Oestrogen removal from biological pretreated wastewater within decentralised sanitation and re-use concepts.

Two parallel researches were performed; one focused on the fate of oestrogens in the biological treatment systems within decentralised sanitation and re-use concepts (DESAR), the second related to the development of a suitable specific removal method. A new affinity membrane was developed using antibodies as specific binding sites for hormone removal. It was found that, especially in anaerobic treatment, the core technology in DESAR, the removal is insufficient and therefore an additional separation method is required. The affinity membrane with antibodies was found to be a suitable additional method, though in the current system it only removes one selected compound. Future research will focus on making this method more feasible in practise.     

Anaerobic digestion potential for ecological and decentralised sanitation in urban areas.

The potential of anaerobic digestion in ecological and decentralised sanitation has been investigated in this research. Different anaerobic digestion systems were proposed for the treatment of sewage, grey water, black water and faeces. Moreover, mathematical models based on anaerobic digestion model no.1 (ADM1) were developed for determination of a suitable design for each system. For stable performance of an upflow anaerobic sludge blanket (UASB) reactor treating sewage, the model results indicated that optimisation of wastewater conversion to biogas (not COD removal) should be selected for determination of the hydraulic retention time (HRT) of the reactor. For the treatment of sewage or black water in a UASB septic-tank, the model results showed that the sludge removal period was the main parameter for determination of the HRT. At such HRT, both COD removal and wastewater conversion are also optimised. The model results demonstrated that for treatment of faeces in an accumulation (AC) system at temperature > or = 25 degrees C, the filling period of the system should be higher than 60 days. For maximisation of the net biogas production (i.e. reduction of biogas losses as dissolved in the effluent), the separation between grey water, urine and faeces and reduction of water consumption for faeces flushing are required. Furthermore, the faeces and kitchen organic wastes and grey water are digested in, respectively, an AC system and UASB reactor, while the urine is stored.     

Centralised or decentralised sanitation in Swedish summerhouse areas in transition to permanent living?

The standard of wastewater management is high in Sweden. Around 90% of the population is connected to central wastewater treatment plants with high requirements of nutrients removal; however, still the problem with algae blooms in the Baltic Sea exists. The aim of the VeVa project was to develop a simple and user-friendly Excel-based model to support environmental decisions of how to select wastewater systems for housing areas where no central sewer system exists. The VeVa model deals with two types of environmental issues: substance flow analysis and energy analysis. Six system structures were studied for the transition area Lill?ngsdal in V?rmd? municipality sorted in three categories: 1) on-site systems for single households; 2) local collective systems; 3) connection to central systems. All studied system structures, except for a Sand filter system, fulfilled the goals of reducing phosphorus and BOD7 according to Swedish guidelines for on-site systems in sensitive areas. All studied systems, except for the Sand filter system, have the potential to fulfil the Swedish National Environmental goal to recycle 60% phosphorus to productive land. The systems with central wastewater treatment plant and local wastewater treatment are the most energy efficient alternatives that also fulfil the requirements of discharges and environmental goals regarding phosphorus recycling.     

住宅区生态卫生排水系统技术和费用效益评价

生态卫生排水系统通过污染源的分类收集,并进行循环利用,其系统构成具有可持续性.针对内蒙古自治区鄂尔多斯市郝兆奎生态小区生态卫生排水(源分离)系统工程,分析了住宅区生态卫生排水系统的技术特征,同时对技术的适用性进行了调查.结果表明,住宅区生态卫生排水系统在技术上基本可行.采用费用效益法,当社会折现率为8%时,郝兆奎生态小区生态卫生排水系统经济净现值(ENPV)大于零,项目经济可行.     

An intelligent visualisation and decision support system for decentralised wastewater treatment plants.

Current sanitation concepts of decentralised wastewater treatment and reuse raise the issue of monitoring and maintenance of such systems. To guarantee high quality of the recycled water, systems with high requirements concerning process technology are essential. With increasing numbers of decentralised treatment systems spread over far distances it will become more and more impossible and uneconomic to have expert personnel on site. Therefore, new visualisation and intelligent information systems are necessary. The paper describes the structure and 3D-demonstrations as a base for information visualisation. Up-to-date visualisation techniques, facilitating the cognition of context-adapted information, make it possible to maximise the amount of information presented to the user without overwhelming her or him. Concerning diagnosis and decision support systems in the domain of wastewater treatment, several interesting approaches are presented, estimating their applicability for decentralised wastewater treatment systems. The intelligent decision support system presented here consists of a combined ontology- and case-based reasoning system in addition to a process monitoring system. It is responsible for plausibility checks, error diagnosis, solution proposals, and optimisation suggestions.     

Making decentralised systems viable: a guide to managing decentralised assets and risks.

Decentralised systems have the potential to provide a viable option for long term sustainable management of household wastewater. Yet, at present, such systems hold an uncertain status and are frequently omitted from consideration. Their potential can only be realised with improved approaches to their management, and improved methods to decision-making in planning of wastewater systems. The aim of this paper is to demonstrate the value of a novel framework to guide the planning of decentralised systems so that asset management and risk management are explicitly considered. The framework was developed through a detailed synthesis of literature and practice in the area of asset management of centralised water and wastewater systems, and risk management in the context of decentralised systems. Key aspects of the framework are attention to socio-economic risks as well as engineering, public health and ecological risks, the central place of communication with multiple stakeholders and establishing a shared asset information system. A case study is used to demonstrate how the framework can guide a different approach and lead to different, more sustainable outcomes, by explicitly considering the needs and perspectives of homeowners, water authorities, relevant government agencies and society as a whole.     

Screening of chemical oxidation processes and other methods for decolorization of urine for its re-use as toilet-flush liquid in ecological sanitation systems.

Because of its potential use as fertilizer, urine ("yellow water") is a resource originating from sanitation. Its separate collection in no-mix toilets is a beneficial aspect of ecological (source control) sanitation. In order to avoid dilution of the fertilizing nutrients with toilet flush water, the utilization of yellow water as toilet flush liquid seems to be advantageous. To be accepted for this purpose, urine has to be decolorized (and also deodorized). In this study activated carbon adsorption, irradiation with UV light of different wavelengths, the advanced oxidation processes ultrasound, UV/H2O2, and photocatalytic oxidation have failed to decolorize urine. Biological treatment caused brown colour of the treated urine. Only ozonation was successful in colour removal, although it did not affect TOC. In spite of darkening of yellow water during biological treatment (generation of humic substances), smaller ozone doses were required for decolorizing the biologically pre-treated urine than for original urine. Photocatalytic oxidation of biologically treated urine also removed brown colour, but the original yellow colour remained. In ozonated urine, yellow colour was reconstituted unless hydrogen peroxide was added. In addition to colour removal, ozone contributed to deodorization as a consequence of ammonia stripping and probably of phenol oxidation.     

生态卫生系统的发展与实践现状

生态卫生系统的基本思想是对生活污水进行分类收集及源处理,以期实现可分别进行营养盐循环回用及水资源再生利用的可持续型废物管理模式.对生态卫生系统的核心理念和发展及实践现状进行了讨论,并对该系统在我国的实施提出了建议.     

Toxicity of domestic wastewater pH to key species within an innovative decentralised vermifiltration system.

The development of innovative decentralised wastewater treatment systems is pertinent to environmental sustainability. However for their appropriate use they require significant research and design to ensure they can be relied upon in the future and in most cases they have received less attention and research than large-scale sewage systems. This study assessed the likelihood of biological inhibition and disruption from pH to key species for vermifiltration. The test firstly assessed the buffer capacity of a vermicompost + manure media finding it had a relatively high buffering capacity for pH. The toxicity after the buffer capacity experiment showed that the species would survive between pH levels of 6.2 and 9.7. At the higher and lower pH levels however the survival of juveniles was impaired, probably due to their ability to uptake greater amounts of soluble salts and inability to regulate them. Overall the study showed that the tolerance of the key vermifiltration species to pH was far less than their survival as previously proposed and further research assessing their long-term population dynamics in a vermifiltration system with pH is warranted.     

Status analysis and strategic framework for sanitation management in Asia and Africa.

Following rapid population increase and industrial development, the ever increasing environmental pollution and the associated sanitation-related problem are no longer regional or local but have become an issue requiring global-dimensional concern and the provision of problem-solving alternatives. Especially, since most problems result from inappropriate sewerage and the lack of sewage treatment system are in a serious state occurring in economically underdeveloped regions, and as such, their significance is enormous. The United Nations Environment Programme (UNEP) has been making efforts to establish the technology selection methodology applicable in developing countries, through the accurate status, investigation and analysis of the wastewater management state in Asian and African regions, and the sanitation management guideline utilisable by political leaders or decision-makers. As part of this effort, the Korea Institute of Water Environment (KIWE), together with the UNEP, selected China and Vietnam (in Asia) and Kenya and Ethiopia (in Africa) as subject countries to investigate and perform on-site sanitation management investigations and analysis in this research. Results obtained from the on-site investigation were analysed, and in order to be helpful in establishing a strategy for sanitation management in underdeveloped countries, the strategic framework (SF) has been made based on characterised results.     

Feasibility of a constructed wetland and wastewater stabilisation pond system as a sewage reclamation system for agricultural reuse in a decentralised rural area.

The performance of a constructed wetland (CW) and wastewater stabilisation pond (WSP) system for sewage reclamation and paddy rice irrigation in a decentralised rural area was examined using a feasibility study. The CW was satisfactory for sewage treatment, with good removal efficiency even in the winter period, but the effluent concentration was relatively high in the winter period owing to the high influent concentration. The CW effluent was further treated in a WSP and the WSP effluent was considered safe for crop irrigation with respect to sewage-borne pathogens. Reclaimed water irrigation did not adversely affect the yield of rice; on the contrary, it resulted in an approximately 50% greater yield than in controls. The chemical characteristics of the soil did not change significantly during the experimental period of irrigation with reclaimed water. In the winter, CW effluent could be stored and treated in a WSP until the spring; the water could then be discharged or reused for supplemental irrigation during the typical Korean spring drought. Overall, sewage treatment and agronomic reuse using a CW-WSP system could be a practical integrated sewage management measure for protecting receiving water bodies and overcoming water shortages in decentralised rural areas.     

Water shortage and needs for wastewater re-use in the north China.

This paper analyses the present condition of the water shortage in north China where annual rainfall is low and per capita water resource is below the line of regular water stress, or even the line of absolute water scarcity. Of the available water resources, the percentge of water withdrawal in all the north basins is high--the Yellow River and Huai River basins being greater than 80% and the Hai River basin mainly depending on interbasin water transfer. Over-withdrawal of water also results in serious water environmental problems including "flow cut-off" of the Yellow River main channel and water pollution of many rivers. The paper also analyses the potential of wastewater as a resource and the demand for treated wastewater re-use. In north China, due to low rainfall and high potential evaporation environmental re-use, gardening, afforestation, etc. is considered as the main usage of the treated wastewater. Considering the economic restrictions in the less developed area, a decentralised system can be taken as an important option in formulating water re-use strategies.     

Safety of treated water for re-use purposes--comparison of filtration and disinfection processes.

A study was conducted on the distribution of pollutants in treated wastewater and the its safety for re-use purposes. Based on the results of a series of tertiary treatment experiments, the effects of three filtration processes, i.e. coagulation-filtration, ozonation-biological activated carbon filtration (O3-BAC) and ultrafiltration (UF), and two chemical disinfection processes, i.e. chlorination and ozonation, on the safety of water re-use were evaluated. It was found that the concentrations of the main pollutants in the secondary effluent and further filtered water follow a log-normal distribution and, therefore, a log-normal probabilistic function can be used to evaluate the suitability of the treated water for re-use purposes. Among the three filtration processes evaluated, UF is the most effective in turbidity removal but less effective in colour and COD removal, while coagulation-filtration and O3-BAC can ensure a good removal of all these pollutants. Regarding chemical disinfection, although chlorine is very effective in inactivation of coliform bacteria, it can not achieve a substantial decrease in viruses. As ozone is applied, effective virus removal can be achieved.     

From conventional to advanced environmental sanitation.

The basic concept of collecting domestic liquid waste in water-borne sewer systems goes back more than 100 years and became in the last century the conventional approach to sanitation in urban areas. Over the years, these sewage disposal systems had to be successively upgraded by additional sewage treatment plants increasing investment, operating and maintenance costs. Although these conventional sanitation systems could improve significantly the public health situation in those countries who could afford to install and operate them, it is highly questionable, if they are economically and ecologically sustainable. The large number of people in the developing world who still do not have access to adequate sanitation is a clear indication that the conventional approach to sanitation is not adapted to the socio-economic condition prevailing in most countries of Africa, Asia and Latin America. Advanced environmental sanitation is aiming not only to protect public health and the integrity of aquatic ecosystems but also to conserve precious freshwater and non-renewable resources. The Bellagio Principles and the Household Centred Environmental Sanitation Approach (HCES) are suggested as guiding principles and a new approach for planing and designing advanced (sustainable) environmental sanitation systems.     

Sustainable sanitation and water in small urban centres.

The objective of this paper is to review the global trends in urbanization with respect to availability of adequate sanitation and water supply services. Urbanization is unrelenting and rapid increase in the urban population in the less developed countries is of major global concern regarding this topic of sustainable sanitation and water. Most global urban growth is in the smaller cities and in the developing world. Half the urban developing world lacks adequate water and sanitation. Global urban access to waterborne sanitation is not affordable and thus is not a realistic option so alternative approaches are necessary. The treatment of drinking water cannot be a substitute for sanitation. In order to achieve sustainable sanitation, a change in attitude about human excreta and use of water is required. Essential features of a sustainable sanitation system are: containment, sanitisation and recycling. To improve water supply, we need to improve management practices, use full-cost pricing, introduce watershed approaches to protection and provide improved sanitation. Small urban initiatives need to go beyond the traditional sectors and new initiatives are required like on-site urban ecostations, source-separation of urine and faeces, decentralised greywater treatment and integration of sanitation into the cost of housing.     

Cost effectiveness of centralised and decentralised storm water treatment

As part of a research & development project commissioned by the Land of North Rhine-Westphalia's Ministry for the Environment and Nature Conservation, Agriculture and Consumer Protection (MUNLV) an examination is being carried out of the general possibilities for centralised and decentralised treatment storm water runoff to be discharged into (canalised) receiving waters and the costs ensuing from this. The examination of the different options is being carried out under real conditions, with the Briller Creek (Wuppertal/Germany) and Müggen Creek (Remscheid/Germany) catchment areas being used as models. The range of investigations deals with a comparison between 'decentralised, semicentralised, centralised' storm water treatment, centralised storm water treatment involving a separate sewer and parameter-specific pollution based storm water runoff control. In the framework of the research project each of the variants is to be elaborated and the costs are to be calculated so as to permit a comparison between the different system designs. In particular, the investigations are to take into account the actual requirements to be met by storm water drainage systems involving separate sewage systems.     

Understanding community receptivity to water re-use: Ku-ring-gai Council case study.

This social research project investigated community receptivity to using rainwater and greywater as alternative domestic water sources. It was focused in the Ku-ring-gai local government area in northern Sydney, and involved a household questionnaire followed by community leader interviews and resident focus groups. Trends, such as a prolonged drought and increasing population, compound the current crisis and concern facing Sydney's available water supply. Substitution of domestic potable water has been promoted as part of the solution. The research results revealed that community receptivity was highest for external uses, such as watering gardens and flushing toilets, and progressively decreased with increasing personal contact. Receptivity to greywater reuse fell more rapidly with the community believing there was a higher health risk associated with its use. Gender and cultural background were revealed as significant variables and give insight into the design of strategies to target these demographic groups. This evidence provides a reliable stocktake of current receptivity revealing that the community has good awareness and positive association with water reuse for many household activities. This now needs to be harnessed through programs targeted at developing skills, resources and motivation for new water reuse practices and technologies across diverse social groupings.     

Aerobic granular sludge: a promising technology for decentralised wastewater treatment.

In order to evaluate the characteristics of aerobic granular sludge, a sequencing batch reactor, feeding with synthetic wastewater at the organic loading rate of 8 kg COD/m3 d, was employed on the laboratory scale. Granules occurred in the reactor within 1 week after the inoculation from conventional flocculent sludge. Aerobic granular sludge was characterised by the outstanding settling properties and considerable contaminates removal efficiencies. The SVI30 values were in the range of 20 to 40 ml g(-1). However, the sludge volume index of short settling time (e.g. SVI10--10 min) is suggested to describe the fast settling properties of aerobic granular sludge. The potential application in the decentralised system is evaluated from the point view of footprint and high bioactivity. The occurrence of sloughing, resulting from the outgrowth of filamentous organisms, would be responsible for the instability of aerobic granules. The starvation phase should therefore be carefully controlled for the maintenance and stability of aerobic granular sludge system.     

Linking environmental and economic sustainability in establishing standards for wastewater re-use in Israel.

Israel is one of the world's leaders in agricultural re-use of wastewater, currently re-using over 60% of produced wastewater. The effects of arid climate, intensive irrigated agriculture and limited water resources make re-use necessary to conserve fresh water for domestic use. Quality standards for wastewater re-use are needed to protect public health and prevent environmental and agricultural damage. This paper examines the environmental and economic sustainability of the proposed upgrade of wastewater quality standards. A tertiary treatment standard was proposed, but has not been approved due to objections from local authorities and farmers. An upgrade will require higher treatment costs, which will be divided between farmers and local authorities through the pricing of the wastewater. Farmers oppose the upgrade because they will not be able to pay higher prices for wastewater, which they use to irrigate low-profit crops. If the price is too high, these farmers may be forced out of business and a substantial reduction in cultivated lands may result. If the price is too low, the poorer local authorities may not be able to comply with the standards, and may discharge improperly treated wastewater, causing environmental damage. A successful policy balances the needs for environmental protection with the economic realities of farmers and local authorities and may require compensation for local authorities or farmers in order to achieve maximum environmental protection.