重视城市污水集中处理投资,收费与运营市场化

本文深入研究了国外城市污水处理的成功经验。就城市污水处理市场化进程中,建立什么样的投资,收费与运营模式进行了讨论。     

好氧颗粒污泥膜生物反应器污泥性状研究

采用厌氧-好氧运行方式的颗粒污泥膜生物反应器（GMBR）,连续运行近120　d表现出良好的有机物去除及同步硝化反硝化能力.对GMBR中污泥粒径分布变化研究表明,GMBR中污泥浓度的增加主要是由于粒径0.18～0.45　mm的小颗粒污泥及小于0.18　mm的絮状污泥的增加造成的,粒径大于0.45　mm的颗粒污泥能够基本稳定维持其颗粒形态,反应器运行末期,GMBR中颗粒污泥（粒径大于0.18　mm的污泥）含量稳定在污泥总量的60％～65％以上.污泥表面电荷量随着污泥组成形态的变化电负性逐渐增加,80　d后稳定在-0.42～-0.80　meq·g^-1之间.污泥表面电荷的负电性增加主要是由小于0.45　mm的污泥造成的,其中小于0.18　mm的絮状污泥对其影响最大.并且,污泥粒径越大污泥表面负电荷量越少,两者具有较好的线性关系.另外,GMBR中SVI稳定在60～90 mL/g之间,并且随着污泥表面电荷负电性的增加污泥SVI值增加,两者之间具有一定的相关性.     

壳体缓释技术对带壳装药慢速烤燃反应烈度的缓解作用研究

为了研究2种典型壳体缓释技术对弹药慢速烤燃响应烈度的缓解作用,基于试验条件分别建立无缓释设计、侧壁加工应力槽和端盖加工泄压孔的带壳PBX装药慢速烤燃仿真模型,提出使用热分解反应动力学模型和燃烧反应模型模拟计算不同约束条件下带壳PBX装药从开始加热发生热分解反应到点火燃烧以及炸药与壳体耦合作用的烤燃过程的计算方法。研究结果表明：通过侧壁加工应力槽以及端盖加工泄压孔的缓释结构设计,可以有效地降低壳体破裂时炸药内部的压力及反应度,以达到缓解反应烈度的目的。     

基于微电荷法的烟气颗粒物浓度检测技术及其应用

目前针对烟气颗粒物浓度的检测方法较多,但均存在不足。详细分析了基于微电荷法的烟气颗粒物浓度检测技术的基本原理和关键的技术难点,介绍了由于微处理器、数字电子技术和材料科学等的飞速发展带来的技术革新,技术的进步为其应用开拓了更为广泛的应用领域并逐步在工业场合得到推广。     

电除尘器电源交流分量对PM_(2.5)等细微颗粒物除尘效率的影响

除尘器对颗粒物的除尘效率与颗粒物的荷电量密切相关,PM2.5等细小颗粒物由于其荷电量不足而导致其吸收效率较低,对环境造成危害。为了增加粒子的荷电量,以粒子荷电原理为理论依据,从离子电流密度和通过电凝并扩大尘粒中位径2个方面研究了电除尘电源中交流电压分量对PM2.5等细小颗粒物荷电特性的影响,得出了电除尘器电源中交流电压分量可从以上2个方面提高装置对PM2.5等微小颗粒物的荷电量,且频率越高,幅值越大,荷电效果越好,从而可以提高装置对细小颗粒物的除尘效率。     

Adsorption of Pb(II) on variable charge soils amended with rice-straw derived biochar

Two Ultisols and one Oxisol from tropical regions of southern China were incubated with rice straw biochar to investigate the effect of biochar on their surface charge and Pb(II) adsorption using batch methods. The incorporation of biochar induced a remarkable increase in soil cation exchange capacity after 30 d of incubation. The incorporation of biochar significantly increased the adsorption of Pb(II) by these variable charge soils; the enhancement of adsorption of Pb(II) by these soils increased with the addition level of biochar. Adsorption of Pb(II) involved both electrostatic and non-electrostatic mechanisms; however, biochar mainly increased Pb(II) adsorption through the non-electrostatic mechanism via the formation of surface complexes between Pb²⁺ and functional groups on biochar. There was greater enhancement of biochar on the non-electrostatic adsorption of Pb(II) by the variable charge soils at relatively low pH. Therefore, the incorporation of biochar decreased the activity and availability of Pb(II) to plants through increased non-electrostatic adsorption of Pb(II) by acidic variable charge soils.     

The electron density distribution in pyridinium and bipyridylium compounds and its relevance to their adsorption by expanding lattice clays

Abstract

Charge distributions in 1, 1'‐ethylene‐2, 2'‐bipyridylium (diquat), 1,1'‐dimethyl‐4,4'‐bipyridylium (paraquat) and 1‐methylpyridinium organocations were calculated by a Complete Neglect of Differential Overlap semi‐empirical quantum mechanical procedure. The data show that the positive charges in the organocations are distributed around the molecules and are greatest in the positions ortho and para to the heterocyclic nitrogen atoms. Earlier interpretations of the mechanisms of adsorption of paraquat and diquat by soils and clays assumed that the charges were located in the heterocyclic nitrogen atoms. Here some consideration is given to the influence of the charge delocalizations on the processes of adsorption by montmorillonite and vermiculite clay preparations.     

浅析报废汽车拆解厂废水循环处理技术的应用现状

报废汽车的回收拆解处理在我国已经逐渐兴起，但由于该产业尚处于发展初期，环保技术手段和可持续性发展意识还不够，因此在回收拆解过程中会产生大量的废水和其他污液。针对某汽车回收拆解厂的废水特性进行实验研究，形成“电荷凝集过滤一活性炭吸附”组合工艺，对报废汽车回收拆解企业的废水处理提供了一定的参考价值。     

耦合装药中扩容半径的理论计算

根据扩容机理,建立了扩容爆破的物理模型,并且根据动量守恒定律得到了不同条件下最终炮孔挤压区域的半径公式.利用这些公式结合炸药和岩石的特性,以及装药参数得到了扩容结果.理论计算结果与试验数据相吻合.这些结果将有助于爆破扩容理论的完善以及该技术发展和推广应用.     

EFFLUENT FEES,AN ALTERNATIVE SYSTEM FOR ACHIEVING WATER QUALITY: A CASE STUDY1

This paper reports the findings of a case study of the relative costs of a uniform standards system and an effluent fee system of water quality control. A 30-mile stretch of the Black Warrior River in Alabama is considered. The analysis demonstrates that the dischargers could reduce total pollution abatement costs by 33 percent under the suggested effluent fee system.