Simulation and control strategy for the variational influent of WWTP

With the development of activated sludge model, the simulation software for the design and operation of wastewater treatment plant （WWTP） was produced and has been widely used. The dynamic change of the quality and flow of influent are major factors causing the unstable operation of wastewater treatment process. As a basic model, ASMI model was used for the simulation of activated sludge process, and double exponential model was selected for the simulation of secondary sedimentation tank. The influences of influent change to the aeration tank and secondary sedimentation tank were investigated, and the relationship among influent change, the quality of effluent and the level of sludge blanket in secondary sedimentation tank was established. On the basis of the simulation results, the operation of the WWTP could be adjusted under the dynamic change of the influent. Furthermore, the controlling strategy combined the feed-forward on the influent flow and the feedback on the level of sludge blanket in the secondary sedimentation tank was studied.     

Precision Measurements from Very-Large Scale Aerial Digital Imagery

Managers need measurements and resource managers need the length/width of a variety of items including that of animals, logs, streams, plant canopies, man-made objects, riparian habitat, vegetation patches and other things important in resource monitoring and land inspection. These types of measurements can now be easily and accurately obtained from very large scale aerial (VLSA) imagery having spatial resolutions as fine as 1 millimeter per pixel by using the three new software programs described here. VLSA images have small fields of view and are used for intermittent sampling across extensive landscapes. Pixel-coverage among images is influenced by small changes in airplane altitude above ground level (AGL) and orientation relative to the ground, as well as by changes in topography. These factors affect the object-to-camera distance used for image-resolution calculations. ‘ImageMeasurement’ offers a user-friendly interface for accounting for pixel-coverage variation among images by utilizing a database. ‘LaserLOG’ records and displays airplane altitude AGL measured from a high frequency laser rangefinder, and displays the vertical velocity. ‘Merge’ sorts through large amounts of data generated by LaserLOG and matches precise airplane altitudes with camera trigger times for input to the ImageMeasurement database. We discuss application of these tools, including error estimates. We found measurements from aerial images (collection resolution: 5–26 mm/pixel as projected on the ground) using ImageMeasurement, LaserLOG, and Merge, were accurate to centimeters with an error less than 10%. We recommend these software packages as a means for expanding the utility of aerial image data.     

治理滇池草海水环境的成套技术

草海是滇池的一部分,大量污水排入使草海水体污染日益严重,水体已达重富营养化水平,生态平衡遭受严重破坏,水功能基本丧失。为了保护滇池,必须彻底根治草海,对草海的根治拟采取如下综合成套技术:①改造城市排水系统;②对重点工业废水中的有毒有害污染物进行治理;③城市面源治理;④草海底泥疏挖;⑤污染物现场清除技术;⑥大型水生植物恢复技术;⑦水资源的合理调整。制定了草海及滇池治理的三期规划,实施总投资约３０亿人民币。      

The influence on the radioxenon background during the temporary suspension of operations of three major medical isotope production facilities in the Northern Hemisphere and during the start-up of another facility in the Southern Hemisphere

Medical isotope production facilities (MIPF) have recently been identified to emit the major part of the environmental radioxenon measured at many globally distributed monitoring sites deployed to strengthen the radionuclide component of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) verification regime. Efforts to raise a global radioxenon emission inventory revealed that the yearly global total emission from MIPF’s is around 15 times higher than the total radioxenon emission from nuclear power plants (NPP's).Given that situation, from mid 2008 until early 2009 two out of the ordinary hemisphere-specific events occured:1) In the Northern hemisphere, a joint temporary suspension of operations of the three largest MIPF's made it possible to quantify the effects of the emissions related to NPP’s. The average activity concentrations of ¹³³Xe measured at a monitoring station close to Freiburg, Germany, went down significantly from 4.5 ± 0.5 mBq/m³ to 1.1 ± 0.1 mBq/m³ and in Stockholm, Sweden, from 2.0 ± 0.4 mBq/m³ to 1.05 ± 0.15 mBq/m³.2) In the Southern hemisphere the only radioxenon-emitting MIPF in Australia started up test production in late November 2008. During eight test runs, up to 6.2 ± 0.2 mBq/m³ of ¹³³Xe was measured at the station in Melbourne, 700 km south-west from the facility, where no radioxenon had been observed before, originating from the isotopic production process.This paper clearly confirms the hypothesis that medical isotope production facility are at present the major emitters of radioxenon to the atmosphere. Suspension of operations of these facilities indicates the scale of their normal contribution to the European radioxenon background, which decreased two to four fold. This also gives a unique opportunity to detect and investigate the influence of other local and long distance sources on the radioxenon background. Finally the opposing effect was studied: the contribution of the start-up of a renewed radiopharmaceutical facility to the build up of a radioxenon background across Australia and the Southern hemisphere.     

In-field radon measurement in water: a novel approach

This paper presents a novel approach of measuring radon in-water in the field by inserting a MEDUSA gamma-ray detector into a 210 L or 1000 L container. The experimental measurements include investigating the effect of ambient background gamma-rays on in-field radon measurement, calibrating the detector efficiency using several amounts of KCl salt dissolved in tap water, and measuring radon in borehole water. The results showed that there is fairly good agreement between the field and laboratory measurements of radon in water, based on measurements with Marinelli beakers on a HPGe detector. The MDA of the method is 0.5 Bq L⁻¹ radon in-water.     

城市绿地系统建设的生态对策——以长春市为例

绿色空间是所有城市实现可持续发展的物质载体和市民接触自然的主要场所。几乎所有城市不同程度地存在着绿地被挤占、破坏、污染严重等各种问题。以长春市为例,提出了大城市进行绿地系统建设的总量控制、构建经色空间网络体系等生态对策,并针对大城市内部用地紧张的矛盾,探讨了市区内部的绿化用地潜力。     

甘肃河西地区土地荒漠化的现状、成因及其防治

甘肃省河西地区是我国荒漠化发生最重要的地区之一,其荒漠化主要类型有风蚀漠化、水蚀荒漠化和土壤盐渍化。全区现有各类荒漠化土地21．3万km^2,其中分布最广泛的沙质荒漠化土有17．59万km^2。荒漠化对当地居民的社会经济生活带来了多方面的危害。河西地区荒漠化的形成有其自然和人为两方面的原因;河西地区自然条件恶劣,干旱、风大、沙多、植被稀疏;以及生产实践中、水、土、植被资源等缺乏科学、合理的利用是引起荒漠化的主要原因。为了防治和轻减河西地区的荒漠化,提出了几点防治对策;首先是控制人口增长、提高人口素质;其次是调整产业结构,合理利用资源;第三是加大荒漠化防治的投入,尤其是防沙治沙中资金、科研、人才的投入,建设重点荒漠化防治项目,使河西地区最普遍的沙质荒漠化得到遏制;第四是加强管理,提高科学管理水平,加强执法力度。     

Water quality assessment at Ömerli Dam using remote sensing techniques

Water quality at Omerli Dam, which is a vital potable water resource of Istanbul City, Turkey was assessed using the first four bands of Landsat 7-ETM satellite data, acquired in May 2001 and water quality parameters, such as chlorophyll-a, suspended solid matter, secchi disk and total phosphate measured at several measurement stations at Omerli Dam during satellite image acquisition time and archived at the Marine Pollution and Ecotoxicology laboratory of the Marmara Research Center, where this study was carried out. Establishing a relationship between this data, and the pixel reflectance values in the satellite image, chlorophyll-a, suspended solid matter, secchi disk and total phosphate maps were produced for the Omerli Dam.     

自制模拟样及留样复测的质控技术探讨

介绍了环境监测标准滤膜、标准滤筒、模拟降尘的制备方法、使用方法、实际效果。阐述了滤膜中铅、土壤样品、底泥（沉积物）、污水厂处理污泥等留样的来源、必要性及作用。探讨了滤膜中铅留样复测质控的评判依据。     

火电厂运煤系统抑尘控制因素探讨

火电厂运煤系统主要工艺过程包括卸煤、贮存、掺烧、煤输送到煤仓等。运煤系统设备及转运站扬尘污染严重,分析了污染发生的原因及解决办法,阐述了运煤系统的优化设计方案。