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%。     

双泥SBR系统的短程硝化反硝化和反硝化除磷研究

针对我国中小城镇污水低C/N值的水质特点,考察了双泥法SBR工艺的脱氮除磷效果。结果表明:硝化反应器采用生物膜SBR并控制溶解氧为1.0mg/L进行连续曝气,可以实现短程硝化反硝化;在厌氧/缺氧反应器中,聚磷菌能同时利用硝酸盐和亚硝酸盐为电子受体进行反硝化除磷,从而降低了对有机碳源和溶解氧的需求以及能耗。小试系统对模拟城镇污水中COD、TN、TP的平均去除率分别为94.9%、81.2%、89.5%,出水水质达到了《城镇污水处理厂污染物排放标准》(GB18918—2002)的一级A标准。     

三峡库区Carrousel氧化沟工艺提标升级改造设计

三峡库区某污水处理厂设计规模为3×10⁴m³/d,采用Carrousel氧化沟工艺,原设计出水标准为《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级B标准。升级改造工程中,针对Carrousel氧化沟脱氮除磷效果不佳、难以满足新的排放标准的问题,通过采取新增前置缺氧池、改变硝化液及污泥回流方式、新增多点进水等改造措施,提高了生化系统的脱氮除磷效率。实际运行结果表明,升级改造后生化系统对TN、TP、NH₃-N的平均去除率均提高,出水水质稳定达到一级A标准。     

反硝化深床滤池深度脱氮效果研究

合肥市某污水处理厂采用A~2/O(厌氧/缺氧/好氧)氧化沟—混凝沉淀—反硝化深床滤池组合工艺处理城市生活污水,要求出水水质优于《城镇污水处理厂污染物排放标准》(GB18918—2002)的一级A标准,其中总磷、总氮、氨氮、COD浓度分别不高于0.3、10、2.0和40 mg/L。重点研究了反硝化深床滤池的深度脱氮效果,并分析了进水溶解氧对反硝化效果及外加碳源消耗量的影响。结果表明,该组合工艺脱氮效果良好,TN去除率达到89.2%,其中前置反硝化去除了68.3%的TN,后置反硝化去除了20.9%的TN。通过适量投加外碳源,反硝化深床滤池可以作为TN达标的保障措施。溶解氧浓度与碳源投加量呈正向关系,和硝态氮去除量呈反向关系。每去除1 kg硝态氮需投加甲醇3.60 kg,其中溶解氧消耗碳源占碳源总投加量的26.2%,建议采取措施消除反硝化深床滤池前段的跌水充氧,预计年节省甲醇费用约36.5万元。     

深沟型氧化沟工艺在污水厂中的应用及运行分析

深沟型氧化沟工艺是在保留传统卡鲁塞尔(Carrousel)氧化沟工艺有机物去除率高、脱氮除磷效果好的基础上,将氧化沟的有效水深从4 m增加到6 m,解决了传统氧化沟占地面积大的问题;并且通过一系列设备调整,改变了传统卡鲁塞尔氧化沟的表面机械曝气装置在不同的水量和水质条件下出现搅拌能力及供氧不足的局限。最终污水处理厂出水水质均能达到GB 18918—2002《城镇污水处理厂污染物排放标准》一级B类标准。     

低C/N值城市污水处理厂出水达标的运行条件优化

某污水处理厂采用微曝气氧化沟和化学除磷微絮凝过滤工艺,进水为低C/N值城市污水,出水水质执行《城镇污水处理厂污染物排放标准》(GB 18918—2002)的一级A标准,针对实际出水TN和TP浓度超标的问题,进行了一系列的工艺调整试验研究。结果表明,在不改变构筑物、不增加投资的条件下,通过采取曝气沉砂池停曝、投加外碳源、氧化沟低氧曝气、关闭内回流、优化化学除磷药剂等措施,可以实现出水水质的稳定达标,其中对TN和TP的平均去除率分别可达到65%和88%。     

后置反硝化生物滤池用于某市政污水厂提标改造

四川省眉山市城市污水处理厂(一期)提标改造工程采用了后置反硝化生物滤池工艺,将原有两级曝气生物滤池中第二级其中一半改造成反硝化生物滤池。主要介绍了该改造工程的参数、挂膜启动以及运行效果。实际运行表明,后置反硝化生物滤池具有明显的脱氮除磷效果,调试时TN最高去除率达95%,出水TN为1.3 mg/L。改造后出水水质稳定达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)的一级A标准。     

改良氧化沟工艺节能降耗及脱氮除磷优化研究

河南省某污水处理厂采用改良氧化沟工艺,在运行中存在脱氮除磷效果欠佳的问题.为了降低该厂的运行能耗,并提高对氮、磷的去除效率,采用低氧控制策略,对氧化沟好氧区的供气量进行了优化控制.通过削减氧化沟前端的曝气量,同时控制氧化沟出口的溶解氧为1～1.5mg/L,在氧化沟前端形成缺氧区,为反硝化除磷和同步硝化反硝化创造条件,并将原有的缺氧/厌氧/好氧运行方式更改为缺氧/厌氧/缺氧/好氧运行方式.稳定运行后,氧化沟出水水质得到大幅度提升,二沉池出水TN、TP平均浓度仅分别为9.0 mg/L和0.19 mg/L,达到了<城镇污水处理厂污染物排放标准>(GB 18918-2002)中一级A标准的要求;处理电耗平均为0.241 kW·h/m3,与调试前相比降低了20%以上.     

多级AO与氧化沟工艺在污水厂扩建工程中应用对比

六安市某污水处理厂扩建规模为1.5×10~4m~3/d,出水水质执行一级A标准,综合比选确定主体工艺采用多级AO+高密池。与一期卡鲁塞尔氧化沟工艺运行效果对比表明,多级AO工艺的反硝化脱氮能力优于氧化沟工艺,各出水指标均能够稳定达到设计要求。介绍了主要构筑物及设计参数,可为其他类似污水处理厂提标扩建提供参考。     

低DO浓度下氧化沟的除污及节能效果分析

以实际污水处理厂的沉砂池出水为研究对象,在微孔曝气氧化沟中试装置中进行了低溶解氧浓度和污泥微膨胀条件下去除污染物的试验并分析了节能效果。通过电动阀控制曝气量,使曝气区的DO维持在0.5～0.9 mg/L之间,SVI值为150～250 mL/g,即污泥处于丝状菌微膨胀状态,可以节省曝气量约50%,且对COD、NH3-N、TN和TP的平均去除率分别达到92.5%、99.1%、82.1%和96.2%,出水SS平均值小于10 mg/L,满足《城镇污水处理厂污染物排放标准》中一级A的要求,实现了低溶解氧浓度和污泥微膨胀状态下的运行与高效脱氮除磷。     

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.     

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。     

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。     

2005年北京办公物业市场七大趋势

趋势一:CBD区域写字楼集中放量从各区域规划方案上看,CBD区域多数项目在03～04年处于项目的报批手续及拆阶段,预计2005年正式推向市场,因此2005年CBD区域将成为北京市场供应集中的域,区域即将供应的项目有北京财富中心(二期)、金地国际花园、万达广场、SOHO尚都、万通中心、世纪财富中心、怡禾国际中心、光华国际等。除去未知项目,2005CBD写字楼办公面积的供应量为60万平方米左右。中关村区域经过一段时间的集中供后开始逐步放缓,2005年供应的体量相对较大的项目有中关村金融中心、新中关。金街区域可能开盘的项目只有2个:英蓝国际中…     

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。     

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.