equilibrium. The model proposed by Siau (1980) for nonisothermal diffusion is consistent with these results. Expressions are given for the two unknown parameters in this model: moisture conductivity and heat of transfer. The constant entropy of water vapor is used to show that the heat of transfer exceeds the activation energy for bound water diffusion by about 25 percent.The author wishes to thank Dr. Christen Skaar for his helpful comments during preparation of this paper for publication     

井点降水在深水承台施工中的应用

文章结合哈尔滨松花江公路大桥8#主墩台基坑井点降水施工的过程，阐述了井点降水在深水承台施工中应用的要点及其优越性。