No / Effective integrated water management is a key component of the World Water Vision and the way in which aspirations for water equity may be realized. Part of the vision includes the promotion of sustainability of water systems and full accountability for their interaction with other urban systems. One major problem is that “sustainability” remains an elusive concept, although those involved with the provision of urban wastewater systems now recognize that decisions involving asset investment should use the “triple bottom line” approach to society, the economy, and the environment. The Sustainable Water Industry Asset Resource Decisions project has devised a flexible and adaptable framework of decision support processes that can be used to include the principles of sustainability more effectively. Decision mapping conducted at the outset of the project has shown that only a narrow range of criteria currently influence the outcome of asset investment decisions. This paper addresses the concepts of sustainability assessment and presents two case studies that illustrate how multicriteria decision support systems can enhance the assessment of the relative sustainability of a range of options when decisions are being made about wastewater asset investment.

The principal aims of this thesis were to examine whether there were hydraulic links between individual on-site wastewater systems in sandy soils at Salt Ash and the Tilgerry Creek estuary near Port Stephens, New South Wales, and whether the chemical and microbiological contaminants from on-site systems could reach surface and groundwaters, and possibly lead to impacts on estuarine oyster growing waters. The research outcomes are contained within the thesis and in four refereed papers presented at conferences, and which have been subsequently published, or are in press. Copies of each of these papers are contained within the thesis Appendices. The presence of faecal contamination from domestic systems in the estuary, and surface drains in particular, has been confirmed by work contained in this thesis. The potential level of risk to human health from the consumption of contaminated oysters is, however, regarded as very low, although an assessment of health risk using established microbial assessment models has not been undertaken / Doctor of Philosophy (PhD)

A degradação da qualidade de água no Brasil é um problema sério que afeta grande parte dos rios e lagos. O objetivo desse trabalho é discutir quais mecanismos podem ser usados para a melhora da qualidade das águas tendo em vista a garantia dos seus usos. A legislação brasileira prevê que o sistema de gestão de recursos hídricos deve definir os usos pretendidos para as águas das bacias hidrográficas. Nos casos em que a qualidade das águas precisa ser melhorada para garantir os usos pretendidos, o sistema de gestão de recursos hídricos deve estabelecer etapas progressivas, em que, para cada etapa, são definidas metas de qualidade de água específicas. Utilizando como exemplo o sistema de gestão de qualidade de água de diferentes países, essa dissertação analisa o sistema brasileiro, a definição de metas e a sua relação com o sistema de gestão de recursos hídricos, conforme as definições previstas na Resolução CONAMA 357/05, e identifica os desafios e estratégias para superá-los. Também demonstra que, para que haja mudanças efetivas no cenário de qualidade das águas, será necessário para o país um planejamento estratégico, com prioridades definidas de acordo com as especificidades locais, os investimentos necessários e os aspectos econômicos, enfatizando-se o planejamento e o controle dos serviços de saneamento. / Water quality degradation is a serious problem that affects large extensions of rivers and lakes. The purpose of this thesis is to discuss which mechanism can be used to improve water quality in order to guarantee designated uses. The Brazilian water law establishes that the water resource management system must define the designated uses for the watershed. In cases where water quality must be improved to guarantee such uses, the water resource management system establishes a step-by-step system in which, for each step, specific water quality targets are defined. Using as an example the water quality management system of different countries, this thesis analyses the Brazilian system, the target definitions and its relations with the water resource management system, as defined by CONAMA Resolution 357/05, and identifies the challenges and the strategic seams to surpass them. It also demonstrates that, in order to get an effective change in the water quality scenario, it will be necessary for the country to work on strategic planning, with priorities based not only on specific local characteristics, but also on financial needs and economical aspects, with special emphasis on regulation and control of wastewater systems.

A degradação da qualidade de água no Brasil é um problema sério que afeta grande parte dos rios e lagos. O objetivo desse trabalho é discutir quais mecanismos podem ser usados para a melhora da qualidade das águas tendo em vista a garantia dos seus usos. A legislação brasileira prevê que o sistema de gestão de recursos hídricos deve definir os usos pretendidos para as águas das bacias hidrográficas. Nos casos em que a qualidade das águas precisa ser melhorada para garantir os usos pretendidos, o sistema de gestão de recursos hídricos deve estabelecer etapas progressivas, em que, para cada etapa, são definidas metas de qualidade de água específicas. Utilizando como exemplo o sistema de gestão de qualidade de água de diferentes países, essa dissertação analisa o sistema brasileiro, a definição de metas e a sua relação com o sistema de gestão de recursos hídricos, conforme as definições previstas na Resolução CONAMA 357/05, e identifica os desafios e estratégias para superá-los. Também demonstra que, para que haja mudanças efetivas no cenário de qualidade das águas, será necessário para o país um planejamento estratégico, com prioridades definidas de acordo com as especificidades locais, os investimentos necessários e os aspectos econômicos, enfatizando-se o planejamento e o controle dos serviços de saneamento. / Water quality degradation is a serious problem that affects large extensions of rivers and lakes. The purpose of this thesis is to discuss which mechanism can be used to improve water quality in order to guarantee designated uses. The Brazilian water law establishes that the water resource management system must define the designated uses for the watershed. In cases where water quality must be improved to guarantee such uses, the water resource management system establishes a step-by-step system in which, for each step, specific water quality targets are defined. Using as an example the water quality management system of different countries, this thesis analyses the Brazilian system, the target definitions and its relations with the water resource management system, as defined by CONAMA Resolution 357/05, and identifies the challenges and the strategic seams to surpass them. It also demonstrates that, in order to get an effective change in the water quality scenario, it will be necessary for the country to work on strategic planning, with priorities based not only on specific local characteristics, but also on financial needs and economical aspects, with special emphasis on regulation and control of wastewater systems.

Residential on-site wastewater systems (OWS) are a potential source of phosphorus (P) which can negatively impact surface water quality in rural watersheds. The magnitude of P loading from OWS is typically not monitored, and is further complicated when agricultural land-uses are intermixed with residential dwellings. Watershed-scale computer simulations are commonly used tools for evaluating the impacts of land-use changes on P loading. Existing models simulate OWS P treatment via vertical flow transport in native soils. However, in Nova Scotia (NS) OWS designs rely pre-dominantly on lateral flow and imported sand filter media. In this thesis, a watershed-scale computer modeling framework for simulating P loads from agriculture and lateral flow OWS designs was developed and tested. The framework consists of the P on-site wastewater simulator (POWSIM), designed specifically for this study, which is used in conjunction with the Soil and Water Assessment Tool (SWAT) model. The POWSIM loading tool has three computational components: (i) OWS disposal field design type selection and treatment media mass calculation; (ii) disposal field P treatment dynamics; and (iii) soil subsurface plume P treatment dynamics. The active P treatment media mass and dynamics equations were developed from numerical modeling (HYDRUS-2D) and lateral flow sand filter (LFSF) OWS disposal field experiments. A 2-part piecewise linear model was found to best represent LFSF P treatment processes. Testing of the modeling framework in the mixed land-use Thomas Brook Watershed (TBW) in NS demonstrated improved simulation of baseflow total P (TP) loads in both a predominantly residential subcatchment and one dominated by agriculture over the SWAT model without POWSIM. Different residential and agricultural development and beneficial management practice (BMP) scenarios were evaluated in the TBW. Agricultural BMPs were most effective at reducing cumulative TP loads while OWS BMPs were best at mitigating in-stream eutrophication impacts. The 50 year simulation period for the various scenarios found peak OWS TP loading occurring between 25 and 50 years, suggesting that modeling for many decades is required for proper evaluation. This study highlights the importance in identifying specific water quality issues that need to be targeted prior to implementing a BMP strategy.

Over the last twenty years, the concepts of sustainability and sustainable development have assumed political importance around the world, and have been largely embraced by governments and prominent international institutions. These concepts have been a means of tackling the challenges of population growth and environmental change. For the UK water sector, these concepts now represent a multitude of challenges. The confluence of climate change and population growth is reducing access to, and the availability of, water resources. The financial costs of inputs such as energy, chemicals, materials and cost of process by-products such as greenhouse gases, carbon, and waste services continue to rise. Government regulators are demanding an improvement in the quality of services, increasingly stringent conditions for emissions to water, air or land, catchment-specific management of the water environment, and the adoption of longterm planning horizons. The UK government has expectations that the water sector will play a role in the delivery of its targets for reducing energy consumption and carbon emissions. Society demands that WaSCs engage in high-level stakeholder consultations and employ long-term visions to guide their decision-making. Finally, WaSCs are increasingly expected to demonstrate and respond to local and global concerns (under the rubric of corporate responsibility) to further justify their value to society. Cont/d.

Today billions of people live without access to basic sanitation facilities, and thousands die every week due to diseases caused by fecal contamination associated with improper sanitation. It has thus become crucial for decision makers to have access to relevant and sufficient data to implement appropriate solutions to these problems. The Global Water Pathogen Project http://www.waterpathogens.org/ is dedicated to providing an up-to-date source of data on pathogen reduction associated with different sanitation technologies that are important if the world is to achieve the Sustainable Development Goals (SDGs) related to health and sanitation provision. In this research, a subset of the Global Water Pathogen Project (GWPP) data is used to access the reduction of bacteria and viruses across different mechanical and natural sanitation technologies. The order of expected removal for bacteria during wastewater treatment was reported as highest for a membrane bioreactor (4.4 log10), waste stabilization pond (2.3 log10), conventional activated sludge (1.43 log10), anaerobic anoxic oxic activated sludge (1.9 log10), trickling filter (1.16 log10), and upflow anaerobic sludge blanket reactor (1.2 log10). Furthermore, the order of expected removal for viruses was reported as highest for a membrane bioreactor (3.3 log10), conventional activated sludge (1.84 log10), anaerobic anoxic oxic activated sludge (1.67 log10), waste stabilization pond (1 log10), upflow anaerobic sludge blanket reactor (0.3 log10) and trickling filter (0.29 log10). It was found that hydraulic retention time (HRT) had a statistically significant relation to the reduction of bacteria in an anaerobic, anoxic oxic treatment system. Similarly, a significant relation was found between the number of waste stabilization ponds in series and the expected reduction of bacteria. HRT was also found to be a significant factor in virus reduction in waste stabilization ponds. Additionally, it was observed that waste stabilization ponds, trickling filters, and UASB reactors could obtain a greater reduction in bacteria (5-7 log10) when combined with additional treatment (e.g., chemical disinfection or use of maturation ponds). Also, mechanized systems, such as activated sludge systems and membrane bioreactors, obtained a greater reduction (2-3 log10) of viruses when compared to a natural system. It was concluded that the selection of the best suitable technology for pathogen reduction depends on environmental, design, and operational factors as well as considering the performance of specific wastewater treatment systems individually as well as when combined with other treatment technologies that may provide added removal of microbial constituents.

The thesis presents and evaluates the application of the paradigm of agents to the management of the urban wastewater system. The system is conceptualised as a multi-agent system from the development of the models of agents and communication paths. In the development, it has become obvious that coordination (of volumes and pollutant loads) between all the wastewater treatment inputs and the available capacity of the treatment is a key point in the system’s performance. To consider this factor, a coordinating agent is defined. This agent executes the coordination of inputs and the prioritisation of industrial wastewaters when the treatment does not have sufficient available capacity. The prioritisation is solved by a meta-heuristic of ant colony optimisation, which has been instantiated by four algorithmic versions. Finally, the system has been implemented and consecutive cycles of simulation have been executed with the conclusion that the paradigm of agents is a feasible proposal. / La tesi presenta i avalua l’aplicació del paradigma d’agents en la gestió d’un sistema d’aigües residuals urbanes. El sistema es conceptualitza com a sistema multiagent a partir del desenvolupament dels models d’agents i d’enllaços de comunicació. En el desenvolupament s’evidencia que la coordinació (de volums i càrregues contaminants) entre totes les aportacions d’aigües residuals al tractament i la capacitat disponible d’aquest, constitueix un punt clau del funcionament del sistema. Per tal de considerar-ho, es defineix un agent Coordinador que executa la coordinació de les aportacions al tractament i a més, la priorització dels efluents industrials quan el tractament no disposa de capacitat suficient per admetre totes les propostes d’aportacions. La priorització es resol emprant una metaheurística d’optimització de colònia de formigues, la qual s’instancia mitjançant quatre versions algorísmiques diferents. Per últim, s’implementa el sistema i s’executen cicles consecutius de simulació mostrant com el paradigma constitueix una proposta factible.

Human excreta contain plant nutrients and have the potentialto be used as a fertiliser in agriculture. Urine contributesthe major proportion of the nutrients (N, P and K) in domesticwastewater whereas faeces contribute a smaller amount andinvolves greater health risks if reused due to the possiblepresence of enteric pathogens. Human urine does not generallycontain pathogens that can be transmitted through theenvironment. Source-separation of urine and faeces is possible by usingurine-separating (or urine-diverting) toilets, available assimple dry toilets or porcelain flush toilets with dividedbowls. The risk for transmission of disease when handling andreusing the urine is largely dependent on thecross-contamination by faeces. In this research, the presenceof human faeces in urine samples was successfully determined byanalysing for faecal sterols. Cross-contamination was evidentin 22% of the samples from urine collection tanks, and in thesequantified to an average (± SD) of 9.1 ± 5.6 mgfaeces per litre urine. Testing for indicator bacteria wasshown to be an unsuitable method for determining faecalcontamination in human urine sinceE. colihad a rapid inactivation in the urine and faecalstreptococci were found to grow within the system. The fate of any enteric pathogens present in urine iscrucial for the risk for transmission of infectious diseases.Gram-negative bacteria (e.g.SalmonellaandE. coli) were rapidly inactivated (time for 90%reduction, T90&lt;5 days) in source-separated urine at itsnatural pH-value of 9. Gram-positive faecal streptococci weremore persistent with a T90of approximately 30 days. Clostridia sporenumbers were not reduced at all during 80 days. Similarly,rhesusrotavirus andSalmonella typhimuriumphage 28B were not inactivated inurine at low temperature (5°C), whereas at 20°C theirT90-values were 35 and 71 days, respectively.Cryptosporidiumoocysts were less persistent with a T90of 29 days at 4°C. Factors that affect thepersistence of microorganisms in source-separated human urineinclude temperature, pH, dilution and presence of ammonia. By using Quantitative Microbial Risk Assessment (QMRA), therisks for bacterial and protozoan infections related tohandling and reuse of urine were calculated to be&lt;10-3for all exposure routes independent of the urinestorage time and temperature evaluated. The risk for viralinfection was higher, calculated at 0.56 for accidentalingestion of 1 ml of unstored urine. If the urine was stored at20°C for 6 months the risk for viral infection was reducedto 5.4 × 10-4. By following recommendations for storage and reuse, whichare dependent on the type of crop to be fertilised, it ispossible to significantly decrease the risk for infections. Sofar, the level of risk that is acceptable is unknown. Theacceptable risk will be one of the main factors determining thefuture utilisation of source-separated human urine inagriculture. <b>Keywords:</b>urine-separation, urine, wastewater systems,wastewater reuse, recycling, enteric pathogens, faecal sterols,indicator bacteria, hygiene risks, microbial persistence,microbial risk assessment, QMRA, fertiliser, crop.

<p>Human excreta contain plant nutrients and have the potentialto be used as a fertiliser in agriculture. Urine contributesthe major proportion of the nutrients (N, P and K) in domesticwastewater whereas faeces contribute a smaller amount andinvolves greater health risks if reused due to the possiblepresence of enteric pathogens. Human urine does not generallycontain pathogens that can be transmitted through theenvironment.</p><p>Source-separation of urine and faeces is possible by usingurine-separating (or urine-diverting) toilets, available assimple dry toilets or porcelain flush toilets with dividedbowls. The risk for transmission of disease when handling andreusing the urine is largely dependent on thecross-contamination by faeces. In this research, the presenceof human faeces in urine samples was successfully determined byanalysing for faecal sterols. Cross-contamination was evidentin 22% of the samples from urine collection tanks, and in thesequantified to an average (± SD) of 9.1 ± 5.6 mgfaeces per litre urine. Testing for indicator bacteria wasshown to be an unsuitable method for determining faecalcontamination in human urine since<i>E. coli</i>had a rapid inactivation in the urine and faecalstreptococci were found to grow within the system.</p><p>The fate of any enteric pathogens present in urine iscrucial for the risk for transmission of infectious diseases.Gram-negative bacteria (e.g.<i>Salmonella</i>and<i>E. coli</i>) were rapidly inactivated (time for 90%reduction, T₉₀<5 days) in source-separated urine at itsnatural pH-value of 9. Gram-positive faecal streptococci weremore persistent with a T₉₀of approximately 30 days. Clostridia sporenumbers were not reduced at all during 80 days. Similarly,<i>rhesus</i>rotavirus and<i>Salmonella typhimurium</i>phage 28B were not inactivated inurine at low temperature (5°C), whereas at 20°C theirT₉₀-values were 35 and 71 days, respectively.<i>Cryptosporidium</i>oocysts were less persistent with a T₉₀of 29 days at 4°C. Factors that affect thepersistence of microorganisms in source-separated human urineinclude temperature, pH, dilution and presence of ammonia.</p><p>By using Quantitative Microbial Risk Assessment (QMRA), therisks for bacterial and protozoan infections related tohandling and reuse of urine were calculated to be<10^-3for all exposure routes independent of the urinestorage time and temperature evaluated. The risk for viralinfection was higher, calculated at 0.56 for accidentalingestion of 1 ml of unstored urine. If the urine was stored at20°C for 6 months the risk for viral infection was reducedto 5.4 × 10^-4.</p><p>By following recommendations for storage and reuse, whichare dependent on the type of crop to be fertilised, it ispossible to significantly decrease the risk for infections. Sofar, the level of risk that is acceptable is unknown. Theacceptable risk will be one of the main factors determining thefuture utilisation of source-separated human urine inagriculture.</p><p><b>Keywords:</b>urine-separation, urine, wastewater systems,wastewater reuse, recycling, enteric pathogens, faecal sterols,indicator bacteria, hygiene risks, microbial persistence,microbial risk assessment, QMRA, fertiliser, crop.</p>