Associação entre variáveis climáticas e qualidade da água para consumo humano por meio de técnicas multivariadas

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Análise de parâmetros de qualidade da água para consumo humano

The Current work to assess the capacity of water potability samples for that, we used seven different brands of mineral water, bought locally, and also collected seven samples of public drinking fountains located in different places on campus headquarters of the State University of Maringá. The parameters analyzed were presence of fecal and total coliform, turbidity, color and compounds with UV-absorption at 254 nm. On the analysis of coliforms, two brands of mineral water and four samples of drinkers showed presence of total coliform, but no analysis indicated the presence of fecal coliforms. In the turbidity parameter, all samples were within the limits allowed by law, for both cases. No apparent color attribute, two samples of mineral water and a sample of drinking were outside the range required by law. Finally, the determination of UV showed the values of light absorption of each sample at a wavelength of 254nm, however, does not yet exist in Brazil a regulation on this parameter. With such analysis, it was possible to compare the results with current legislation. After these findings, it appears that more stringent hygienic practices should be adopted throughout the processing of mineral water as drinking in public. It is also necessary for greater oversight over the other parameters for determining the quality of water.

Influência da adubação orgânica na qualidade da água destinada à irrigação de hortaliças

Pós-graduação em Microbiologia Agropecuária - FCAV

Bacteriological quality of irrigation water from vegetable gardens in the municipalities of Araraquara, Boa Esperança do Sul and Ibitinga, SP

This work aimed to assess the bacteriological quality of water used in the irrigation of vegetable gardens in the municipalities of Araraquara, Boa Esperança do Sul and Ibitinga, São Paulo, Brazil. A total of 80 samples of water used in the irrigation of 40 vegetable gardens were analyzed, two samples coming from each vegetable garden. They were collected at the same site in different months, which resulted in two sample collection groups. The most probable number (MPN/100mL) of total coliforms, thermotolerant coliforms and enterococci was identifi ed by means of the multiple tube technique. The analysis of the fi rst group samples showed quantities of thermotolerant coliforms above the amount allowed by current law for irrigation water (CONAMA Resolution n. 357) in nine cases. The owners of those vegetable gardens were then instructed in water disinfection procedures. After the analysis of the second group samples, it was noticed that only one sample did not meet the quality standards, and it was collected at a site where no disinfection procedure had been carried out. According to the results, 77.5% of the vegetable gardens were using water whose samples meet the quality standards. After the owners were instructed with regard to disinfection procedures, that number changed to 97.5%, which confi rms the importance of controlling and supervising irrigation water quality

Evaluation of the use of probiotic acid lactic bacteria in the development of chicken hambúrguer

The objective of this study was to investigate the effect of fermentation with Lactobacillus acidophilus CRL 1014 on the physicochemical, microbiological and sensory characteristics of a hamburger product like processed with chicken meat and okara flour, with reduction of curing salts. A mixture of ingredients containing 90% chicken meat and 10% okara flour was subjected to the following treatments: F1: fermented with Lactobacillus acidophilus; F2:75 mg nitrite/kg and fermented with Lactobacillus acidophilus; F3: 150 mg nitrite/kg and unfermented. The quality of the “hamburgers” was assessed by physical and chemical analysis (pH, cooking yield and shrinkage), chemical composition, microbiological tests (Salmonella spp., count of sulphite-reducing clostridia, staphylococos coagulase-positive, total coliforms and Escherichia coli) and sensory analysis (sensory acceptance and purchase intent). During the first six days of fermentation, there was a decrease in pH from approximately 6.33 to 5.10. All the samples showed the same chemical composition (p < 0.05). The fermentation process was observed to inhibit the multiplication of microorganisms of several groups: coagulasepositive staphylococci, sulphite-reducing clostridia, Salmonella spp. and E. coli. The different “hamburgers” formulations showed high scores for all the sensory attributes evaluated, without differing from each other (p < 0.05). The results showed that the use of L. acidophilus CRL 1014 enabled the production of a safe product, with good physicochemical and sensory characteristics, in the absence of curing salts.

Resistência antimicrobiana em coliformes totais isolados de tanques de refrigeração de leite bovino

Milk that is adequate for consumption must be of hygienic quality, nutritional value, and should maintain its organoleptic properties. Isolation of fecal and/or total coliforms from bovine milk is considered an indicator of hygiene and good management practices, and can be used as a quality indicator. This study aimed to isolate, identify, and assess the resistance profile of coliforms isolated from collective bulk tanks and individual milk tanks. A total of 89 milk samples were collected from collective bulk tanks and, from these, 21 Klebsiella spp., one E. coli, and 29 Enterobacter spp. were isolated, whereas 102 milk samples from individual tanks showed isolation of one Klebsiella spp. and seven Enterobacter spp. In collective bulk tanks, at least 47% of Klebsiella spp. and Enterobacter spp. were resistant to cephalexin and 30% to ampicillin. From these, at least 24% showed multidrug resistance. Among the microorganisms isolated from the individual tanks, 85% or more were resistant to ampicillin. The ESBL phenotype and the blaTEM gene were detected in strains of Klebsiella spp. isolated from both tanks. It was concluded that contamination of milk with resistant total coliforms, and especially the storage of raw milk from several small producers in the collective bulk tank increase the risk of contamination.

Avaliação de sistema de tratamento de dejetos suínos instalado no estado de Santa Catarina

Os dejetos suínos contribuem de forma significativa em prol da degradação dos recursos naturais e para a diminuição da qualidade de vida na região sul do estado de Santa Catarina, Brasil. O excesso de dejetos gerados pelo grande número dos suínos por unidade de área dificulta a solução do problema. Este trabalho teve como objetivo avaliar o comportamento de um sistema de tratamento de dejetos suínos, em série e em escala real, composto de unidades anaeróbias, unidades aeróbias e pós-tratamento. Os parâmetros analisados foram: DBO, DQO, PT, P-PO₄, N-NH₃, NTK, pH, clorofila a, biomassa algal, coliformes totais e coliformes fecais (Escherichia coli). O sistema mostrou que após um ano de funcionamento as eficiências de remoção foram satisfatórias para matéria orgânica e nutrientes, alcançando valores de 97% para DBO, 95% para DQO, 88% para N-NH₃ e 74% para PT/P-PO₄, mesmo com as variações de vazão e de carga orgânica aplicada. Entretanto, a remoção de coliformes fecais nas unidades aeróbias foi baixa, reduzindo somente 0,86 unidades log na lagoa facultativa aerada e 0,80 unidades log na lagoa de maturação.

Microbiological quality and safety of minimally processed vegetables marketed in Campinas, SP-Brazil, as assessed by traditional and alternative methods

In this study, a total of 172 samples of minimally processed vegetables (MPV) were collected from supermarkets in the city of Campinas, Brazil. The MPV were analyzed using traditional and/or alternative methods for total aerobic mesophilic bacteria, total coliforms, Escherichia coil, coagulase positive staphylococci, Salmonella and Listeria monocytogenes. All the MPV analyzed presented populations of aerobic mesophilic microorganisms and total coliforms were >4 log(10) CFU/g and 1.0-3.4 log(10) CFU/g, respectively. E. coil was enumerated in only 10 samples out of 172 collected, while none of the 172 samples of MPV presented contamination by coagulase positive Staphylococcus (<10(1) CFU/g). Among the four methods used for detection of Salmonella in MPV (Vidas, 1,2 Test, Reveal, and Traditional), when Reveal was used a total of 29 positive samples were reported. For L monocytogenes, the four methods tested (Vidas, Vip, Reveal, and traditional) performed similarly. The presence of Salmonella and L monocytogenes in MPV was confirmed in one (watercress) and two samples (watercress and escarole), respectively. In conclusion, it has been observed that the microbiological quality of MPV commercialized in Campinas is generally satisfactory. Besides, the choice of microbiological method should be based not only on resource and time issues, but also on parameters such as sensitivity and specificity for the specific foods under ahalysis. (C) 2012 Elsevier Ltd. All rights reserved.

On the implementation of good manufacturing practices in a small processing unity of mozzarella cheese in Brazil

This study reports the implementation of GMPs in a mozzarella cheese processing plant. The mozzarella cheese manufacturing unit is located in the Southwestern region of the state of Parana, Brazil, and processes 20,000 L of milk daily. The implementation of GMP took place with the creation of a multi-disciplinary team and it was carried out in four steps: diagnosis, report of the diagnosis and road map, corrective measures and follow-up of GMP implementation. The effectiveness of actions taken and GMP implementation was compared by the total percentages of non-conformities and conformities before and after implementation of GMR Microbiological indicators were also used to assess the implementation of GMP in the mozzarella cheese processing facility. Results showed that the average percentage of conformity after the implementation of GMP was significant increased to 66%, while before it was 32% (p < 0.05). The populations of aerobic microorganisms and total coliforms in equipment were significantly reduced (p < 0.05) after the implementation of GMP, as well as the populations of total coliforms in the hands of food handlers (p < 0.05). In conclusion, GMP implementation changed the overall organization of the cheese processing unity, as well as managers and food handlers' behavior and knowledge on the quality and safety of products manufactured. (C) 2011 Elsevier Ltd. All rights reserved.

Parasitological risk assessment from wastewater reuse for disposal in soil in developing countries

The purpose of this work is to analyze the parasitological risks of treated wastewater reuse from a stabilization pond in the city of Piracicaba, in the State of Sao Paulo (Brazil), and the level of treatment required to protect public health. Samples were taken from raw and treated wastewater in stabilization ponds and submitted to a parasitological, microbiological and physicochemical analysis. The study revealed on treated wastewater the presence of Ascaris sp. and Entamoeba coli with an average density of 1 cysts L-1 and 6 eggs L-1, respectively. For Ascaris, the annual risks of infection due to the accidental ingestion of wastewater irrigation were 7.5 x 10(-2) in 208 days and 8.7 x 10(-2) in 240 days. For Total Coliforms and Escherichia coli in treated wastewater, the average density was 1.0 x 10(5) MPN/100 ml and 2.7 x 10(4) MPN/100 ml respectively, representing 99% and 94% removal efficiency, respectively. For BOD, COD, TS and TSS removal efficiency was 69, 80, 50 and 71%, respectively. The removal efficiency for nitrogen; ammonia nitrogen and total phosphate was 24, 19 and 68%, respectively. The average density of helminths eggs in treated wastewater is higher compared to the density of the limit value of <= 1 egg L-1 and tolerable risk is above the level recommended by the World Health Organization. Multiple barriers are necessary for the reduction of organic matter, chemical contaminants and parasites from treated wastewater. Standards for the sanitary control of treated wastewater to be reused in agricultural irrigation areas should be compiled for developing countries in order to minimize public health risks.

Enhancing spiral-wound ultrafiltration performance for direct drinking water treatment through operational procedures improvement: A feasible option for the Sao Paulo Metropolitan Region

This work aimed to evaluate the influence of specific operational conditions on the performance of a spiral-wound ultrafiltration pilot plant for direct drinking water treatment, installed at the Guarapiranga's reservoir, in the Sao Paulo Metropolitan Region. Results from operational tests showed that the volume of permeate produced in the combination of periodic relaxation with flushing and chlorine dosage procedures was 49% higher than the volume obtained when these procedures were not used. Two years of continuous operation demonstrated that the ultrafiltration pilot plant performed better during fall and winter seasons, higher permeate flow production and reduced chemical cleanings frequency. Observed behavior seems to be associated with the algae bloom events in the reservoir, which are more frequent during spring and summer seasons, confirmed by chlorophyll-a analysis results. Concentrate clarification using ferric chloride was quite effective in removing NOM and turbidity, allowing its recirculation to the ultrafiltration feed tank. This procedure made it possible to reach almost 99% water recovery considering a single 54-hour recirculation cycle. Water quality monitoring demonstrated that the ultrafiltration pilot plant was quite efficient, and that potential pathogenic organisms, Escherichia coil and total coliforms, turbidity and apparent color removals were 100%, 95.1%, and 91.5%, respectively. (C) 2012 Elsevier B.V. All rights reserved.

Study of water use and supply in the district of Independencia, Peru

Peru is a developing country with abundant fresh water resources, yet the lack of infrastructure leaves much of the population without access to safe water for domestic uses. The author of this report was a Peace Corps Volunteer in the sector of water & sanitation in the district of Independencia, Ica, Peru. Independencia is located in the arid coastal region of the country, receiving on average 15 mm of rain annually. The water source for this district comes from the Pisco River, originating in the Andean highlands and outflowing into the Pacific Ocean near the town of Pisco, Peru. The objectives of this report are to assess the water supply and sanitation practices, model the existing water distribution system, and make recommendations for future expansion of the distribution system in the district of Independencia, Peru. The assessment of water supply will be based on the results from community surveys done in the district of Independencia, water quality testing done by a detachment of the U.S. Navy, as well as on the results of a hydraulic model built in EPANET 2.0 to represent the distribution system. Sanitation practice assessments will be based on the surveys as well as observations from the author while living in Peru. Recommendations for system expansions will be made based on results from the EPANET model and the municipality’s technical report for the existing distribution system. Household water use and sanitation surveys were conducted with 84 families in the district revealing that upwards of 85% store their domestic water in regularly washed containers with lids. Over 80% of those surveyed are drinking water that is treated, mostly boiled. Of those surveyed, over 95% reported washing their hands and over 60% mentioned at least one critical time for hand washing when asked for specific instances. From the surveys, it was also discovered that over 80% of houses are properly disposing of excrement, in either latrines or septic tanks. There were 43 families interviewed with children five years of age or under, and just over 18% reported the child had a case of diarrhea within the last month at the time of the interview. Finally, from the surveys it was calculated that the average water use per person per day is about 22 liters. Water quality testing carried out by a detachment of the U.S. Navy revealed that the water intended for consumption in the houses surveyed was not suitable for consumption, with a median E. coli most probable number of 47/100 ml for the 61 houses sampled. The median total coliforms was 3,000 colony forming units per 100 ml. EPANET was used to simulate the water delivery system and evaluate its performance. EPANET is designed for continuous water delivery systems, assuming all pipes are always flowing full. To account for the intermittent nature of the system, multiple EPANET network models were created to simulate how water is routed to the different parts of the system throughout the day. The models were created from interviews with the water technicians and a map of the system created using handheld GPS units. The purpose is to analyze the performance of the water system that services approximately 13,276 people in the district of Independencia, Peru, as well as provide recommendations for future growth and improvement of the service level. Performance evaluation of the existing system is based on meeting 25 liters per person per day while maintaining positive pressure at all nodes in the network. The future performance is based on meeting a minimum pressure of 20 psi in the main line, as proposed by Chase (2000). The EPANET model results yield an average nodal pressure for all communities of 71 psi, with a range from 1.3 – 160 psi. Thus, if the current water delivery schedule obtained from the local municipality is followed, all communities should have sufficient pressure to deliver 25 l/p/d, with the exception of Los Rosales, which can only supply 3.25 l/p/d. However, if the line to Los Rosales were increased from one to four inches, the system could supply this community with 25 l/p/d. The district of Independencia could greatly benefit from increasing the service level to 24-hour water delivery and a minimum of 50 l/p/d, so that communities without reliable access due to insufficient pressure would become equal beneficiaries of this invaluable resource. To evaluate the feasibility of this, EPANET was used to model the system with a range of population growth rates, system lifetimes, and demands. In order to meet a minimum pressure of 20 psi in the main line, the 6-inch diameter main line must be increased and approximately two miles of trench must be excavated up to 30 feet deep. The sections of the main line that must be excavated are mile 0-1 and 1.5-2.5, and the first 3.4 miles of the main line must be increased from 6 to 16 inches, contracting to 10 inches for the remaining 5.8 miles. Doing this would allow 24-hour water delivery and provide 50 l/p/d for a range of population growth rates and system lifetimes. It is expected that improving the water delivery service would reduce the morbidity and mortality from diarrheal diseases by decreasing the recontamination of the water due to transport and household storage, as well as by maintaining continuous pressure in the system to prevent infiltration of contaminated groundwater. However, this expansion must be carefully planned so as not to affect aquatic ecosystems or other districts utilizing water from the Pisco River. It is recommended that stream gaging of the Pisco River and precipitation monitoring of the surrounding watershed is initiated in order to begin a hydrological study that would be integrated into the district’s water resource planning. It is also recommended that the district begin routine water quality testing, with the results available to the public.

The evidence for groundwater as a source of enteric illness in developing countries: A systematic review of the literature

Groundwater constitutes approximately 30% of freshwater globally and serves as a source of drinking water in many regions. Groundwater sources are subject to contamination with human pathogens (viruses, bacteria and protozoa) from a variety of sources that can cause diarrhea and contribute to the devastating global burden of this disease. To attempt to describe the extent of this public health concern in developing countries, a systematic review of the evidence for groundwater microbially-contaminated at its source as risk factor for enteric illness under endemic (non-outbreak) conditions in these countries was conducted. Epidemiologic studies published in English language journals between January 2000 and January 2011, and meeting certain other criteria, were selected, resulting in eleven studies reviewed. Data were extracted on microbes detected (and their concentrations if reported) and on associations measured between microbial quality of, or consumption of, groundwater and enteric illness; other relevant findings are also reported. In groundwater samples, several studies found bacterial indicators of fecal contamination (total coliforms, fecal coliforms, fecal streptococci, enterococci and E. coli), all in a wide range of concentrations. Rotavirus and a number of enteropathogenic bacteria and parasites were found in stool samples from study subjects who had consumed groundwater, but no concentrations were reported. Consumption of groundwater was associated with increased risk of diarrhea, with odds ratios ranging from 1.9 to 6.1. However, limitations of the selected studies, especially potential confounding factors, limited the conclusions that could be drawn from them. These results support the contention that microbial contamination of groundwater reservoirs—including with human enteropathogens and from a variety of sources—is a reality in developing countries. While microbially-contaminated groundwaters pose risk for diarrhea, other factors are also important, including water treatment, water storage practices, consumption of other water sources, water quantity and access to it, sanitation and hygiene, housing conditions, and socio-economic status. Further understanding of the interrelationships between, and the relative contributions to disease risk of, the various sources of microbial contamination of groundwater can guide the allocation of resources to interventions with the greatest public health benefit. Several recommendations for future research, and for practitioners and policymakers, are presented.^

Investigación técnica y económica sobre desinfección de aguas residuales por sistemas de oxidación

Un incremento de la demanda del agua, junto con el aumento de la contaminación, ha provocado que hoy en día la reutilización de las aguas depuradas sea necesaria, pero la reutilización de aguas debe garantizar y minimizar los posibles riesgos sanitarios y medioambientales que su práctica pueda provocar. En España estos parámetros se encuentran regulados por el RD 1620/2007 relativo al régimen jurídico de la reutilización de las aguas depuradas. Las aguas regeneradas son aguas que ya han sido sometidas a un tratamiento de depuración, y a las cuales se aplica un posterior tratamiento adicional o complementario que permita adecuar su calidad al uso al que vaya a destinarse. Siendo requeridos para los distintos reúsos procesos de desinfección, uno de los principales sistemas utilizados es el cloro, debido a su sencilla aplicación y costos bajos, sin tomar en cuenta la posible formación de compuestos organohalogenados potencialmente cancerígenos. Es por esto que surge la necesidad de aplicar distintos sistemas de oxidación objeto de estudio en esta tesis, como el dióxido de cloro estabilizado, ozono y los procesos avanzados de oxidación (Advanced Oxidation Processes, AOP), ozono/peróxido y uv/peróxido. En esta tesis se investiga los rendimientos que pueden alcanzar estos sistemas en la eliminación de los ácidos húmicos y los fenoles, siendo las principales sustancias formadoras de subproductos de la desinfección, así mismo, se considera necesario garantizar la desinfección del agua a través del estudio de tres grupos de microrganismos, los coliformes totales, e. coli y enterococos, siendo un punto importante el posible recrecimiento microbiológico debido a una desinfección escasa, por la permanencia en el agua de los compuestos antes mencionados, o por alguna fuente de alimento que pudieran encontrar en el sistema de distribución. Lo más importante será la calidad que se pueda alcanzar con estos desinfectantes, con el fin de obtener agua para los distintos reúsos que existen en la actualidad. Y así no limitar los alcances que puede tener la reutilización de las aguas residuales. Basándose en lo antes mencionado se procedió a realizar la caracterización del agua del rio Manzanares, con el fin de determinar la cantidad de ácidos húmicos disueltos y fenoles, obteniendo valores bajos, se decidió incorporar a las muestras de rio 5 mg/L de estos compuestos, con el fin de observar de que manera podrían interferir en la desinfección de esta agua. De esta forma se logran obtener resultados óptimos de los sistemas de desinfección estudiados, siendo el Ozono un oxidante eficiente en la desinfección de los microrganismos y en la eliminación de ácidos húmicos y fenoles con tiempos de contacto cortos, mostrando deficiencias al permitir el recrecimiento de los coliformes totales. Del sistema de oxidación avanzada UV/Peróxido se determino como un eficiente desinfectante para garantizar la inexistencia de rebrotes, al paso del tiempo. Así mismo se concluye que tiene buenos rendimientos en la eliminación del ácido húmico y los fenoles. An increase in water demand, coupled with increasing pollution, has caused today reuse of treated water is necessary, but must ensure water reuse and minimize potential health and environmental risks that their practice is cause. In Spain these parameters are regulated by Royal Decree 1620/2007 on the legal regime of the reuse of treated water. The reclaimed water is water that has already been subjected to a depuration treatment, which is applied as a subsequent further treatment that will bring quality to the use to which is to be delivered. As required for various reuses disinfection processes, one of the main systems used is chlorine, due to its simple implementation and low costs, without taking into account the possible formation of potentially carcinogenic halogenated organic compounds. That is why there is a need to apply different oxidation systems studied in this thesis, as stabilized chlorine dioxide, ozone and advanced oxidation processes (AOP), ozone/peroxide and UV/peroxide. This thesis investigates the rates can reach these systems in removing humic acids and phenols, the main substances forming disinfection byproducts, likewise, it is considered necessary to ensure water disinfection through the study of three groups of microorganisms, total coliform, e. coli and enterococci, the important point being a possible regrowth due to microbiological disinfection scarce, the water remaining on the aforementioned compounds, or a food source which may be found in the distribution system. The most important quality is that achievable with these disinfectants, with the water to obtain various reuses that exist today. And thus not limit the scope that can be reuse of wastewater. Based on the above we proceeded to perform characterization Manzanares river water, in order to determine the quantity of dissolved humic acids and phenols, obtaining low values, it was decided to incorporate river samples 5 mg / L of these compounds, in order to observe how they might interfere with the disinfection of the water. Thus optimum results are achieved for disinfection systems studied, being efficient ozone oxidant in the disinfection of microorganisms and the removal of humic acids and phenols with short contact times, showing gaps to allow regrowth total coliforms. Advanced oxidation system UV / peroxide were determined as an efficient disinfectant to ensure the absence of volunteers, the passage of time. Also it is concluded that has good yields in removing humic acid and phenols.

Ocorrência e remoção dos protozoários patogênicos Giardia spp. e Cryptosporidium spp. em sistemas de tratamento de esgoto sanitário

O propósito do presente estudo foi investigar e monitorar a remoção de cistos de Giardia spp. e oocistos de Cryptosporidium spp. por diferentes processos de uma estação de tratamento de esgoto (ETE) em escala plena, composta basicamente por tratamento preliminar, reator UASB e flotador por ar dissolvido, e verificar a ocorrência desses protozoários no lodo do reator UASB e do flotador. Além disso, avaliou-se a remoção desses parasitos pelo processo de flotação por ar dissolvido em escala de bancada (equipamento Flotateste). Analisou-se a qualidade das amostras a partir de variáveis físicas e químicas, e pela detecção de microrganismos indicadores - E. coli, coliformes totais e Clostridium perfringens. Os métodos de detecção de protozoários se basearam nas etapas de concentração (tripla centrifugação ou filtração em membrana seguida de tripla centrifugação); purificação por separação imunomagnética (IMS); detecção por reação de imunofluorescência direta (RID). As recuperações de cistos variaram de 32,6 a 67,0 % dependendo do método adotado, já para os oocistos as recuperações estiveram na faixa de 5,6 a 12,0 %. Na ETE-Monjolinho foram detectadas significativas quantidades de cistos de Giardia spp. em 100% das amostras de esgoto analisadas, com concentração média de 1,89 x 104 e 2,35 x 102 cistos.L-1 no esgoto bruto e tratado, respectivamente. Já os oocistos de Cryptosporidium spp. foram detectados em 39,0 % das amostras de esgoto, com concentração média de 1,35 x 102 oocistos.L-1 no esgoto bruto e 5,87 oocistos.L-1 em esgoto tratado (após flotador). A remoção global da ETE para remoção de Giardia spp. foi em média 2,03 log. O lodo do reator UASB e lodo do flotador apresentaram altas quantidade de (oo)cistos, constatando-se a tendência desses sistemas em concentrar os (oo)cistos por seus processos físicos. Algumas correlações significativas foram encontradas, como correlação entre a concentração de cistos no lodo e a variável sólidos totais, a concentração de cistos no esgoto bruto e as variáveis cor aparente, DQO total e particulada, e a concentração de cistos no efluente UASB e o microrganismo Clostridium perfringens. Diferentemente do flotador em escala plena, o processo do flotação por ar dissolvido em escala de bancada alcançou elevadas remoções médias de cistos de Giardia spp., entre 2,5 e 2,7 log nas diferentes condições de floculação estudadas.