酸化碱渣对氨氮的吸附和解吸性能

研究了氨氮质量浓度、体系温度、时间、酸化碱渣溶液的pH等对酸化碱渣吸附氨氮性能的影响,比较了作为解吸剂的蒸馏水和NaCl溶液对氨氮的解吸效果。在选定的实验条件下,酸化碱渣对氨氮的最大吸附量可达13．9mg／g。氨氮吸附量随其质量浓度的增加而增大、随体系温度的升高而降低,酸化碱渣溶液的pH对吸附性能的影响可以忽略。酸化碱渣表面吸附作用力主要为偶极间力和氢键力,吸附过程可用一级动力学方程模拟。NaCl溶液对氨氮的解吸效果好于蒸馏水,最大解吸率为25．7％。     

污染土壤的物理/化学修复

将土壤污染物分为非卤代VOCs、卤代VOCs、非卤代SVOCs、无机物等8大类型,并在分析污染土壤原位修复和异位修复两种方式不同特点的基础上,根据各种修复技术的不同作用原理,较为全面地介绍了目前国内外各种物理/化学修复的技术原理、适用性、局限性、实施时间及处理成本等,具体包括化学淋洗、蒸汽抽提、强化破裂、空气喷射、可渗透反应墙、固化/稳定化、电动学、物理分离、热解吸、玻璃化等修复技术.针对几种常见的土壤污染类型,列举了一些可行的组合修复工艺.     

演艺厅噪声治理工程实例

对一家演艺厅的噪声现状进行分析,并提出改善墙壁、屋面隔声性能,降噪的有效途径。     

建设绿色重庆构建和谐社会

"十一五"是我国经济社会发展的重要战略机遇期,也是环境保护工作极具挑战的时期.我们将以党的十六届五中全会精神为指针,以建设"绿色重庆"为目标,以"预防为主、综合治理,不欠新账、多还旧账,创新机制、强化监管,突出重点、分类指导,典型示范、带动全面"为基本原则,发展循环经济,解决突出问题,改善环境质量,建立工作机制,努力构建环境友好型社会.     

UASB-接触氧化-气浮处理柠檬酸废水

介绍了UASB-接触氧化-气浮工艺处理柠檬酸废水的工程应用.工程运行表明,柠檬酸废水在进水SS、COD和BOD5分别为3427 mg/L、18 853 mg/L和11778 mg/L的条件下,经该工艺处理后,外排废水SS、COD和BOD5浓度分别为147.5 mg/L、223 mg/L和51.9 mg/L.该工艺具有占地面积小、工程投资和运行费用低及处理效果稳定等特点,能广泛应用于柠檬酸废水的处理.     

Spatial distribution and potential ecologic risk assessment of heavy metals in the sediments of the Nansi Lake in China

The contamination levels and ecological risks of heavy metals in the sediments of the Nansi Lake were investigated. The contents of Cd, Cr, Cu, Pb, Zn, Ni, and Co in the surface sediments collected at 20 sites ranged from 0.08 to 1.12, 58.92 to 135.62, 38.09 to 78.65, 24.51 to 53.95, 110.51 to 235.36, 11.30 to 65.40, and 4.12 to 20.14 mg/kg, respectively. The results of partitioning analysis revealed that the proportions of soluble and exchangeable fraction were less than 1 %, the proportions of carbonate, amorphous oxides, organic matter, and crystalline oxides fraction were less than 10 %, and 10.52 % of Cd was associated with carbonate. The average proportions in the residual fraction ranged from 48.62 % for Cu to 73.76 % for Ni, indicating low mobility and bioavailability. The geoaccumulation index (I _geo), relative enrichment factor (REF), sediment pollution index (SPI), and potential effect concentration quotient (PECQ) values of the heavy metals in the sediments were not in agreement with each another. The average REF values of Cd and Zn were higher than those of other metals. However, the average PECQ values were higher for Cr and Ni than those of other metals, indicating that these two metals would cause higher adverse biological effects. Therefore, it is suggested that future management and pollution control might focus on Cd, Zn, Cr, and Ni in the sediments of the Nansi Lake.     

Impact of land use and land cover changes on ecosystem services in Menglun, Xishuangbanna, Southwest China

Changing the landscape has serious environmental impacts affecting the ecosystem services, particularly in the tropics. In this paper, we report changes in ecosystem services in relation to land use and land cover over an 18-year period (1988--2006) in the Menglun Township, Xishuangbanna, Southwest China. We used Landsat TM/ETM and Quickbird data sets to estimate changes in ten land use and land cover categories, and generalized value coefficients to estimate changes in the ecosystem services provided by each land category. The results showed that over the 18-year period, the land use and land cover in the study area experienced significant changes. Rubber plantations increased from 12.10% of total land cover to 45.63%, while forested area and swidden field decreased from 48.73 and 13.14 to 27.57 and 0.46%, respectively. During this period, the estimated value of ecosystem services dropped by US $11.427 million (approximately 27.73%). Further analysis showed that there were significant changes in ecological functions such as nutrient cycling, erosion control, climate regulation and water treatment as well as recreation; the obvious increase in the ecological function is provision of raw material (natural rubber). Our findings conclude that an abrupt shift in land use from ecologically important tropical forests and traditionally managed swidden fields to large-scale rubber plantations result in a great loss of ecosystem services in this area. Further, the study suggests that provision of alternative economic opportunities would help in maintaining ecosystem services and for an appropriate compensation mechanisms need to be established based on rigorous valuation.     

Dissipation and residue of MCPA (4-chloro-2-ethylphenoxyacetate) in wheat and soil

A rapid and simple HPLC method has been developed for the quantitation of 4-chloro-2-methylphenoxyacetic acid (MCPA) in both wheat and soil samples. Samples were extracted in acidic media and cleaned up by solid-phase extraction with C(18) cartridges before HPLC-DAD detection. The limits of detection and quantification of MCPA were 0.02 ng and 0.01 mg/kg for both wheat and soil. The mean recoveries ranged from 87.1% to 98.2%, and the RSDs ranged from 0.604% to 3.44% for the three spiked levels (0.01, 0.1, 0.5 mg/kg). The proposed method was successfully applied to the analysis of MCPA residues in wheat and soil samples from an experimental field. The dissipation half-lives in soil were calculated to be 3.22 days (Beijing) and 3.10 days (Tianjin), respectively. Direct confirmation of the analytes in real samples was achieved by gas chromatography-mass spectrometry. The results indicated that at harvest time, the residues of MCPA in wheat were well below the maximum residue levels and were safe to apply in wheat.     

The emergy analysis of loop circuit

Emergy analysis can analyze the resource utilization and environmental performance of a system. Loop circuit is a common structure in the process industry, but when emergy analysis is carried out to such structure, mistakes such as emergy double counting often occur. To avoid emergy double counting, two types of loop circuit-direct loop circuit and indirect loop circuit-are theoretically distinguished, and the methods to avoid such mistake are proposed. Finally, PVC production and vinyl acetate production are adopted to demonstrate the methods.