水环境中污染物同位素溯源的研究进展

水环境中污染物的源辨识及污染过程控制是当前流域水污染治理的难题,利用同位素示踪技术对污染物来源及污染过程进行追踪是解决该问题的有效手段之一。综述了近几年同位素技术在国内外水环境污染源解析研究中的应用状况,简要介绍了同位素技术的基本原理与特点,重点总结了稳定同位素技术在示踪水环境中不同污染物及其迁移转化过程的研究进展;提出同位素示踪技术与传统水化学方法相比,有其独特的优势,但也存在一些不足,结合传统水化学分析和荧光光谱等技术,可提高同位素技术的示踪效率及环境友好程度;对同位素示踪技术的应用前景进行了展望。     

絮凝沉淀法测定地表水中氨氮的方法改进

本文通过比较监测黑臭河流氨氮时人员比对的结果,对絮凝沉淀预处理过程的关键因素进行了改进。结果表明,直接在离心管中絮凝沉淀、离心、取样分析,精密度和准确度更好,而且方便快捷,值得推广。     

悬浮电解法回收废旧电子印刷线路板中的铜

以废旧电子印刷线路板中的金属铜为处理对象,采用悬浮电解法制取纯铜粉。选择了4个影响铜粉的纯度、脱落率和电流效率的因素,每个因素3个水平进行正交实验。实验结果表明,硫酸铜的浓度、氯离子的浓度和电流密度对铜粉的纯度、脱落率和电流效率有较大的影响。通过对正交实验结果的分析得出最优的电解条件,在此电解条件下可得到铜粉的纯度99.8%、脱落率99.6%和电流效率99.7%。     

基于Fe~0的PRB去除地下水中硝酸盐的模拟研究

由于地下水中硝酸盐污染的普遍性、难去除性和对人体健康的潜在危害性而引起人们的广泛关注。本研究通过柱实验,研究了不同条件(进水pH、砂/Fe0体积比和添加锯末)对基于Fe0的模拟渗透性反应墙(permeable reactivebarrier,PRB)去除地下水中硝酸盐的影响。结果表明,由于黄土的碱性和缓冲作用,进水pH的影响不显著;5~6∶1的砂/Fe0(S/Fe)体积比既可提高铁粉利用率,又有利于硝酸盐的还原并延长PRB的有效期;铁腐蚀产物引起铁粉粘固而导致PRB的渗透性和反应性降低,尤其在反应区的进水口端;虽然酸预处理Fe0有助于硝酸盐的还原,但更容易引起堵塞,而在Fe0体系中加入活性炭不仅可提高硝酸盐的去除率,还可延长PRB的有效期,是一种很好的辅助填料;同时添加锯末和Fe0的生物-化学联合法更有助于硝酸盐还原并提高出水水质,具有很好的应用潜力;不同条件下,出水中的氨和亚硝酸盐的浓度相差较大,但可溶性铁浓度均低于饮用水标准(0.3 mg/L)。Fe0的化学还原和锯末的生物反硝化是硝酸盐去除的主要机理。本研究表明,基于Fe0的PRB用于去除中性或偏碱性地下水中的硝酸盐污染具有很大的潜力。     

溶藻放线菌改性制剂对铜绿微囊藻的控藻能力研究

采用喷雾干燥法制备了一种溶藻放线菌粉剂,此粉剂按1∶10 000的质量比投加4 d后对铜绿微囊藻的溶藻效率可达90%,该粉剂经过壳聚糖改性处理后,在1∶20 000的质量投加比下,0.5 h即可絮凝去除90%的藻细胞,4 d后的溶藻效率仍可达80%。由于既能快速絮凝除藻,又能长效溶藻,使得改性溶藻放线菌粉剂具有更为广阔的应用前景。     

Decoupling Relationship Between Cultivated Land Occupation by Construction and Economic Growth in China During 1998-2007

With the rapid development of economy, the conversion of cultivated land into nonagricultural land occurs more frequently and makes cultivated land sparser. This article based on the decoupling theory takes the situations of cultivated land occupation by construction and economic growth in China from 1998 to 2007 as an example to evaluate and analyze the decoupling. The conclusions are drawn as follows. First, the article applies IU curve and gross method. The decoupling status by gross method, in contrast to that by IU curve, can express the pressure from cultivated land occupation better and is similar to the decoupling status based on the model of decoupling in this article. Second, in most provinces of China, the relationship between the cultivated land occupation by construction and economic growth has transformed from expansive negative decoupling to strong decoupling. In general, the transformation was firstly from economically advanced eastern municipalities under the central government directly, then to economically advanced eastern coastal provinces, and lastly to central, western and northeastern regions. Third, the decoupling status was relative to contemporaneous policies and laws on cultivated land protection and regional development planning. Their effect is obvious and positive.     

GIS-Supported Precision Agricultural Fertilization Management at Small Scale

Precision agricultural fertilization technique at small scale is the key for regional cultivated land protection and management. Taking Dingzhuang Town (located in Guangrao County, Shandong Province) as a case study, this article explores the precision agricultural fertilization technique at small scale. First, three main cropping systems are identified via field investigation, namely wheat–maize–soybean, garlic–maize and cotton. Then, application amount of fertilizer N, P and K under the three cropping sys...     

Experimental field estimation of organic nitrogen formation in tree canopies

The content of organic N has been shown in many studies to increase during the passage of rain water through forest canopies. The source of this organic N is unknown, but generally assumed to come from canopy processing of wet or dry-deposited inorganic N. There have been very few experimental studies in the field to address the canopy formation or loss of organic N. We report two studies: a Scots pine canopy exposed to ammonia gas, and a Sitka spruce canopy exposed to ammonium and nitrate as wet deposition. In both cases, organic N deposition in throughfall was increased, but only represented a small fraction (<10%) of the additional inorganic N supplied, suggesting a limited capacity for net organic N production, similar in both conifer canopies under Scottish summertime conditions, of less than 1.6 mmol N m⁻² mth⁻¹ (equivalent to 3 kg N ha⁻¹ y⁻¹).     

异波折板水解酸化-A2O一体化反应器实验研究

设计了异波折板水解酸化-A2O一体化反应器,进行生活污水处理的实验研究。10个月的实验结果表明,系统的最佳水力停留时间（HRT）为8 h时,最适COD进水浓度为240-100mg/L,最佳混合液回流比（r）-污泥回流比（R）为250%-100%。控制反应器于以上运行参数下,25±2℃所对应的COD、TN和TP去除率分别为96.84%、67.55%和81.92%。当温度降至7℃时,其COD、TP和TN分别降至86.35%、50.25%和65.68%。基于实验分析结果,阐明了一体化反应器高效性的机理在于异波折板水解酸化段具有高效传质特性和A2O段具有复合式活性污泥-接触氧化好氧池的特点。     

城市环境承载力分析与评估——以湛江市为例

介绍了环境承载力的涵义以及城市环境承载力的评估方法,以PSR模型研究环境压力所对应的环境状态,以此评估城市环境承载状态,并以湛江市为对象,展开城市环境承载力的现状分析,在此基础上对未来不同发展阶段的环境承载力做情景分析,从减压—改善—优化层次上提出湛江市环境承载力提升的对策建议。