Greywater treatment and reuse results from a 50-person trial

The paper describes a seven year project to develop a greywater treatment plant for lavatory flushing. Site surveys and laboratory research was used to produce a design for a 50-person residential University hall. The final design included a balancing tank (13:1 peak to average capacity) screening (5 mm), a moving bed bioreactor and alternating deep bed double filtration (reticulated foam). The plant achieved a recycled water quality of 3 mg/l biochemical oxygen demand (BOD) (used as an indicator of odour potential and regrowth) a water clarity of 2 nephelometric turbidity units (NTU) and 2 mg/l suspended solids. Ultra violet (UV) disinfection was added to meet the UK guidelines of zero microbial indicator organisms. The demonstration trial lasted 5 years and users were unable to differentiate between the recycled water and mains water in the blind trial.     

Greywater reuse for irrigation: Effect on soil properties

A controlled study of the effect of greywater (GW) irrigation on soil properties was conducted. Containers of sand, loam and loess soils were planted with lettuce, and irrigated with fresh water, raw artificial GW or treated artificial GW. Greywater was treated using a recirculating vertical-flow constructed wetland. Soil samples were collected every 10 days for the 40-day duration of the study, and plant growth was measured. Soils were analysed for physicochemical and biological parameters to determine changes caused by the different treatments. It was demonstrated that raw artificial GW significantly increased the development of hydrophobicity in the sand and loam soils, as determined by water droplet penetration time. No significant changes were observed for the loess soil under all treatments. Observed hydrophobicity was correlated with increased oil and grease and surfactant concentrations in the soil. Zeta (ζ) potential of the soils was measured to determine changes in the soil particle surface properties as a result of GW irrigation. A significant change in ζ-potential (less negative) was observed in the raw artificial GW-irrigated sand, whereas no difference was observed in the loam or loess. Soils irrigated with fresh water or treated GW exhibited no increase in hydrophobicity. Fecal coliform bacteria were absent or < 10 CFU g^− 1 in soils irrigated with fresh water or treated GW, but at least 1 order of magnitude higher in raw artificial GW irrigated soils. Only in the last sampling event and only for the loess soil was plant growth significantly higher for fresh water irrigated vs. raw or treated GW irrigated soils. This study demonstrates that treated GW can be effectively irrigated without detrimental effects on soil or plant growth; however, raw GW may significantly change soil properties that can impact the movement of water in soil and the transport of contaminants in the vadose zone.     

Grey-Water Reclamation for Non-Potable Re-Use

Direct water recycling has become an important part of water conservation in the dry areas of the world and is now being seriously considered for the UK. This paper reviews current demands in large buildings and balances these against non-potable re-use. Work is also described on the development of a sustainable low running cost treatment unit. Results are presented from a 751/day prototype biological process operated with a synthetic sewage, which achieved a near potable standard at a cost of 25 p/m³. The design, performance and costings of a 40 'population equivalent'demonstration unit are also given.     

期待建筑防火设计制定系统的安全性能标准和设计导引

建筑防火设计规范需要制定系统的安全性能标准和设计导引细则,从源头控制建筑防火的安全度。     

Disinfection With Peracetic Acid for Domestic Sewage Re-Use in Agriculture

This paper describes a four-month pilot study on peracetic acid disinfection of unchlorinated tertiary effluent for unrestricted re-use in agriculture carried out at West Bari (Italy) sewage-treatment works. Dosages and contact times ranging from 1 to 500 mg/1 and 5 to 60 mins, respectively, indicated that 10 mg/1 of peracetic acid, with a 30-min contact time, achieved the WHO faecal coliform guideline (1000 CFU/100ml). Much higher doses (£400 mg/l and 30 mins) were required to meet the corresponding Californian limit of two colony-forming units/100 ml, which has also been adopted in Italy. Efficient mixing of the disinfectant (in one shot addition) was mandatory - particularly at lower dosages (1–10 mg/l) where there was a higher concentration of suspended solids (>5 mg/l).     

Health-based targets for greywater reuse in residential schools in Madhya Pradesh,India

In line with developments in the water reuse sector, this paper applied quantitative microbial risk assessment (QMRA) techniques to seven greywater reuse systems used for recycling shower water for toilet flushing. The objective of the study was to establish a scientific basis for health-based greywater targets for India. It involved qualitative risk assessments and quantitative microbiological analysis using Enterococci, thermotolerant coliforms (TTC) and coliphage indicator organisms. Four conclusions are drawn from this study. Firstly, the systems indicated a low risk and high quality, and secondly that low levels of risk were present in systems, resulting in the recommendation of guideline of 5000 cfu/100 mL rather than 10 000 cfu/100 mL for greywater utilised for direct toilet flushing. Thirdly, disability adjusted life years (DALYs) are a useful indicator of risk for evaluating the performance of a greywater reuse system in addition to chemical/microbiological indicators DALYs, and finally that TTC are a useful surrogate microbial indicator for analysis of greywater in developing countries with limited analytical facilities.     

The process of fire safety design—development ofFire Engineering Guidelines in Australia

Australia is quickly moving toward adopting performance-based regulations for building fire safety. This approach offers owners and designers more flexibility, greater opportunity for innovation, and more cost-effective construction.To help introduce a performance approach, the Fire Code Reform Centre has developedFire Engineering Guidelines, which document an agreed methodology for performance-based design and draws on earlier Australian research and similar developments in a number of countries.The guidelines are the first step in a broader research program to develop a full risk assessment methodology as the basis for fire safety design in Australia.     

浙江乡村风貌与空间营建导则研究

面对浙江乡村建设中存在的风貌特色缺失等相关问题,该文从宏观、中观、微观三个层面对乡村聚落的区域分布、公共空间以及建筑营建进行了深入剖析,遵循与实际操作并行同步的方式给出针对性的营建导则。研究着眼于乡村风貌营建与管理工作,整合风貌特色与空间营建的行动导则可在一定程度上避免实施中由于单一视角切入而产生的低效与片面。同时关注对乡村内在特质和主体行为层面的表达,期望对浙江地区乃至更广范围的乡村建设起到一定的指导意义。     

浅析城市设计导则的作用与编制原则

城市设计导则是城市设计项目编制的核心内容,是城市设计参与城市建设管理的重要途径。加强城市设计导则的编制工作将有助于城市设计及其控制在城市建设中的实施。本文着重介绍城市设计导则的分类、基本功能以及设计导则编制应遵循的原则。     

Reuse of greywater for irrigation around homes in Australia: Understanding community views,issues and practices

We examined people's views on a number of water issues and their motivation, practices and concerns about greywater reuse for irrigation of around homes. Survey participants (275) from different socio-economic background from 125 suburbs in the Western Sydney region, Australia took part in the study. Regardless of their age and gender, when asked which was the most important issue regarding water in their region from a prescribed list, the majority of participants identified water quality as the most important and availability without water restriction as the least important. About half of the participants reused greywater regularly or at some time during the last few years. The cost of plumbing and health risks to people, plants and soil are critical issues for greywater reuse and need attention. For the reusing widely and sustainably, there is a need for easily accessible, user-friendly information packages to create ‘greywater reuse literacy’ in the community.     

当前我国城市设计导则编制的适应性思考

结合我国当前市场经济、规划体制和社会环境的条件背景下城市设计导则编制的基本需求,该文尝试探讨了具有一定本土适应性的导则编制体系及作用方式,以层次递进的导则控制体系、强化管理手段与导控兼施的控制方式,实现城市设计成果的动态适应。     

Derivation of numerical values for the World Health Organization guidelines for recreational waters

In April 2001, draft ‘Guidelines’ for safe recreational water environments were developed at a World Health Organization (WHO) expert consultation. Later the same month, these were presented and discussed at the ‘Green Week’ in Brussels alongside the on-going revision of the European Union Bathing Water Directive 76/160/EEC. The WHO Guidelines cover general aspects of recreational water management as well as define water quality criteria for various hazards. For faecal pollution, these include faecal indicator organism concentrations and an assessment of vulnerability to faecal contamination. Central to the approach set out in the WHO Guidelines are: (i) the concept of beach profiling to produce a ‘sanitary inspection category’ which implies a priori hazard assessment as a core management tool and (ii) the prediction of poor water quality to assist in real time risk assessment and public health protection. These management approaches reflect a harmonized approach towards the assessment and management of risk for water-related infectious disease being applied by WHO. Numerical microbiological criteria for intestinal enterococci are proposed in the new Guidelines. These were developed using a novel approach to disease burden assessment, which has been applied to both recreational waters and urban air quality. This paper explains the scientific rationale and mathematical basis of the new approach, which is not presented in the WHO Guidelines for recreational waters.     

北京城市设计导则运作机制健全思路与对策

我国正处在高速城市化进程中,城市建设需要及时应对社会经济、文化和生活等领域不断产生的新需求,城市空间形态也因此经历着急剧的变化,这种快速发展模式在满足各种城市需求的同时也暴露出一系列的问题.随着经济社会的发展,人们对城市建设的关注也逐渐集中到提升城市空间品质方面,因此.将城市设计纳入规划管理,并通过城市设计的控制与引导提高城市整体品质成为当今城市发展的一大诉求.研究从城市设计编制与管理的角度出发,结合《北京中心城地区城市设计导则编制标准与管理办法研究》,从规范编制、纳入管理和推广实施三个方面对如何健全北京城市设计导则的运作机制进行探讨,以期为规划师们提供有益参考.     

汶川地震灾后重建之侨爱小学设计导则分析

5．12汶川大地震后,结合海外华侨赈灾的爱心捐款,国务院侨务办公室主持开展了“侨爱小学”系列工程,本设计导则通过指令性和指导性设计要求,并提供设计范例,对具体项目进行建筑设计上的总体调控,使该系列工程充分体现“侨爱”的精神内涵并形成风格统一、特色鲜明的类型建筑。     

施工企业签订承包合同时应注意的事项

针对施工企业承包合同的重要性,对施工合同签订中要注意的问题进行了分析论述并提出了解决的办法,从而为避免合同漏洞,签订严密的施工合同打下基础,可以为广大施工单位参考学习。     

Environmental risk assessment of zinc in European freshwaters: A critical appraisal

A risk assessment report (RAR) on zinc and zinc compounds has recently been prepared in the framework of the European Union (EU) Council Regulation 793/93/EEC on Existing Chemicals. The EU Scientific Committee on Human and Environmental Risks (SCHER) has, however, expressed some fundamental, science-based concerns about the approach followed and the conclusions. The main objective of the present study was to assess the potential environmental risks associated with current use patterns of Zn in nine EU river basins in Germany, France and Belgium, thereby using more advanced methodologies which are largely in line with the recommendations made by SCHER. This included (i) avoiding working with measured Zn concentrations from monitoring stations that were potentially influenced by point sources and/or historical contamination, (ii) the full bioavailability normalization of all chronic ecotoxicity data to river basin specific physico-chemistry using biotic ligand models (BLM), prior to deriving predicted no effect concentrations (PNEC) with the species sensitivity distribution (SSD) approach, and (iii) the use of a probabilistic framework for risk characterization. Further, a total risk approach instead of an added risk approach was used, and the PNEC was equated to the HC5-50 without an additional assessment factor. Based on monitoring data we estimated predicted environmental concentrations (PEC) for the different EU river basins between 1.3 and 14.6 µg dissolved Zn/L. PNEC values varied between 22.1 and 46.1 µg dissolved Zn/L. This resulted in deterministic risk characterization ratios (RCR) that were below 1 in all river basins, suggesting that there is no deterministic regional risk associated with current use patterns of Zn in these river basins. With the probabilistic approach we identified rather limited risks, i.e., between < 0.4 and 18.3%. When the EU RAR approach was applied to the same monitoring datasets, deterministic risks were found in different river basins. A detailed analysis showed that this different deterministic conclusion of risk is mainly due to the fact that the EU RAR (i) uses an additional assessment factor of 2 to derive the PNEC and (ii) uses a more conservative approach for implementing bioavailability (BioF approach). We argue that the larger conservatism in the EU RAR mainly originates from decisions made to deal in a pragmatic way with (i) uncertainty related to the across-species extrapolation of BLMs and (ii) the relatively high sensitivity of some multi-species toxicity studies.     

地铁机电安装综合管线施工管理与技术指引

对地铁车站机电安装工程综合管线施工管理与技术做了指引性阐述,对综合管线施工安装布置原则作了介绍,在地铁车站施工中得到了实际应用,效果明显。     

A methodology for estimating airborne virus exposures in indoor environments using the spatial distribution of expiratory aerosols and virus viability characteristics

This study investigated the feasibility of using the spatial distribution of expiratory aerosols and the viability functions of airborne viruses to estimate exposures to airborne viruses in an indoor environment under imperfectly mixed condition. A method adopting this approach was tested in an air-conditioned hospital ward. Artificial coughs were produced by aerosolizing a simulated respiratory fluid containing a known concentration of benign bacteriophage. The bacteriophage exposures estimated on the basis of the spatial aerosol distributions and its viability function were in reasonable agreement with those measured directly by biological air sampling and culturing. The ventilation flow and coughing orientation were found to play significant roles in aerosol transport, leading to different spatial distribution patterns in bacteriophage exposure. Bacteriophage exposures decreased with lateral distance from the infector when the infector coughed vertically upward. In contrast, exposures were constant or even increased with distance in the case of lateral coughing. The possibility of incorporating the proposed exposure estimation into a dose-response model for infection risk assessment was discussed. The study has also demonstrated the potential application of viability functions of airborne viral pathogens in exposure assessment and infection risk analysis, which are often unavailable in literature for some important communicable diseases. PRACTICAL IMPLICATIONS: The proposed method makes use of the viability function of the virus and the spatial distribution of the expiratory aerosols for virus exposure estimation. Spatial differences in aerosol distribution and its influences on virus exposure in an air space can be determined. Variations in infectious dose with carrier aerosol size could also be considered. The proposed method may serve as a tool for further investigation of ventilation design and infection control in clinical or other indoor environments.     

Decentralized water management: rainwater harvesting and greywater reuse in an urban area of Beijing,China

Large-scale centralised wastewater treatment system has often prevailed in industrial countries, and has been regarded as a successful approach during the last century. However, transfer of this highly water-consuming system and so-called ‘end-of-pipe’ technology to developing countries, especially in fast-growing cities with scarce water resources, has been extremely limited. Decentralized water treatment is not a new technology and has been successfully implemented in many rural areas worldwide. However, there are few applications in urban areas. This study at Tianxiu Garden in Beijing, China, investigated the potential and feasibility of water management based on a decentralized approach, but modified for application of greywater recycling and rainwater harvesting in a densely populated semi-urban area. A high degree of drinking water substitution (more than 25%) could not be attained by rainwater harvesting. Recycling of treated greywater for toilet flushing was shown to be an efficient method for minimisation of drinking water consumption, and a more suitable technique than rainwater harvesting for saving water in Beijing, China.