Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2014-12-03T17:13:28Z No. of bitstreams: 2 Dissertação - Sílvia Maria Gonçalves Santos de Lacerda - 2002.pdf: 515502 bytes, checksum: a6d159edda0641f849ebfcf6fc2c44d7 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2014-12-04T14:49:29Z (GMT) No. of bitstreams: 2 Dissertação - Sílvia Maria Gonçalves Santos de Lacerda - 2002.pdf: 515502 bytes, checksum: a6d159edda0641f849ebfcf6fc2c44d7 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-12-04T14:49:29Z (GMT). No. of bitstreams: 2 Dissertação - Sílvia Maria Gonçalves Santos de Lacerda - 2002.pdf: 515502 bytes, checksum: a6d159edda0641f849ebfcf6fc2c44d7 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2002-04-26 / The environmental crimes have been a reason of ostentation all over the Word. The judiciary has been finding difficulty to individualize the responsible for such criminal acts the environment. The research in discussion is themed: “The responsibility of the legal entity in the penal range in such crimes as the contamination of the potable water according to hydric resources”. In this purpose, the references of environmental crimes throughout the word were discussed in wide variety, and also the rhetoric function of the expression “sustainable development” was analyzed, as well, starting from the fact of recognition that susceptibility is the natural principal and it cannot be substituted by developer, hurrying on to rapidly avoid its destruction. Through bibliographic and field research, some doctrinaire commentaries were emphasized about the understanding of the true environmental problematic, insinuating vulnerable points referring to the self object of word, such as the neglect of the public government according to environmental protection, who are the responsible for the contamination of the potable water and some other questions related to the topic in discussion. Furthermore, the chapter “from the waters” relates about the volume of the ocean water throughout the globe, showing its resources, its provenance with the contaminated sources, highlighting the industry as the biggest water contamination of all. Some quotations entitled as “juridical tutelage” commented about the legal guardianship of the water in the federal constitution of Brazil as relevant and some other legal definitions as well. Institute treated in the comparison of law, analyzing the institutional laws that distinguished themselves by establishing laws that will preserve the hydric resources on the planet. The environmental politic in Brazil had importance in many blanches of law study, the tutelage of the environment. Although all of the evolution of the civil responsibility theory, reaching up to the objective responsibility, by applying different sanctions, going from giving away fines to the obligations of recovering the environment, even though it shows not being so efficient to solve the problem, as little as it seems, produces side effects in many other biomes. The main aspect of the research was to show the penal responsibility of the legal entity due to the contamination states that the legal entity is also responsible for the environmental crimes, such as the law of “environmental crimes” as seen in article 225, third paragraph, first cut. It also shows that the juridical corporation in the entity responsible for such crimes in the civil and penal range, and also administrable responsible for the environmental crimes, establishing sanctions to be comminated in many areas of law study. / Os crimes ambientais que tem sido motivo de alarde em todo o universo. O judiciário tem encontrado dificuldades em individuar os responsáveis por tais condutas criminosas ao meio ambiente. A pesquisa ora em questão tem como tema: “A responsabilidade da pessoa jurídica no âmbito penal nos crimes de contaminação de água potável em relação à poluição dos recursos hídricos”. Nesse propósito inicialmente foram abordados de forma ampla, referências sobre os crimes ambientais no mundo, momento em que foi também analisada a função retórica da expressão “desenvolvimento sustentável”, partindo-se do reconhecimento de que a sustentabilidade é o capital natural e este não é substituível pelo fabricado, urgindo evitar urgentemente sua destruição. Através da pesquisa bibliográfica e pesquisa de campo, foram destacados comentários doutrinários e legais sobre a compreensão da verdadeira problemática ambiental, pontos vulneráveis referentes ao próprio objeto de trabalho, tais como a omissão do poder público quanto a preservação ambiental, quem são os responsáveis pela contaminação da água potável e outras questões referentes ao tema. Em passo seguinte - no capítulo “Das águas”, tratou-se do volume das águas no planeta, a forma de sua apresentação, a procedência dos elementos contaminantes, ressaltando a indústria como a maior contaminadora das águas entre tantas. Foi relevante num terceiro momento, algumas citações intituladas como “Da tutela Jurídica”, onde comentou-se sobre a disposição legal das águas nas Constituições do Brasil e outras definições legais no mesmo sentido. Instituto tratado no direito comparado, analisando as legislações que mais se destacaram ao instituir leis com objetivo de preservar os recursos hídricos no planeta. A política ambiental no Brasil teve importância nos vários ramos do direito, a tutela do meio ambiente. Apesar de toda evolução da teoria da responsabilidade civil, chegando até mesmo à responsabilidade objetiva, com aplicação de sanções diferenciadas, indo da aplicação de multa à obrigatoriedade de se recuperar o ambiente danificado, embora demonstrando não ser suficiente para solucionar o problema, que por menor que seja, produz reflexos em vários outros biomas. O cerne da pesquisa foi apontar a responsabilidade penal da pessoa jurídica em razão da contaminação da água potável em razão de se constatar que a Constituição Federal ao dispor no artigo 225 § 3º, inciso I, que a pessoa jurídica também é responsável pelos crimes ambientais, bem como a lei “dos crimes ambientais” também preveja a corporação jurídica responsável no âmbito civil, penal e administrativamente pelos crimes ecológicos, estatuindo sanções a serem cominadas nas diversas áreas do direito.

Os sistemas prediais de água não potável podem ser do tipo centralizado, quando os efluentes oriundos de diversas edificações são coletados e transportados para um único local de tratamento e redistribuídos para um conjunto de residências; ou descentralizado, quando a coleta, o tratamento e o transporte dos efluentes ocorrem próximos ao local de produção. Porém, tanto o sistema centralizado quanto o descentralizado possui particularidades que os fazem interessantes ou não em aspectos sociais, econômicos e ambientais. Desta forma, o objetivo principal desta pesquisa foi formular modelos matemáticos que permitissem comparar o sistema centralizado com o descentralizado. Para o desenvolvimento do estudo realizou-se uma revisão bibliográfica com o intuito de coletar informações sobre as principais variáveis que interferem na tomada de decisão de cada tipo de sistema. A partir dos princípios da Programação Linear Inteira foram formulados três modelos que permitiram encontrar qual tipo de sistema apresenta o menor custo total acumulado, quanto é o valor desse custo ao longo do tempo e quantos sistemas são necessários instalar para atender a uma demanda específica. Com base nos dados da literatura consultada, o sistema centralizado apresentou-se mais vantajoso do que os sistemas descentralizados quanto aos custos de implantação, de manutenção e de operação considerando uma vida útil de 20 anos. Todavia, verificou-se que a escolha do sistema mais viável não deve se concentrar apenas nos custos, mas também devem ser consideradas variáveis qualitativas. Deste modo, as formulações gerais dos modelos permitem a inserção de outras variáveis de decisão e restrições para aprimorar a tomada de decisão quanto ao tipo de sistema predial de água não potável a ser implantado. / Non-potable water systems may be of the centralized type when effluents from several buildings are collected and transported to a single treatment site and redistributed to a set of residences; or decentralized, when the collection, treatment and transportation of the effluent occurs near the place of production. However, both the centralized and decentralized systems have particularities that make them interesting or not in social, economic and environmental aspects. In this way, the main objective of this research was to formulate mathematical models that allowed to compare the centralized system with the decentralized one. For the development of the study a bibliographic review was carried out in order to collect information on the main variables that interfere in the decision making of each type of system. From the principles of Linear Programming, three models were formulated that allowed to find out which type of system has the lowest cumulative total cost, what is the value of this cost over time and how many systems are needed to meet a specific demand. Based on the data of the literature, the centralized system was more advantageous than the decentralized systems in terms of the implantation, maintenance and operation costs considering a useful life of 20 years. However, it has been found that the choice of the most viable system should not only focus on costs but should also be considered as qualitative variables. In this way, the general models formulations allow the insertion of other decision variables and constraints to improve the decision making regarding the type of non-potable water system to be implanted.

A preocupação mundial com o cenário de escassez do recurso natural \"água\" é sintetizada no slogan adotado pela WateReuse Research Foundation em campanha pelo reuso de água: \"Water... it\'s too valuable to be used just once\". Progressivamente tem-se melhorado os processos de gestão da água, com controle de desperdício, procedimentos e utilização de fontes alternativas de abastecimento, não apenas na escala dos sistemas públicos, mas nos sistemas prediais. No Brasil, seguindo esta tendência global, existem iniciativas independentes de sistemas prediais de água não potável sendo instalados em edifícios residenciais e comerciais. Estas iniciativas, no entanto, contam hoje com pequeno respaldo técnico normativo, diretrizes ou legislação que orientem gestores, executores e profissionais sobre as práticas adequadas de implantação, gestão e monitoramento deste tipo de sistema, colocando em risco a segurança dos usuários e o sucesso da tecnologia. Considerando-se que para produzir um edifício de qualidade é fundamental atender às necessidades dos usuários, adequando as soluções ao uso que será feito do produto, a Avaliação Durante Operação (ADO) do edifício apresenta-se como uma ferramenta adequada para a análise da situação atual do sistema. Inserindo-se neste contexto, esta pesquisa tem o objetivo de propor uma ferramenta que auxilie a avaliação de desempenho de sistemas prediais de água não potável durante sua operação em edifícios residenciais, no que se refere à operação e manutenção. Para tanto, foi realizado levantamento bibliográfico sobre sistemas prediais de água não potável, tratamentos de água disponíveis e avaliação de desempenho. Seguindo a metodologia de ADO, foram realizados estudos de casos em edifícios residenciais para levantamento de dados atuais de desempenho. Ao término da análise dos casos selecionados, foi possível validar a ferramenta proposta e constatar que a falta de capacitação técnica, normas técnicas e legislações específicas que orientem projetistas, executores, gestores e usuários e padronizem os sistemas prediais de água não potável contribui para o cenário encontrado nos estudos, caracterizado por sistemas que operam com desempenho inferior ao adequado para atender às necessidades e garantir a segurança de seus usuários. / The global concern with the scenario of increasing natural resource scarcity is synthesized in the slogan adopted by WateReuse Research Foundation for a reuse campaign: \"Water... it\'s too valuable to be used just once.\" Progressively, the water management processes have been improved, by controlling waste, procedures and use of alternative sources of water supply, not only at the city level but also individually. In Brazil, following this global trend, there are independent initiatives of non-potable water systems being installed in residential and commercial buildings. These initiatives, however, have today little technical normative support, guidelines or legislation to orientate managers, performers and professionals on the appropriate practices for deployment, management and monitoring of this type of system, endangering the safety of users and the success of technology. Considering that to produce a quality building it is critical to meet the user\'s needs, suiting the solutions according to the product use, the evaluation during operation (EDO) presents itself as adequate tool for analyzing the current situation and proposing improvements on the system performance. In this context, this study aims to propose a tool that assists the performance evaluation of non-potable water systems during its operation in residential buildings, regarding the design, implementation, operation and maintenance. In order to do that, it was performed bibliographical survey on nonpotable water systems, available water treatments and performance evaluation. Following the EDO methodology, case studies were conducted in a sample of residential buildings for current performance data collection. Upon completion of the analysis of selected cases, the proposed tool was validated and it was found that the lack of technical training, technical standards and specific legislation to guide designers, performers, managers and users, and to standardize the non-potable water systems contributes to the scenario found in the case studies, characterized by systems operating with performance unsuited to meet the needs and ensure the safety of its users.

PhDRDV / Institute for Rural Development / Potable water supply is a fundamental human right and protected by international conventions and national laws. Access to it and having in place an appropriate water supply system remain the building blocks to improving and maintaining the welfare of any community for it to enjoy a healthy and productive life. The supply of potable water, especially in Africa's rural areas, however, remains a challenge. The demand for a system to provide sustainable water supply has been on the increase due to population growth and the climate change phenomenon. Vhembe District Municipality (VDM), as the responsible authority for water supply in sections of the Limpopo Province, faces many challenges, including - aging water supply infrastructure, lack of capacity of officials, and lack of funds for maintenance; these often lead to a breakdown of the supply system. This challenge results, for example, in increased health hazards that often cause tension between the District and the residents. The study’s main objective was to investigate the water supply system in Vhembe so as to suggest an effective intervention strategy for potable rural water supply system to improve the supply in the Vhembe District Municipality of the Limpopo Province. The specific objectives were - to determine the current potable water supply sources in rural communities of the VDM, examine the system’s ability to meet the needs of the rural communities in VDM and to identify the challenges and coping strategies used to meet potable water supply in VDM. A mixed-method, of both qualitative and quantitative research designs and techniques, was adopted and focus group discussions and in-depth interviews were used to gather data. From the four local municipalities of VDM, 14 wards were purposively selected through proportional representation of 448 households, which were randomly selected. Three municipal officials responsible for the water supply system in the VDM were selected through census. Key-informant discussions were held with councillors from the 14 wards, with focus group discussions used to engage the 448 households, and traditional leaders. Thematic content analysis was used to identify common themes, ideas, and patterns of meaning that came up frequently from qualitative data. The IBM Statistical Package for the Social Science (SPSS) version 25 was used to analyse data using descriptive statistics, one way ANOVA and Chi-Square test.The results revealed that in Vhembe District Municipality, the primary sources of water were boreholes (45.3%) followed by piped water from the dams (35.3%). The majority of the households (53.6%) obtain water from boreholes once per week, with 4% resorting to obtaining water from rivers, 5.4% obtained water from fountains and 10% obtained their water from Municipality water tankers (truck tankers). These results indicate that the District continues to face challeges in its efforts to fulfill its mandate as the responsible authority for water supply, in the rural communities due to lack of a sustainable system to supply the required minimum water needs for households. The study recommended that all stakeholders should join hands to invest in a system that has more water supply options to sustainably meet the needs of the growing population. The system should have management ii structures relevant for villages, as critical pillars to assist - with the management system, address minor maintenance requirements, and monitor and report any water supply system-related issues. It was also suggested that rural communities be encouraged to pay for water supply services, for the system's sustainability and that the system in VDM would be improved when stakeholders (communities, government, and NGOs) come together. / NRF

Reverse osmosis (RO) is widely used for water reclamation and is one of the most feasible technologies for addressing water scarcity around the world. RO membrane fabrication procedures are continually being optimized and modified to enhance the treatment performance and efficacy of the RO process. A review of the existing literature published on membrane fabrication revealed that a detailed and reproducible methodology consistent among prior studies was not available. Therefore, the primary objective of this study was to utilize techniques from prior research to develop a reliable lab-scale membrane fabrication process for studying the potable reuse applications of TFC RO membranes. Phase inversion was used to create a polysulfone (PSF) support layer on a non-woven fabric sheet. Then, the process of interfacial polymerization (IP) between amine and acyl chloride monomers was utilized to form a highly selective and ultrathin polyamide (PA) layer on the PSF support surface. The resulting membrane composition and performance was dependent on a wide range of parameters during the fabrication process. The optimal support materials, reactant types and concentration, and reaction conditions were determined through trial and error. The best performing membranes utilized N-methyl-2-pyrrolidone (NMP) as the solvent, Novatexx-2471 non-woven fabric for mechanical support, and 15 wt% PSF concentration for phase inversion. The optimal immersion duration was five minutes for the aqueous amine monomer solution during the IP process. The flux for membrane triplicates was 20.2  3.6 liters per square meter per hour (LMH) while the salt rejection was 96.8  2.0%. The relatively low standard deviation for flux and salt rejection indicates that the fabrication method developed herein is consistent. A commercial Dow Filmtec BW30 flat sheet PA-TFC RO membrane was tested for comparison and exhibited a flux of 44.9 LMH and a salt rejection of 98.5%. Thus, the membranes developed in this study achieved salt rejection on par with commercial membranes but exhibited a flux that was significantly lower. Furthermore, this study investigated modifications to the traditional TFC membrane using engineered silica nanomaterials with the goal of enhancing the membrane flux while maintaining high salt rejection. Two types of nonporous silicon dioxide nanoparticles (SDNPs), non-functionalized and amine functionalized, were dispersed in the aqueous and organic IP solutions. Ultrasonication of the non-functionalized SDNPs in the aqueous solution was observed to produce the most stable dispersion. Compared to the unmodified TFC membranes, the average flux of the SDNP-modified (TFC-NP) RO membrane triplicates was higher at 25.4  2.0 LMH with 0.1% (w/v) SDNPs incorporated in the PA layer. The salt rejection was lowered to 92.3  0.1% for the TFC-NP membranes. In addition, the membranes fabricated in this study were characterized using scanning electron microscopy (SEM), Fourier Transport Infrared Spectroscopy (FTIR), atomic force microscopy (AFM), and goniometry measurements. SEM images showed that the TFC-NP membranes contained larger spaces between ridges and valleys of the PA pore structure. FTIR confirmed the PA layer formation on the membranes fabricated herein but a spectral peak from the SDNPs was not observed for the TFC-NP membranes. AFM measurements indicated an increase in surface roughness of the modified membranes, likely because of the incorporation of SDNPs. The surface of TFC-NP membranes was found to be more hydrophilic than the unmodified TFC membranes based on contact angle measurements. Further optimization of the fabrication method developed herein is warranted before pursuing additional RO research topics, such as the disinfection byproduct precursor removal of TFC membranes.

No description available.

Hållbarhets- och klimatfokus driver aktörer inom bygg- och anläggningsbranschen att utveckla nya arbetssätt och verktyg för att minimera klimatpåverkan från den egna verksamheten. Livscykelanalyser, LCA, som ett miljöledningsverktyg för att analysera och minska klimatpåverkan från processer kräver stora resurser för att applicera LCAmetodik på hela entreprenadprojekt. Ett flertal nischade beräkningsverktyg har därför utvecklats av intressenter inom ledningsrenovering. Som ledningsnätsägare har Norrvatten höga krav på kvalitet vid nyläggning och renovering av huvudvattenledningar. Men även ett miljöfokus och engagemang för nya tekniker som mynnat ut i användandet av nya schaktfria metoder för renoveringsprojekt, ibland i grunden av praktiska skäl men där en betydande minskning av klimatpåverkan kan anses uppstå till följd. Genom större insyn i klimatpåverkan från entreprenadprojekt skapas underlag för framtida beslutsfattande, arbetsprocesser och fortsatta studier. Syftet med studien var att se över tillgängliga beräkningsverktyg och deras användbarhet och användarvänlighet. Vidare att analysera aktuella vattenledningsentreprenadprojekt utförda i öppen schakt samt schaktfri metod för att se om dessa val kan påverka hur entreprenader kan utföras mer hållbart, ur ett klimatmässigt och ekonomiskt perspektiv. Under studien uppstod problem vid resursinventering för entreprenaderna, där faktiska mängder från entreprenörer ej kunde erhållas. Endast övergripande kartläggning och analys utfördes därför av entreprenaderna, i kombination med ett antal beräkningsverktyg tillgängliga på marknaden. Studien visar att många nischade beräkningsverktyg baserade på LCA-metodik saknar anpassning för analys av ledningsentreprenader med större rördimensioner, vanligt förekommande inom Norrvattens ledningsnät. Beräkningsverktyg saknar även den transparens och därmed jämförbarhet som renodlade LCA-verktyg. Resultatet visade dock att, även trots antagen och uppskattad analys av ingående parametrar för projekten, skapades en ganska likartad bild av den procentuella sänkningen av kg CO2-ekvivalenter mellan de olika teknikerna. Den beräknade klimatpåverkan var omkring 80% lägre per meter ledning för påverkanskategori GWP, liknande det resultat som kunde erhållas från nischade beräkningsverktyg. Med hänsyn tagen till att den schaktfria metoden infodring är relativt ny för dricksvattenledningar samt har en halverad teoretisk materiallivslängd kan en teoretisk brytpunkt beräknas till 231,8 år eller drygt fyra schaktfria renoveringar innan klimatpåverkan uppgår till motsvarande renovering i traditionell öppen schakt. Fortsatta studier kan med fördel mer ingående fokusera på resursinventering av entreprenader och fördjupning inom transparenta LCA-verktyg likt miljöberäkningsverktyget, BM 1.0. Alternativt bygga vidare på rapportens analys och beräkningsdel för framtagning av ett nischat beräkningsverktyg. / Sustainability and environmental focus drives actors in the construction industry into developing new working methods and tools to minimize the climate impact from their own activities. Life cycle assessment, LCA, as an environmental management tool for analyzing and reducing the climate impact of processes require considerable resources to apply the methodology to entire construction projects. A number of niche calculation tools have therefore been developed by actors working with trenchless technologies. As a grid owner, Norrvatten has high demands on quality when installing and renovating main water pipes. But also, an environmental focus and commitment to new technologies that have resulted in the use of new shaft-free methods for renovation projects, sometimes for practical reasons but where a significant reduction in climate impact can result. Greater transparency in the climate impact from contracting projects creates the basis for future decision-making, work processes and further studies. The purpose of the study was to review available calculation tools and their usefulness and ease of use. Furthermore, to analyze current projects carried out in open shafts and shaft-free method to see if these choices can affect how contracts can be carried out more sustainably, from a climate and economic perspective. During the study there were problems with gathering information about used resource from the contractors, therefore actual quantities from contractors could not be obtained. Only overall mapping and analysis was carried out, in combination with a number of calculation tools available on the market. The study shows that many niche calculation tools based on LCA methodology lack adaptation for analysis of management contracts with larger pipe dimensions, commonly found in Norrvatten's pipeline network. Calculation tools also lack the transparency and thus comparability as general LCA tools. The result also showed that despite rough assumptions and analysis using several different calculation tools, with different input parameters, a fairly similar picture was created of the percentage reduction in kg CO2 equivalents between the different technologies. The calculated result in climate impact category GPW was about 80% lower per meter pipeline. A similar result that could be obtained from niche calculation tools. Given that the NoDig-method with liner for potable water pipes is fairly new on the market and has a halved theoretical material-lifespan, a theoretical break-even can be estimated to 231,8 years or just over four life cycles of rehabilitation of pipes with the use of this NoDig-technology, before reaching the climate impact corresponding to traditional open shafts. Continued studies can advantageously focus more on resource inventory of contracts and in-depth in transparent LCA-tools like the environmental calculation tool, BM 1.0. Or deeper analysis and further development on a niche calculation tool.

Fresh water scarcity is an alarming issue for communities across the globe. The development of water recycling and reuse technologies has become crucial in expanding the limited water resources. Reverse osmosis (RO) is among the key processes that can treat wastewater to meet potable water reuse standards. Despite the advancements in RO membrane technologies, many challenges persist regarding the operation and maintenance of RO membranes, such as membrane fouling. Extensive research investigations have focused on developing RO membrane modifications to combat the decreased performance due to fouling. Polyethylenimine (PEI) is a promising polymer used for enhancing the anti-fouling properties of thin film composite (TFC) RO membranes. PEI, a positively charged polymer with high charge density, is commonly grafted on TFC RO membrane surfaces to produce smoother, more hydrophilic membranes to minimize fouling. However, little research is available on the optimal PEI placement within the composite RO membrane layers for enhancing antifouling properties. The current study aimed to investigate whether alternative positions within the membrane layers could yield better anti-fouling performance compared to incorporation PEI on the membrane surface. Unmodified (i.e., control) and PEI-modified TFC RO membranes were fabricated in the laboratory. The PEI-modified membranes were produced in two variations with regards to the position of PEI in the composite membrane layer. The first variation, named PEI-1, involved immersing the polysulfone (Psf) support layer of the membrane in an aqueous PEI solution, before the active polyamide (PA) layer was formed. The second variation, named PEI-2, consisted of immersing the fully formed TFC RO membrane in an aqueous PEI solution to incorporate PEI on the surface of the active PA layer. The PEI used in the study for membrane modification had branched configuration with molecular weight of 1200 g/mole. The laboratory-scale TFC RO membranes produced herein were characterized and tested for water flux, salt rejection, and fouling behavior. The water flux and salt rejection, commonly referred to as permselectivity, of all the membranes produced were evaluated in a crossflow filtration unit. On the other hand, the fouling tests were conducted in a dead-end membrane filtration unit because of operational limitations of the crossflow unit. The PEI-1 membrane produced a water flux of 18.7 LMH (L/m2hr) and a stable salt rejection of 82.1%. The PEI-2 membrane resulted in a water flux of 22.4 LMH and a salt rejection of 85.2%. These results indicate that incorporating PEI on the membrane PA active surface layer achieved better permselectivity compared to PEI-1, which is the membrane with PEI incorporated inside the structure (i.e., incorporated on the Psf support layer). However, both PEI-modified membranes exhibited lower permselectivity performance compared to the unmodified control membrane, which produced a water flux of 23.9 LMH and salt rejection of 88.2%. To test fouling of the unmodified and PEI modified RO membranes, bovine serum albumin (BSA) was chosen as a model foulant based on preliminary investigations conducted herein to compare BSA to sodium alginate. After the foulant was introduced in the feed, the unmodified membrane exhibited a 31.8% total fouling ratio, the decrease in flux from the foulant solution compared to running clean DI water. However, a 90.7% flux recovery ratio was achieved when a final DI water rinse was performed. The PEI-1 membrane had a 39.7% total fouling ratio and a 81.6% flux recovery ratio after rinsing with DI water. The PEI-2 membrane showed a 43.1% total fouling ratio as a result of BSA fouling and a 94% flux recovery ratio when rinsed with DI water at the end of the fouling test. Water contact angle (WCA) analysis confirmed that the PEI-2 membrane had the most hydrophilic surface (WCA 25.1°) compared to the control membrane (WCA 52.9°). The higher hydrophilicity of PEI-2 aligns with its higher flux recovery results, which indicated reduced membrane fouling. Furthermore, the PEI-2 membrane had a drastically lower WCA than those reported in the literature for PEI-modified membranes, which ranged from (63° – 80°). In conclusion, the increased flux recovery and surface hydrophilicity of the PEI-2 membrane indicated that the best anti-fouling performance would likely be obtained when PEI is grafted onto the surface of the active PA membrane surface. Future research is warranted to optimize the PEI-2 membrane by exploring the effect of PEI concentration, molecular weight, and structural configuration (i.e., branched versus linear), on anti-fouling performance of the membranes.

The study investigates the contribution of WDM towards mitigating scarcity of potable water in cities with particular reference to Bulawayo.WDM origins and its successes are traced. The study classifies scarcity representations into four categories and reveals that the scarcity in Bulawayo satisfies all the four representations hence calls it total scarcity. The research employed document study, questionnaires, interviews and a focus group to collect data. Document study revealed that water restrictions successfully mitigate the scarcity in Bulawayo. Field work partially confirmed the usefulness of WDM in the life of the city and revealed the need to synchronize the conceptualizations of WDM among different stakeholders in order for the paradigm to do even more in terms of mitigating scarcity. The results were interpreted in terms of TPB. The key recommendation of the study is that the city invests in water use behaviour change in order to realise huge water savings. / Development Studies / M.A. (Development Studies)

The study investigates the contribution of WDM towards mitigating scarcity of potable water in cities with particular reference to Bulawayo.WDM origins and its successes are traced. The study classifies scarcity representations into four categories and reveals that the scarcity in Bulawayo satisfies all the four representations hence calls it total scarcity. The research employed document study, questionnaires, interviews and a focus group to collect data. Document study revealed that water restrictions successfully mitigate the scarcity in Bulawayo. Field work partially confirmed the usefulness of WDM in the life of the city and revealed the need to synchronize the conceptualizations of WDM among different stakeholders in order for the paradigm to do even more in terms of mitigating scarcity. The results were interpreted in terms of TPB. The key recommendation of the study is that the city invests in water use behaviour change in order to realise huge water savings. / Development Studies / M.A. (Development Studies)