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Struvite Recovery From Source-Separated Urine Utilizing Fluidized Bed TechnologyGagnon, Alexandria Augusta 06 September 2016 (has links)
Source-separating urine for nutrient recovery may provide multiple benefits with regards to wastewater management, water conservation, and an impending phosphorus fertilizer shortage. Municipal wastewater systems are designed to treat the combination of urine, feces and graywater produced in household applications. Urine accounts for 1% of wastewater by volume, but provides 70-90% of nitrogen, 35-70% of phosphorus and 50% of the contaminants of emerging concern entering municipal wastewater treatment (Larsen and Gujer 1996). Research has shown managing source-separated urine for nutrient recovery is a more cost effective and less treatment intensive method than using traditional systems found in municipal wastewater plants.
Phosphorus fertilizer shortages are projected as current sources diminish and become increasingly difficult to extract and refine. Phosphorus based-fertilizer recovery, in the form of 99.9% pure struvite (MgNH4PO4•6H2O), has been demonstrated successfully in full-scale sidestream treatment using dewatering liquor from anaerobically digested solids (centrate) processed through upflow fluidized bed reactor technologies (Britton et al. 2005). Prior research determined the influence of pH, magnesium to phosphorus (Mg:P) molar ratio, and age of urine on purity, pharmaceutical content and pathogen inclusion in struvite precipitated from source-separated urine. This is the first known example of an attempt to produce a commercially viable struvite product from source-separated urine in a fluidized bed reactor of a design that has been used successfully for struvite recovery in conventional wastewater applications.
In order to assess the feasibility of nutrient recovery of phosphorus-based fertilizer recovery from source-separated urine, the first office-based urine separation and collection building was implemented in the U.S. Urine was collected, in a 400 gallon capacity underground sealed manhole, from HRSD's Main office building beginning in March 2015 from 5 men's waterless urinals and one women's separating toilet. Urine was collected from the manhole on a monthly basis in 275 and 330 gallon plastic totes stored at the HRSD Nansemond WWTP in Suffolk, VA. Collected urine was allowed to age while in storage to encourage the precipitation of excess multivalent cations that may interfere with struvite precipitation and inactivation of pathogens that may be present.
An upflow fluidized bed reactor (UFBR) was used to recover struvite as a slow-release phosphorus based fertilizer (prill), the reactor was loaned to HRSD by the University of British Columbia. A magnesium solution was injected at the bottom of the reactor to facilitate precipitation along with the recycle urine stream and feed urine as shown. Prill production design for the reactor was 0.5 kilograms per day, but while using centrate to determine best operations practices, under loading the reactor to 0.25 kilograms per day maximized struvite recovery while minimizing particulate phosphorus loss. Urine was fed into the reactor for struvite removal based on phosphorus loading with recovery determined through removal of orthophosphate and harvesting of the struvite product. Consistency, size and quality of product including compactness, crystal structure, purity and presence of pharmaceuticals and pathogens were assessed.
The UFBR was run for 50 days total; 10 days for a short term run to compare to operation of the reactor under the same conditions with centrate from anaerobically digested solids as a feed source, 30 days to assess consistency of operations over long term with respect to struvite recovery, and a 10 day test with urine spiked with pharmaceuticals and bacteriophage to evaluate inclusion of trace organics and viruses in recovered struvite. In total 2,040 gallons of urine were fed to the reactor targeting 12.45 kilograms of struvite recovery, a mass of 7.54 kilograms of prills were harvested from the reactor with 1.90 kilograms of phosphorus lost as particulate struvite (representing an recovery efficiency of 60.5%). Overall reactor operation using urine as a feed solution behaved similar to centrate, with slightly less removal of phosphorus. Urine-derived prills were lower in quality due to the lack of compact density seen in struvite recovered during full scale operation but had a visible orthombic pattern seen in precipitated struvite.
Pharmaceuticals that were present in urine feed solution were found in struvite but at less than 1% of the feed mass. Some of this inclusion may have occurred due to porous characteristics of the small-scale UFBR recovered struvite rather than through actual inclusion in the mineral crystal itself. Spiking of caffeine and ibuprofen to high concentrations in the urine yielded no statistical difference from the non-spiked tote. Urine was non-detect for bacteriophage pathogen indicators leading to the assumption that no pathogens were present in urine-derived struvite. Spiking the urine with double-stranded DNA (T3) and single-stranded RNA (MS2) bacteriophage capable of infecting bacterial cells such as Escherichia coli yielded 10^6 plaque forming units per milliliter in source separated urine.
Creating urine-derived struvite prills with minimal inclusion of pharmaceuticals using upflow fluidized bed technology is feasible on a small scale. Large-scale application, recovering 500 kilograms per day of struvite or more, will most likely create a higher quality prill with regards to compactness and diminished presence of pharmaceuticals and virus inclusion. Pretreatment of urine and post-treatment of prills with heat will aid in inactivation of virus that may be present.
' / Master of Science
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Urine Diversion & Reuse in Australia : A homeless paradigm or sustainable solution for the future?Cordell, Dana January 2006 (has links)
<p>Diverting urine from faeces or mixed wastewater and reusing it to fertilize crops, is a traditional method used in Asia. It is also a contemporary approach to sustainable nutrient and water management in Scandinavia and other parts of Europe. Urine diversion and reuse is a proven socio-technical system that has significant potential benefits on both a local and global scale, such as recirculating scarce plant nutrients like phosphorus back to agriculture, reducing eutrophication of waterways and improving water and sanitation systems. This thesis explores the nature of these benefits in Australia and the global context and what barriers would need to be overcome if a urine diversion and reuse system were implemented in Australia to achieve significant environmental benefits. These questions are investigated through stakeholder interviews in Sweden, to identify the ‘lessons learnt’ from the Swedish experience with urine diversion and reuse, and, through interviews with relevant stakeholders in Australia to identify possible barriers and opportunities, costs and benefits, and roles and responsibilities in the Australian context. Findings from both the stakeholder interviews are triangulated with other sources of knowledge, such as the literature, personal communications and a qualitative assessment of costs and benefits.</p><p>This thesis found that while urine diversion is likely to benefit the Australia situation and warrants further research, these benefits are fragmented and spread across a range of discourses and separate institutions. Its acceptance and effective introduction into Australia might therefore be challenged by its lack of a single obvious organisational home. To overcome this and other identified challenges, several recommendations are made. For example, an Australian demonstration trial of urine diversion and reuse is recommended where clear drivers and opportunities exist, such as: in new developments adjacent to agricultural land; in regions where algal blooms are a critical problem and are predominantly caused by municipal sewage discharges; and where synergies with waterless urinals are being considered for water conservation value. This thesis does not promote urine diversion and reuse as the ‘silver bullet’ to Australia’s water and nutrient problems, however it does recommend that it be considered on an equal basis next to other possible options. For example, if reducing nutrient loads on receiving water bodies is a key objective, then a cost-effective analysis of urine diversion and reuse, compared to other options to reduce nutrient loads, could be undertaken, ensuring all relevant costs and benefits to the whole of society are included in the analysis.</p>
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Urine Diversion & Reuse in Australia : A homeless paradigm or sustainable solution for the future?Cordell, Dana January 2006 (has links)
Diverting urine from faeces or mixed wastewater and reusing it to fertilize crops, is a traditional method used in Asia. It is also a contemporary approach to sustainable nutrient and water management in Scandinavia and other parts of Europe. Urine diversion and reuse is a proven socio-technical system that has significant potential benefits on both a local and global scale, such as recirculating scarce plant nutrients like phosphorus back to agriculture, reducing eutrophication of waterways and improving water and sanitation systems. This thesis explores the nature of these benefits in Australia and the global context and what barriers would need to be overcome if a urine diversion and reuse system were implemented in Australia to achieve significant environmental benefits. These questions are investigated through stakeholder interviews in Sweden, to identify the ‘lessons learnt’ from the Swedish experience with urine diversion and reuse, and, through interviews with relevant stakeholders in Australia to identify possible barriers and opportunities, costs and benefits, and roles and responsibilities in the Australian context. Findings from both the stakeholder interviews are triangulated with other sources of knowledge, such as the literature, personal communications and a qualitative assessment of costs and benefits. This thesis found that while urine diversion is likely to benefit the Australia situation and warrants further research, these benefits are fragmented and spread across a range of discourses and separate institutions. Its acceptance and effective introduction into Australia might therefore be challenged by its lack of a single obvious organisational home. To overcome this and other identified challenges, several recommendations are made. For example, an Australian demonstration trial of urine diversion and reuse is recommended where clear drivers and opportunities exist, such as: in new developments adjacent to agricultural land; in regions where algal blooms are a critical problem and are predominantly caused by municipal sewage discharges; and where synergies with waterless urinals are being considered for water conservation value. This thesis does not promote urine diversion and reuse as the ‘silver bullet’ to Australia’s water and nutrient problems, however it does recommend that it be considered on an equal basis next to other possible options. For example, if reducing nutrient loads on receiving water bodies is a key objective, then a cost-effective analysis of urine diversion and reuse, compared to other options to reduce nutrient loads, could be undertaken, ensuring all relevant costs and benefits to the whole of society are included in the analysis.
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Strategy for developing an ecological sanitation system at the Barrage informal settlementMokoena, Mita January 2015 (has links)
The Barrage informal settlement (BIS) is a peri-urban community of about 300 people resident on private land close to the banks of the Vaal River in Gauteng South Africa. The study focuses on the living and sanitation conditions in which people find themselves. Measured against the Millennium Development Goals (MDGs) BIS and its residents clearly are far from meeting MDG 7 target 7 C. For the purposes of this study the researcher investigated ecological sanitation (EcoSan) as an alternative solution for the current local sanitation conundrum. Residents either use the veld or a dysfunctional pit system. The data used for the project was generated both in a qualitative and quantitative mode. Semi-structured interviews were randomly conducted. Participants were requested and subsequently assisted in completing a questionnaire. There were also several focus group discussions for gathering relevant data. The researcher tried to form an impression of the perceptions of community members in terms on the type of sanitation system they wished to use. Community members actively engaged in strategies aimed to find out how they perceive sanitation, potable water supply and matters of hygiene.
The findings revealed dissatisfaction regarding to current conditions in BIS. Residents are uncertain because the land on which they reside on does not belong to them. This, in turn, creates uncertainty and feelings of insecurity, about the relevance of a potential water-based sanitation system. At the same time members of the community indicated they had no interest in a dry toilet system. Neither are they keen on the use of community ablution blocks (CABs) as alternative. Residents showed no willingness and are also not prepared to pay for sanitation because they cannot afford it. The dilemma is that residents are at the mercy of Emfuleni Local Municipality (ELM) and the private owners of the land on which they reside. Where do we find the solution to all of the issues? Participatory deliberation strategies were used to determine which system of sanitation local residents preferred. They clearly came out in favour of the Water Bank concept as a feasible sanitation system option. However, as a result of the unfulfilled promises of Emfuleni Local Municipality (ELM) and landowners the community remains in a state of uncertainty about the permanence of the BIS.
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Strategy for developing an ecological sanitation system at the Barrage informal settlementMokoena, Mita January 2015 (has links)
The Barrage informal settlement (BIS) is a peri-urban community of about 300 people resident on private land close to the banks of the Vaal River in Gauteng South Africa. The study focuses on the living and sanitation conditions in which people find themselves. Measured against the Millennium Development Goals (MDGs) BIS and its residents clearly are far from meeting MDG 7 target 7 C. For the purposes of this study the researcher investigated ecological sanitation (EcoSan) as an alternative solution for the current local sanitation conundrum. Residents either use the veld or a dysfunctional pit system. The data used for the project was generated both in a qualitative and quantitative mode. Semi-structured interviews were randomly conducted. Participants were requested and subsequently assisted in completing a questionnaire. There were also several focus group discussions for gathering relevant data. The researcher tried to form an impression of the perceptions of community members in terms on the type of sanitation system they wished to use. Community members actively engaged in strategies aimed to find out how they perceive sanitation, potable water supply and matters of hygiene.
The findings revealed dissatisfaction regarding to current conditions in BIS. Residents are uncertain because the land on which they reside on does not belong to them. This, in turn, creates uncertainty and feelings of insecurity, about the relevance of a potential water-based sanitation system. At the same time members of the community indicated they had no interest in a dry toilet system. Neither are they keen on the use of community ablution blocks (CABs) as alternative. Residents showed no willingness and are also not prepared to pay for sanitation because they cannot afford it. The dilemma is that residents are at the mercy of Emfuleni Local Municipality (ELM) and the private owners of the land on which they reside. Where do we find the solution to all of the issues? Participatory deliberation strategies were used to determine which system of sanitation local residents preferred. They clearly came out in favour of the Water Bank concept as a feasible sanitation system option. However, as a result of the unfulfilled promises of Emfuleni Local Municipality (ELM) and landowners the community remains in a state of uncertainty about the permanence of the BIS.
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Diverting human urine from outhouses into agriculture in Nicaragua : for sanitation, fertilizer and recycling purposesAdolfsson, David January 2017 (has links)
Human urine is a valuable resource which has good potential to be used as a fertilizer all over the world. In the developing countries sanitation and food security are both issues that need urgent attention. A urine separation toilet can be constructed with minimal investment in the Nicaraguan context, and the usage of the urine as a fertilizer can help establish higher yields and is a good alternative to chemical fertilizers. This field experiment is trying this in practice in the context of rural Nicaragua, to determine the effect of urine on two plants on. For this study, the common bean (Phaseolus vulgaris) and the Chaya (Cnidoscolus aconitifolius) was selected and the results confirm that urine has potential as a fertilizer in the Nicaragua context. The common bean yield was twice as large after urine fertilization and the Chaya reacted positively to urine fertilization. For urine separation purposes, two different separators were constructed on the site to showcase the benefits with separating the urine from the faeces, creating lower latrine volume and better sanitation in the outhouse. The risks associated with human urine are low if the urine is separated securely to avoid crosscontamination from faeces. If a safety-barrier system is adopted, the overall risks with using urine as a fertilizer are negligible. The spreading potential of urine separation and fertilization in rural Nicaragua is high, but more experiments and demonstrations are needed to reach adopters of the technology. / La orina humana es un recurso valioso que tiene un buen potencial para ser utilizado como fertilizante en el mundo entero. En los países en vías de desarrollo, el saneamiento y la seguridad alimentaria son dos temas que necesitan atención urgente. Un inodoro de separación de orina puede ser construido con una inversión mínima en el contexto Nicaragüense, y el uso de la orina como fertilizante puede ayudar a establecer mayores rendimientos y es una buena alternativa a los fertilizantes químicos. Este experimento de campo está probando esto en la práctica en el contexto de Nicaragua rural, para determinar la diferencia en crecimiento entre dos cultivos con y sin fertilización de orina. Para este estudio se seleccionó el frijol común (Phaseolus vulgaris) y la Chaya (Cnidoscolus aconitifolius) El rendimiento de frijol fue dos veces mayor después de la fertilización de la orina y el Chaya reaccionó positivamente a la fertilización de la orina. Para fines de separación de orina, se construyeron dos separadores diferentes en el sitio para mostrar los beneficios con la separación de la orina de las heces, creando un menor volumen de letrina y un mejor saneamiento. Los riesgos asociados con la orina humana son bajos si la orina se separa con seguridad para evitar la contaminación cruzada de las heces. Si se adopta un sistema de barrera de seguridad, los riesgos generales con el uso de orina como fertilizante son insignificantes. El potencial de propagación de la separación de orina y la fertilización en Nicaragua rural es alto, pero se necesitan más experimentos y demostraciones para llegar a los usuarios de la tecnología. / <p>2017-06-02</p>
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On-site sanitation systems - An integrated assessment of treatment efficiency and sustainability / Små avloppsystem – En integrerad utvärdering av funktion och hållbarhetVidal, Brenda January 2018 (has links)
Small on-site sanitation systems for wastewater collection and treatment are prevalent in suburban and rural areas in many countries. However, these systems often underperform, causing potential impact to the receiving waters and increasing the risks to public health, thus hindering the overall sustainability of the systems. Understanding the different sustainability dimensions and trade-offs between assessment indicators can support the planning of sustainable on-site sanitation systems for a specific context. The overall aim of this thesis was to evaluate the sustainability and function of on-site sanitation systems by defining a set of indicators to assess on-site sanitation options and estimating them for different scenarios, and by investigating the treatment efficiency of on-site facilities for domestic wastewater treatment in a field study. Particular attention was given to the removal of phosphorus (P) and indicator bacteria due to their relevance in terms of eutrophication risk and public-health concern. In a multi-criteria approach, twelve indicators were defined to assess nine on-site sanitation systems. A reference group representing stakeholders’ views assigned weights to express the relative importance of each indicator. The reference group assigned the highest weights to the indicators robustness, risk of pathogen discharge and nutrient removal. Assessing the robustness proved to be challenging, as there is a gap between how the sanitation systems are expected to perform based on their design, and how they actually perform in practice, mainly due to incorrect construction, operation and maintenance. The discriminating power of the indicators was calculated using the entropy method, which showed that the indicators energy recovery and capital cost had little impact in the final ranking of the alternatives. A sustainability ranking was obtained by using the method ELECTRE III. A scenario analysis based on different settings of interest based on socio-economic and geographical factors was done to evaluate the changes in the ranking of alternatives. Overall, the greywater–blackwater separation system ranked the highest in the baseline scenario and when nutrient-related indicators were important (Scenario 2), together with the urine diversion system. The sand filter and drain field were the most sustainable options when nutrient removal and recycling was not important (Scenario 1), and (in combination with chemical P-removal) when the indicators related to energy and climate change had the highest weights (Scenario 3). In terms of P-removal, chemical removal outranked the alkaline P-filter. In a field study, the effluent wastewater from twelve on-site wastewater treatment facilities with sand and alkaline P-filters was evaluated in terms of removal and discharge of organic content, total and dissolved phosphorus, and indicator bacteria (E. coli, total coliforms, intestinal enterococci and C.perfringens). The results showed that the investigated sand filters generally had low P-removal capacity and sometimes exceeded the criteria for excellent water quality set by the EU bathing water directive with regard to intestinal enterococci and E. coli. Only one sand filter of eight was confirmed to remove P according to the Swedish guidelines for areas with non-sensitive receiving waters with a tot-P effluent concentration below 3 mg L−1. This indicates that a downstream treatment step is needed to meet the guidelines regarding P discharge concentrations. Alkaline P-filters generally removed P efficiently. Despite high effluent pH, the collected data did not generally confirm a further reduction of the bacterial content of the wastewater in the P-filters, as had been previously hypothesized. However, effluent concentrations of indicator bacteria showed moderate positive correlations with effluent concentrations of P and organic matter, indicating the potential of the P-filters to serve as a polishing step also for bacteria. / Små lokala avloppssystem för insamling och rening av avloppsvatten är vanligt förekommande i omvandlings- och landsbygdsområden i många länder. Dessa system fungerar ofta sämre än förväntat vilket kan leda till effekter på recipienter, ökad risk för folkhälsan och begränsa systemens hållbarhet. En djupare förståelse för hållbarhetsdimensioner och avvägningar mellan olika indikatorer kan stödja planering och implementering av hållbara lokala avloppsystem för specifika sammanhang. Det övergripande syftet med denna uppsats var att utvärdera hållbarhet och funktion av enskilda avloppssystem. Detta utfördes genom att först definiera en uppsättning indikatorer för bedömning av ett antal enskilda avloppsalternativ och sedan utvärdera dem för olika scenarier. Vidare var syftet att undersöka några systems prestanda för rening av hushållsavloppsvatten i en fältstudie. Särskilt fokus lades på reduktion av fosfor (P) och indikatorbakterier på grund av deras relevans i relation till övergödningsrisk och folkhälsoperspektiv. I en multikriteriestudie definierades tolv indikatorer för att bedöma nio typer av enskilda avloppssystem. En referensgrupp som representerade olika intressenter viktade indikatorerna för att uttrycka den relativa betydelsen av varje indikator. Referensgruppen gav systemens robusthet, risk för utsläpp av patogener, och näringsreduktion störst vikt. Att bedöma robusthet var en utmaning i studien, eftersom det finns ett gap mellan hur systemen förväntas fungera, och hur de faktiskt fungerar i praktiken, mestadels på grund av felaktig konstruktion, drift och underhåll. Indikatorernas diskriminerande effekt räknades ut med entropimetoden, som visade att indikatorerna energiåtervinning och kapitalkostnad hade liten inverkan på alternativens slutgiltiga rangordning. En scenarioanalys genomfördes baserad på socioekonomiska och geografiska faktorer. En hållbarhetsrankning erhölls genom att använda ELECTRE III-metoden. Överlag rankades system som separerar gråvatten – svartvatten samt urinseparerande system högst i basfallsscenariot och när näringsrelaterade indikatorer var viktiga (scenario 2). Markbäddar och infiltrationsanläggningar var de mest hållbara alternativen när rening och återvinning av näringsämnen inte var viktigt (scenario 1) och (i kombination med kemisk P-rening) när indikatorer relaterade till energi och klimatförändringar viktades högst (scenario 3). När det gäller P-rening, gav system med kemisk rening ett bättre utfall än de med alkaliska P-filter. I en fältstudie utvärderades tolv enskilda avloppsanläggningar med markbaserade system och alkaliska P-filter med avseende på rening och utsläpp av organiskt innehåll, totalt och löst P och indikatorbakterier (E.coli, totala koliformer, intestinala enterokocker och C.perfringens). Resultaten visade att de markbaserade systemen generellt hade låg P-reningskapacitet och ofta överskreds kriterierna för utmärkt vattenkvalitet enligt EUs badvattendirektiv avseende intestinala enterokocker och C. perfringens. Endast ett markbaserat system av åtta uppvisade en P-rening som låg under de svenska riktlinjerna för områden med normal skyddsnivå, med en utsläppskoncentration på under 3 mg L-1 tot-P. Detta indikerade att markbäddar behöver nedströms placerade reningssteg för att uppfylla nuvarande riktlinjer för utsläpp av P. Alkaliska P-filter avskilde generellt P effektivt. Trots högt pH-värde kunde ingen ytterligare minskning av bakterieinnehåll i avloppsvattnet från P-filtren påvisas statistiskt. Utsläppen av indikatorbakterier uppvisade emellertid måttliga positiva korrelationer med utsläpp av P och organiskt material, vilket visar på en viss potential att P-filtren kan fungera som ett ytterligare poleringssteg även för bakterier.
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Design and operation criteria for urine-diversion ecological sanitation systems with particular reference to public healthAustin, Lorimer Mark 31 January 2008 (has links)
SANITATION, PUBLIC HEALTH AND THE ENVIRONMENT The approach to sanitation worldwide should be ecologically sustainable, i.e. concerned with protection of the environment. This means that sanitation systems should neither pollute ecosystems nor deplete scarce resources. It further implies that sanitation systems should not lead to degrading water or land and should, where possible, ameliorate existing problems caused by pollution. More research and better designs are needed. Human excreta can be rendered harmless, and toilet designs that do this in harmony with agricultural and social customs hold promise for the future. Problems with conventional sanitation systems have been shown to include inadequate institutional capacity to deal with the sanitation process, a fixation with providing either a full waterborne system or a VIP toilet, the social acceptability of various systems, and the perception that dry, on-site sanitation systems are inherently inferior. The basic purpose of any sanitation system is to contain human excreta (chiefly faeces) and prevent the spread of infectious diseases, while avoiding damage to the environment. An alternative sanitation technology known as urine-diversion (UD) performs these functions with fewer operational and maintenance problems than those associated with conventional VIP toilets, (for example, it is a major and expensive operation to desludge full pits, which is not the case with UD toilets as the vaults can be quickly and easily emptied using hand tools) and also provides a free, easily accessible and valuable agricultural resource for those who wish to use it. This technology represents one aspect of an approach, or philosophy, termed “ecological sanitation” or “ecosan.” Key features of ecosan are prevention of pollution and disease caused by human excreta, treatment of human excreta as a resource rather than as waste, and recovery and recycling of the nutrients. In nature, excreta from humans and animals play an essential role in building healthy soils and providing valuable nutrients for plants. Conventional approaches to sanitation misplace these nutrients, dispose of them and break this cycle. UD systems have been successfully implemented in many countries, including South Africa where more than 60 000 of these toilets have been built since 1997. However, despite much research having been carried out internationally and locally, various questions still remain, particularly on the health aspects of operation, maintenance, and excreta use or disposal. Not enough is known about the dehydrating processes taking place inside the faeces vault, and there is still disagreement on safe retention periods and microbiological stability of the final product. The roles of dryness, pH, temperature and time in pathogen destruction also need to be further clarified. In addition, it is critically important that toilet users are able to operate and maintain their systems easily and safely, particularly while emptying the vaults and recycling or otherwise dealing with the contents. Engineers need to understand and take all these issues into consideration before they can properly design and implement sustainable UD sanitation systems. It is therefore important to develop guidelines for sanitation practitioners that set out best practices for construction and operation of UD toilets. Construction recommendations are important because good construction facilitates easy operation, and also promotes rapid pathogen destruction. Easy operation in turn directly influences the health risks associated with removing faecal material from the vaults. Handling of faecal material is an aspect inherent in the operation of UD ecological sanitation systems, because emptying of the vault is usually done using hand tools. If the faecal material is also used for agricultural purposes then further handling must of necessity take place. As such, there is a health concern, both for the person(s) handling the material and for the wider public who may be consumers of the fertilised crops. It is therefore necessary that these health concerns be quantified, in order that proper regulation may take place. <b<CONCLUSIONS FROM THE LITERATURE REVIEW The primary aim of sanitation is to prevent the transmission of excreta-related diseases. However, with all sanitation systems there is a risk of disease transmission related to the handling or use of the end product. Therefore, even a well functioning system could enhance pathogen survival and lead to an increased risk of disease transmission for those handling the end products or consuming crops fertilised with them. A greater understanding of pathogen die-off in dry sanitation systems is required where handling and/or use of excreta are expected. Pathogen destruction in dry sanitation systems, particularly in the vaults of urine-diversion (UD) toilets, is mainly dependent on storage time, pH, temperature, humidity, moisture content, organic content of the faecal material, and type of bulking agent added. It is of utmost importance to ensure that the material is safe to handle. This implies that the primary treatment in the vault should, as far as possible, ensure the required level of safety. While much research has been carried out internationally into pathogen destruction in the vaults of UD toilets, the same cannot be said of South Africa. There is also a wide range of results and conclusions, with recommended storage times varying from six months to two years. Construction and operational guidelines are required in order to assist practitioners in these and other respects. Sound management practices could play an important role in reducing the health risks involved in emptying the vaults of UD toilets and the disposal or further use of faecal material. From the public health viewpoint, it is necessary to reduce, as far as possible, the risk of handling faecal material. To do this, a better understanding of the factors influencing pathogen die-off in the vaults is required. FOCUS OF THIS THESIS The primary aim of this thesis is to investigate the efficacy of various methods aimed at enhancing pathogen destruction in the vaults of UD toilets, with the aim of (a) establishing the best combination of factors/methods, in particular the vault storage period required, and (b) producing guidelines for the construction, operation and regulation of these systems. The overall purpose of the research is to establish safety criteria for handling of faecal material from UD toilets. FIELD TRIALS: MICROBIOLOGICAL EFFECTS ON FOOD CROPS FERTILISED WITH FAECAL MATERIAL FROM URINE-DIVERSION TOILETS Recycling excreta to soils reduces the need for chemical fertilisers; however, pathogens are recycled to humans if improper agricultural practices are followed. Concerns about using faecal material include higher pathogenic content in developing countries compared to that in developed countries. This material, as well as that from other sanitation alternatives in small-scale systems, demands more personal involvement from the users (including handling), which constitutes a higher human exposure level compared to that from conventional piped systems. Nevertheless, it is considered that where the material can improve agricultural productivity, it can contribute to improving the nutritional status of the population, thus improving public health. Although ecosan technology is spreading all over the world, and with it the recycling of excreta to soils, only a few researchers have addressed the problems associated with the revalorization practice or documented the pathogen die-off. Moreover, little data about the microbial quality of ecosan faecal material from developing countries (where the health risks are the highest) are available. The objective of this research was thus to investigate the potential health risks of using faecal material in agriculture by determining the pathogen uptake on the surfaces of the edible portions of the crops. Faecal material of between one and three months old was extracted from a number of UD toilets in the eThekwini (Durban) municipal area. This was used primarily for the experimental work described in the next section, but for the purposes of this particular experiment it was first left in a heap in the open air for a further four months. Thereafter it was used as a soil amendment in the cultivation of spinach and carrots. Detailed microbiological tests were conducted on this material as well as on the in situ soil before sowing and after harvesting, on the irrigation water, and on the harvested crops. Applying different rates of material to spinach and carrots, two common edible crops, it was found that the bacteria and fungi content were only noticeable for the higher application rates (>35t/ha), while the helminth ova content varied, both in leaves and stems, depending on the quantity of material applied. Helminth ova content was, for both crops, more prevalent in leaves, suggesting that the ova adhere preferentially to plants rather than soil. It was thus illustrated that there is a health implication involved in growing edible crops in soils amended with ecosan biosolids. Even if in this case the spinach and carrots were cooked before consumption, normal handling of the crops during harvesting and preparation could have caused infection if personal hygiene was unsatisfactory. It is therefore important that crop growers and consumers, as well as proponents of biosolids use, are aware of the storage and treatment requirements for ecosan biosolids before these are applied to soils where crops are grown. DETAILED INVESTIGATION INTO VAULT PROCESSES It is hypothesised that the most advantageous approach to pathogen destruction in a UD toilet vault is to maximise the effects of various environmental factors, e.g. high pH, high temperature, low moisture, type of bulking agent and storage time. In order to quantify these effects a field experiment was set up consisting of 12 UD toilet vaults, each with a different combination of faeces and bulking agent (soil, ash, wood shavings, NaOH or straw), ventilation (ventpipe / no ventpipe) and vault lid material (concrete, metal or perspex). Faecal material was obtained from UD toilets in the eThekwini area, as described above. Temperature probes, which were connected to a data logger, were inserted in the heaps and the logger monitored over a period of nearly 10 months. This enabled a number of graphs to be drawn illustrating the effect of the above parameters on heap temperature over the experimental period. During the coldest week in winter the mean heap temperatures averaged 16,8°C, while the minimum and maximum averaged 14,8°C and 18,8°C respectively. During the warmest week in summer mean heap temperatures averaged 27,6°C, while the minimum and maximum averaged 25,6°C and 29,3°C respectively. In addition, samples were taken at various intervals from each vault as well as from the main heap of faecal material that was left exposed to the elements. The samples were subjected to microbiological testing in order to quantify the pathogen die-off over time for each vault as well as for the main heap. In the vaults, total coliform reduced by 3 log10 (99,9%) at between 130 and 250 days, faecal coliform between 100 and 250 days, and faecal streptococci from 125 days and longer. In the main heap, these times varied from 115 days for both total and faecal coliform to 140 days for faecal streptococci. Viable Ascaris ova were reduced to zero between 44 and 174 days in the vaults and by 44 days in the main heap. The conclusions drawn from the xperimentation were the following: <ul> <li>Influence of ventpipe Ventilation of the vault by means of a ventpipe does not result in any meaningful difference in either the vault temperature or rate of pathogen die-off.</li> <li>Influence of vault lid material The lid material, and by inference also the material of the vault walls, has no significant effect on the temperature of the heap or the associated pathogen die-off.</li> <li>Type of bulking agent While the type of bulking agent used does not significantly influence the temperature of the faecal material, it does have an effect on the rate of pathogen die-off. The ordinary soil mix was seen to give the best results, and this was ascribed to the effect of competing microorganisms in the soil itself.</li> <li>Influence of sunshine and rain The main heap of material (faeces/soil mix) that was exposed to the elements performed among the best in terms of pathogen die-off. Apart from the influence of competing microorganisms in the soil on the pathogens as described above, this good performance was also ascribed to the effect of UV radiation and alternate wetting/drying and heating/cooling cycles, which suggests that open-air exposure is likely to provide the best treatment.</li></ul> Comparing the results of this research with other local and international research, it appears that there is a great deal of convergence in the results. It is concluded that vaults of UD toilets should be sized for a storage period of 12 months from last use. RECOMMENDATIONS FOR CONSTRUCTION, OPERATION AND REGULATION OF URINE-DIVERSION TOILETS The standard of UD toilets in South Africa varies greatly. While there are many good examples of the technology, there are also many that have been ill-conceived and are badly built and poorly operated. Project implementers are responsible for the quality of sanitation schemes and should be equipped with the necessary information to oversee the process. The guidelines are aimed at providing implementers with, firstly, the necessary technical information to build good quality UD toilets and, secondly, the basic operation and maintenance tasks that should be conveyed to the toilet owners. Basic regulatory guidelines for the responsible authorities are also given. The guidelines are intended to be a stand-alone document and some repetition of information from earlier chapters is thus unavoidable. The technology of urine diversion is introduced, followed by basic design and construction guidelines, including drawings, for the superstructure and vault of a UD toilet. Both single- and double-vault toilets are discussed. A number of photographs are also provided, illustrating good and bad building practices. Further aspects discussed are requirements for urine pipes and ventilation. Operation and maintenance of UD toilets are subsequently covered. Topics discussed are dehydration, odour, fly control, cleaning of the pedestal, disposal of anal cleansing material, urine collection and disposal, clearing of blockages in urine pipes, and faeces management. The above guidelines are aimed at designers, builders and toilet users. However, organisations responsible for administering public and environmental health, such as Departments of Health, Environmental Affairs, etc, as well as the local and regional authorities that actually implement the sanitation schemes, should become actively involved in regulating the operation of UD toilets, particularly the removal and disposal of faecal material. Some regulatory guidelines are therefore also included to assist these organisations to set uniform (high) standards in their respective jurisdictions. RECOMMENDATIONS FOR FURTHER RESEARCH RELATED TO THIS THESIS It is deemed important that the field trials conducted in the various vaults as described earlier are repeated in other climatic areas, for example a hot and dry area, as it is likely that different results regarding recommended minimum storage periods will be obtained. This should be supplemented by trials involving co-composting of the faeces mix with other organic material, in order to compare the efficacy of this method with the dehydration process. Further, vault lids made of PVC should be tested for enhancing heat gain in the vaults. Finally, long-tem measurements of heap pH should be made in order to ascertain if high pH amendments (wood ash, lime, etc) do in fact maintain their initial pH level. Additional field trials, similar to those described earlier for spinach and carrots, should be undertaken with a view to making recommendations regarding maximum application rates of faecal material. These should consist of food crops where the edible portions are either in or near to the soil, such as beetroot, onion, potatoes, tomatoes, etc. Trials involving urine should also be considered in order to determine the most advantageous application rate for the various crops. Another important topic is recommended for further research on the subject of UD toilets. At present, virtually all the UD toilets built in the country have been for communities on the lower end of the income scale and who previously had no formal sanitation facility at all or, at best, an unimproved pit toilet. Research carried out by CSIR in a number of communities has revealed people’s resistance to handling their faecal material, while in others it has not been a problem. There is often a general viewpoint in a village that “the municipality must take the faeces away.” However, willingness has also been expressed in some villages to pay for a faeces removal service. For instance, this has borne fruit in an area of Kimberley with UD toilets where householders pay a local resident to remove the faecal material on a regular basis. This is done by means of a wheelbarrow, and the material is stockpiled at a nearby approved facility from where it is destined for co-composting with other municipal waste. However, this has not yet been attempted on a large scale in an area with hundreds, or even thousands, of UD toilets. While a theoretical desktop study has been carried out on the feasibility of setting up a large-scale faeces collection concern, such an enterprise does not yet exist in the country. It is suggested that one be set up utilising a horse- or donkey-drawn cart in a village, or group of villages, with sufficient UD toilets available to ensure that a viable business can be conducted. The cooperation of the particular local authority will be required. If successful faeces collection/disposal services could be established in areas with UD toilets it would greatly enhance the social acceptability, and therefore the viability, of this sanitation technology. / Thesis (PhD(Civil Engineering))--University of Pretoria, 2008. / Civil Engineering / unrestricted
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Pilotstudie av källsorterande avloppslösning : Identifiering av systemlösning för källsorterat avloppsavfall i Sydöstra staden i Uppsala / Pilot study of source separation sewage systemEkblad, Linnea January 2022 (has links)
Utanför Uppsalas stadskärna planeras det att bygga en ny stadsdel till år 2050, kallad Sydöstra staden. Uppsala kommun vill vara i framkant gällande hållbar stadsplanering och är därför intresserade av att utreda möjligheter till att tillvarata resurser i avloppsvattnet, som ett alternativ till konventionell rening. I dagsläget står hanteringen av avloppsvatten inför nya typer av utmaningar som rör utsläpp av växthusgaser, bristande resursåtervinning och energieffektivitet samtidigt som kraven på rening ökar. Ett tillvägagångssätt som skulle kunna möjliggöra hantering av dessa utmaningar är genom implementering av källsorterande system. Ett källsorterande avloppssystem separerar vattenfraktionerna för enskild behandling, vilket möjliggör att resurser så som energi och näringsämnen kan återvinnas. Syftet med arbetet var att kartlägga drivkrafter och utifrån dessa identifiera systemlösningar för källsorterat avloppsavfall i Sydöstra staden i Uppsala. Genom studie gällande drivkrafter samt efterföljande workshop med en referensgrupp från Uppsala Vatten kunde möjliga drivkrafter för Uppsala identifieras: Vattenbesparing, Uppfyllande av höga reningskrav, Resurseffektivitet vad gäller energi och näring, Kunskapsgivande samt Klimatneutralitet. Identifiering av drivkrafter resulterade i litteraturstudie för att identifiera anläggningar med liknande drivkrafter som referensgruppen. Studien visade att drivkrafter likt de ovan nämnda resulterade i teknik såsom membranbioreaktor för rötning av källsorterat avloppsavfall. Därefter, genomfördes intervjuer med personer som varit/är delaktiga i pilotprojekt i Sverige för att specifiera vad som krävs för ett genomförande. I nuläget har det visat sig vara svårt att kräva implementering av ett källsorterande system med huvudsyfte att återföra produkter, då kretsloppsaspekten inte har varit ett tillräckligt juridisk motiv för genomförande. I Helsingborg underlättades genomförandet av en hög ambitionsnivå samt en tydlig målbild från kommunen. Slutsats från arbetet är att systemlösningen som bäst lämpar sig för de identifierade drivkrafterna inkluderar rötning av källsorterat avfall i membranbioreaktor (AnMBR), samt urinsortering med efterföljande torkning. Beräkningar gällande en potentiell implementering resulterade i att pilotanläggningen i Sydöstra staden ska dimensioneras för 900 personer. Gällande systemet för behandling av urin, resulterade den dagliga urinproduktionen i att torkningsbädden bör ha en area motsvarande 30 m2 alternativt 23 m2 (beroende på torkningshastighet). För behandling av fekalier, fastställdes mått på membranreaktorn till radien 5 meter och höjden 11 meter, med volymen spolvatten som huvudsaklig orsak till den stora volymen. / Outside the city center of Uppsala, a new district called ”the Southeastern city” will be built by 2050. Uppsala municipality wants to be at the forefront of sustainable planning and is therefore interested in investigating opportunities to utilize resources found in wastewater, as an alternative to conventional treatment of wastewater. Wastewater management is facing new types of problems related to greenhouse gas emissions, resource recycling and energy efficiency. One approach that enables management of these challenges is through the implementation of source separation sewer systems, that separates the household wastewater into different fractions. This enables resources such as energy and nutrients to be recycled. The purpose of the work was to identify drivers and from these drivers identify a solution for source separated sewage fractions in the southeastern city of Uppsala. Through a literature study followed by a workshop with Uppsala Vatten, possible drivers for Uppsala were determined to be Water Saving, Fulfillment of purification requirements, Resource efficiency regarding energy and nutrition, Obtaining knowledge and Climate neutrality. The determination of possible drivers resulted in further literature study, to identify facilities with similar drivers as Uppsala. The study showed that drivers as the ones identified for Uppsala have resulted in technology such as membrane bioreactor for digestion of source separated wastewater. Interviews were also conducted with people who have been or are involved in pilot projects in Sweden to specify what is required for implementation of a source separation system. It is currently difficult to require the implementation of such system with the main argument of recycling products, as the recycle aspect has not been a motive enough juridically for implementation. In Helsingborg, the ambition and a clear vision from the municipality was crucial for the implementation. In conclusion, the system best suited to the identified drivers include anaerobic digestion of source separated waste water in membrane bioreactor (AnMBR), as well as urine dehydration. Calculations were performed regarding a potential implementation resulted in that the treatment plant should treat wastewater from 900 people. For the treatment of urine, the daily urine production resulted in an area of the drying bed of 30 m2 or 23 m2 for varying drying rates. For treatment of faeces, dimensions of the membrane reactor were determined to radius 5 meters and 11 meters height, where the volume of flush water was the main reason for the large reactor.
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Towards Sustainable Phosphorus Management : Material Flow Analysis of phosphorus in Gothenburg and ways to establish nutrient recycling by improving urban wastewater systems / Mot en mer hållbar fosforhantering : Substansflödesanalys av fosfor i Göteborg och sätt att uppnå näringsåtervinning genom att förbättra urbana avloppssystemBorgestedt, Helena, Svanäng, Ingela January 2011 (has links)
All life forms require the nutrient phosphorus and it cannot be substituted by any other element. The global cycle of phosphorus is special among the major biogeochemical cycles, since it has no significant gaseous compounds and only closes every 10-100 million years. However, human activities, as application of mineral fertilizers, conversion of natural ecosystems to arable land and releases of untreated waste, intensify remarkably thephosphorus flows. The problems with linear flows of a limited resource leading to eutrophication of aquaticenvironments, for instance, have generated national environmental quality objectives for phosphorus in Sweden. The main objective of this master thesis is to get a holistic overview of how phosphorus is moving through Gothenburg today, using Material Flow Analysis as method. The spatial system boundary is the municipality of Gothenburg and the temporal system boundary is the year of 2009. One way of dealing with the linear flows ofphosphorus might be to develop the wastewater systems used in Gothenburg today. Possible changes in phosphorus flows, if kitchen grinders or urine-diverting toilets were installed in Gothenburg, are evaluated. In order to make the phosphorus management more sustainable, the linear flows have to be closed to a larger extent than today. One way towards this ambition is to emphasize other fertilizers than the mineral ones, like urine and low-contaminated sludge. The MFA shows that the absolutely largest input of phosphorus to Gothenburg is via the food. The two large outputs of the same magnitude are the digested sludge from the wastewater treatment plant of Rya and the ashes from the waste-fuelled district heating power plant of Sävenäs. About 7% of the phosphorus input to Gothenburg continues into the aquatic environment. According to this study, urine diversion and separate collection of food seem prospective in order to decrease the phosphorus flows in digested sludge from the wastewater treatment plant, ashes and aquatic deposition. An additional advantage would be generation of recycled fertilizing products with good quality. / Näringsämnet fosfor är nödvändigt för alla levande organismer och kan inte ersättas av något annat grundämne. Den globala fosforcykeln är speciell då den inte innehåller några gasformiga föreningar och sluts var 10-100 miljonte år. Användning av konstgödsel, omvandling av tidigare orörda ekosystem till odlingsmark och utsläppav förorenat avfall är exempel på mänskliga aktiviteter som intensifierar fosforflöden. Problemet med att linjäraflöden av denna begränsade resurs leder till övergödning av vattenmiljöer har genererat nationella miljömål i Sverige för fosfor. Det huvudsakliga målet med detta examensarbete är att få en översikt av hur fosfor rör sig genom Göteborg idag med hjälp av substansflödesanalys. Den rumsliga systemgränsen är kommungränsen för Göteborg och den tidsmässiga avgränsningen är året 2009. Ett sätt att förbättra de linjära fosforflödena kan vara att utveckla deavloppssystem som idag används i Göteborg. Förändringarna som uppstår i fosforflödena vid installation av urinsorterande toaletter alternativt köksavfallskvarnar undersöks. Linjära flöden måste bli återcirkulerade i en högre utsträckning än idag ifall fosforhushållningen ska gå mot hållbarhet. Ett sätt att nå denna ambition är att lyfta fram andra gödselprodukter än konstgödsel, exempelvis urin och renare slam. Flödesanalysen visar att det definitivt största inflödet av fosfor till Göteborg är via livsmedel. De två största fosforutflödena, båda i samma storleksordning, är rötat slam från Ryaverket och aska från sopförbränningsanläggningen Sävenäs. Cirka 7% av den fosfor som flödar in i Göteborg fortsätter vidare ut i vattenmiljön. Enligt denna studie verkar urinsortering och separat insamling av matavfall vara goda lösningar för en framtid med mindre fosfor i slammet från Rya och i aska samt till vattenmiljön. En ytterligare fördel skulle vara erhållandet av hållbara gödselprodukter med god kvalitet. / <p>This master thesis has also been published as a technical report at Chalmers with Report No. 2011:124.</p>
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