Tesi sul tema "Rainwater tanks"

This project examined the chemical water quality of urban rainwater tanks, with a focus on quantifying the contribution of contaminants from urban air pollution. It also assessed the health risk for people utilising rainwater tanks as their main drinking water source. Tank water was sampled from 26 tanks at 23 locations spread across Brisbane, on a monthly basis, for a whole year. Sampling of atmospheric deposition (bulk deposition) at 16 sites was conducted concurrently. 13 locations had both tank water and bulk deposition monitored at the same site. Tank water and bulk deposition was analysed for a suite of 30 metals, 8 anions, organic carbon and inorganic carbon. The physicochemical characteristics of pH, electrical conductivity, hardness, langelier index and temperature were also monitored in tank water whilst bulk deposition was also analysed for total solids. Selected bulk deposition and tank water samples were also analysed for 122 pesticides, up to 19 polycyclic aromatic hydrocarbons and 16 phenolic compounds. The variation of water quality was examined for tanks on daily and annual time scales, at different locations and for different catchment and tank materials. The deposition of chemical contaminants was also examined for variation with location and season. Some observations on roof materials input, tank sludge, outlet height and filtering are included. To quantify the sources of contaminants, various tools for source apportionment were applied to both tank water and bulk deposition data. These included dispersion modelling using TAPM (Hurley 2005a) and multivariate receptor modelling using Positive Matrix factorisation (US EPA 2008), as well as some lead (Pb) isotope and particle size analysis. Results show that water from rainwater tanks in Brisbane was generally of good chemical water quality and in most cases presented minimal health risk if used for drinking. The harvested rainwater was soft and generally slightly acidic, with the exception of new concrete tanks which had alkaline water. The Langelier index of corrosion potential indicated that harvested rainwater was moderately corrosive. The corrosion of plumbing materials and fittings has the potential to increase contaminants such as copper (Cu), nickel (Ni) and lead (Pb) with the use of rainwater. The alkaline water from concrete tanks had low Pb concentrations, as most Pb precipitates out at pH >7. The limited sampling of organic contaminants did not identify any as a health hazard in this project. The main identified health hazard was Pb, which exceeded the Australian drinking water guideline (2004) in 15% of samples and nearly 14% of tanks. The annual volume weighed average concentration of Pb in atmospheric deposition was only 2 μg/L, and thus was not the main source of Pb in tanks with concentrations above the ADWG. The majority of Pb in atmospheric deposition originated from crustal matter, probably due to historical contamination of urban soil from leaded fuel use. The second major contribution of Pb in atmospheric deposition was from anthropogenic activity due to a mixture of motor vehicle, industrial and secondary pollutant sources. The contribution from motor vehicles was generally the dominant source of current primary emissions. The anthropogenic sources of Pb in deposition were increased in inner city and industrial areas. However, where the concentrations were >5 μg/L the majority of Pb in tank water originated from Pb in paint, or Pb flashing on the roof. Plumbing materials also contributed Pb in tank water. Roof catchment and tank materials generally contributed much more to tank water concentrations of relevant contaminants (e.g zinc (Zn)) than atmospheric deposition.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
Full Text

Melbourne, the capital of Victoria Australia leads the world in having the highest quality drinking water. The Victorian State Government has set targets for reducing per capita water consumption by 15%, 25% and 30% by 2010, 2015 and 2020 respectively and has announced stringent water restrictions to curtail water demand. In this resource constraint environment it is opportune to look for alternative sources of water to supplement Melbourne's traditional water supply. In Melbourne, legislation has been changed to make it possible to use rainwater harvested from domestic tanks for non potable purposes. The annual rainfall in Melbourne's metropolitan area varies from 450mm in the West to 850mm in the East to over 1000mm in the North East mountain ranges. The objectives of the current study are to develop a methodology to estimate the optimal size of the rainwater tank at a particular location considering the local rainfall, roof area, demand for water and the reliability of supply (supply security) required; to quantify the rainwater volume that could be harvested at site using domestic rainwater tanks to minimise pressure on the potable water supply secured from traditional catchment sources until the desalination plant is commissioned in 2013; to analyse the efficacy of rainwater tanks to reduce the stormwater runoff and improve the quality of the stormwater that will otherwise flow into urban drains and to estimate the cost effectiveness ratio and payback period of inst alling rainwater tanks. A simple water balance model was developed to calculate the tank size based on daily rainfall, roof area and the expected demand. The concept of 'reliability' was introduced to measure supply security. Rainfall data from 20 rainfall stations scattered around Melbourne were used to determine the variation in the rainwater tank size dependent on the above stated parameters. It was observed that to achieve the same supply reliability (90%) and to meet a specific demand (toilet and garden use), the tank size required in the western side of Melbourne is as high as 7 times as that required in the north-east side. As a result, the

The utilisation of rainwater tanks and bore wells are very common in many parts of rural Australia and Papua New Guinea. In Australia, on-site collection and storage of potable water for domestic use is carried out by approximately 30.4 percent of the rural population while 90% of the population in Papua New Guinea access water from on-site collection and storage of potable water. Few studies have monitored the quality of such water supplies on a seasonal and event associated basis. The aim of this study was to evaluate the microbiological and physio-chemical properties of the on-site domestic water supply systems and various factors that may influence characteristics of the water. It aimed to evaluate the relationship of microbiological and physio-chemical characteristics in the water supply systems. 14 rainwater tanks, 4 bore well and 10 reticulated water supply sites in Hawkesbury District, NSW Australia were investigated. Characteristics of the sites physical situation and natural environmental condition were considered to be similar to on-site water supply situations in Papua New Guinea. The results and techniques of the study will be used as a model in Papua New Guinea in the assessment of water quality issues. As the study showed that the quality of water in rainwater tanks was below WHO guideline recommendations on numerous instances, it was proposed that water treatment and maintaining the cleanliness of roof catchments, gutters and tanks should be addressed for domestic use systems. A protocol for sampling, assessment and data interpretation of faecal indicator bacteria populations in domestic catchment supply systems was developed and demonstrated
Master of Science (Hons)

Water security is increasingly becoming a cause of concern in Australia with population growth and climate change set to exacerbate the variability of supply in both rural and urban regions. During recent drought conditions in Queensland there was a strong emphasis on water restrictions to reduce residential consumption, as well as water policy strategies such as modifying building codes to require all new residential and commercial buildings to conserve and/or substitute potable water. Additionally, there was a heightened emphasis on having an Integrated Urban Water Management (IUWM) approach to water management. IUWM involves the use of alternative water supplies and demand management practices to ensure a sustainable approach to water management by integrating both the demand and supply-based management approaches. Within Queensland, mandatory regulations required residents to save on household water consumption by using alternative water measures in order to offset mains (potable) demand. The installation of rainwater tanks and the reuse of greywater, connected to toilets, cold water laundry and outdoor use, were some approaches adopted by householders to achieve the water saving targets. In addition, current mandatory regulations require new households to install minimum efficient rated water appliances to contribute to water savings.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering
Science, Environment, Engineering and Technology
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Greensmart housing is an Australian industry initiative to encourage the uptake of responsible building processes which deliver less impacting houses. Increasing public knowledge is growing demand for better housing and stimulating industry change which is being supported by both government and industry bodies. Greenhouse pollution, reduced rainfall and reliability, ageing population and other changing social trends combined with continuing population growth are all requiring a move towards responsible and sustainable housing. Three Greensmart houses, constructed at Springfield Lakes, 28 kms south west of Brisbane, were analysed and compared to current mainstream (100% impacts) and sustainable housing (zero impacts). The key finding placed the three Greensmart houses about half way between the two through an evaluation of subdivision and passive design, water and energy issues, material selections, site and waste management and social design elements. The other major findings were:- * when compared to current mainstream housing, the cost impacts averaged over the three houses resulted in a 2.3% increase for passive design elements (extra insulation, higher ceilings, shading and special glazing); 2.3% increase for water saving and efficiency to realise a 75% potable water saving; 1% increase for energy efficiency (50% greenhouse gas saving); almost no increase for superior air quality via planned ventilation and low or non-toxic paints and finishes; 0.2% increase for social design elements but resulting in huge improvements in accessibility, safety and security * 80% reduction in construction waste to landfill by recycling * urgent need for clarity and consistency for housing assessment tools on a state and possibly national basis Details of assessment tools, lessons learnt from the planning, design and construction phases of the houses and other research findings are also presented in this thesis.

Reliable access to safe drinking water is one necessity for humans to live without concern for major health risks. The overall goal of this research is to improve the public health, through improved drinking water, for communities in the Rakai District in Uganda, directly, and other communities in the world, indirectly, via dissemination of knowledge. This study specifically assessed the knowledge of drinking water quality in regards to public health, their sanitation measures, and water treatment methods for users of Brick by Brick rainwater harvesting tanks in the Rakai District (N = 28) by using a knowledge, attitudes, and practice survey and a sanitary inspection; tested the water quality of the Brick by Brick rainwater harvesting tanks (N = 33) in the Rakai District for physical, chemical, and microbial parameters; and piloted a sustainable treatment technology called the chulli system that uses excess heat from a cookstove to treat water. Twenty of the participants identified contaminated water as a cause of diarrheal disease (N = 28). Participants perceived boiling (1), chlorine (2), and filtering (3) as the best three methods of treating water. The average score for the sanitary inspection was 2.27±2.31, which falls between the low and medium expected risk score categories. Fourteen of the thirty-three samples showed detectable levels of colony forming units for coliforms, and two of the thirty-three samples showed detectable levels of colony forming units for E. coli. A demonstration chulli system was constructed for St. Andrew’s Primary School in Rakai District and operated successfully. The research supports that the chulli system along with proper sanitation measures identified in the sanitary inspections can be a sustainable option for users of Brick by Brick rainwater harvesting tanks in the Rakai District.

The utilisation of rainwater tanks and bore wells are very common in many parts of rural Australia and Papua New Guinea. In Australia, on-site collection and storage of potable water for domestic use is carried out by approximately 30.4 percent of the rural population while 90% of the population in Papua New Guinea access water from on-site collection and storage of potable water. Few studies have monitored the quality of such water supplies on a seasonal and event associated basis. The aim of this study was to evaluate the microbiological and physio-chemical properties of the on-site domestic water supply systems and various factors that may influence characteristics of the water. It aimed to evaluate the relationship of microbiological and physio-chemical characteristics in the water supply systems. 14 rainwater tanks, 4 bore well and 10 reticulated water supply sites in Hawkesbury District, NSW Australia were investigated. Characteristics of the sites physical situation and natural environmental condition were considered to be similar to on-site water supply situations in Papua New Guinea. The results and techniques of the study will be used as a model in Papua New Guinea in the assessment of water quality issues. As the study showed that the quality of water in rainwater tanks was below WHO guideline recommendations on numerous instances, it was proposed that water treatment and maintaining the cleanliness of roof catchments, gutters and tanks should be addressed for domestic use systems. A protocol for sampling, assessment and data interpretation of faecal indicator bacteria populations in domestic catchment supply systems was developed and demonstrated

An emerging field in rainwater harvesting (RWH) is the application of communal rainwater harvesting system. This system's main advantage compared to individual RWH is the centralization of water treatment, which some users of individual RWH find difficult to maintain. Despite alleviating one concern, this communal approach does not increase the RHW system's (RWHS) reliability nor necessarily satisfy all water demands, and hence is not a major improvement in terms of system performance. This research tackles this challenge with a novel approach to communal RWH for single-family houses. Instead of the traditional communal approach to RWH which uses only one storage location, we propose connecting multiple single-family homes' RWHSs to a communal backup tank, i.e., capturing overflow from multiple RWHS, which will increase reliability and water demand met in a way that will significantly improve the current performance of communal RWH. The proposed system will potentially maximize the availability of potable water while limiting spillage and overflow. We simulated the performance of the system in two cities, Houston and Jacksonville, for multiple private and communal storage combination. Results show that volumetric reliability gains, of 1.5% - 6% and 1.5% - 4%, can be achieved for seven to ten and six to seven connected households, respectively, for Houston and Jacksonville if the emphasis is on volumetric reliability (VR). As per total storage capacity, the system achieves higher VR gains for lower total storage capacity in Houston while the system achieves higher VR gains for higher total storage capacities in Jacksonville. With regards to the total cost of ownership per household for the individual system and for the communal storage system, the lifecycle cost of the system was performed using the Net Present Value (NPV) method, with an interest rate of 7% over 30 years. The NPV of the total system costs per household in the city of Houston is lowest for nine to ten connected households, as well as comparable to the base case of a rainwater harvesting system that is not connected to a communal tank for seven and eight connected households. This communal system is more resilient and can be a worthy addition to water and stormwater infrastructures, especially in the face of climate change.
Doctor of Philosophy
An emerging field in rainwater harvesting (RWH) is the application of communal rainwater harvesting system. This system's main advantage compared to individual RWH is the centralization of water treatment, which some users of individual RWH find difficult to maintain. Despite alleviating one concern, this communal approach does not increase the RHW system's (RWHS) reliability nor necessarily satisfy all water demands, and hence is not a major improvement in terms of system performance. This research tackles this challenge with a novel approach to communal RWH for single-family houses. Instead of the traditional communal approach to RWH which uses only one storage location, we propose connecting multiple single-family homes' RWHSs to a communal backup tank, i.e., capturing overflow from multiple RWHS, which will increase reliability and water demand met in a way that will significantly improve the current performance of communal RWH. The proposed system will potentially maximize the availability of potable water while limiting spillage and overflow. We simulated the performance of the system in two cities, Houston and Jacksonville, for multiple private and communal storage combination. Results show that volumetric reliability gains, of 1.5% - 6% and 1.5% - 4%, can be achieved for seven to ten and six to seven connected households, respectively, for Houston and Jacksonville if the emphasis is on volumetric reliability (VR). As per total storage capacity, the system achieves higher VR gains for lower total storage capacity in Houston while the system achieves higher VR gains for higher total storage capacities in Jacksonville. With regards to the total cost of ownership per household for the individual system and for the communal storage system, the lifecycle cost of the system was performed using the Net Present Value (NPV) method, with an interest rate of 7% over 30 years. The NPV of the total system costs per household in the city of Houston is lowest for nine to ten connected households, as well as comparable to the base case of a rainwater harvesting system that is not connected to a communal tank for seven and eight connected households. This communal system is more resilient and can be a worthy addition to water and stormwater infrastructures, especially in the face of climate change.

Thesis (MEng)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: The focus of the study is to theoretically assess tank-water demand and employ methods to establish the actual tank-water demand at selected houses in a case study area. This study also examines the influence of domestic rainwater harvesting systems when used in combination with a municipal water distribution system. The case study comprises of 410 low cost housing units in the Western Cape. The system demand patterns of low cost housing units are uncharacteristic, when compared with suburban system demand patterns, and cannot be defined by traditional models. Similarly, the use of rainwater harvesting systems in these areas follows an unconventional routine that is yet to be defined. A stochastic end-use model for water demand is developed which produces temporal profiles for water supplied from both sources, namely the water distribution system and the rainwater harvesting system. The model approximates a daily system and tank-water demand pattern for a single domestic household, using @RISK software. The demand estimation methodology is clarified through application on a particular case study site where harvested rainwater is frequently utilized. Estimates of the parameter values are based on consumer surveys and previous studies on the case study area, where the household size was defined in the form of a probability distribution. The results confirm the atypical system demand patterns in low cost housing units units. Although two clear peaks exist in the morning and in the evening, a relatively constant average flow is present throughout the day. A sensitivity analysis of all the model parameters verified that the household size has the most substantial influence on the tank-water demand pattern. The system and tank-water demand patterns were compared to published average daily water demand guidelines, which confirmed that increased water savings could be achieved when the rainwater source is accessible inside the household with minimal effort. The stochastic demand profiles derived as part of this research agree with the metered system demand in the same area. The results of this study could be incorporated into the future development of national standards.
AFRIKAANSE OPSOMMING: Die fokus van die studie is om die tenkwater-aanvraag teoreties te ontleed en metodes in werking te stel om die werklike tenkwater-aanvraag vas te stel by geselekteerde huise in ‘n gevallestudie area. Hierdie studie ondersoek ook die invloed van plaaslike reënwater-herwinningstelsels wanneer dit gebruik word in kombinasie met ‘n munisipale waterverspreidingstelsel. Die gevallestudie bestaan uit 410 laekoste behuisingseenhede in die Wes-Kaap. Die stelsel-aanvraagpatrone van laekoste behuisingseenhede is verskillend wanneer dit met voorstedelike stelsel-aanvraagpatrone vergelyk word en kan nie gedefinieer word deur tradisionele modelle nie. Soortgelyk volg die gebruik van reënwater-herwinningstelsels in hierdie areas ‘n onkonvensionele roetine. ‘n Stogastiese eindgebruikmodel vir water-aanvraag is ontwikkel, wat tydelike profiele genereer vir water wat van beide bronne verskaf word, naamlik die waterverspreidingstelsel en die reënwater-herwinningstelsel. Die model bepaal by benadering ‘n daaglikse stelsel- en tenkwater-aanvraagpatroon vir ‘n enkele plaaslike huishouding, deur @RISK sagteware. Die aanvraag-beramingstegnieke word verduidelik deur toepassing op ‘n spesifieke gevallestudie, waar herwinde reënwater gereeld gebruik word. Die parameter waardeberamings is gebaseer op verbruikers-opnames en vorige studies oor die gevallestudie-gebied, waar die grootte van die huishoudings bepaal was in die vorm van 'n waarskynlikheidsverspreiding. Die resultate bevestig die atipiese stesel aanvraagpatrone in laekoste behuisingseenhede eenhede. Alhoewel twee duidelike pieke in die oggend en die aand voorkom, is ‘n relatiewe konstante vloei dwarsdeur die dag teenwoordig. ‘n Sensitiwiteitsanalise van al die modelparameters bevestig dat die grootte van die huishouding die grootste beduidende invloed op tenkwater- aanvraagpatrone het. Die stelsel- en tenkwater-aanvraagpatrone was vergelyk met gepubliseerde gemiddelde daaglikse water-aanvraag riglyne wat bevestig dat meer waterbesparings bereik kan word waar die reënwaterbron binne die huishouding beskikbaar is met minimale moeite. Die stogastiese aanvraagprofiele, wat as deel van hierdie navorsing afgelei was, stem saam met die gemeterde stelsel-aanvraagpatroon van dieselfde area. Die resultate van hierdie studie kan in die toekomstige ontwikkeling van nasionale standaarde opgeneem word.

This diploma thesis deals with sanitation installations in residential building in Brno. The theoretical part is devoted to the analysis of the topic with emphasis on Individual ways of preparation hot water in residential buildings. Technical part then solves the sanitation instalations of this building in the selected variation. Calculation part contains design and proportions of sewerage and rainwater system, internal water installations and their connection to present technical networks. I tis a multi-story building with two underground floors used for parking and five floors designed for housing. Project was done according to current Czech and Europe standarts and regulations.

This master’s thesis deals with the overall sanitary and gas pipeline installation in a supermarket. The theoretical part deals with equipment and requirements for large kitchens with regard to the food preparation in this building. The computing and design part deals with the sewerage, water supply and gas distribution in the supermarket. The property counts over six thousand square meters and is partly two-storeyed. There are also several smaller sales units in addition to the sales areas, facility for staff and warehouses. The diploma thesis is based on current Czech and European regulations.

The subject of this master thesis is a design of wine house which comes together with restaurant and accommodation in Strazovice near Kyjov. It includes design study and all the detailed drawings of the building. The building is designed with three services - winery, restaurant and accommodation. Winery is divided into separate rooms for wine processing, finishing and wine aging, also storage, distribution and sale of wine. Canteen service includes kitchen with accessories, restaurant with dining, separated lounge, vaulted cellar and room for degustation. Lounge, cellar and degustation room is primary determined for different corporate events, conferences, weddings, family events and others. For building were chosen descending lands at the edge of Strazovice.. The main reason for this decision is the view that this place provides because of its higher position. Also this village is a part of region, for which wine production is typical. The shape of the object is rectangular and consists of three floors. Two upper floors are receding with comparison to the first floor. This formed a part of terrace which is connected with the oval part on pillars. Basement is situated completely below ground, only the south side is partly uncovered. Construction is made of reinforced concrete. Ground floors are with ventilated frontage. Frontage of the first floor is covered with wooden cladding, and frontage of the second floor is covered with plaster. Vertical constructions are made of lime-sand blocks and horizontal constructions are reinforced concrete. The roof is built of wooden trusses with arched upper part. On the roof there are installed photovoltaic panels for electricity which is used in the building. Rainwater is held in tank, servers as a water supply for the building. Wastewater is depurated in small sewage plant which is further conducted into the building. Other wastewater is captured in the sump. Projection of the winery emphasis, inter alia, on static and

M.Ing. (Civil Engineering Science)
In recent years, there has been an international trend towards installing rainwater tanks in an attempt to save water. However, there are no clear guidelines for determining the optimal size of such a tank in South Africa. This study investigates the possibility of simplifying the process of sizing a rainwater tank for optimal results. It utilises daily data from four rainfall stations, namely Kimberley, Mossel Bay, Punda Maria and Rustenburg, obtained from the South African Weather Services. The water use is considered to be for indoor purposes only, therefore assuming a constant daily demand to be extracted from the tank. The required size of a rainwater tank is influenced by the MAP, the area of the roof draining into the tank, the water demand (both the average demand and seasonal variations), the desired reliability of supply, and the rainfall patterns. The first step in simplifying the process is to consolidate the above variables. The tank volume is expressed as the number of days it could supply the average daily water demand. Another variable is created which provides the ratio of the total water volume which could theoretically be harvested from the roof in an average year, to the total water demand, from the tank, for a year. This has the effect of consolidating the MAP, the roof area, the water demand and the tank volume into two variables only and eliminates the need to consider numerous demand values. Using simulations over 16 years for each location, the relationships between these variables were determined to ensure 90%, 95% and 98% assurance of supply.

Although many developing countries use harvested rainwater (HRW) for drinking and other household purposes, its quality is seldom monitored. Continuous assessment of the microbial quality of HRW would ensure the safety of users of such water. The current study investigated the prevalence of pathogenic Escherichia coli strains and their antimicrobial resistance patterns in HRW tanks in the Eastern Cape, South Africa. Rainwater samples were collected weekly between June and September 2016 from 11 tanks in various areas of the province. Enumeration of E. coli was performed using the Colilert®18/Quanti-Tray® 2000 method. E. coli isolates were obtained and screened for their virulence potentials using polymerase chain reaction (PCR), and subsequently tested for antibiotic resistance using the disc-diffusion method against 11 antibiotics. The pathotype most detected was the neonatal meningitis E. coli (NMEC) (ibeA 28%) while pathotype enteroaggregative E. coli (EAEC) was not detected. The highest resistance of the E. coli isolates was observed against Cephalothin (76%). All tested pathotypes were susceptible to Gentamicin, and 52% demonstrated multiple-antibiotic resistance (MAR). The results of the current study are of public health concern since the use of untreated harvested rainwater for potable purposes may pose a risk of transmission of pathogenic and antimicrobial-resistant E. coli.

Stormwater run-off from urban developments, if left untreated can be detrimental to the quality of the receiving waters. To counteract the effects of urban development on the natural environment, holistic management strategies and treatment at the source have been introduced in Australia, in the form of catchment management authorities, legislation (e.g. Building And Sustainability IndeX) and design techniques, such as Water Sensitive Urban Design (WSUD). In practice, these principles result in lot scale (re)development with a Rainwater Tank (RWT), an On Site Detention (OSD) system and an infiltration or bio-retention system, with most of the overflows discharging to the existing drainage systems. It is argued in this thesis that the implementation of these systems on a lot scale often results in over design and can be considered costly for developers, thereby reducing the opportunity of (re) developments. OSD is currently installed only to control water quantity therefore, the question raised in this thesis is what effect does a RWT have on water quality and quantity discharges on a lot scale and how does this affect the discharges on a catchments scale. This study was based in Western Sydney, in particular Hawkesbury City Council (HCC), which is one of the fastest growing areas in Sydney and is part of the North-West growth sector. A developed catchment, with known drainage issues, and five RWT were selected within the Council area for the longitudinal cross-sectional water quality and quantity data collection. The results of this longitudinal cross-sectional investigation were utilised in a commercial modelling software package (XP-SWMM) for calibration and verification of a lot and catchment scale stormwater quality and quantity models. Testing of the collected water quality samples revealed that the overflow of a RWT had elevated numbers of microbes, and high concentrations of nutrients and some heavy metals. This contamination was speculated to be the effect of run-off and possibly biofilm growth at the air/liquid interface, flowing out of the tank. Furthermore, the data also indicated that RWT are more likely to exceed the drinking water guidelines for lead, Escherichia coli (E. coli) and Enterococci spp. after a storm event. The modelling of the lot scale showed reduction in discharges due to a RWT on-site, but the amount of reduction in the discharges was dependent on the end uses of the RWT. It also indicated that up to a 1-year Average Recurrence Interval (ARI) storm event could be stored within the RWT, provided the RWT is connected to multiple end uses. The lot scale water quality and quantity modelling on a lot scale showed minimal errors with the observed data. The catchment model indicated a 6% reduction in predicted run-off discharges to the receiving stream, if RWT are utilised throughout the catchment, but can increase in volume due to significantly reduced overland flooding. This shows that the gradual implementation of RWT through governmental incentives and (re) developments can have a notable impact on the run-off discharges from a catchment. It is concluded, as a result of these findings, that significant changes should be made in the relevant council legislation. These recommendations include strategies to assist in the implementation of WSUD on a catchment scale and development of RWT design guidelines. An OSD system can be replaced with a RWT for up to the 1-year ARI rainfall event. Further investigations should be conducted on the effect of bio-retention systems on the discharges from both a lot and catchment scale developments, and the contamination levels in the associated overflows from the RWT and filtration systems.

Short duration intense rainfall causes an increase in rainfall derived infiltration and inflow (RDII) in aging sewer networks, which leads to Sanitary Sewer Overflows (SSOs). This, in turn, causes various detrimental impacts, both on human health and the environment. This research aims to quantify the benefits of Water Sensitive Urban Design (WSUD) approaches to mitigate the negative impacts of rainfall induced SSOs. In this context, this research develops a generalised framework for assessing and mitigating the impacts of intense rainfall on the performance of the sanitary sewer network. The first part of the developed framework involves detailed hydraulic modelling to evaluate the performance of the sewer network. The second part deals with the development of SSO mitigation strategies based on popular WSUD approaches. This study also demonstrates the application of the developed framework for a case study catchment in Melbourne, Australia. A detailed hydraulic modelling to analyse the performance of the case study sewer network during a wet (2010) and a dry year (2008) has been presented. The hydraulic performance analysis found that the system experienced 23 ML of sewer overflow volume in 2010 as compared to 3.42 ML in 2008. Towards mitigating the negative impacts of SSOs, this study has implemented two commonly used WSUD approaches, namely rainwater tanks and rain gardens for the case study sewer network. A detailed hydraulic modelling has been undertaken with rainwater tanks and rain gardens (individually and in combination) for the wet year 2010. It was observed that rainwater tanks (individually) could lead to a maximum reduction in SSO volume by 33% when compared to the base case overflow volume of 23 ML. A higher reduction in SSO volume up to a maximum of 45% was observed when rain gardens were implemented in conjunction with rainwater tanks. Such an analysis will benefit the urban water authorities to develop sustainable WSUD based mitigation strategies for controlling SSOs in their sewer system. Thus, the study will be beneficial for the community and the environment.

Dissertação de mestrado integrado em Engenharia Civil
A procura de estratégias de racionalização no consumo de água ou de fontes alternativas de água têm levado ao surgimento de várias soluções, sendo algumas já utilizadas no passado mas caídas em desuso com o desenvolvimento das sociedades. Uma das soluções já adotada de forma significativa em vários países é o aproveitamento da chuva em todo o tipo de utilizações. Neste trabalho explora-se a viabilidade da implantação de um sistema de aproveitamento de água pluvial (SAAP) para fins domésticos em Portugal continental. Esta dissertação pretende ajudar a resolver a problemática do aproveitamento de água pluvial em contexto doméstico, determinando onde um SAAP pode constituir um sistema economicamente atraente e uma fonte alternativa credível de água não potável. O investimento inicial na implantação de um SAAP constitui o maior entrave na expansão deste tipo de sistema, sendo o reservatório de armazenamento de água pluvial o elemento mais dispendioso. Desenvolveu-se um programa denominado PSAAP, para fazer a simulação do aproveitamento de água pluvial. O PSAAP foi desenvolvido com o objetivo de dimensionar a capacidade ideal do reservatório e estudar a viabilidade económica do SAAP. Para um determinado SAAP, este simulador calcula iterativamente até encontrar a capacidade ideal. A capacidade ideal do reservatório de um SAAP será a capacidade que levar a que o SAAP tenha o menor período de recuperação do investimento (PRI) possível. Através do PSAAP, o utilizador pode obter a capacidade do reservatório recomendável para a sua localização, consumo e capacidade de captação da chuva, conseguindo também perceber qual o investimento inicial e o PRI associados ao respetivo SAAP. Na aplicação da ferramenta, estuda-se a implantação de um SAAP em cidades de diferentes regiões de Portugal continental, de forma a perceber a sua viabilidade em condições distintas. Estudou-se numa primeira análise a utilização de um SAAP que abastece-se apenas uma moradia unifamiliar e numa segunda análise estudou-se a utilização de um SAAP que abastece-se um conjunto de quatro moradias unifamiliares, de forma a verificar se o projeto beneficia economicamente por ser um sistema de maior dimensão. Através das simulações efetuadas no PSAAP, conclui-se que quanto mais elevado for o nível de consumo, o custo da água consumida, área de captação e a precipitação disponível, menor é o PRI do SAAP.
The demand for rationalizing strategies or alternative sources of water have led to the appearance of several solutions, some already used in the past, but have fell into disuse with the development of societies. One of the significantly solutions, already adopted in several countries, is the use of rainwater. This work explores the economic viability of implementing a rainwater harvesting system (RWHS) for domestic purposes in Portugal mainland. This dissertation aims to help solve the problem of use rainwater in the domestic context, determining where a RWHS can be an economically attractive system and a credible alternative source of non-potable water. The initial investment in the implementation of a RWHS is the major obstacle in the expansion of this type of system where the rainwater storage tank is the most expensive element. In order to study the economic viability of a RWHS and calculate the ideal capacity to the storage tank under different conditions, was developed a program for simulation of rainwater harvesting called PSAAP. For a RWHS with different storage capacities, this simulator calculates iteratively to find the ideal capacity. The ideal capacity of a RWHS’s storage tank is the capacity that leads to the RWHS has the lowest possible payback period. Through PSAAP, the user can get the recommended capacity of the reservoir to its location, consumption and ability to capture the rain. This program can also help the user realize the initial investment and the payback period associated with the respective RWHS. In the application of this tool, was study the implementation of a RWHS in cities of different regions of Portugal mainland in order to understand its viability in different conditions. It was studied the use of a RWHS that supplies just one dwelling unfamiliar house and has also been studied the use of a RWHS which supplies a set of four dwelling unfamiliar houses in order to benefit from a larger dimension. Through simulations performed on PSAAP, it is concluded that the higher the level of consumption, the cost of water consumed and precipitation available, the lower is the payback period.

Cape Town, South Africa, falls within a winter rainfall region, making it difficult to assess the feasibility of rain- and stormwater harvesting. The reason for this is because the region’s high water demand period coincides with the low rainfall summer season, thereby limiting the availability of this alternative water resource when most needed. During this study, rainwater harvesting for toilet flushing purposes, collected from roof surfaces, was practically assessed by means of inserted flow meters at a pilot study site in Kommetjie, Cape Town. The combined and single system roof- and land surface runoff yields and savings of commercial buildings within the Kommetjie business area, were also theoretically assessed by making use of a mathematical roof- and land surface runoff model specifically developed during this study. The statistical testing of the hypotheses statements relating to the pre- and post-harvesting savings at the pilot study building, compared against the average actual municipal water usage, were performed. Hypotheses testing were also performed in order to compare the theoretical rain- and stormwater runoff yields for the commercial business area against the average actual municipal water consumption. The conclusions drawn from this study indicated that valuable potable water, as well as related financial savings, can be achieved within a winter rainfall region, thereby making rain- and stormwater harvesting a feasible option for commercial businesses in Cape Town.
Environmental Sciences
M.Sc. (Environmental Management)