Xylem Inc. develops pumps and integrated solutions for sewages systems. A new concept has been designed to reduce the levels of hydrogen sulphide, H2S, in wastewater. H2S is a toxic, stinking gas that smells at levels above 0.002-0.2 ppm. Recommended exposure level is 15 ppm for 15 minutes. The gas is soluble in water and arises with both increasing temperatures and long retention times. Levels of H2S normally differ between 0-1000 ppm, depending on the time of year. The new concept, a pre-chamber installed upstream a pump station, is called Odomin. Inside Odomin H2S is oxidized to sulphuric acid, H2SO4, on moist surfaces. A plate is used to splash thewastewater onto the moist surfaces surrounding the plate. This master thesis aims to find the reduction rate, in terms of H2S, between Odomin 65 and the pump sump and to evaluate three factors that have possibility to improve the performance of Odomin 65. The investigated factors are 1) a sacrificial anode made from carbon steel 2) a reduced area of the inlet which increases the splash effect and 3) an increased inner area to increase themoist surfaces inside Odomin. The evaluation is made with 23 factorial design. The analysis indicates that no factor affect the daily mean value with a significance at 5%. The sacrificial anode is the one factor showing a reduction by the levels of H2S in the pump sump for both mean and extreme values. The general reduction rate is 5.33 and this can be increased with 55% by using the splash. The tests were affected by several influences that impact the trustworthiness of the results. Therefore this analysis needs additional investigations in order to be verified. / Xylem Inc. utvecklar pumpar och lösningar för avloppssystem. De har utvecklat ett nytt koncept för att reducera halten av svavelväte, H2S, i avloppsvattnet. H2S är en giftig, illaluktande gas med kännbar lukt vid 0.002-0.2 ppm. Rekommenderat är att utsättas för högst 15 ppm under 15 minuter. Gasen är löslig i vatten och nivåerna ökar med både höga temperaturer och långa uppehållstider i ledningarna. Normalt sätt kan nivåerna av H2S variera mellan 0-1000 ppm, beroende på årstid. Det nya konceptet som kallas Odomin är en för-kammare som installeras uppströms till en pumpstation. I Odomin oxideras H2S till svavelsyra, H2SO4, på våta ytor. Genom att avloppsvattnet kaskaderar på en platta kan gasen komma i kontakt med våta ytor kring plattan. Examensarbetet syftar till att hitta reduktionstalet mellan Odomin 65 och pumpsumpen samt utvärdera 3 faktorer som kan förbättra effekten av Odomin. De undersökta faktorerna är 1) en offeranod av kolstål 2) en minskad inloppsarea för att öka kaskadet och 3) en ökad inre area, för att öka andelen våta ytor, i Odomin. De 3 faktorerna utvärderas med faktorförsök (factorial design). Utvärderingen ger indikationen att ingen av de tre faktorerna påverkar det dagliga medelvärdet på en 5 % signifikansnivå. Offeranoden är den faktor som tenderar minska både medelvärdet och extremvärdet i pump sumpen. Reduktionen av H2S mellan Odomin 65 och pump sumpen är 5.33 och analysen visar att en ökad kaskadeffekt kan öka reduktionen med 55 %. Testerna influeras av flera yttre faktorer vilket påverkar resultatens trovärdighet. Denna analys bör därför repeteras för att resultaten ska kunna verifieras.

Svavelväte, H2S, är en giftig och illaluktande gas. Den karakteristika ''ruttet ägg''-lukten kan kännas redan 0.02ppm och det hygieniska gränsvärdet för exponering under en arbetsdag ligger på 5ppm, enligt arbetsmiljöverkets restriktioner. Dessutom är gasen korrosiv på betong och övrig utrustning och minskar därmed livslängden på ledningssystem. Svavelväte bildas i avloppsvatten under anaeroba förhållanden vilka typiskt uppstår i spillvattenledningar med långa uppehållstider. Syftet med detta arbetet var att kartlägga vilka åtgärder för att minska bildningen av svavelväte som användes, hur dessa har fungerat i praktiken samt försöka hitta ett samband mellan vilka åtgärder som passar i vilket typ av system. Detta gjordes med en grundläggande litteraturstudie samt datainsamling via telefon, e-mail och intervjuer. Studien visar att dosering med kemikalier var den vanligaste åtgärden följt av någon typ av luftningsanordning. Mätningar på hur svavelvätehalter påverkas i samband med dessa åtgärder var dock svåra att hitta.  Arbetet visade på en komplexitet i bildandet av svavelväte. De fysiska förutsättningarna i ledningarna såsom dimensioner, flödeshastighet, temperatur etc. påverkar också svavelvätebildingen. Förutsättningarna i ledningarna beror av många faktorer vilka ständigt varierar. Samtliga beskrivna åtgärder har enligt de kommuner där de införts och testats haft önskad effekt utifrån en subjektiv bedömning. Studien visar att grundläggande mätningar är nödvändiga för att klargöra vilka åtgärder som är mest effektiva vid givna förutsättningar. För att i framtiden kunna tackla detta antagligen växande problem i svenska ledningsnät bör alltså fler och noggrannare mätningar göras. Mätningarna bör göras både innan och efter en åtgärd sats in samt uppföljande mätning för att se om åtgärden bibehåller önskad effekt. En databas med denna typ av mätningar skulle dels gynna framtida forskning, dels hjälpa kommuner att välja rätt metod för att lösa svavelvätereleaterade problem. / Hydrogen sulphide is a toxic gas with a malodorous smell. Even in very low amounts, 0.02ppm, the rotten egg odor is noticable. The limit exposure per day is 5ppm according to The Swedish Work Environment Authority's restrictions. In addition, the gas is very corrosive to concrete and equipment, thus reducing the lifetime of wastewater collection systems. Hydrogen sulphide is formed in wastewater under anaerobic conditions, which typically occur in wastewater systems with long residence times. The aim of this study was to find which methods are used to reduce the formation of hydrogen sulphide. How these have preformed in practice and try to find a connection between which methods are suitable in which type of system. This was done with a literature study as well as data collection via telephone, e-mail and interviews.  Dosing with chemicals proved to be the most common method to reduce hydrogen sulphide, followed by some kind of ventilation devices. Measurements of hydrogen sulphide content in connection with these methods was, however, difficult to find among the contacted users.  This study showed a complexity in the formation of hydrogen sulphide since the conditions in wastewater collection systems depend on many factors which constantly varies. According to the municipalities where methods were introduced and tested, the desired effect based on a subjective assessment was reached. The study shows that measurements are necessary to clarify which methods are most effective under given conditions.  In order to deal with this possibly growing problem in Swedish waste water collection systems, more accurate data collection should be done. Both before, after and follow up data, regarding the intervention should be collected when studying this issue. Doing so would greatly benefit future research and help municipalities in solving this problem.

<p>Starting point to this Paper is the idea and wish to adapt the society and its different activities to a recycle society. A building area in Göteborg is planned and investigated for such adaptation. In the district named Skogaberg, about 130 households totally are planned from what 20 are blocks of flats. The idea with this project is to constitute an alternative sewage system, a Blackwater system, were the fractions of most nutrients and least pollution are separated, taken care of and utilised. The aim is to get a market and use the nutrients of the organic waste from the household in agriculture use. The Swedish Environmental Protection Agency (EPA) pays attention to water- and sewage systems from a recycle perspective and the aim of a long-termed sustainable development. The agriculture sector has also an intention to protect the environment and the means for sustainability. </p><p>The object of this study is to map and analyse a planned alternative sewage system in Skogaberg from recommended criteria for water and sewage systems. The alternative solution in Skogaberg will be analysed compared to a conventional solution. A specific aim is to estimate the possibilities and limitations of the alternative system when it comes to recycle of nutrients. Phosphorus and cadmium are chosen to describe and indicate the resource utilisation and environmental impact of different nutrient sources. Sanitation and risks with diseases, environmental&resource saving criteria together with technical&socio-economic criteria are intended to constitute a general background for the analysis. Criteria recommended, to concern environmental adapted water and sewage system by the Swedish EPA, is used in order to make an assessment of the planned system and a more viewed assessment and analyse is done from experiences and observations that I have got from literature sources and place studies. The results show good theoretical possibilities to get and recycle nutrients from the system with an alternative solution. With an alternative sewage system in Skogaberg opportunities that the users reflect and care are created. This project may provide us with innovations and ground for further research and development in future project. But it is also important to consider that these projects are established in the system of the society and that these recycle systems are not directly comparable with ecological recycling system in nature.</p>

Detta arbete syftar till att göra en utvärdering av hur de två skilda spillvattensystemen LTA (Lätt TryckAvlopp) och konventionellt självfallsavlopp står sig mot varandra ur ett långtidsperspektiv. Aspekter så som investering, drift, underhåll, miljöpåverkan, teknik och anläggning har analyserats och sammanställs av denna rapport, samt ett program som beräknar den ekonomiska aspekten mellan respektive system. Programmet, där användaren ges möjligheten att specificera sitt eget område, ger en fingervisning om den lösning som ur ekonomisk aspekt är mest fördelaktig. Detta kombinerat med den kunskap som samlats i rapporten ska leda till ett mer medvetet val hos kommuner och andra VA-huvudmän i Sverige. / The purpose of this report is to make a comparison between the two currently used sewage solutions, PSS (Pressure Sewage System) and the more conventional gravity based sewage-system during a vast period of time. Aspects such as investment, maintenance, upkeep, environmental, technology and terrain have been analyzed. The research has resulted in this report and an Excel-program which calculates an estimated economical difference between the two solutions, in a specific case chosen by the user, to determine which is more economically beneficial. This program, used hand in hand with the report, is suppose to increase the knowledgebase regarding the subject of sewage solutions among officials working with these kinds of matters in Sweden.

This thesis report describes the design and development of an automated rat trap for sewage system. This rat trap has been designed to have a working duration of 2 months or approximately 15749 hits with trap dimensions length 535 mm, width 430 mm and a height range of 931 – 1151 mm with respect to different sewer pipe diameters. The trap weighs about 16.46 kg without the battery, pipe connectors and support connections. The trap has a response time range between 0.027 – 0.095 seconds with a striking pressure range between 16.05 – 56.19 MPa at the kill pad. The trap has a modular design to be able, to fit into different sewer pipe dimeters (100, 150, 160, 200, 225, 250, 300, 350 mm). The materials and components used for the rat trap satisfy all the requirement classifications such as working temperature, resistance to moisture and dirt, resistance to corrosion and ATEX classification. This rat trap design will be further used by Nomor AB to prototype and test it according to the Naturvårdsverket (Swedish Environmental Protection Agency) guidelines and regulations. A background study on brown rat physical characteristics and habitat, rat biology and existing trap technology were performed to set the trap’s requirement specifications in order to develop concepts. Furthermore, this thesis report concludes to a proposed evaluated trap design concept and its detailed design with analytical calculations of its motor specifications, gear box selection, trap speed, impact forces, trigger spring specifications and trap battery capacity. In addition to, a number of easily available market trap components have been studied and selected to aid with the prototyping. The critical components of the rat trap have been identified in order to validate the structural integrity of the design by finite element analysis. Finally, this report includes future work recommendations for the automated sewage rat trap. This automated sewage rat trap is a unique modular design and will help to control the ever-increasing rat population in one of its most safe habitats and is a stepping stone for more advanced sewage rat traps in the future. / Detta examensarbete beskriver utformning och utveckling av en automatiserad råttfälla för avloppssystem. Denna råttfälla har utformats för att ha en arbetstid på 2 månader eller cirka 15 749 träff med mått längd 535 mm, bredd 430 mm och ett höjdintervall på 931 - 1151 mm med avseende på olika avloppsrörsdiametrar. Fällan väger cirka 16,46 kg utan batteri, röranslutningar och stödanslutningar. Fällan har ett svarstidsintervall mellan 0,027 - 0,095 sekunder med ett slående tryckintervall mellan 16,05 - 56,19 MPa vid dödplattan. Fällan har en modulär design för att kunna monteras i olika avloppsrörsdimetrar (100,150,160,200,225,250,300,350 mm). Materialen och komponenterna som används för råttfällan uppfyller alla kravklassificeringar som arbetstemperatur, motståndskraft mot fukt och smuts, korrosionsbeständighet och ATEX-klassificering. Denna råttfälla kommer att användas ytterligare av Nomor AB för att testa den enligt Naturvårdsverket (Naturvårdsverket) riktlinjer och föreskrifter. En bakgrundsstudie om bruna råttarsfysiska egenskaper och livsmiljö, råttbiologi och befintlig teknologi utfördes för att ställa in fällans kravspecifikationer och för att utveckla ett koncept. Vidare avslutas denna avhandlingsrapport med ett föreslaget utvärderat fällesignkoncept och dess detaljerade konstruktion med analytiska beräkningar av dess motorspecifikationer, val av växellåda, fällhastighet, slagkrafter, dragfjäderspecifikationer och fällbatterikapacitet. Dessutom har ett antal lättillgängliga marknadskällkomponenter studerats och valts ut för att underlätta prototyptillverkning. De kritiska komponenterna i råttfällan har identifierats för att validera konstruktionens integritet med ändlig elementanalys. Slutligen innehåller denna rapport framtida arbetsrekommendationer för den automatiska avloppsråttfällan. Denna automatiserade avloppsråttfälla är en unik modulär design och hjälper till att kontrollera den ständigt ökande råttpopulationen i en av sina mest säkra livsmiljöer och är en språngbräda för mer avancerade avloppsråttfällor i framtiden.

Starting point to this Paper is the idea and wish to adapt the society and its different activities to a recycle society. A building area in Göteborg is planned and investigated for such adaptation. In the district named Skogaberg, about 130 households totally are planned from what 20 are blocks of flats. The idea with this project is to constitute an alternative sewage system, a Blackwater system, were the fractions of most nutrients and least pollution are separated, taken care of and utilised. The aim is to get a market and use the nutrients of the organic waste from the household in agriculture use. The Swedish Environmental Protection Agency (EPA) pays attention to water- and sewage systems from a recycle perspective and the aim of a long-termed sustainable development. The agriculture sector has also an intention to protect the environment and the means for sustainability. The object of this study is to map and analyse a planned alternative sewage system in Skogaberg from recommended criteria for water and sewage systems. The alternative solution in Skogaberg will be analysed compared to a conventional solution. A specific aim is to estimate the possibilities and limitations of the alternative system when it comes to recycle of nutrients. Phosphorus and cadmium are chosen to describe and indicate the resource utilisation and environmental impact of different nutrient sources. Sanitation and risks with diseases, environmental&amp;resource saving criteria together with technical&amp;socio-economic criteria are intended to constitute a general background for the analysis. Criteria recommended, to concern environmental adapted water and sewage system by the Swedish EPA, is used in order to make an assessment of the planned system and a more viewed assessment and analyse is done from experiences and observations that I have got from literature sources and place studies. The results show good theoretical possibilities to get and recycle nutrients from the system with an alternative solution. With an alternative sewage system in Skogaberg opportunities that the users reflect and care are created. This project may provide us with innovations and ground for further research and development in future project. But it is also important to consider that these projects are established in the system of the society and that these recycle systems are not directly comparable with ecological recycling system in nature.

This master thesis deals with the design of a wastewater treatment plant, which will be controlled by a PLC. The theoretical part describes the types of wastewater and sewage systems that are important in the design of wastewater treatment plants. The thesis also describes programmable logic controllers, theirs programming languages, SCADA (Supervisory Control And Data Acquisition) systems and automation.The thesis also deals with theoretical description of wastewater treatment plants, their functions and security. Next part describes the design of the wastewater treatment plant. The last part of the thesis describes implementation of the wastewater treatment plant controlled by a PLC.

This report presents a case study on the Water and Sewage (abbreviated as WS in the following) system of Stockholm, which is faced with several challenges over the coming decades. The purpose is to explore the current and future threats and challenges that can have an impact on the WS system, with the aim of identifying a sustainable and resilient way of handling potential issues and incorporating a wider perspective when planning for a continued water and sewage infrastructure of sufficient capacity and quality. The study asks what the current and potential future challenges for the Stockholm WS system are, what is required to enable a sustainable and resilient WS system in a long-term perspective, which actors are involved or need to be involved beyond Stockholm Water, to provide Stockholm with a resilient and sustainable WS system, and what would be required for efficient governance? A content analysis of literature was made in order to develop three possible future scenarios, each with its own set of challenges. The scenarios were discussed with several interviewees from the WS-sector. The information provided during the interviews was used in a resilience analysis, based on the framework developed by the Resilience Alliance Workbook for Practitioners. A discussion follows in relation to the connected theoretical concepts of futures studies, resilience theory, governance and sustainability. The findings in this study suggests that the main challenges facing the WS system are primarily climate change and population increase. The WS system has to expand to support a growing population, as well as be adapted to cope with the consequences of climate change. Also pulse disturbances, such as sabotage and bio-terrorist attacks, were discussed and constitute a worry to which there is less preparedness. Further, a different challenge was found in the difficulties in planning for this required expansion and development where there is a lack of support, funding, communication and division of responsibilities. In order to retain a WS system that is able to provide high quality water services of sufficient quantity, communication and coordination between actors need to improve, and someone has to take a lead in continued work to ensure that all actors and stakeholders move in the same direction. Long-term planning is required on all parts, and there is a need to make decisions that will enable a sustained water and sewage structure in the long run. It is also required that water is made a priority; that water and sewage related issues are allowed more space in the municipal planning process and are discussed at a much earlier stage. Further, all municipalities will face challenges that concerns the WS system, leading to an increasing requirement of a more extensive regional cooperation, where planning and development occurs across municipal borders, focusing on watershed- and drainage areas. This study focuses on specified resilience, which means that only a limited number of challenges and events that could affect the WS system have been studied. Further studies are encouraged to determine the general resilience of the system, and provide a more detailed and comprehensive assessment.

Sveriges kommunala spillvattenledningsnät står idag inför en enorm utmaning, då eftersattunderhåll i kombination med klimatförändringar kommer kräva stora framtida investeringaroch tidskrävande analyser. Detta examensarbete har utförts med målet att förenkla dettastundande förnyelsearbete. Som metod har en enkät utformats, och besvarats av totalt 84kommuner, med syftet att presentera en lägesbild. Vidare har ett artificiellt neuralt nätverkutvecklats, och tillämpats på data från Täby kommun, med syftet att förutspå vilkaspillvattenledningar i ett ledningsnät som har behov av förnyelse. Resultatet visar att det finns ett stort förbättringsbehov i det strategiska förnyelsearbetet.Störst behov, och potential, finns i hantering och insamling av data, där artificiella neuralanätverk kan tillämpas och utnyttjas som ett effektivt och intelligent verktyg. Det artificiellaneurala nätverket som utvecklats, och tillämpats, i detta examensarbete uppnådde en högprecision (93 %), och beräknade att Täby kommun har ca 10-20 spillvattenledningar medoupptäckt förnyelsebehov. Detta bör dock tas med viss reservation pga. bristandedatakvalitet. Avslutningsvis kan konstateras att lösningen för framtidens ledningsförnyelserelateradeproblem och utmaningar, ligger i förmågan att effektivt och intelligent samla in, struktureraoch analysera data om ledningsnäten. Artificiella neurala nätverk är ett verktyg som kanoch bör användas för detta ändamål då man, med hjälp av artificiell intelligens, kan göraprecisa analyser och skapa helhetsbilder över ledningsnät, vilket kan spara bådefinansiella, temporala och personella resurser. / Aging sewer systems and deferred maintenance pose one of the greatest challenges toSwedish municipal infrastructure in the future. This degree project has been completedwith the aim to develop a method with which to sufficiently solve these future challenges,and help decision makers to properly invest in the networks, and optimise the pipe renewalprocess. As a methodology, a survey has been created, and answered by 84representatives from various municipalities and water and waste organisations, in order topresent a deeper understanding of the current situation in Sweden. Furthermore, anartificial neural network has been developed, and trained with data from Täby municipality,with the purpose of predicting which pipes in a sewer network that need to be renewed. The results show that there is a great need for improvement in the strategic renewalplanning. The greatest need, and potential, is found in the collection and processing ofdata, where artificial neural networks can be applied as a highly efficient and intelligenttool, which is proven by the high accuracy (93 %) and strong ability to predict pipes withrenewal needs (ca 10-20 pipes for Täby municipality) that the neural network developedfor this degree project showed. It is, however, important to emphasize that the quality ofthe obtained data from Täby was relatively low, and that the results therefore has to beviewed with some skepticism. It is nevertheless reasonable to assume that artificial intelligence, and more specifically,artificial neural networks, will play an important role in tackling future challenges related tostrategic asset management and renewal planning for underground sewer infrastructure.The main solution lies in the ability to efficiently and intelligently collect, structure, andprocess data, and this is a field where artificial neural networks, as made evident by thisdegree project, certainly have abilities to flourish and contribute to savings in bothfinancial, temporal and human resources.

A necessidade de investimento em saneamento no Brasil é essencial, pois está vinculada à melhoria da qualidade de vida da sociedade. Os projetos de saneamento exigem altos investimentos e, para garantir a prestação dos serviços, é necessário um sistema complexo de infraestrutura. Os elevados custos envolvidos e a limitação de recursos financeiros fazem com que seja preciso estabelecer prioridades para execução de projetos de saneamento. Com efeito, o objetivo desta pesquisa é propor um modelo multicritério de decisão para apoiar decisões de hierarquia de projetos de abastecimento de água e esgotamento sanitário. A pesquisa abordada tem enfoque qualitativo, sendo também vista como metodológica, pois sua finalidade é envolver métodos e procedimentos adotados como científicos. Assim, traz como escopo apoiar e estruturar o processo de decisão em que são definidos: os elementos (intervenientes, alternativas potenciais, critérios, problemática); tipos de decisão em grupo; escolha dos métodos multicritérios (PROMETHEE II & GAIA e ELECTRE IV); modelagem de preferência; sistemas de apoio à decisão (D-SIGHT e ELECTRE III-IV); avaliação de resultados e análise de sensibilidade. Procura-se garantir que a pesquisa tenha caráter prático, razão por que foi realizada a aplicação numérica do modelo no contexto da bacia dos rios Piracicaba, Capivari e Jundiaí, região sudeste do Brasil. / The need of investment in water supply and sewage projects in Brazil is substantial to improve the quality of life. These projects require high investments and, mostly, to ensure the provision of these services it is necessary a complex infrastructure. Due to the high costs associated with the lack of resources, it is relevant to prioritize projects. Thus, the purpose of this research is to propose a multicriteria decision model to support decisions hierarchy of water supply and sewage projects. This work has a qualitative and methodological approach; the goal is to inquire a scientific procedure. The object is to structure the decision-making process defined by its main concepts (actors, potential alternatives, criteria, problems), group decision making; selection of multiple criteria methods (PROMETHEE II & GAIA, ELECTRE IV); preference modeling, decision support systems (D-SIGHT and ELECTRE III-IV), evaluation and sensitivity analysis. This study seeks a practical purpose, so the proposed model, is applied in the basin of Piracicaba, Capivari e Jundiaí. The contribution here to aid similar situations where is necessary to establish priorities of sanitation projects.