环境质量模糊综合评价及其应用

环境质量评价是环境科学的重要研究课题之一，作者评述了常用指标法的不足，提出用模糊数学中综合模糊评价法评价环境质量，建立了评价模式和计算程序，并用于科学城的环境质量评价，评价计算给出的多层次数据所提供的信息，与监测结果所体现的环境质量状况符合，所建模糊评价程序是适用的。     

我国沙漠化灾害的发展及其危害

沙漠化灾害是在特定自然环境背景下产生的,严重危及人类生产和生存。文章着重阐述沙漠化发展对农、牧业、工矿交通及环境等方面造成的经济损失。据初步统计,全国每年因沙漠化遭受的直接经济损失达36～45亿元,间接经济损失高达292亿元以上。同时,指出沙漠化的实质是从根本上毁损土壤肥力,丧失人类赖以生存的土地。因此,从沙漠化发生时间的频繁性、经常性,空间分布的广泛性,致害的多样性及造成的经济损失严重性看,沙漠化灾害是我国严重自然灾害之一。     

降低采油污水处理中污泥产生量技术研究——室内试验研究——

为了降低采油污水处理过程中产生的污泥量,对“降低采油污水处理中污泥产生量技术”进行了研究,并在采油一厂文一污水站进行了为期66天的现场实验。结果表明,降低采油污水处理污泥产生量技术通过化学反应将污水中的部分离子转变为对污水净化有用的组分,并通过控制污水中的氧含量、pH及离子平衡,达到去除水中悬浮物、控制腐蚀、维持水中离子平衡的目的。当复合碱按600 mg/L加入并使系统的pH值控制在7.0～7.3且絮凝剂、助凝剂加入浓度分别为150 mg/L、100 mg/L时,污水的pH、含油量、总铁、悬浮物由处理前的6.0、109 mg/L、13.5 mg/L、78 mg/L下降为7.0、0、0～0.42、1～2,滤膜系数为35;污水腐蚀速率为0.0691 mm/a;处理后水中SRB、TGB含量分别为0、101个/mL;经中国科学院渗流流体力学研究所等单位监测和技术评价证实,处理后污水与地层水配伍性良好,对地层不伤害,所产生污泥可初步用做建筑材料。     

Institutions,policies and soil degradation:theoretical examinations and case studies in Southeast China

Southeast China is one of the severe soil degradation areas in China. This paper theoretically examines the impact of some important institutional arrangements and policies, like land management pattern, the rural off-farm employment, land property change and changes in prices of agricultural products, on soil degradation in this area. It further conducts some case studies to confirm the potential relationship between the institutions & policies and soil degradation, applying the surveyed and the second hand data. The paper at last makes some conclusions and proposes some suggestions on how to promote soil conservation by improving the ways of policy decision-making and the effects of policies on land use.     

含糖废水活性污泥制备生物柴油的方法探究

本研究以处理葡萄糖废水的活性污泥为研究对象,考察了细胞破壁方法、油脂萃取溶剂及甲酯化方案对制备生物柴油的影响,并提出适用于活性污泥制备生物柴油的方法,以期为实现剩余污泥资源化、降低生物柴油生产成本提供技术支持.实验采用了盐酸加热、盐酸加热-超声、超声及液氮冷冻4种细胞破壁方法,选用二氯甲烷-甲醇和正己烷-甲醇-丙酮两种油脂萃取溶剂组合,使用油脂萃取-甲酯化(两步法)和原位甲酯化(一步法)两种方案,以降解含糖废水的活性污泥为原料,制取生物柴油.研究结果表明,盐酸加热破壁配合二氯甲烷-甲醇提取油脂的两步法获得的生物柴油产量最高,每克污泥(干重)的生物柴油产量达(60.4±3.5)mg·g-1.超声破壁一步法虽产量偏低((45.5±3.2)mg·g-1,以SS计),但步骤相对简单,化学试剂用量少.通过GC-MS分析发现,不同甲酯化方案所制备的脂肪酸甲酯(FAMEs)在组分上差别不大,除了含有月桂酸甲酯、肉豆蔻酸甲酯、棕榈油酸甲酯、棕榈酸甲酯、油酸甲酯、硬脂酸甲酯,还含有5种带甲基支链的脂肪酸甲酯及两种单不饱和脂肪酸甲酯,这可能对改善生物柴油的低温流动性有一定的帮助.     

Removal of tetracycline from water by Fe-Mn binary oxide

Significant concerns have been raised over the presence of antibiotics including tetracyclines in aquatic environments. A series of Fe-Mn binary oxide with different Fe:Mn molar ratios was synthesized by a simultaneous oxidation and coprecipitation process for TC removal. Results showed that Fe-Mn binary oxide had higher removal efficiency than that of hydrous iron oxide and hydrous manganese oxide, and that the oxide with a Fe:Mn molar ratio of 5:1 was the best in removal than other molar ratios. The tetracycline removal was highly pH dependent. The removal of tetracycline decreased with the increase of initial concentration, but the absolute removal quantity was more at high concentration. The presence of cations and anions such as Ca²⁺, Mg²⁺, CO₃^2- and SO₄^2- had no significant effect on the tetracycline removal in our experimental conditions, while SiO₃^2- and PO₄^3- had hindered the adsorption of tetracycline. The mechanism investigation found that tetracycline removal was mainly achieved by the replacement of surface hydroxyl groups by the tetracycline species and formation of surface complexes at the water/oxide interface. This primary study suggests that Fe-Mn binary oxide with a proper Fe:Mn molar ratio will be a very promising material for the removal of tetracycline from aqueous solutions.     

国家应通过立法，强制推行中水回用

西南部地区干旱突显出我国水资源的供求矛盾。中水回用可以提高水资源的使用效率、缓解水资源匮乏的问题，但从全国看，推行的阻力很大。建议通过立法，强制推行中水回用政策，以实现水资源的可持续利用和社会经济的可持续发展。     

Simulated wetland conservation-restoration effects on water quantity and quality at watershed scale

Wetlands are one of the most important watershed microtopographic features that affect hydrologic processes (e.g., routing) and the fate and transport of constituents (e.g., sediment and nutrients). Efforts to conserve existing wetlands and/or to restore lost wetlands require that watershed-level effects of wetlands on water quantity and water quality be quantified. Because monitoring approaches are usually cost or logistics prohibitive at watershed scale, distributed watershed models such as the Soil and Water Assessment Tool (SWAT), enhanced by the hydrologic equivalent wetland (HEW) concept developed by Wang [Wang, X., Yang, W., Melesse, A.M., 2008. Using hydrologic equivalent wetland concept within SWAT to estimate streamflow in watersheds with numerous wetlands. Trans. ASABE 51 (1), 55–72.], can be a best resort. However, there is a serious lack of information about simulated effects using this kind of integrated modeling approach. The objective of this study was to use the HEW concept in SWAT to assess effects of wetland restoration within the Broughton's Creek watershed located in southwestern Manitoba, and of wetland conservation within the upper portion of the Otter Tail River watershed located in northwestern Minnesota. The results indicated that the HEW concept allows the nonlinear functional relations between watershed processes and wetland characteristics (e.g., size and morphology) to be accurately represented in the models. The loss of the first 10–20% of the wetlands in the Minnesota study area would drastically increase the peak discharge and loadings of sediment, total phosphorus (TP), and total nitrogen (TN). On the other hand, the justifiable reductions of the peak discharge and loadings of sediment, TP, and TN in the Manitoba study area may require that 50–80% of the lost wetlands be restored. Further, the comparison between the predicted restoration and conservation effects revealed that wetland conservation seems to deserve a higher priority while both wetland conservation and restoration may be equally important.     

Survey of composition and generation rate of household wastes in Beijing, China

It is recognized that information on both quantity and composition of residential waste is important for the effective planning of household waste handling infrastructure. In this paper, we present the results of a survey on household waste generation and composition in Beijing, China. Sample communities were selected by the integration of five indices including family population, income, age, and education. Wastes were sampled on a daily basis from 113 households in six different districts of Beijing City for ten days. The results showed that the generation rate of household wastes was 0.23 kg/pers/day. The bulk density was approximately 221 kg/m³, and the moisture content was approximately 50%. Household waste consisted of kitchen waste, paper/cardboard, plastics, textiles, metals, glass and other wastes, the proportion of each waste was approximately 69.3%, 10.3%, 9.8%, 1.3%, 0.8%, 0.6% and 2.7%, respectively. An evaluation of the relationship between daily per capita generation of household waste and socio-economic factors indicated that household size and income both showed a negative relationship with household waste generation (kg/pers/day). As for the effect of education, families with a secondary educational level produced fewer household wastes (kg/pers/day) than those with a primary or advanced educational level.     

人口、就业与土地非农化的相互关系研究

在Carlino-Mills区域增长模型的基础上,通过引入农地非农化变量,应用两阶段最小二乘法(TSLS)和普通最小二乘法(OLS),利用中国232个地级及以上城市1999年和2005年两个时间段的截面数据,从一个整体的视角分析了人口、就业与土地非农化的关系.分析结果表明:①城市人口与非农就业相互影响,非农就业对城市人口的影响要大于城市人口对非农就业的影响;城市人口与第二产业就业呈正相关关系,而与第三产业就业呈负相关关系;②城市人口和非农就业对农地非农化有显著的正的影响,城市人口对农地非农化的影响要大于非农就业对农地非农化的影响;农地非农化与第二产业就业正相关,与第三产就业负相关;③就业非农化高的地区,农地非农化将有所减缓,人口城市化高的区域,农地非农化则加剧.根据上述研究结果,本文提出了相应的政策建议.