生活垃圾焚烧飞灰生物脱氯机制研究

垃圾焚烧飞灰中的高氯含量是限制其在水泥工业中资源化利用的重要因素,如何实现垃圾焚烧飞灰的有效脱氯是飞灰应用于水泥工业亟需解决的关键技术问题.在对我国7个典型垃圾焚烧厂飞灰组成及特征分析的基础上,开发了飞灰与污泥共处置脱氯工艺,结果表明,我国典型生活垃圾焚烧厂飞灰氯含量达4.6%~12.7%;不同地区焚烧飞灰中氯含量差异性比较明显,主要原因是不同地区垃圾组成不同,其中工业垃圾是飞灰中不可溶氯的主要来源之一;对比水洗前后飞灰同步辐射X射线衍射分析结果,飞灰中可溶氯主要以KCl、NaCl、CaClOH形态存在,不可溶氯主要以AlOCl形态存在;飞灰与污泥按质量比8:2混合,并共处置150d后,飞灰氯含量由14%降低至0.03%,满足我国《通用硅酸盐水泥》(GB175-2007)标准所规定的水泥氯含量不高于0.06%的要求;飞灰与污泥共处置发酵产酸使得混合体系pH值降低,促进飞灰中不可溶氯盐向可溶性氯盐转化是飞灰生物脱氯的主要机制.     

乌鲁木齐采暖期前期与后期TSP、PM_(10)、PM_5、PM_(2.5)中重金属分布特征研究

从乌鲁木齐工业区、交通区、生活区、风景对照区4个典型区域入手,利用崂应2050型大气自动采样器及TSP/PM10/PM5/PM2.5/切割头对大气中TSP、PM10、PM5、PM2.5进行同步采集,并采用火焰原子吸收分光光度法及石墨炉原子吸收分光光度法对TSP、PM10、PM5、PM2.5中的6种重金属Cd、Pb、Cu、Ni、Zn、Mn的含量进行了测定。测定结果为:Cd的浓度为0.52~10.72 ng/m3;Pb的浓度为25.66~356.87 ng/m3;Cu的浓度为12.57~173.93 ng/m3;Ni的浓度为1.85~78.22 ng/m3;Zn的浓度为67.58~431.49 ng/m3;Mn的浓度为18.87~310.20 ng/m3。大气颗粒物中各重金属之间存在一定的相关性,重金属的分布与风力也有一定的关系。     

生物扰动对沉积物中污染物环境行为与生物可利用性的影响

疏水性有机污染物进入环境水体后易于与沉积物结合,对沉积物中的底栖动物造成危害。底栖动物引起的生物扰动作用可以通过改变沉积物的地球化学性质,对其中污染物的赋存形态、迁移转化和生物可利用性产生重要影响。在综述了国内外生物扰动影响沉积物中污染物环境行为和生物可利用性的最新研究进展基础上,重点讨论了沉积物颗粒交换、水体环境条件改变、疏水有机污染物解吸释放过程以及对生物扰动影响的定量化表征。最后对该研究方向进行了展望,指出应重点研究多种污染物及不同生物共存条件下的生态效应,以及造成沉积物扰动的影响因素的定量化表征等。     

Leaching of indium from obsolete liquid crystal displays: Comparing grinding with electrical disintegration in context of LCA

In order to develop an effective recycling system for obsolete Liquid Crystal Displays (LCDs), which would enable both the leaching of indium (In) and the recovery of a pure glass fraction for recycling, an effective liberation or size-reduction method would be an important pre-treatment step. Therefore, in this study, two different types of liberation methods: (1) conventional grinding, and (2) electrical disintegration have been tested and evaluated in the context of Life Cycle Assessment (LCA). In other words, the above-mentioned methods were compared in order to find out the one that ensures the highest leaching capacity for indium, as well as the lowest environmental burden. One of the main findings of this study was that the electrical disintegration was the most effective liberation method, since it fully liberated the indium containing-layer, ensuring a leaching capacity of 968.5mg-In/kg-LCD. In turn, the estimate for the environmental burden was approximately five times smaller when compared with the conventional grinding.     

Flow characteristic and wastewater treatment performance of a pilot-scale airlift oxidation ditch

A pilot-scale airlift oxidation ditch using bubble diffuser and baffle as aerator was operated in a wastewater treatment plant (WWTP) to investigate its flow characteristic and wastewater treatment performance. Compared with the conventional oxidation ditch process, effective depth and oxygen utilization efficiency of this new process was improved by underwater aeration. Furthermore, it had a reversed velocity distribution, which decreased from the bottom to the top on vertical section. Velocity measurement showed that a velocity over 0.2m/s at the bottom was sufficient to prevent sludge settlement during long term operation. Application of these concepts would save land area and energy consumption by about 25%―50% and 55%, respectively. In this new system, organic biodegradation and nitrification could be well achieved. Denitrification could occur steadily in the straight part by adjusting the airflow rate. An average TN removal rate of 63% was achieved with dissolved oxygen (DO) concentrations between 0.6mg/L and 1.5mg/L. The main pollutants in the effluent could meet the strictest discharge standard (COD<50mg/L, NH₄⁺―N<5mg/L, and TN<15mg/L) in China now.     

中国降水量区域变化稳定性研究

利用中国气象中心160站点的实际观察资料,对中国半个世纪的降水变化进行了系统分析,发现中国的夏季降水变化稳定性有显著的纬度与海拔效应:纬度越高,方差值越小,降水变化的幅度也越小,稳定性越大;从海拔来看,海拔越高,降水稳定性越好,降水量的变化稳定性与海拔是成反相关关系.除过受区域水汽来源稳定性的影响,主要受全球降水稳定性的分布规律所制约;在海拔上,降水量稳定性的分布,除过受水汽来源影响外,还与水汽凝结的高度效应有一定的关系.     

生物酶在医院污水处理中的应用研究

处理医院污水常用的工艺有A2/O工艺和AB工艺,以上两种工艺存在磷酸盐及氨氮去除与水温等工艺条件相关因素有关,而造成处理效果不稳定,经试验采用生物酶改良剂＋SBR反应器处理医院污水,加入生物酶原液为50 000 mg/L加入一定数量,按SBR工艺条件控制,经处理后,COD去除率达90%以上,出水中磷酸盐及氨氮浓度达到综合废水一级排放标准。在SBR反应器中,当生物酶与医院污水比例为0.1/10 000-1/10000时,对COD的去除率显著提高,在处理医院污水时,曝气时间4 h,此时COD去除率小于90%。能加速聚磷菌对磷的释放和吸收,可使出水达到或接近一级排放标准,同时在好氧段生物酶能显著提高NH3-N的硝化速度,能将硝化时间缩短2h,从而降低了医院污水的处理成本。     

双圆形衬砌隧洞对柱面SH波作用下附近场地动力响应的影响分析∗

在柱面SH波作用下,由于弹性半空间中存在水平和垂直平行双圆形衬砌隧道,附近场地的动力响应将会受到影响。因此,本文基于弹性波理论,采用波函数展开法分析了双隧洞周围的柱面SH波散射问题,给出了双圆形衬砌隧道附近场地的位移解析解,并验证了该解的收敛性。通过对衬砌隧洞的衬砌刚度、隧洞埋深、两隧洞的中心间距以及入射波频率等参数的分析,研究了双圆形衬砌隧洞附近场地土体的位移幅值沿水平方向和深度方向的变化规律。结果表明:衬砌刚度、隧洞埋深、中心间距以及入射频率对双圆形衬砌隧洞附近场地的动力响应有着显著的影响。     

Soil temperature and moisture sensitivities of soil CO2 e ux before and after tillage in a wheat field of Loess Plateau, China

As a conventional farming practice, tillage has lasted for thousands of years in Loess Plateau, China. Although recent studies show that tillage is a prominent culprit to soil carbon loss in croplands, few studies have investigated the influences of tillage on the responses of soil CO2 e ux (SCE) to soil temperature and moisture. Using a multi-channel automated CO2 e ux chamber system, we measured SCE in situ continuously before and after the conventional tillage in a rain fed wheat field of Loess Plateau, China. The changes in soil temperature and moisture sensitivities of SCE, denoted by the Q10 value and linear regression slope respectively, were compared in the same range of soil temperature and moisture before and after the tillage. The results showed that, after the tillage, SCE increased by 1.2–2.2 times; the soil temperature sensitivity increased by 36.1%–37.5%; and the soil moisture sensitivity increased by 140%–166%. Thus, the tillage-induced increase in SCE might partially be attributed to the increases in temperature and moisture sensitivity of SCE.     

Eco-Compensation in Multi-District River Networks in North Jiangsu, China

Eco-compensation is a multi-disciplinary topic. There is no consensus on the issue of river eco-compensation across districts. Although policies regarding river eco-compensation have been issued in China since 2008, due to the high cost, eco-compensation has not been well implemented in the Taihu pilot region. Therefore, a simplified method based solely on water quality (both water quality and water volume included in the Taihu method) was proposed for North Jiangsu province (NJP). However, the formula was flawed and it led to payments being too low. Three problems need to be solved: (1) how to specify the eco-compensation areas; (2) how to test a reasonable eco-compensation model and (3) how to determine the compensation criterion. Solving these issues is already a priority. In this paper, three potential solutions surrounding eco-compensation are discussed: (1) three principles for selecting the representative eco-compensation areas are suggested; (2) the compensation calculation method based on contaminant flux above the ultra standard is revised and (3) a compensation criterion model based on the treatment costs of sewage is proposed. In the NJP case in 2009, the average eco-compensation criterion for chemical oxygen demand (COD) is 2,000 Chinese Yuan (CNY) per ton and ammonia nitrogen (NH₄–N) and total phosphorus (TP) are 8,000 CNY and 80,000 CNY per ton, respectively. Five districts needed to be compensated. The payments in the revised scheme were 4.15–586 million CNY, which were 16–48 times greater than that in the draft method. The new method can provide an important template for managers when drafting river eco-compensation schemes.