AAO工艺在烟台市辛安河污水处理厂运行中存在的问题

本文介绍了AAO工艺的原理及特点,针对烟台辛安河污水处理厂运行中出现的二沉池污泥上浮现象,分析了主要原因及对策。结果表明,二沉池污泥停留时间过长和底部污泥发生的反硝化作用是二沉池污泥上浮的主要原因。     

A/O除磷工艺丝状菌污泥膨胀的研究

丝状菌污泥膨胀是影响活性污泥法高效、稳定运行的重要因素。采用A/O生物除磷工艺中试装置处理实际生活污水,分析了污泥膨胀发生的原因及恢复系统性能的方法。结果显示,长期曝气不均匀是导致丝状菌污泥膨胀的重要原因,通过调控系统运行参数可以有效控制由低DO值或者高负荷引起的丝状菌污泥膨胀。当发生污泥膨胀后,首先降低负荷至0.45 kgCOD/(kgMLSS.d),调节回流比为83%,同时控制好氧池各段的DO分别为1.5、1.0、1.0 mg/L以淘汰丝状菌,在SVI值降至200 mL/g以下后继续降低回流比至53%,同时降低曝气量以形成1.0、0.5、0.5 mg/L的DO浓度梯度。采取上述调控措施后,SVI值由569.8 mL/g降至150 mL/g以下,污泥性状得以恢复;同时出水COD和TP分别在50、0.5 mg/L以下,去除率分别约为85%、95%。     

桐乡市城市污水处理厂对丝状菌污泥膨胀的控制实践

介绍了桐乡市城市污水处理厂丝状菌污泥膨胀的处理对策,对发生污泥膨胀时的水质特点、工况条件进行分析,认为此次丝状菌污泥膨胀主要是由于低污泥负荷率、低溶解氧引起的。通过调整泥龄、污泥负荷、DO等运行参数,投加NaClO溶液杀灭丝状菌等措施成功控制了此次污泥膨胀,可供同行参考。     

Highsludge(R)工艺中氮的沿程变化与同步脱氮研究

采用Highsludge(R)工艺处理城市污水,考察了氮的沿程变化与同步脱氮情况.结果表明,在第二好氧池中只发生了硝化作用,总氮无明显的下降;而在第一好氧池中总氮有明显的下降,去除率在16.8%～62.3%变化,平均去除率为33.19%,表明在该池中发生了明显的同步脱氮反应.该工艺的除污效果良好,对COD、BOD5、TN、NH4+-N的去除率分别为95%、96%、84%和82%,且污泥沉降性能良好,并未因污泥浓度高而发生丝状菌污泥膨胀、沉淀池污泥上浮等现象.     

纯氧曝气系统污泥膨胀原因及控制

通过对天津石化供排水厂纯氧曝气系统污泥膨胀前后的运行状况进行分析，认为长时间低负荷运行后受到冲击、污泥老化、二沉池局部缺氧是导致污泥膨胀的原因，并给出了相应的预防和控制措施。     

推流廊道式曝气池丝状菌性污泥膨胀分析

介绍了丝状菌性污泥膨胀的诱发机理,对推流廊道式曝气池引起丝状菌污泥膨胀的原因做了深入分析,并介绍了在实际生产中控制污泥膨胀的方法,解决了污水处理工艺中的难题,以供同行参考。     

改良氧化沟工艺启动调试及脱氮除磷优化控制

乌鲁木齐市达坂城区第二污水处理厂采用改良Carrousel 2000氧化沟工艺。针对调试期间发生的污泥上浮及出水TN、TP超标问题,通过检测主要水质指标和微生物镜检,结合污水处理厂的工艺运行参数,找到该问题的原因：污泥龄过长、曝气量过大引起氧化沟内污泥老化上浮;没有及时补充碱度和碳源、缺氧段DO过高导致反硝化过程无法正常进行而使脱氮效果不佳,同时引起二沉池污泥发生反硝化上浮;污泥龄过长是除磷效果不佳的主要原因。对相关运行参数进行调整,通过2个月的试运行,虽然该污水厂进水量少、水质波动较大,但系统出水各项指标均达到《城镇污水处理厂污染物排放标准》（GB 18918—2002）一级A标准,对COD、TP、TN、NH₄⁺-N、SS的去除率分别达到96.7%、98.5%、92.4%、99.3%、96.5%。     

A/O-MBR工艺丝状菌膨胀的发生及其控制

针对A/O-MBR生物脱氮工艺处理模拟化工废水,考察了系统发生丝状菌污泥膨胀的可能性。结果表明,过度的硝化反应和较大的冲击负荷都能引起丝状菌污泥膨胀的发生。针对这两种因素引发的丝状菌污泥膨胀,单纯地依靠恢复工艺运行参数并不能达到控制丝状菌的目的。而通过提高曝气池内pH值至9.0左右,并维持一段时间,能够达到抑制和杀灭丝状菌的目的,并且在短时期内不会引起丝状菌污泥膨胀的复发。     

丝状菌颗粒污泥形成过程及其对膨胀控制的启示

通过试验和观察,从粒径、密度、沉速、基质交换和孔隙率等方面对比分析了丝状菌颗粒污泥与普通好氧颗粒污泥、黑色颗粒污泥的异同,同时研究了丝状菌颗粒污泥的形成过程及丝状菌的缠绕特性与演替规律。研究表明丝状菌对于聚集体的形态有一定的选择性,而且易于被改造的丝状菌结构与丝状菌的类型也有一定的关系;另外,剪切力及丝状菌网眼的尺寸在丝状菌污泥颗粒化过程中亦具有重要意义。最后论证了通过颗粒化技术改变丝状菌发散式生长模式使其自我缠绕致密生长的可行性,为丝状菌污泥膨胀控制提供了一种新思路。     

丝状菌污泥膨胀的原因及其控制方法

对引起丝状菌污泥膨胀的几种原因作了分析，并介绍了在实际生产中控制污泥膨胀的方法，同时探讨了在设计过程中应注意的问题。     

浅析高速公路工程招投标中的最低评标价法

结合目前高速公路施工项目招投标活动的实际情况,阐述了最低评标价法的概念,归纳了其优点及存在问题,对完善最低评标价法提出几点策略,以期促进招标投标市场更加规范有序。     

Place-Making in Megaprojects in Melbourne

This article analyses state-led place-making practices in Melbourne. The two levels of government that influence planning in Melbourne make much of the city as ‘culturally vibrant’ and ‘creative’, and have incorporated creative city-inspired place-making principles into many layers of the planning system. An examination of the development of two mixed-use megaprojects in central Melbourne reveals however that ideals of culturally engaging public places, and indeed of creative landscapes for middle-class consumption, wither in the face of more basic imperatives for economic development. In these case studies the ‘creative city’, no matter how the idea is interpreted, has little traction either as a set of inclusive place-making principles or as a gentrification strategy. The article concludes that the creative city-inspired place-making objectives in the planning system at both state and local levels are ambiguous in their overall intents and completely unsupported by statutory controls. Such place-making objectives as are realised are the compromised results of the interplay of uncoordinated decisions, delivered at the pleasure of the developer.     

Pathogens in septage in Vietnam

Septage is widely acknowledged as a major source of infectious pathogens while disposal of septage, and the operation and maintenance of septic tanks, is not regulated in many developing countries. Twenty untreated septage and septage sludge samples were taken from Can Tho City, Vietnam to examine their pathogen content, and indicator micro-organisms. Escherichia coli and Enterococcus spp. were detected in all samples, regardless of sludge storage time. Phages were detected in 80% of samples. Salmonella spp. were detected in 70% of the untreated septage and 60% of septage sludge samples. Concentrations of phages and bacteria tested in septage sludge after many years of tank storage were much higher than the expected levels. Helminth ova were present in 95% of untreated septage samples with an average of 450 ova l^− 1, and were detected in all septage sludge samples with an average of 16,000 ova l^− 1. Twelve varieties of helminth ova were identified. More helminth ova varieties in higher concentrations were found in septage than those reported from stool samples. The varieties' frequency ranged from 10% to 50% and Ascaris lumbricoides predominated. Results show that pathogens and indicator micro-organisms, especially helminth ova, accumulate in sludge. Thus helminth ova should be considered when septage sludge is treated and used for agriculture. Proper health protection measures must be applied for people handling septage.     

新时期广东城市化的新特点

新时期广东城市化出现以下特点:知识源导向、城市由单体向群体化发展、产业集群推动、政府主导自上而下的集约化发展、城镇化向城市化转变、由重“数量”发展向重“质量”发展的转变。     

在市场中实践在实践中学习在学习中进步--工程公司市场化进程的回顾与展望

近两年来，工程公司在提高市场竞争意识、推动市场化进程中做了大量工作，其中坚持走出去的方针是我们自我加压、推行加快市场化步伐的一个重要战略步骤。     

新形势下高校强化基建财务管理的探讨

在市场条件下高校基建财务人员在加强日常财务管理的同时,必须树立起高度的工作责任心,抓好事前监督、事中监督、事后监督三个环节,全面理解、贯彻执行《高等学校财务制度》,管好用好各项基本建设资金,提高基建财务管理水平,更好地完成高校各项基建任务,以有限的投资,最快的建设速度,获得最大的投资效益。     

Variation in property taxation in Tulsa

Conclusions It may be reasonably concluded from this study that the range of variation in these ratios of assessed to actual value are of a reasonable size for the great majority of cases. The frequency distribution of these sample ratios was not normal, however, as was assumed a process of this type would produce. On the other hand, the failure of the regression analysis to identify any significant variables which would explain these variations would tend to re-enforce the assumption that the fluctuations were indeed of a random nature.To sum it up in one paragraph, aside from a few extreme cases, the assessing process appears to give estimates which are more consistent than would be expected under the assumption that any errors would be of a random nature, but the regression analysis was unable to isolate any particular socioeconomic characteristics which would explain the variation which was present.Financial support for this research project was furnished by the University of Tulsa.     

2008年日本火灾情况

<正>1火灾总数在2008年(1～12月),日本发生的火灾总数为52 394起,与2007年相比减少了2 188起(4.0%)。这相当于平均1天大约发生143起火灾,每10min发生一起火灾。火灾类别(见表1)。     

谈城市历史保护规划的误区

由于缺乏起码的历史文化知识,忽视历史文化遗产的保护,错误的决策导致了建设性的破坏,要加强城市保护的教育,培养合格人才。     

浅谈我国工程项目建设成本控制存在的问题

结合目前我国施工企业工程项目成本管理现状,对工程项目成本管理过程中存在的问题进行了较详细的分析,并提出了一些解决问题的办法,以做好项目成本控制工作,进而增强企业经济实力。