CASS工艺用于小城镇污水处理的工程设计研究

CASS是SBR的一种改进型污水处理工艺,在污水处理特别是小城镇污水处理中有着广泛应用。本文介绍了CASS工艺在广东某镇污水处理厂的工程应用情况,主要包括CASS的工艺流程、设计参数及设计要点。对运行效果和经济技术指标进行了总结,并对工艺的运行和管理提出相应的建议。实际运行结果表明,该厂在处理规模为1万m^3／d条件下,出水达到《城镇污水处理厂污染物排放标准》（GB18918-2002）一级B标准,达到设计要求。该项目的成功实施,为CASS工艺在小城镇污水处理厂的应用提供了参考。     

低C/N条件下MUCT工艺数学模型的参数校正与验证

基于ASM2d模型建立了稳定运行的MUCT工艺营养物质去除过程的动力学反应模型,比较各种COD、TN、NH 4＋-N、TP的实测值和模拟值,以确定系统在低C/N条件下运行时的动力学和化学计量学参数.模拟结果表明,稳态模型中的动力学参数qPHA、KA、KPP、YPO3-4、μAUT和ηNO-3分别取值2.90 g.（g.d）-1、3.85 g.m-3、1.35 g.（g.d）-1、0.35、1.6和0.8.其他的动力学和化学计量学参数可采用IWA给出的默认值.     

预腐蚀铝合金材料裂纹萌生寿命评估

铝合金在航空工业中广泛应用,因此对于铝合金构件的寿命评估很重要。利用扫描电子显微镜(SEM)原位观测技术,研究了预腐蚀铝合金试件在循环应力作用下的疲劳裂纹萌生和扩展行为。结果表明腐蚀坑对于裂纹萌生扩展行为具有强烈的影响。基于局部应变法,提出了一种预测带有腐蚀损伤的铝合金疲劳裂纹萌生寿命的评估公式。     

对黑龙江省森工林区小城镇环境规划和管理的探索

首先界定了森工林区小城镇的定义;确定林区小城镇环境规划的技术方法,其中着重介绍了水、气、固体废物的环境预测方法;同时探讨了适用于森工林区的环境规划的原则和主要内容,综合以上几个方面提出针对森工林区小城镇的环境管理,应加强环境规划的合理性与科学性、加快林区环境整体治理、建立林区环境规划管理体系、完善林区小城镇基础设施建设,张显林区特色、突出生态建设。     

小城镇建设项目环境影响评价相关问题探讨——以聊城经济开发区蒋官屯小城镇建设项目为例

在中国的城市化进程中,小城镇建设发挥了重要的作用,引起了各级政府的重视。本文以聊城经济开发区蒋官屯小城镇建设项目为例,结合小城镇建设项目的特点,就小城镇建设项目的环境影响评价中相关问题进行了探讨,主要从环境影响评价的特点、评价的主要内容、评价重点、项目建设对环境的影响分析及外环境对项目的影响分析、生态及社会环境影响分析、公众参与、项目选址合理性分析、应特别关注的环境问题等几个方面进行阐述,以期为小城镇建设项目环境影响评价提供参考。     

植被净初级生产力对气候变化的响应研究——以黄土高原燕沟流域为例

Vegetation net primary productivity (NPP) is a sensitive indicator to characterize the response of terrestrial ecosystems to the climate change. Projections of the NPP changes of the Loess Plateau under future climate scenarios have great significances in revealing the interactions among terrestrial ecosystems and climatic systems, as well as instructing future vegetation construction of this region. Here, we carried out a case study on the Yangou watershed in the Loess Plateau. Using the vegetation-producing process model (VPP) established for such small watersheds, we simulated the NPP of the Yangou watershed under different scenarios of climate changes. The results showed that the NPP significantly increased with the precipitation increasing and evidently decreased with the temperature increasing where the climate change occurred in the whole year or in the summer half year. However, where the climate change occurred in the winter half year, the increased precipitation had little effect on the NPP, and the increased temperature significantly reduced the NPP. There were clear differences among the response sensitivities of different vegetation types with trees and shrubs were more sensitive to the changes in temperature and precipitation than crops and grasses. Currently, the most favourable climate change scenario to the NPP in the Yangou watershed was T0P15 under which the precipitation increased by 15% and the temperature did not changed, in the whole year; in the meantime, the most unfavourable climate change scenarios was T2P-15 under which the precipitation declined by 15% and the temperature increased by 2℃, in the whole year.     

沈阳城市化进程对大气边界层影响研究

利用沈阳气象站2000-2010年高空观测数据,统计分析了各年探空温度和风速曲线,还依据统计得到的中性层结风速廓线资料,利用莫宁-奥布霍夫相似理论计算了下垫面的空气动力学参数,综合研究了沈阳城市化进程对大气边界层的影响。结果表明:(1)随着城市化进程的发展,地面平均温度呈逐年升高的趋势,但升温幅度很小;高层温度也有增加的趋势,增温幅度很小。(2)垂直温度递减率有增加的趋势,这表示城市化程度的发展对边界层的影响也是显著的。(3)由于下垫面城市化程度的提高,在不同高度上风速都有不同程度的减小的趋势。(4)摩擦速度逐年增加,对风速的消减作用逐渐增强;粗糙度逐年增高和零平面位移逐年增大,可见沈阳下垫面城市化的程度逐年增加。     

小回流比条件下污泥浓度分区试验研究

用次毫米过滤（sub-milliFiltration,SMF）组件将生物处理系统内的污泥分为高浓度区和低浓度区,使高浓度区保持大量污泥,强化对有机物的去除,使低浓度区污泥浓度满足膜分离的要求.主要验证了小回流比（R为0.5、1.0、1.5、2.0）条件下污泥浓度分区的效果,考察了采用SMF组件后,系统对COD的去除效果,并将各小回流比条件下A、B两区污泥浓度的理论值和实测值做比较.结果表明,在小回流比条件下可实现污泥浓度分区,低浓度区的MLSS在9 g.L-1以下,高浓度区的MLSS在20 g.L-1以上;系统的COD平均去除率超过90%;A、B两区MLVSS的理论值与实测值具有相关性.     

高径比对猪场废水脱氮与沼气脱硫耦联反应器的影响

采用填料鼓泡塔反应器研究其高径比对猪场废水脱氮与沼气脱硫耦联过程的影响,比较了3种不同高径比(8∶1、3∶1、2∶1)反应器的废水脱氮与沼气脱硫效能.在温度30～32℃、空塔停留时间6.70 min、水力停留时间3.35 d、沼气中H2 S浓度1 414～1 838 mg.m-3、进水NO x--N浓度114～243 mg.L-1的条件下,高径比2∶1反应器的运行较稳定,且处理效果较好,硫化氢去除率平均值为96.7%,NO x--N去除率平均值达到88.7%;而高径比8∶1和3∶1反应器的运行不太稳定,硫化氢去除率的平均值分别为68.0%、80.4%,NO x--N的去除率平均值分别为89.7%、90.2%.主要是因为高径比2∶1反应器的实际气速(3.12×10-2 m.s-1)比高径比3∶1、8∶1反应器的实际气速(分别为3.62×10-2 m.s-1和6.64×10-2 m.s-1)更慢,其气液传质系数(1.79×10-5 s-1)比高径比3∶1、8∶1反应器的气液传质系数(分别为1.64×10-5 s-1和1.55×10-5 s-1)更大,传质效果更好.处理效能试验结果以及反应器流体力学特征参数均表明,高径比2∶1反应器为最适合的反应器.     

Time allocation between work and recreation and the associated injury risks among young people

PROBLEM: The purpose of this study was to examine the relationship between overall risk of injury and time use patterns between work and active recreation among adolescents and young adults. METHODS: Using a representative sample of 9,795 Canadians aged 15-24 years, a multivariate logistic regression on the likelihood of any medically attended injury was conducted, including sociodemographic, individual, and time factors. RESULTS: Young people who engaged in a combination of high work and high activity hours were twice as likely to sustain a medically attended injury compared to those who worked low hours, but did not participate in any recreational activity. Those respondents who were not in school had a 43% increase in injury risk compared to full-time students. SUMMARY: Our findings suggest that injury risk was not a simple function of fatigue and cumulative exposure time. Our findings suggest the importance of considering time use and the associated injury risk tradeoffs. IMPACT ON INDUSTRY: Relevant to state and federal work safety policy makers, our findings suggest the importance of understanding where youth might otherwise spend their time if constraint were placed on their employment opportunities, and the associated injury risk tradeoffs must be taken into consideration.