Promoting the reuse of stormwater runoff in the Maltese islands

The Maltese Islands have long suffered from a water resource problem to the extent that extensive reliance is made on desalination by reverse osmosis technology. Whilst this has solved the quantitative problem, it is undoubtedly amore expensive technology when compared to groundwater extraction. Moreover, the carbon footprint of desalinated water is much higher than that of groundwater due to the energy intensive nature of desalination. Notwithstanding, groundwater resources have been exploited to such an extent that current estimations of an annual extraction of 34 hm³ are 11 hm³ in excess of sustainable extraction levels.

The Maltese Islands are also highly urbanised and it is estimated that, in urban areas, up to 80% of runoff could be lost to the sea depending on the geography and land use of the catchment. This resource could potentially be useful in recharging existing aquifers. The aim of this paper is to characterise the quality of stormwater derived from one of Malta's most urbanised catchments with a view to determining its suitability for reuse and recharge.     

城市规划与空气质量关系研究

针对城市规划与大气环境关系在定量化方面建立研究,即通过空间数据、气象数据等将城市规划、气象条件和生态环境三者相互对应,紧密结合起来,并通过精细的城市信息资料确立数学物理模型和数值计算,实现支撑技术保障。以沈阳市为例,采用不同尺度气象模式与大气化学输送扩散模式联结,运用科学合理的大气环境评估指标,建立城市规划大气环境影响评估系统,用以分析各种空气污染物对城市的影响,掌握了城市及周边地区的大气环境特征,为城市规划建设总体布局及人居环境的综合评价提供了科学依据。     

The Management and Control of Urban Runoff Quality

W ater QUALITY problems from impermeable urban surface runoff are presenting increasingly significant effects at both the short-term, acute, and longer term, chronic, timescale. The paper identifies the anachronisms in, and the diversity of, historical organizational responsibilities for urban runoff as being a principal mitigating factor in limiting satisfactory, cost-effective, catchment control. It is recommended that effective source control procedures for stormwater runoff control must form the basis for best practical options for achieving integrated pollution control in urban catchments.     

Suspended particle characteristics in storm runoff from urban impervious surfaces in Toowoomba,Australia

Total suspended solids as a measure of suspended particles in urban stormwater has limitations and the alternative suspended sediment concentration method was adapted to determine non-coarse particle (NCP) concentration, defined as particles smaller than 500 μm. NCP was partitioned into the following classes: very fine particles (<8 μm, VFP), fine particles (8–63 μm, FP) and medium particles (63–500 μm, MP). A site mean concentration approach was adopted to differentiate the suspended particle characteristics between three impervious surfaces (roof, road and car park) using runoff data collected for 35 storms. Runoff particle size distribution (PSD) of all surfaces was dominated by particles less than 63 μm. A weak trend of relatively constant VFP concentration was present in the road runoff data. Roof runoff PSD became finer as NCP concentration increased and, overall, the PSD of car park runoff was coarser compared to road and roof runoff. These findings have runoff treatment implications as settling processes are influenced by particle size.     

Influence of stormwater control measures on water quality at nested sites in a small suburban watershed

ABSTRACT

Stormwater control measures (SCMs) are designed to mitigate the deleterious impacts of urban runoff on the water quality of receiving waters. To assess the cumulative effects of SCMs at the watershed scale, we monitored longitudinal changes in storm discharge and stream water chemistry at high temporal resolution in a suburban headwater stream in Charlotte, NC. SCMs significantly decreased or stabilized instream concentrations of reactive solutes (nitrate, soluble reactive phosphorus, and dissolved organic carbon) relative to the upstream control site. However, SCM outflows minimally influenced concentrations of less reactive solutes (major ions) which increased with urbanization. Additionally, instream concentration variability correlated with antecedent moisture conditions – representative of watershed storage availability – highlighting the role that SCM storage availability plays in the timing of solute delivery to the stream. Our results show that SCMs decrease instream concentrations of biogeochemically reactive solutes but the mitigation potential is temporally dynamic and influenced by antecedent conditions.     

用于控制策略评估的燃气空调模型的建立

本文基于燃气空调机组各部件的能量平衡与质量平衡关系,建立了燃气空调的数学模型。根据建市的模型模拟了一台并联流程的双效燃气空调机组,模拟的结果与厂商提供的样本数据吻合,说明该模型能真实反映燃气空调机组的运行情况,从而为其优化控制提供具体依据。     

Survey of priority substances entering thirty English wastewater treatment works

Crude influent sewages were collected from 30 English wastewater treatment works representing rural, urban and industrial catchments as part of a screening study to assess the significance of the concentrations of substances from the Water Framework Directive priority pollutants list in crude sewage. Composite samples were analysed for a range of determinands including metals and organic compounds. Of the determinands quantified, the pesticides were almost exclusively below the limit of detection. Most trace metals (with the exception of mercury) were detectable in all wastewaters, reflecting their ubiquitous nature. Organic determinands detected in the influent at μg/L levels included surfactants (linear alkylbenzene sulphonates and nonylphenol ethoxylates), phthalates (diethylhexyl phthalate), polynuclear hydrocarbons and solvents. Trace concentrations of trichlorobenzene, tributyltin and polychlorinated biphenyl 153 were detected in a limited number of works. Little correlation was observed between runoff or trade effluent inputs entering the works and determinand concentration (chromium being the only exception).     

The potential of green roofs to manage Urban Stormwater

Green roofs have considerable potential for stormwater source control, both for new developments and as a retrofit option. In the United Kingdom the lack of local quantitative performance data and modelling tools, together with more general barriers to sustainable drainage systems (SUDS) implementation, may explain their limited uptake to date. This paper presents preliminary findings from a small-scale instrumented green roof test plot located in Sheffield, UK. During spring 2006 the average volume retention was 34% and the average peak reduction was 57%. The key hydrological determinants were the antecedent dry weather period (ADWP), mean rainfall intensity and rainfall depth. Detailed examination of rainfall–runoff relationships in summer 2007 demonstrates the dependency of performance on antecedent moisture conditions. Structural appraisal of a range of flat roof types suggests that retrofitting a green roof will be a feasible option in many cases, particularly for concrete slab roofs.     

Implications for the design of artificial lakes of a study of the Craigavon lakes

Two linked artificial lakes in the new town of Craigavon in Northern Ireland are used for both stormwater management and recreation. The lakes have not only fulfilled their engineering function of preventing flooding but the water quality has been high enough to allow recreation on and beside them. A study of water quality has shown that phosphorus loading-trophic state models apply to these artificial lakes. These models may be able to be used in the design of artificial lakes elsewhere to achieve optimum design and acceptable water quality.     

绿色雨水设施的在线监测系统设计

智慧城市中,物联网技术正逐步改变风景园林师的设计方式。针对中小尺度绿色雨水设施（green stormwater infrastructure, GSI）监测设计的技术问题,从风景园林学科视角探讨在线监测的指标、方法及系统原型。重点阐述了一种基于水量平衡的绿色雨水设施出入流计算及监测方法。针对不同GSI流域开放/封闭、下渗/不可下渗及有无稳定水体的情景,提出了3种传感设计原型,为风景园林师开展相关监测提供了初步指南。进一步介绍典型的物联网数据传输方案并指出：在线监测系统的搭建是通过较小的空间干预,来实现虚拟数据空间与实体空间的融合。     

钻孔过程监测(DPM)对工程岩体质量评价方法的完善与提升

提出能够完善和提升现有工程岩体质量评价方法的一套新技术、新方法和新规律.新技术为现场钻孔过程监测(DPM)技术.新方法为钻孔过程时空数据的快速直观时间序列分析方法.新规律为钻头进深随时间曲线呈分段线性变化,每段钻进速度是常数,每一常数钻速段代表一个均匀抗钻岩石(岩块),常数钻速之间的突变点或低钻速段分别为钻孔穿过岩块间断面的截点或截段.DPM可以提供工程岩体质量评价完善和提升所需要的新的测量方法和数据,从而可以快速、有效、定量地测量到岩石块体的单轴抗压强度、大小和地下分布,以及岩石块体之间界面断面的产状、延伸、凸凹起伏平整度、厚度和充填物质的物理和力学性质.通过实例来介绍、分析和解释这套技术、方法和规律.并且给出DPM钻孔过程监测完善和提升现有工程岩体质量评价RQD,Q,RMR和BQ方法的具体途径和计算公式,能更客观全面地确定岩块单轴抗压强度、岩体质量指标、岩体完整程度、岩石坚硬程度和间断面.     

Partition of pollution between dissolved and particulate phases: what about emerging substances in urban stormwater catchments?

This paper presents results about the occurrence, the concentrations of urban priority substances on both the dissolved and the particulate phases in stormwater. Samples were collected at the outlet of a dense urban catchment in Paris suburb (2.30 km²). 13 chemical groups were investigated including 88 individual substances. Results showed that stormwater discharges contained 45 substances among them some metals, organotins, PAHs, PCBs, alkylphenols, pesticides, phthalates, cholorophenols and one volatile organic compound, i.e. methylene chloride. With respect to the European Water Framework Directive, these substances included 47% of the priority hazardous substances (n = 8), 38% of the priority substances (n = 10). The remaining substances (n = 27) belong to a list of others specific urban substances not included in the Water Framework Directive but monitored during this work. Finally, stormwater quality was evaluated by comparing the substance concentrations to environmental quality standards (EQS) and the particulate content to Canadian sediment quality guidelines. This showed that stormwater was highly contaminated and should be treated before being discharged to receiving waters in order to avoid any adverse impact on the river quality.     

Red-List Substances: Selection and Monitoring

The conference of Ministers representing North Sea littoral states, held in November 1987, agreed certain initiatives to reduce inputs of potentially dangerous substances to the North Sea from land-based sources. The UK Government has responded by proposing reductions of substances on a 'red list', selected on the basis of ecotoxicity, persistence, potential for bio-accumulation and estimated concentration in the environment.
This paper describes the approaches which have been used in selecting candidate substances for the red list and other priority-setting exercises, highlighting the difficulties presented by the lack of data for individual chemicals and the use of default values.
The estimation of input loads via rivers and direct discharges is discussed, with particular reference to monitoring requirements and analytical performance criteria.     

直径1.6米水煤气两段炉热平衡及物料平衡的计算与分析

本文对直径１．６ｍ水煤气两段炉热平衡和物料平衡的计算方法作了探讨，计算出理论空气量、煤、蒸汽的消耗量和煤气、鼓风烟气及灰渣产量，并与实际情况进行了比较和分析，提出了改进的建议。     

大直径改制机头顶管施工技术

结合工程特点,介绍大直径改制机头顶管施工关键技术及其与普通顶管机头的异同和优越性,并对其进行经济效益分析比较。     

基于物联网在线监测的景观项目雨洪管理过程可视化与绩效评估

雨洪管理研究中,实地监测分析的准确性远高于模型模拟与水文计算,高精度监测数据可有效支撑景观项目雨洪管理过程还原及绩效评估。以清华大学胜因院为研究场地,利用无线传感网络(WSN)在线监测技术,通过系统设计组织多种传感器收集分钟级的降雨、树冠截留、土壤持水量、下渗、积水、溢流等雨洪管理数据。研究依据16场降雨数据,定量评估了场地树木冠层及终端雨水花园所发挥的径流削减作用,并分析指标相关性,可视化复杂的土壤水文过程。本研究提供的监测指标、系统及分析方法在景观项目雨洪管理监测中具有较强的推广性。     

Structural investigations of aquatic humic substances by pyrolysis-field ionization mass spectrometry and pyrolysis-gas chromatography/mass spectrometry

The present state-of-the-art in structural investigations of aquatic humic substances and their fractions such as fulvic and humic acids by pyrolysis-field ionization mass spectrometry is outlined. An integrated approach to interpretation uses complementary data of elemental analysis, functional group determinations, Cu²⁺-complexation, H⁺-capacity and results from u.v.-vis- and FT-i.r.-spectroscopy. Proposed building blocks of the molecular structure are supported by chromatographic investigations using Curie-point Py-GC/MS and the available literature reports. The potential and limitation of the applied methodology are discussed.