Relief organizations and governments strive to provide safe drinking water to natural disaster survivors as quickly as possible. However, drinking water is typically provided either as bottled water or via mobile water treatment equipment, both of which can be difficult or expensive to transport rapidly into disaster zones. An alternative is the waterbag point-of-use treatment device developed at Cal Poly that allows survivors to produce safe drinking water from contaminated local sources. The waterbag is a 10-L bladder designed for use with Procter & Gamble Purifier of Water (PŪR®) sachets, which contain coagulant and chlorine compounds. Following treatment with PŪR®, treated water in the waterbag is flowed through an outlet port to a filter, primarily for parasitic cyst removal. Currently, the commercial version of the waterbag uses an effective but expensive hollow-fiber membrane microfilter (>$10 each). This cost will likely decrease the use of the waterbag by relief organizations responding to large disasters. The goal of the present thesis research was to develop a novel, low cost (~$5), effective, low-profile filter to be used with the waterbag in large-scale disaster relief. This new filter is referred to as an envelope filter due to its geometry and size. Various prototype envelope filters were constructed using layers of nonwoven polypropylene filter cloth. Two types of cloth were used: a nominally-rated 1-µm pore size cloth and an absolute-rated 1-µm cloth. The filters tested were both internal and external to the waterbag and of various geometries. Filters were attached to the waterbag and used to filter defined test water after it had been treated with a PŪR® sachet. Test water for design experiments consisted of tap water with addition of standard dust (to increase turbidity) and seasalts (to increase salinity). In addition to this basic test water, mock U.S. EPA Challenge Water #2 with added bacteria and cyst surrogates (fluorescent microspheres) was used to evaluate the filter prototype designs prior to testing according to U.S. EPA Guide Standard and Protocol for Testing Microbiological Water Purifiers in a commercial laboratory. The filter design and mock challenge experiment results indicated that a 2-ply filter with one nominal and one absolute layer was the optimal filter design. In the mock U.S. EPA challenge tests, a flowrate of 20 mL/min allowed this filter met the turbidity, bacteria, and microsphere removal requirements determined by the WHO and The Sphere Project for emergency drinking water treatment as well as the U.S. EPA Guide Standard and Protocol for Testing Microbiological Water Purifiers.. This filter design was further tested using the U.S. EPA Challenge Water #2 with triplicate waterbags at the U.S. EPA-certified BioVir Laboratories in Benicia, Calif. All three waterbags with envelope filters met the recommendations for turbidity (<5 >NTU) and for virus removal (>4-log removal). Two of the three waterbags met the bacteria and microsphere removal requirements (>6- and >3-log removal, respectively). The failure of one of the prototypes to meet the requirements could have been due to improper setting of valve that throttled the flowrate through the filter or due to a slightly leaking hose pinch valve. Future work should include incorporating more reliable valves and improving the envelope filter design and materials to achieve higher allowable flowrates.

Made available in DSpace on 2016-06-02T19:56:49Z (GMT). No. of bitstreams: 1 4842.pdf: 3843983 bytes, checksum: dba16fdf2f921799ee872793185384b3 (MD5) Previous issue date: 2012-10-31 / The filtration of gases is an important industrial operation with the primary aim of removing unwanted solid particles contained in a gas. The filtration of gases at high pressures is an operation widely used in natural gas industry with the aim of separating impurities called black powder, from rust inside pipelines along the transportation. These residues can cause wear on equipment such as, for example, rotor pump, obstruction of gauges and pressure decrease in product quality. Despite being an operation widely used, few studies exist in the area to study what the best type of filter. Therefore this study is very useful to improve the steps of transportation, measurement and purity of the final product. To simulate this process, we used the dry compressed air, injecting a phosphate rock as particulate matter. The filters were tested RAD cellulose and acrylic. The surface speed of filtration was kept constant at 0.05 m / s, throughout the filtering operation. The flow of compressed air used were 14 l / min to the total pressure 1 bar, 42 l / min at a total pressure of 3 bar and 86 l / min at a total pressure of 6 bar. Total load losses were 5, 10, 20 and 30 mbar. The results showed that, initially, the curves of head loss versus deposited mass showed the same growth trend. However, when forming a layer of cake from about 0.03 kg/m2, the filtrations higher pressures had lower pressure loss. This is because the larger pressure forming pies more porous and less resistant to air flow. At the end of the study it was also observed that the acrylic filter performed better compared to the cellulose RAD, due to its greater mass of accumulated dust and low pressure drop. / A filtração de gases é uma importante operação industrial com o principal intuito de remover as partículas sólidas indesejadas contidas em um determinado gás. A filtração de gases a altas pressões é uma operação muito utilizada na indústria de gás natural com o objetivo de separar as impurezas denominadas pó preto, provenientes da oxidação no interior de gasodutos ao longo do seu transporte. Estes resíduos podem causar desgaste de equipamentos como, por exemplo, rotor de bombas, obstrução de aparelhos de medição de pressão e diminuição da qualidade do produto. Apesar de ser uma operação muito utilizada, poucas pesquisas existem na área a fim de estudar qual o melhor tipo de filtro. Por isso este estudo é muito útil no sentido de melhorar as etapas de transporte, medição e pureza do produto final. Para simular este processo, foi utilizado o ar comprimido seco, injetando-se a rocha fosfática como material particulado. Os filtros testados foram de celulose RAD+ e acrílico. A velocidade superficial de filtração foi mantida constante em 0,05 m/s, durante toda a operação de filtração. As vazões do ar comprimido utilizadas foram de 14 l/min para a pressão total de 1 bar, 42 l/min para a pressão total de 3 bar e 86 l/min para a pressão total de 6 bar. As perdas de carga totais foram de 5, 10, 20 e 30 mbar. Os principais resultados mostraram que, inicialmente, as curvas de perda de carga versus massa depositada apresentaram igual tendência de crescimento. Porém, no momento que forma uma camada de torta a partir de aproximadamente 0,03 kg/m2, as filtrações de maiores pressões apresentaram menor perda de carga. Isso porque as maiores pressões formam tortas mais porosas e menos resistentes ao escoamento de ar. Ao final do estudo observou-se também que o filtro de acrílico obteve melhor desempenho comparado com o de celulose RAD+, por apresentar maior massa de pó acumulada e menor perda de carga.