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151.
中国城市水资源消费与气候的关系研究 总被引:2,自引:0,他引:2
论文利用多项式法将气候耗水量从水资源消费总量中分离出来,用统计分析的方法探讨了气候耗水量与气候因子之间的关系。研究表明:温度、降水量和相对湿度是影响气候耗水量的主要气候因子,在不同地区、不同季节有不同表现,在我国东部,二者的相关性较显著,西部不太明显,而且冬、春季的区域分异明显,夏、秋季不明显,其中冬季在南北向的分异明显,春季在东西向的分异明显。 相似文献
152.
REN Nan-qi YAN Xian-feng CHEN Zhao-bo HU Dong-xue GONG Man-li GUO Wan-qian 《环境科学学报(英文版)》2007,19(2):129-134
The lack and pollution of water resource make wastewater reuse necessary. The pilot scale long-term tests for submerged membrane bioreactor were conducted to treat the effluents of anaerobic or aerobic treatment process for the high-strength Chinese traditional medicine wastewater. This article was focused on the feasibility of the wastewater treatment and reuse at shorter hydraulic retention time (HRT) of 5.0, 3.2 and 2.13 h. MLSS growth, membrane flux, vacuum values and chemical cleaning periods were also investigated. The experimental results of treating two-phase anaerobic treatment effluent demonstrated that the CODfilt was less than 100 mg/L when the influent COD was between 500-10000 mg/L at HRT of 5.0 h, which could satisfy the normal discharged standard in China. The experimental results to treat cross flow aerobic reactor effluent demonstrated that the average value of CODfilt was 17.28 mg/L when the average value of influent COD was 192.84 mg/L at HRT of 2.13 h during 106 d, which could completely meet the normal standard for water reuse. The maximum MLSS and MLVSS reached 24000 and 14500 mg/L at HRT of 3.2 h respectively. Membrane flux had maximal resume degrees of 94.7% at vacuum value of 0.02 MPa after cleaning. Chemical cleaning periods of membrane module were 150 d. A simulation model of operational parameters was also established based on the theory of back propagation neural network and linear regression of traditional mathematical model. The simulation model showed that the optimum operational parameters were suggested as follows: HRT was 5.0 h, SRT was 100 d, the range of COD loading rate was between 10.664-20.451 kg/(m3.d), the range of MLSS was between 7543-13694 mg/L. 相似文献
153.
环境空气质量预报评估是提升预报能力的重要助力,为更好支撑空气质量精细化管理,将我国空气质量细化为12个半级别,参照英国预报评估方法,对2020年“2+26”城市AQI、 PM2.5浓度和O3-8h浓度预报开展探索性半级别预报效果评估,通过与AQI范围预报和AQI级别范围预报评估对比发现,半级别预报评估方法可将两者兼容合一,在城市业务预报评估中具有一定可行性和应用价值.具体的半级别预报评估结果表明,“2+26”城市AQI和O3-8h浓度在低段级别和高段级别的预报效果明显差于中段级别,不同级别PM2.5浓度预报效果相对稳定;AQI、 PM2.5和O3-8h浓度预报准确率月变化曲线分别呈双峰型、先升后降型和平缓型,PM2.5浓度各月偏高预报显著;不同城市AQI和O3-8h浓度预报准确率差距相对较小,PM2.5浓度预报准确率波动较大;北京和天津AQI预报准确率高于周边省份,北京和河南PM2... 相似文献
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155.
绿色发展是资源型城市高质量转型的重要体现。通过构建绿色发展效率评价体系,基于MinDs模型、泰尔指数、地理探测器等方法,测算2001—2019年西部资源型城市绿色发展效率时空分异特征,分析其驱动因素。结论如下:(1)西部资源型城市绿色发展效率以2015年为界,呈“先升后降”变化,西北、广西的资源型城市整体上升,西南和内蒙古的资源型城市近年呈下降趋势,成长型城市发展较为稳定,成熟型和再生型城市2017年后下降明显,衰退型城市呈上升趋势;(2)西部资源型城市绿色发展效率表现为极低和极高区间数量少、中间得分数量多的正态分布特征;(3)绿色发展效率空间非均衡的问题较为严重,其中,西北与西南地区的成熟型城市的变化是导致绿色发展效率差异扩大的主要原因;(4)经济发展、城市化、城市规模和技术创新能够显著提升西部资源型城市绿色发展效率,不同空间范围和不同生命周期下的资源型城市绿色发展效率驱动因素各有特点。研究对提升西部各类资源型城市绿色发展效率有实际意义。 相似文献
156.
Seasonal Variations and Chemical Forms of Heavy Metals in Soils and Dusts from the Satellite Cities of Seoul, Korea 总被引:10,自引:0,他引:10
This research investigated heavy metal pollution of soils and dusts in two representative satellite cities of Seoul, Korea and studied the seasonal variations in metal concentrations through the rainy season and the chemical forms of metals using a sequential extraction analysis. The metal dispersion pattern was illustrated to match with urban structure. Soil and dust samples were collected from the cities of Uijeongbu and Koyang, which are the northern and northwestern satellite cities of Seoul (the capital), before and after rainy season. Concentrations of Cu, Pb and Zn were higher than those of the world averages for soils, and their levels decreased after rain, particularly in highly contaminated samples. Relatively high pH values were found in roadside soils, but no seasonal variation was found after the rainy season. The three metals (Cu, Pb and Zn) in soils and dusts were associated with various chemical fractions of soils and dusts as distinguished by the sequential extraction scheme, and a strong similarity of metal association between soils and dusts was found, which indicates that airborne dust may be a principle source of soil contamination. Copper is uniformly distributed, and Pb is largely associated with the reducible phase. There is an appreciable proportion of total Zn in the exchangeable/water-acid soluble fraction. After the rainy season, the most soluble fractions in soils and dusts were leached away. In terms of mobility and bioavailability of metals in soils and dusts, the order Zn >> Cu > Pb is suggested. Geographical variations of total metals corresponded well with urbanised areas of cities, especially the industrial complex and major motorways. 相似文献
157.
本文介绍了一种高效除尘脱硫装置三相流化床的性能和原理,并对三相流化床除尘脱硫工业中试系统的试验结果进行了分析。试验表明三相流化床除尘效率可达956脱硫效率达70%,运行安全可靠。 相似文献
158.
基于利益相关者和政策过程理论,以某地耕地重金属污染治理试点为案例,对农业主管部门、环境主管部门、粮食收储部门、科研单位、农资生产商、农资流通主体、农户以及新型农业经营主体等八类利益相关者的利益诉求、行为特征以及与政策的相互影响进行了深入分析。研究表明,不同相关者的利益诉求和行为特征构成了试点区错综复杂的治理格局。在政策过程中,农业主管部门的主导作用明显,存在着因有效互动不足造成的政策制定缺乏共识,政策执行成本较高、阻力较大,政策评估有待完善等问题。虽然现行政策在一定程度上调动了除部分农资流通主体外其余利益相关者的积极性,但尚未形成利益相关者共同治理且与政策良性互馈的局面,需从政策过程视角加以完善。 相似文献
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160.