Effects of sample storage on biosolids compost stability and maturity evaluation

Compost stability and maturity are important parameters of compost quality. To date, nearly all compost characterization has been performed using samples freshly collected because sample storage can affect compost stability and maturity evaluation. However, sample preservation is sometimes necessary, especially for scientific research purposes. There is little information available on the effects of sample storage on compost stability and maturity. Samples of biosolids compost with different levels of stability and maturity were collected from four compost facilities in Florida (referred to as Register, Winslow, Sunset, and Meadow). Comparisons of CO2 evolution, seed germination rate, and water-soluble organic carbon (WSOC) were made between fresh samples with short storage at 4 degrees C for less than 1 wk and air-dried or frozen compost samples stored for 1 yr. The effects of storage (air-dry or frozen) on the measured parameters depended on compost stability and maturity and on the compost material source. Frozen storage reduced the peak CO2 evolution of Register samples by 12 to 29%, while accumulated CO2 evolution was reduced by 43 to 64% and 110 to 277% with air-dry and frozen storage, respectively. The storage effect on CO2 evolution with more stable compost was inconsistent. Storage did not affect compost phytotoxicity, except for samples from the Sunset facility. Air-drying reduced the WSOC by up to 35%, and freezing increased it by up to 34%, while both storage methods had no significant effect on samples of low WSOC. Despite all these variations, WSOC had a significant and consistent relation to CO2 evolution and seed germination rates with R2 of 0.78 and 0.57, respectively, regardless of storage methods.     

Simulation of cooling-water discharges from power plants

Accurate simulation of the temperature distribution in a cooling lake or reservoir is often required for feasibility studies of engineering options that increase the cooling capacity of the waterbody. A three-dimensional hydrodynamic and temperature model has been developed and applied to several cooling lakes in the south-eastern United States. In this paper, the details of the modeling system are presented, along with the application to the Flint Creek Lake.     

The enhancement methods for the degradation of TCE by zero-valent metals

Batch tests were performed to compare the degradation rates of TCE on Fe0 and Zn0. Our results indicated that the degradating capability of Zn0 to TCE was nearly 10 times higher than that of Fe0. On the other hand, the degradation rates of Fe0 or Zn0 in conjunction with other metals for reduction of TCE was investigated. The selected metals were nickel (Ni0) and palladium (Pd0) both of which have a strong enhancement effect. The reduction rates of Zn0/Pd0 and Zn0/Ni0 for TCE were the fastest. Fe0 that had lost its surface activity could be activated again by the addition of Pd0 or Ni0.     

钻井环境污染源头控制技术综述

通过对国内外石油行业的钻井环境污染源头控制技术的简单综述,分析了钻井工艺可采用小孔径钻井、连续软管工艺、新型固控设施等的技术特点,对选择合适的钻井液以及应用环保型钻井液来减轻污染方面进行了探讨。并展望了我国石油行业钻井环境污染源头控制技术的发展。     

广州市地面塌陷的形成原因与时空分布

地面塌陷是珠江三角洲城市地质灾害的主要类型之一。广州市地面塌陷灾害频繁发生,近10年来呈波动式上升趋势。其塌陷类型分为岩溶塌陷和工程地面塌陷两种,岩溶塌陷主要分布在广花盆地的花都区、白云区,工程地面塌陷主要分布在中心城区。地面塌陷灾害孕灾环境复杂、致灾因子多样,承灾体脆弱,灾害后果严重。人为因素是地面塌陷的主要诱发因素。岩溶塌陷主要是由于过量抽取地下水或矿山疏干排水、地下采空、暴雨触发所致;工程塌陷主要是人类工程行为所致,其主要致灾因子包括排水疏干与突水(突泥)作用、人工加载、人工振动、人工开挖桩基、地表渗水、地铁等地下工程盾构掘进等。     

首都大学生的自然灾害认知调查与减灾教育建议

2006年国际减灾日的主题是"减灾始于学校",了解学生的灾害认知水平有助于减灾教育工作的有效开展。以北京5所高校的大学生为调查对象,通过问卷方式调查大学生对自然灾害的关注程度、防灾意识、灾害理论知识、应急行为知识以及对减灾教育的看法。问卷统计结果表明:大学生总体的灾害认知水平较低,现行减灾教育方式和内容与学生的期望有较大偏差。在此基础上,提出了减灾教育内容要将学生"该知道的"与"想知道的"相结合,通过演练演习等方式提高学生的防灾应急实际技能等减灾教育建议。     

在线衍生化吹扫捕集-气相色谱/质谱分析水中的五氯酚

建立了通过乙酸酐衍生化-吹扫捕集-气相色谱／质谱分析水中五氯酚的新方法，探讨了吹扫时间、样品池温度、离子强度以及衍生化试剂的加入量等条件对捕集效果的影响。结果表明：采用吹扫时间25min、样品池温度60℃、离子强度20％氯化钠以及衍生化试剂的量200μl等条件对水中的五氯酚有较好的捕集效果，用于水中五氯酚的测定，结果满意。     

基于粒子群算法的城市垃圾中转站的空间布局研究

随着城市化的进程，垃圾处理设施成为影响城市化质量的重要指标。依据人们实际所关注的垃圾处理设施的总成本和负效应两个因素，在前人研究的基础上，建立了垃圾收运多目标模型，使得总成本和负效应最优化。根据模型设计了粒子群算法，该算法属于智能算法，且精度高，收敛快，在许多领域也得到广泛应用。用设计的粒子群算法并结合案例求出了Pareto最优解，给出三种决策方案，验证了模型和算法的有效性和可行性，为决策者提供了一种理论参考。     

行车司机职业适应性评价原理探讨

简要介绍了行车司机职业适应性测试和评价的基本原理及其重要性。