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1概述三沟式氧化沟是由丹麦kruge公司创建,首先在国内邯郸市东污水处理厂运用。因其处理流程简单,构筑物少,运行可靠,操作灵活方便而越来越被中小规模污水处理厂青睐。莒县污水处理厂日处理规模4万m3,采用三沟式氧化沟工艺。本文以莒县污水处理厂为例介绍三沟式氧化沟运行原理、工艺设计、产泥量以及能耗等,说明三沟式氧化沟工艺特点。2三沟式氧化沟基本布置与运行方式三沟式氧化沟其平面布置见图1。该氧化沟运行时,两侧的A、C两池交替用作沉淀池、曝气池,中间的B池则一直维持曝气。进水交替地引入A池、B池或C池,… 相似文献
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针对市政污水处理厂A/A/O工艺特点和提标改造需求,以深圳龙华污水处理厂为例,分析了生物处理单元和深度处理单元改造的重点和技术路线,对"HYBAS+磁混凝澄清"和"MBR+臭氧氧化"两种组合工艺进行比较,从建设投资、运行成本、占地面积和运行稳定性等方面考虑,最终选定"HYBAS+磁混凝澄清"工艺对深圳龙华污水处理厂进行提标改造。 相似文献
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江苏省于2018年6月颁布了DB 32/1072—2018《太湖地区城镇污水处理厂及重点工业行业主要水污染物排放限值》,随后太湖流域城镇污水处理厂开展了新一轮的提标改造。以太湖流域某市政污水处理厂为研究对象,采用全流程分析方法作为评估诊断的手段,探讨奥贝尔(Orbal)氧化沟工艺在实际运行过程中存在的主要问题。结果表明:该厂活性污泥的反硝化潜力和速率分别为8.0,2.24 mg NO3--N/(g VSS·h),通过化学需氧量(COD)及总氮(TN)的全流程分析可知,碳源相对缺乏、内回流比低、氧化沟底部淤积等因素限制了脱氮效率的进一步提高,优化运行后尚有一定的脱氮潜力。这为该厂的实际运行管理及后续的提标改造方案设计提供依据,也为类似具有提标改造需求的城镇污水处理厂提供借鉴。 相似文献
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为达到国家《城镇污水处理厂污染物排放标准》(GB18918—2002)一级A要求,对沈阳市污水处理厂实施提标改造工程。通过对沈阳市城市污水处理厂现状、处理工艺特征及运行情况调研分析,根据沈阳市城市污水处理厂需要提标改造存在的问题,提出工艺优化以及提标改造解决对策,为沈阳市城市污水处理厂提标改造的工程建设提供技术支撑。 相似文献
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森林与径流关系——一致性和复杂性 总被引:17,自引:1,他引:16
@论文综述国外近一个世纪以来在配对集水区研究方面所取得的结论,从水的自然属性出发,从森林变化对径流(年径流量、洪峰与枯水径流)的影响,径流响应的干扰临界值及水文恢复各方面探讨森林变化与径流关系的一致性与复杂性。森林变化与径流关系的一致性主要表现在由较长时间尺度表达的年径流量上。绝大多数的配对集水区的试验研究表明,采伐森林就会增加年径流量,而在荒地上造林就会减少年径流量。而由较短时间尺度表达的洪峰径流与枯水流量则呈现较大的复杂性和难预估性。综述表明,对径流特别是洪峰与枯水径流的定义及分析方法的不同也是造成森林与径流关系复杂性的重要原因。森林与径流关系的复杂性要求人们在研究及应用其关系时就必须有系统观,必须考虑植被、径流与其它过程(土壤变化、气候变化等)的相互作用。论文还认为尽管配对集水区试验作为一种研究方法为研究者提供了许多可靠的结论,但由于许多研究者只把集水区看作是“黑箱”Q从而对认识森林与径流关系的复杂性有一定的局限性。未来的研究应把配对集水区的试验与其它对过程的研究技术(同位素、GIS等技术)结合起来。 相似文献
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Fuellen G 《Die Naturwissenschaften》2008,95(6):469-481
The analysis of the ever-increasing amount of biological and biomedical data can be pushed forward by comparing the data within and among species. For example, an integrative analysis of data from the genome sequencing projects for various species traces the evolution of the genomes and identifies conserved and innovative parts. Here, I review the foundations and advantages of this "historical" approach and evaluate recent attempts at automating such analyses. Biological data is comparable if a common origin exists (homology), as is the case for members of a gene family originating via duplication of an ancestral gene. If the family has relatives in other species, we can assume that the ancestral gene was present in the ancestral species from which all the other species evolved. In particular, describing the relationships among the duplicated biological sequences found in the various species is often possible by a phylogeny, which is more informative than homology statements. Detecting and elaborating on common origins may answer how certain biological sequences developed, and predict what sequences are in a particular species and what their function is. Such knowledge transfer from sequences in one species to the homologous sequences of the other is based on the principle of 'my closest relative looks and behaves like I do', often referred to as 'guilt by association'. To enable knowledge transfer on a large scale, several automated 'phylogenomics pipelines' have been developed in recent years, and seven of these will be described and compared. Overall, the examples in this review demonstrate that homology and phylogeny analyses, done on a large (and automated) scale, can give insights into function in biology and biomedicine. 相似文献
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真菌和细菌对染料的吸附脱色及再生能力的研究 总被引:9,自引:0,他引:9
进行了真菌和细菌共培养对染料的吸附脱色和吸附脱色能力再生的研究。结果表明,青霉菌G-1首先对偶氮染料S-119、蒽醌染料艳紫KN-B(C.I.Reactive violet 22)水溶液中染料进行快速吸附去除,菌丝对同种染料的吸附速度随菌丝培养液中葡萄糖浓度的增加而加快,吸附染料的G-1菌丝在与细菌的共培养中完成对染料的脱色降解,脱色速度受培养液中葡萄和氮源浓度影响较大,从吸附速率和完全脱色时间综合评价,以葡萄糖浓度为5g/L、酒石酸铵为20mmol/L的培养基中培养的菌丝对染料的吸附脱色效果最好,吸附在菌丝上的艳紫KN-B脱色后菌丝吸附脱色能力得到再生,菌丝对100mg/L的艳紫KN-B染料水溶液可重复处理4次。青霉菌G-1对酸性染料废水处理3h,色度去除率为75.9%,吸附染料的菌丝在与细菌共培养中完成对染料的脱色,对试验所用染料废水,菌丝的处理能力获得1次再生。 相似文献
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韩文峰 《安全.健康和环境》2011,11(3):40-43
以某联合站为例,根据油气集输联合站站场功能,将联合站划分为油气处理、储运及污水处理3个单元,对各单元发生火灾爆炸事故的可能条件进行分析,并利用DNV公司的SAFETI软件对事故后果进行模拟计算,根据事故影响范围数据,提出相应的安全措施。 相似文献
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Pesticides and trace elements in cannabis: Analytical and environmental challenges and opportunities
Caley B. Craven Nicholas Wawryk Ping Jiang Zhongshan Liu Xing-Fang Li 《环境科学学报(英文版)》2019,31(11):82-93
Cannabis is increasingly used for both medicinal and recreational purposes with an estimate of over 180 million users annually. Canada has recently legalized cannabis use in October 2018, joining several states in the United States of America (e.g., Colorado, California, and Oregon) and a few other countries. A variety of cannabis products including dry flowers, edibles, and oil products are widely consumed. With high demand for cannabis products worldwide, the quality of cannabis and its related products has become a major concern for consumer safety. Various guidelines have been set by different countries to ensure the quality, safety, and efficacy of cannabis products. In general, these guidelines require control of contaminants including pesticides, toxic elements, mycotoxins, and pathogens, as well as residual solvents in regard to cannabis oil. Accordingly, appropriate analytical methods are required to determine these contaminants in cannabis products for quality control. In this review, we focus on the current analytical challenges and method development for detection of pesticides and toxic elements in cannabis to meet various guidelines. 相似文献
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土壤及果树中HCH和DDT残留及分布规律研究 总被引:5,自引:0,他引:5
采用索氏提取、弗罗里土固相微萃取小柱净化结合GC-ECD测定了苹果园土壤和果树样品中4种六六六(HCH)和4种滴滴涕(DDT)的残留量,并对果树的根、枝、叶中HCH和DDT的分布规律进行了研究。实验结果表明,土壤和果树样品中均有HCH和DDT检出。土壤样品中两类农药的含量分别在0.51~3.97ng/g和1.46~15.55ng/g之间,其中β-HCH是六六六残留的主体,滴滴涕类的含量以p,p'-DDT为最高,并且(DDE+DDD)/DDT<1表明近期果园中有新的DDT输入。果树样品中,HCH和DDT的残留量分别在0.22~2.01ng/g和0.38~6.08ng/g之间,都要低于相应土壤中有机氯农药的浓度。果树中总OCPs的含量在4.88~17.94ng/g之间,是土壤和大气中OCPs污染共同作用的结果。根部的OCPs的含量明显高于枝和叶,其分布规律为根>叶>枝,这主要取决于根、枝、叶各组织的结构以及农药的理化性质。 相似文献
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A total of 2931 women randomized to either transabdominal CVS, transceirvical CVS, or amniocentesis were studied. Unless intended or unintended abortion had occurred, they had completed up to 28 weeks of pregnancy. No significant difference was seen between total fetal loss in the transabdominal CVS group and the amniocentesis group (6.5 and 6.8 per cent, respectively, SE difference = 0.92 per cent, p = 0.01). The total fetal loss in the transcervical CVS group was 10.1 per cent. After pooling our data with data from the Canadian randomized study and the American non-randomized study, the difference in risk between trans-cervical CVS and amniocentesis was 1.8 per cent (SE difference = 0.64 per cent, p = 0.8). When the number of failed procedures and those cases evaluated as infeasible for the assigned method-for anatomical reasons-are compared, the overall sampling efficacy is poorer transcervically than transabdominally. 相似文献