Occurrence and densities of fungi from northern Greek coastal bathing waters and their relation with faecal pollution indicators

The objective of this study was to determine the frequency and densities of yeasts and filamentous fungi in coastal water samples as well as their correlation with the indicator bacteria of faecal pollution. The prevalence of fungi was investigated in parallel with the standard pollution indicator microorganisms in 197 marine water samples from six northern Greek prefectures during the bathing season May–October 1999. Filamentous fungi were isolated from all the examined samples and yeasts from 29 (14.7%) of them; among the positive samples, their mean counts were 90.9 and 38.4 cfu/100 ml, respectively. A total of 23 genera of filamentous fungi and four genera of yeasts were identified. Prevailing genera of filamentous fungi were Penicillium, Aspergillus and Alternaria spp., whereas Candida spp. was the most frequently isolated yeast. Counts of yeasts were significantly (p<0.01) correlated with those of total and faecal coliforms, whereas no correlation was found between filamentous fungi and the indicator bacteria of faecal pollution. Significantly higher counts of total and faecal coliforms (p<0.05), and enterococci (p<0.001), were found during the months with the higher water temperatures and bather numbers. In the six prefectures, significant differences were observed in the counts of filamentous fungi and yeasts as well as in the counts of all the faecal pollution indicators. The results of this study indicate that coastal water can be a path for contamination of swimmers with yeasts and filamentous fungi and that the pollution indicator microorganisms cannot always predict their presence.     

Cost models for small wastewater treatment plants

The cost models of small wastewater treatment plants serving to population sizes of 2000 to 25,000 were prepared for Turkey with intermediate degree of accuracy. In the first phase, kinetic models of aerated lagoon, stabilization pond, trickling filter, oxidation ditch and rotating biological contactor (RBC) were derived in terms of area and flow rates at various treatment efficiencies considering different temperature ranges. Secondly the construction, mechanical, electrical equipment, operation and maintenance costs were computed as function of flow rates for each biological treatment process in the development of cost models. These models will be employed in the selection of the appropriate biological treatment process before investment of limited funds.     

Estimating capital costs of wastewater treatment plants at the strategical level

ABSTRACT

The present paper aims at the establishment and testing of construction cost functions for wastewater treatment plants (WWTP) based on their hydraulic and physical characteristics. A five-step methodology is followed: (1) database construction and asset characterization; (2) present cost value calculation; (3) key parameters and cost functions establishment; (4) cost modelling; and (5) model testing. A large set of construction costs and infrastructure data from several Portuguese wastewater utilities is analysed including 147 WWTP. Simple linear regression analysis is carried out to obtain cost functions for five types of WWTP. The cost modelling also includes the estimation of 90% prediction bands. Each developed cost function is tested for checking their statistical significance. Results allow the estimation of capital costs of new WWTP and the assessment of the current value of existing assets at the strategical and tactical planning levels without the knowledge of the specific components of the facilities.     

铁路隧道病害有效整治技术研究

隧道工程施工中,其病害一直以来都很难避免,整治难度相对较大,整治费用更是相当地昂贵。文章从隧道工程病害的分类、成因等着手,从深层次,多角度的施工工艺、质量控制、技术特点进行分析,给出了隧道渗漏水、衬砌裂纹或裂缝、二次衬砌厚度不足、初期支护或二次衬砌背后脱空、仰拱或隧底虚碴、二次衬砌混凝土局部强度不足等的整治原则和针对性整治方法。最后,结合工程实际,提出了隧道施工过程病害控制的相关建议,以供同行或科技工作者分享、参考。     

The optimum operational condition of membrane bioreactor (MBR): cost estimation of aeration and sludge treatment

A methodology to obtain the most economical operational condition of membrane bioreactor (MBR) is developed. In order to achieve the optimum design parameters of MBR with which operational costs are minimized, aeration and sludge treatment costs were estimated for various operational conditions. Generally sludge treatment cost and aeration cost were inversely proportional to each other, which means sludge treatment cost is minimized when aeration cost is maximized and vice versa. Therefore, there might exist an optimum point between the two extreme cases. However, sludge treatment cost turned out to overwhelm the aeration cost over the reasonable operational conditions. Therefore, sludge minimization was considered to be a key for the economical operation of MBR. In the case of typical municipal wastewater of which COD was 400mgL(-1), steady-state MLSS was expected to increase from 11,000 to 15,000mg/L without sludge removal when HRT was decreasing from 16 to 12h. For the range of operational conditions considered in this study, economically optimum HRT and target MLSS were turned out to be 16h and 11,000mg/L, respectively. Under this condition, aeration for the biodegradation of organic matters would be 13.3m(3) air/min when influent was 1000m(3)/day.     

Economic evaluation of alternative wastewater treatment plant options for pulp and paper industry

Excessive water consumption in pulp and paper industry results in high amount of wastewater. Pollutant characteristics of the wastewater vary depending on the processes used in production and the quality of paper produced. However, in general, high organic material and suspended solid contents are considered as major pollutants of pulp and paper industry effluents. The major pollutant characteristics of pulp and paper industry effluents in Turkey were surveyed and means of major pollutant concentrations, which were grouped in three different pollution grades (low, moderate and high strength effluents), and flow rates within 3000 to 10,000 m³/day range with 1000 m³/day steps were used as design parameters. Ninety-six treatment plants were designed using twelve flow schemes which were combinations of physical treatment, chemical treatment, aerobic and anaerobic biological processes. Detailed comparative cost analysis which includes investment, operation, maintenance and rehabilitation costs was prepared to determine optimum treatment processes for each pollution grade. The most economic and technically optimal treatment processes were found as extended aeration activated sludge process for low strength effluents, extended aeration activated sludge process or UASB followed by an aeration basin for medium strength effluents, and UASB followed by an aeration basin or UASB followed by the conventional activated sludge process for high strength effluents.     

Advantages of Using 3-D CAD Plant Models on the Construction Site

Abstract: For many engineering and construction firms, the majority of a project's total cost is often incurred in the construction phase. In order to address the productivity and profitability of construction projects, one has to consider a variety of factors. This paper presents new techniques that RUST International has employed to address construction cost reduction. It focuses on using the intelligence built into the three-dimensional (3-D) computer-aided design (CAD) plant model during design and applying it to construction project management at the job site. The Jacobus Technology JSpace system is used for modeling and interacting with the large and complex 3-D plant model. Applications developed by RUST on the JSpace platform, which provide for construction planning, material control, and support of plant startup, will be introduced. The analysis shows that use of the 3-D CAD model on the job site can provide substantial reductions in work hours and office costs, provide marked reductions in craft labor costs, and help reduce bulk material surplus as well as shorten project schedules. The system is shown to be an effective communication tool in bringing engineers, contractors, and owners together by using advanced 3-D animation of the plant.     

基于 SD 模型的绿色建筑建造成本控制研究

国家和地方政府在推进碳中和目标落地的同时将绿色建筑的发展作为主要工作方向。然而,因为绿色建筑成本较高,其推广和发展相对缓慢。为了有效降低绿色建筑建造成本, 提出了一种动态的成本分析方法,即采用系统动力学模型,结合情景模拟分析,挖掘绿色建筑建造成本的关键影响因素。结果表明:室内外环境设计、节能设计、节材设计在情景模拟下率先促使建造成本水平值达到 100,确定其为关键因素。当逐渐加大节材设计的投入时,建安费用会出现负值,进而促使建造成本会出现下降趋势。 该模型能全面反映绿色建筑建造成本系统的整个动态情况,为投资方做出精确决策提供一定参考。     

Environmental and economic profile of six typologies of wastewater treatment plants

The objective of wastewater treatment plants (WWTPs) is to prevent pollution. However, it is necessary to assess their sustainability in order to ensure that pollution is being removed, not displaced. In this research, the performance of 24 WWTPs has been evaluated using a streamlined Life Cycle Assessment (LCA) with Eutrophication Potential (EP) and Global Warming Potential (GWP) as environmental indicators, and operational costs as economic indicators. WWTPs were further classified in six typologies by their quality requirements according to their final discharge point or water reuse. Moreover, two different functional units (FU), one based on volume (m³) and the other on eutrophication reduction (kg PO₄³⁻ removed) were used to further determine sustainability. A correlation between legal requirements and technologies used to achieve them was found: Organic matter removal plants were found to be less costly both in environmental and economic terms if volume was used as the functional unit, while more demanding typologies such as reuse plants showed a trade-off between lower EP and higher cost and GWP; however, this is overcome if the second FU is used instead, proving the sustainability of these options and that this FU better reflects the objectives of a WWTP.     

中小型城市污水处理厂技术经济调查与分析

通过网络调查和实地走访等方式对我国已建的100余座污水处理厂进行了技术经济调查.对工艺类型、投资、规模、成本等关键参数进行了统计分析,得出了不同工艺类型的建造投资与流量的函数关系;比较了不同工艺类型的直接运行成本和总成本;按照污染物单因子（BOD、COD、SS、氨氮、磷）计算得出单位污染物的处理成本.为了便于优化设计和科学决策,还利用现行手册中的典型设计,拟合计算出主要单体处理构筑物的费用模型.     

A feasibility study of alum recovery in wastewater treatment plants

In this paper the recovery of alum used as a coagulant in water treatment has been examined. This chemical has a very large influence on the operating costs of treatment plants. A factorial design has been used in the experimental work. The factors tested have been pH of coagulation, pH of redissolution and temperature. Optimal recovery conditions have been found regarding these variables and the recovered alum has proved to have coagulation characteristics as good as the fresh one. A detailed engineering cost analysis has also been made for the optimal conditions achieved. The feasibility study has shown the high profit level of the process.     

工程造价与施工技术进步的关联度分析

技术进步可以减少施工成本,增加施工企业的利润;但社会平均施工成本降低后,工程造价(定额标准)也会随之调低。针对二者的关系,通过对四种有代表性的新技术、新设备进行费用测算、对比,并对技术进步与造价管理的关联度进行分析;在此基础上对定额修编等提出建议,以促进工程造价管理与施工技术进步的共同提升。     

Cost–benefit analysis of constructing a filtration plant for the National Water Carrier in Israel

The paper presents an economic cost–benefit analysis (CBA) of the construction of a filtration plant for the Israeli National Water Carrier (NWC). Its main contribution lies in the comparison between the costs and the benefits of filtration in the context of a concrete policy choice. The first part of the paper presents a cost analysis of two alternative engineering systems: central filtration and localized filtration. The analysis shows that the costs of constructing and operating a central filtration plant are significantly lower than those of a system of local plants. The second part of the paper presents a two‐stage method for assessing the benefits of filtration. First, we valuate the damages caused by consumption of unfiltered water; then we estimate consumers' willingness to pay (WTP) for improved water quality, taking into account households' potential risk aversion. The main result is that total WTP significantly outweighs the costs of constructing and operating the plant.     

装配式住宅设计施工阶段经济效益分析

我国当前装配式建筑发展尚不成熟,装配式建筑成本是影响其发展的重要因素。针对开发商关注的前期建设阶段,探究装配式住宅的经济效益。以深圳市某住宅项目为例,从设计成本、施工成本方面的直接效益,工期和政策方面的间接效益,来计算装配式住宅在设计施工阶段较现浇式住宅的经济效益,并分析影响各部分经济效益的因素。研究发现,装配式住宅在设计施工阶段能产生经济效益,其中工期效益对增量效益影响最大,施工成本效益对增量成本影响最大。     

Balancing-market design and opportunity cost: The Swiss case

The energy transition entails many changes to the existing system. This study focuses on the Swiss electricity balancing market and its adaptation in the context of the energy transition. An operational model for a set of Swiss hydropower plants is used to quantify the opportunity costs of balancing provision under the past, current, and future market designs. The results show that compared to the former balancing-market design, significant cost savings can be achieved by the planned modifications. In addition, the analysis shows how the cost dynamics may change in the future with an increasing share of renewable energies.     

基于BIM 的建筑设计企业设计质量管理问题研究

作为建设工程项目重要环节之一,建筑工程设计质量,不仅影响着整个建设工程项目的投资,还影响着建筑工程的整体进度以及建筑工程质量管理。因此,为了有效提高建筑工程设计水平,加强企业设计质量管理,近年来,BIM(建筑信息模型)被引入中国,BIM带来的不仅是先进技术,同时,也是一种先进的质量管理理念,如何更好地发挥BIM的价值,本文基于BIM的建筑设计企业设计质量管理问题进行了探讨。     

进水以高浓度工业废水为主的污水处理厂扩建工程设计

浙江某污水厂进水中含有70%的工业废水,具有有机物浓度高、冲击负荷大、乳化油浓度较高的水质特点,且出水水质要达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)中一级A标准。已建一期工程(2×10⁴m³/d)采用AAO+高效沉淀池+滤布滤池工艺处理污水,出水有机物超标严重。为此,二期扩建工程(2×10⁴m³/d)采用调节池+混凝气浮组合池+A/O生化池+高效沉淀池的工艺流程。设计中增设调节池调节进水水质水量;采用混凝气浮组合池去除进水中的乳化油,以避免对后续工艺运行造成干扰;延长生化池停留时间,强化对有机物的去除,避免在深度处理阶段设置高级氧化工艺,节省建设、运行费用;气浮污泥采用离心脱水,生物污泥采用带式脱水机处理。工程试运行期间出水水质稳定达到设计标准,直接运行成本为0.56元/m³。     

海外项目建筑电气工程施工图深化设计及管理

随着国际先进项目施工管理模式的引入以及海外工程承包项目的开展,施工图深化设计逐渐被纳入项目管理中,成为了其不可或缺的一部分。深化设计不仅能推进项目进度的发展,还可以在一定程度上节约施工成本。     

Analysis of chemicals and energy consumption in water and wastewater treatment,as cost components: Case study of Oslo,Norway

Adopting a systems-approach to an urban water and wastewater system, while applying a triple bottom line strategy to management, entails a careful analysis of all the sub-systems and components thereof with a view to improving service levels, optimising expenditure, augmenting investments, and also reducing the life-cycle environmental impacts associated with setting up, maintaining and operating the system. The scope for optimising expenses is system-wide, though it varies from one sub-system to another, depending on inherent lock-ins and external factors beyond the direct control of the water and wastewater utility. Optimising the consumption of energy and chemicals and improving the cost-efficiency thereof, is always on the agenda of water treatment plants (WTPs) and wastewater treatment plants (WWTPs). This paper analyses the consumption of and the expenditure on chemicals and energy at Oslo's WTPs and WWTPs over time. Energy and chemicals for water and wastewater treatment, on an average account for 10.8% of the total operational expenses in the water supply sub-system and 13.7% for the wastewater handling sub-system. There is a perceptible increase in this share from 5.2% in 2004 to 14.9% in 2009 for water and 12.3% to 14.2% for wastewater. Chemicals cost more than energy for the WWTPs, while it was the other way round for the WTPs. The total real cost of energy and chemicals per cubic metre, in year-2007 currency, was between 4 and 5.2 Euro cents for the WTPs, and between 1 and 4.5 Euro cents for the WTPs. The total (WTP + WWTP) per-capita real costs of energy and chemicals, expressed in year-2007 currency, rose from around 10 Euros in year 2000 to about 12.2 Euros in year 2007.     

Estimating exergy prices for energy carriers in heating systems: Country analyses of exergy substitution with capital expenditures

Exergy represents the ability of an energy carrier to perform work and can be seen as a core indicator for measuring its quality. In this article we postulate that energy prices reflect the exergy content of the underlying energy carrier and that capital expenditures can substitute for exergy to some degree.We draw our line of argumentation from cost and technology data for heating systems of four European countries: Austria, Finland, The Netherlands, and Sweden. Firstly, this paper shows that the overall consumer costs for different heating options, widely installed in those countries, are in the same range. In this analysis we derived an overall standard deviation of about 8%. Secondly, additional analysis demonstrates that the share of capital costs on total heating cost increases with lower exergy input. Based on the data used in this analysis, we conclude that for the case of modern cost effective heating systems the substitution rate between exergy and capital is in the vicinity of 2/3. This means that by reducing the average specific exergy input of the applied energy carriers by one unit, the share of capital costs on the total costs increases by 2/3 of a unit.