壳聚糖-活化硅酸处理低温低浊水的试验研究

对壳聚糖-活化硅酸处理低温低浊度水进行了初步的探讨,考察了壳聚糖-活化硅酸的用量、pH、壳聚糖分子量等因素对处理效果的影响,找到了最佳的工艺条件.试验结果表明,在原水浊度为8～10 NTU,水温为5～10℃的条件下,当活化硅酸投加量为2 mL/L,壳聚糖投加量为1.2 mg/L时,出水浊度可达到0.54 NTU.     

微絮凝过滤、O3消毒工艺处理微污染水库水

微絮凝直接过滤、O3消毒工艺处理微污染水库水的试验结果表明：（1）微絮凝直接过滤工艺对水库水浊度的去除效果好于传统的混凝沉淀过滤工艺,处理后出水浊度≤1．0NTU;（2）O3消毒能减少消毒投氯量和有效控制处理出水的三氯甲烷、四氯化碳含量,确保三氯甲烷＜60μg/L、四氯化碳＜3μg/L,其最佳投加量为6．9g/m^3;（3）该工艺的药剂费用为0．082元／m^3,比传统处理工艺增加0．061元／^3,但可省去混凝沉淀工序的混凝反应池和沉淀池,降低了工程投资。     

杭州市南星水厂O3/BAC工艺的运行效果分析

杭州市南星水厂深度处理一期工程采用预臭氧、常规处理、后臭氧、生物活性炭工艺。结合生产性试验确定了预臭氧及后臭氧段的臭氧投量分别为0．30～0．60mg／L和1．50～1．70mg／L。工程投产后的运行结果表明：O、／BAC工艺对微污染源水的处理效果良好，对浊度、CODM。NH4^＋-N、NO2^--N的去除率分别为99．2％、（57％～77％）、（61％～99．7％）、（-25％～99．74％），出水浊度〈0．2NTU、色度〈3倍，CODMn、NH4^＋-N、NO2^-N分别为0．48～1．57mg／L及0．237、0．053mg／L以下；季节对O3／BAC工艺的净化效果影响较大，春、夏、秋季的除污效果较好，冬季的相对较差。深度处理工艺的制水成本为0．561元／m^3，较常规工艺的（0．447元／m^3）仅增加约0．114元／m^3。     

处理低温、低浊宁波白溪水库水的混凝剂优化

通过烧杯试验，考察了聚合氯化铝（PAC）、聚合硫酸铁（PFS）及两者分别与聚二甲基二烯丙基氯化铵（PDM）复配后对低温、低浊白溪水库水的除浊效果。结果表明：对温度〈10℃、浊度约为1．5NTU的原水，在试验确定的混凝搅拌条件下，PFS的处理效果最佳，在3mg／L的投量下可使剩余浊度〈0．2NTU；投加PAC时，能在2．5mg／L的投量下将剩余浊度降至最低，为0．8NTU。PDM与PFS复配后，最低能使剩余浊度降至0．4NTU左右，除浊效果比单独使用PFS时差；PDM与PAC复配后，没有明显的除浊效果。PFS可用于对低温、低浊白溪水库水的混凝处理，PDM不适宜作为其强化混凝的助凝剂。     

气液混合泵气浮系统处理低浓度二级出水的研究

气浮-过滤是一种经济有效的污水深度处理工艺。通过小试研究了气浮单元对低浓度二级出水（COD〈60mg／L）的处理效果,并以COD、TP和浊度为去除对象,考察了絮凝剂种类、溶气压力和回流比对处理效果的影响。结果表明,对于低浓度的二级出水,采用气液混合泵的气浮单元可将COD、TP和浊度分别降低到20mg／L、0．5mg／L和0．5NTU;聚合氯化铝（PAC）对COD和浊度的去除效果要好于聚合硫酸铁（PFS）,而PFS对磷的去除率要高于PAC;适宜的工作参数为：PFS的授加量为50mg／L,PAC的授加量为30mg／L,溶气压力为343～441kPa,回流比为30％～50％。     

呼延水厂低温低浊水的絮凝试验研究

针对太原市呼延水厂出水浊度不达标的问题进行了絮凝试验研究.结果表明:该厂原水属低温低浊水,有机胶体较多,絮凝效果差,其根本原因是絮凝剂投量不足.进一步的试验表明:以聚合氯化铝(PAC)为絮凝剂、以活化硅酸为助凝剂,除浊效果较好;活化硅酸的投加时间对絮凝效果有较大的影响,以快速混合用时1min、聚合氯化铝投量为15 mg/L、延迟30 s后投加0.5～1mg/L的活化硅酸(以SiO2,计)为最佳运行条件;滤池反冲洗排水回流至配水井有利于低温低浊水的处理,并可节省絮凝剂或助凝剂的投量.     

蒽醌染整废水的混凝沉淀-Fenton催化氧化处理

采用混凝沉淀-Fenton催化氧化组合工艺对蒽醌染整废水进行处理，研究了混凝剂和Fenton试剂投加量以及各种反应条件对处理效果的影响。试验结果表明，当pH值为6．2、A12（SO4）3投量为300mg／L、PAM投量为3mg／L、沉淀时间为30min时，混凝沉淀出水的COD为233～260mg／L，色度为15～20倍；后续处理采用Fenton试剂催化氧化，当FeSO4投量为200mg／L、H2O2投量为100mg／L、pH值为5．0、反应时间为30min时，出水色度≤10倍，BOD5≤10mg／L，COD≤50mg／L。     

混凝沉淀工艺深度处理污水厂二级出水的混凝剂优化

通过烧杯试验，确定了采用混凝、沉淀工艺深度处理城市污水处理厂二级出水时，最佳的混凝剂组合及投量。结果表明，铝盐混凝剂与PAM组合使用时比铁盐混凝剂与PAM组合使用时的处理效果更好，当PAC＋PAM的组合投量为20mg／L＋5mg／L或30mg／L＋1mg／L、硫酸铝＋PAM的组合投量为30mg／L＋5mg／L时，混凝、沉淀出水浊度为2．5～3．5NTU，COD为25-40mg／L，TP为0．06-0．12mg／L。由于混凝后水中所形成的絮体较小，难于沉淀，因此混凝沉淀工艺对SS的去除效果较差，实际工程中可考虑增设过滤单元。     

絮凝-溶气气浮处理低温、低浊水(中试)

采用絮凝－溶气气浮（DAF）工艺处理密云水库低温、低浊水的中试结果表明,碱化度B值越高的PAC,其电中和能力越强,而且在相同的除浊效果下絮凝剂投量也越少。该工艺对于不同浊度的原水可达到70％－85％的除浊率,且原水浊度越度,除浊率也越高,此外该工艺对浊度为100NTU的排洪水有足够的缓冲能力。     

气浮系统在低温低浊期节能降耗初探

采用气浮工艺可以提高低温低浊处理效果,但投药量较大且气浮系统的能耗较高.通过中试设备进行优化工艺研究得出:降低混凝剂的投加量,关闭气浮容器装置,在气浮池后投加阴离子PAM助滤剂,可使滤后水浊度达到0.35 NTU以下.达到了既提高水质,又节能降耗的目的.     

Low Carbon,Low Risk,Low Density: Resolving choices about sustainable development in cities

Urban areas face a conundrum, they need to reduce their greenhouse gas emissions and consumption of resources, whilst also increasing their resilience to climate change and extreme weather, and improving wellbeing. However, it is widely recognized that well intended intervention to address one of these sustainability objectives in isolation can undermine other objectives. This paper presents a framework to efficiently identify spatial development strategies that provide the best outcomes against multiple objectives. The framework has been applied to London (UK) to identify strategies that can simultaneously: (i) minimize exposure to future heat wave events; (ii) minimize the risk from flood events; (iii) minimize transport emissions; (iv) minimize urban sprawl; (v) maximize brownfield development; and, (vi) prevent development of greenspace that is recognized as important to wellbeing. Prioritizing each objective in isolation leads to considerably different spatial planning structures, exposing conflicts between many objectives. These include tradeoffs between urban heat risk and transport emissions; and also previously undocumented conflicts between minimizing flood and heat risks. Allowing greater flexibility in development density is shown to provide benefits in terms of heat risk reduction, whilst not significantly affecting mitigation objectives. The framework is shown to significantly improve upon the London Spatial Development Strategy for the objectives analyzed. Further analysis identifies optimal spatial strategies to achieve a Low Carbon, Low Risk or Low Density city - however, these cannot be simultaneously maximized. This work shows there are difficult, and often irreconcilable, choices to be made in the spatial planning of sustainable cities. Spatial search and optimization tools strengthen the evidence-base for planning. Rapid identification of development strategies that satisfy, and minimize conflicts between, multiple objectives helps planners to develop strategies that simultaneously improve urban sustainability and reduce the risks from natural hazards.     

Low cost housing

Architect and Town Planner, Amitava Deb of the Central Buildng Research Institute, Roorkee, describes the problems of maintaining mass housing in India and concludes that whilst zero maintenance should be an objective, concerted efforts are needed to develop compatible building materials, that will turn the dream into a reality. The paper was presented at the Paris Congress.     

Low energy houses

Domestic buildings absorb about 1/4 to 1/3 of the UK's primary energy. New houses can be designed which use half, or even considerably less than half of the energy consumed by their contemporaries. Typical examples are the Danish Zero Energy House and the Saskatchewan House. Unfortunately the U.K. building industry and its clients generally ignore long-run costs, in favour of lower initial capital investment. Such a position favours insulation and passive solar techniques, as opposed to more complex methods, for reducing network energy consumption in buildings.     

Low cost housing

Architect and Town Planner, Amitava Deb of the Central Buildng Research Institute, Roorkee, describes the problems of maintaining mass housing in India and concludes that whilst zero maintenance should be an objective, concerted efforts are needed to develop compatible building materials, that will turn the dream into a reality. The paper was presented at the Paris Congress.     

微涡旋混凝低脉动沉淀技术处理低温低浊水

依据低温低浊水的特点,对其处理过程中的亚微观传质及絮凝过程中的动力特性进行分析,并通过试验结果阐明了该技术的可应用性和实用性以及低耗高效的特点。     

谈谈合理低价中标

建设工程实行工程量清单招标合理低价中标方式在招标实践中评标委员会如何确定合理低价,如何防止投标人恶性竞争,以低于成本的价格竞价是一个值得研究解决的现实问题。文章从工程费用的组成、评标委员会的构成,以及工程实施过程中采用的经济行政手段等方面,提出了合理低价的确定以及规范评标的具体方法。     

低成本屋顶方案

来自Corus的Hi-Point是一种新型的非现场制造的屋顶体系，它是在海德克（Corus建筑体系和Kalzip的基地）专用场所进行建造生产的。快速的建筑工程由于时间和空间的限制需要进行非现场施工，而Hi-Point正是一种理想的选择。     

低硬、低碱度水的再矿化对管道腐蚀的控制效果

以深圳市的低硬、低碱度水为研究对象,考察单独投加石灰或CO,/石灰联用的两种再矿化工艺对管道腐蚀的控制效果。结果表明:当单独投加石灰提高水样的pH值时,水的腐蚀性并未有明显改变,而CO2/石灰再矿化工艺控制腐蚀的效果较明显。与未矿化的出厂水相比,当再矿化后水的碱度提高到80 mg/L(以CaCo3计)时,对A3钢、镀锌钢、灰口铸铁和球墨铸铁的腐蚀速率分别降低了73.3%、70.0%、59.7%和67.9%,并且此时腐蚀产物中碳酸钙的含量超过了60%,能很好地形成碳酸钙保护膜以抑制管道腐蚀。     

低碳低水泥用量自密实混凝土的研究

以较低水泥用量180kg/m3,大掺量矿渣粉、粉煤灰研制出C50高强高性能自密实混凝土,混凝土排碳量仅为88.136kg/m3,是普通自密实混凝土的49.52%。试验表明该混凝土和易性好、流动性保持性好,性能与采用高水泥用量配制出的自密实混凝土相当。该文研究的自密实混凝土大大降低了水泥用量,降低混凝土的排碳量,同时大大降低混凝土成本。     

低温低有机物浓度下EGSB反应器的运行特性

在10℃左右的低温、100～500 mg/L的低有机物浓度下,考察了EGSB反应器的运行效果,并分析了液体上升流速、HRT和有机负荷率等运行参数的影响.结果表明:在温度为10℃左右、COD为100～500 mg/L、HRT为1.7 h、液体上升流速为2.8 m/h的条件下,EGSB反应器能够获得70.33%～86.67%的COD去除率;液体上升流速明显影响着EGSB反应器的运行效果,在不同的运行条件下,EGSB反应器均存在着最佳的液体上升流速;在温度为10℃左右、COD为400 mg/L的条件下,EGSB反应器的最佳HRT为1.7 h、进水有机负荷为10～15 kgCOD/(m3·d),此时对COD的去除率高达81.84%～85.70%.