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1.
J Environ Manage ; 254: 109825, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31733467

RESUMO

Microalgae harvesting is one of the major bottlenecks for the production of high-value microalgal products on a large scale, which encourages investigations of harvesting methods with better cost-benefits. Among these harvesting techniques, flotation stands out as a promising method, however it is still minimally explored when compared to the sedimentation method. In this study, the pH modulation followed by dissolved air flotation (DAF) was tested as a harvesting method for Chlorella sorokiniana cultivated in wastewater. The main aims of this study were to optimize the operational parameters of coagulation (pH, velocity gradient, and mixing time) and flotation (recirculation rate), check their reproducibility and resilience with the variability of wastewater characteristics, and evaluate the final wastewater quality after treatment using an optimized harvesting method. Parameter optimization was carried out using the one-factor-at-a-time method. The optimal parameters were a velocity gradient of 500 s-1, mixing time of 30 s, pH 12, and 20% of recirculation rate. High efficiencies were obtained for C. sorokiniana removal (96.5-97.9%), making it a successful process. Moreover, the photobioreactor effluent quality was also improved significantly after microalgae harvesting, with high nutrient removal (88.6-95.1% of total Kjeldahl nitrogen and 91.8-98.3% of total phosphorus) and organic matter removal (80.5-86.8% of chemical oxygen demand). The results showed the pH modulation and DAF as an effective process for wastewater treatment and biomass harvesting. This study also indicated the importance of operational optimization, not studied until now, in which the achieved results could be potentially applied as practical guidelines for microalgae harvesting on a large scale.


Assuntos
Chlorella , Microalgas , Biomassa , Concentração de Íons de Hidrogênio , Reprodutibilidade dos Testes , Águas Residuárias
2.
Environ Technol ; : 1-7, 2019 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-31136251

RESUMO

Lab-scale studies were carried out to investigate the efficiency of dissolved air flotation (DAF) for the removal of Giardia spp. cysts and Cryptosporidium spp. oocysts from anaerobic effluent from the pilot UASB reactor. Raw wastewater, UASB and DAF effluent samples were collected weekly and protozoan (oo)cysts were concentrated using IMS followed by protozoa detection using immunofluorescense assay (IFA). The number of Cryptosporidium spp. oocysts in the raw wastewater was always lower than that of Giardia spp. cysts with 28-33 oocysts L-1 and 3177-4267 cysts L-1, respectively. Log10 removal of Giardia cysts utilising polyaluminium chloride (PACl) was higher than that with FeCl3, but no statistically significant difference between the two coagulants was observed. Cryptosporidium was absent in most of the treated effluent samples. The results indicate that DAF reached more than 2 log of cyst removal. In addition, the results demonstrated that these parasites are prevalent in the study area and E. coli and total coliforms were not good indicator microorganisms in terms of cyst and oocysts numbers.

3.
Bioresour Technol ; 286: 121352, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31030067

RESUMO

Amongst harvesting processes, alkaline flocculation stands out as a technically feasible and low cost method. The interference of model wastewater components with alkaline flocculation of Chlorella sorokiniana (pH 8-12), induced by calcium phosphate (CaP) precipitates, was evaluated. Between the compounds tested, inorganic nitrogen, sodium alginate, salinity and algal organic matter had no effect on flocculation efficiency (FE). The negative effect of humic acids, sodium dodecyl sulphate and alkalinity on FE was partial. Bovine serum albumin and bacterial organic matter (BOM) of Escherichia coli showed the strongest disruption of FE. The impact of BOM can be explained by the high protein content (65% of total organic carbon). Proteins, negatively charged at alkaline pH, interrupt microalgae flocculation by preferentially interacting with positively charged CaP precipitates. The simultaneous effects of multiple substances were tested to simulate real wastewater. The results confirm the need to investigate the composition of wastewater prior to alkaline flocculation.


Assuntos
Chlorella , Microalgas , Biomassa , Fosfatos de Cálcio , Floculação , Águas Residuárias
4.
Environ Technol ; 40(26): 3492-3501, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29813004

RESUMO

The protozoa Giardia and Cryptosporidium are associated with numerous outbreaks of waterborne diseases worldwide. This study aimed to evaluate the concentration of Giardia spp. cysts, Cryptosporidium spp. oocysts, total coliforms, Escherichia coli and Clostridium perfringens in raw wastewater and their removals at UASB reactor, activated sludge system (operated conventionally and extended aeration) and slow sand filtration. Giardia spp. cysts were present in 100% and Cryptosporidium spp. oocysts in 31.4% of the analysed wastewater samples. The UASB reactor followed by activated sludge system obtained approximately 2.0 log of removal for total coliforms and E. coli, whereas for C. perfringens and Giardia spp. cysts, it obtained 1 log. There was a high percentage of (oo)cysts still viable after secondary treatment, therefore, the risk of contamination of water courses and, consequently, for public health is considerable. However, after tertiary filtration, no (oo)cysts were found in any of the filtered effluent samples, being a good option for future reuse. Seasonal variations did not affect the concentrations and removals of microorganisms observed. Lack of correlations of concentrations of indicator microorganisms and (oo)cysts raise caveats and doubts regarding the true microbiological quality when using only indicator microorganisms.


Assuntos
Cryptosporidium , Cistos , Animais , Escherichia coli , Giardia , Oocistos , Águas Residuárias
5.
Water Sci Technol ; 80(8): 1505-1511, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31961813

RESUMO

Decentralized sanitary wastewater treatment has become a viable and sustainable alternative, especially for developing countries and small communities. Besides, effluents may present variations in chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total nitrogen values. This study describes the feasibility of using a pilot upflow anaerobic sludge blanket (UASB) reactor to treat wastewater with different organic loads (COD), using black water (BW) and sanitary wastewater, in addition to its potential for preserving nutrients for later recovery and/or reuse. The UASB reactor was operated continuously for 95 weeks, with a hydraulic retention time of 3 days. In Phase 1, the reactor treated simulated BW and achieved 77% CODtotal removal. In Phase 2, treating only sanitary wastewater, the CODtotal removal efficiency was 60%. Phase 3 treated simulated BW again, and CODtotal removal efficiency was somewhat higher than in Phase 1, reaching 81%. In Phase 3, the removal of pathogens was also evaluated: the efficiency was 1.96 log for Escherichia coli and 2.13 log for total coliforms. The UASB reactor was able to withstand large variations in the organic loading rate (0.09-1.49 kg COD m-3 d-1), in continuous operation mode, maintaining a stable organic matter removal.


Assuntos
Esgotos , Purificação da Água , Anaerobiose , Reatores Biológicos , Projetos Piloto , Eliminação de Resíduos Líquidos
6.
Environ Technol ; 38(10): 1245-1254, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27573723

RESUMO

Sewage and sewage sludge have been recognized as potential sources of two important waterborne pathogenic protozoa: Giardia spp. and Cryptosporidium spp. Due to the lack of studies about the occurrence of these pathogens in sewage and sludge in Brazil, an investigation was conducted at various stages of a municipal wastewater treatment plant (WWTP) aiming to assess the occurrence of Giardia spp. cysts and Cryptosporidium spp. oocysts, their removal by the treatment processes, which are upflow anaerobic sludge blanket (UASB) reactor and dissolved air flotation process, and also the correlations between protozoa and indicator microorganisms. Significant quantities of cysts were detected in 100% of the analyzed wastewater samples, while oocysts were detected only in 39.0% of all wastewater samples. The overall removal of Giardia spp. cysts from the WWTP was on average 2.03 log, and the UASB reactor was more efficient than flotation. The sludge samples presented high quantities of (oo)cysts, implying the risks of contamination in the case of sludge reuse or inadequate disposal. Giardiasis prevalence was estimated between 2.21% and 6.7% for the population served by the WWTP, while cryptosporidiosis prevalence was much lower. Significant positive correlation was obtained only between cysts and Clostridium spores in anaerobic effluent.


Assuntos
Cryptosporidium/isolamento & purificação , Giardia/isolamento & purificação , Águas Residuárias/parasitologia , Poluentes da Água/análise , Brasil/epidemiologia , Cidades/epidemiologia , Clostridium perfringens/isolamento & purificação , Criptosporidiose/epidemiologia , Enterobacteriaceae/isolamento & purificação , Monitoramento Ambiental , Giardíase/epidemiologia , Humanos , Oocistos , Prevalência , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/análise , Águas Residuárias/microbiologia
7.
Environ Technol ; 38(19): 2392-2399, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27852162

RESUMO

Controlling Giardia cysts in sewage is an essential barrier for public health protection, reducing possible routes of protozoa transmission. The aim of this study was to evaluate the capability of dissolved air flotation (DAF), on a bench scale, to remove Giardia cysts from anaerobic effluent. Moreover, removals of indicator microorganisms and physical variables were also investigated. Flocculation conditions were studied, associating different flocculation times with different mean velocity gradients. DAF treatment achieved mean log removals in the range of 2.52-2.62 for Giardia cysts, depending on the flocculation condition. No statistical differences were observed among the flocculation conditions in terms of cyst removal. Low levels of turbidity and apparent color obtained from the treated effluent may indicate good treatment conditions for the DAF process in cyst removal. Indicator microorganisms were not able to predict the parasitological quality of the wastewater treated by flotation in terms of cyst concentrations. The DAF process provided an effective barrier to control cysts from sewage, which is an important parasite source.


Assuntos
Giardia , Esgotos , Purificação da Água/métodos , Ar , Cistos , Floculação , Águas Residuárias
8.
J Water Health ; 13(3): 811-8, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26322766

RESUMO

More precise methods are needed to recover Giardia and Cryptosporidium (oo)cysts from wastewater in order to advance research related to their inactivation, removal, quantification, and species differentiation. This study applied different methods to recover the maximum number of (oo)cysts from wastewater samples using ColorSeed®. Immunomagnetic separation assisted in capturing oocysts mainly in samples with medium and low turbidity. A triple centrifugation method reached recovery rates of 85% and 20%, for Giardia cysts and Cryptosporidium oocysts, respectively, in raw wastewater, and 62.5 and 17.5% in secondary-treated effluent. For low turbidity-treated effluent, membrane filtration reached 67.5% recovery for Giardia cysts and 22.5% for Cryptosporidium oocysts. Simple, quick and low-cost methods do not involve much handling of the samples and could be useful, particularly in developing countries.


Assuntos
Cryptosporidium/isolamento & purificação , Giardia/isolamento & purificação , Oocistos/citologia , Águas Residuárias/parasitologia , Purificação da Água/métodos , Filtração , Separação Imunomagnética
9.
Artigo em Inglês | MEDLINE | ID: mdl-26301847

RESUMO

This research studied the sequential ozone and chlorine process with respect to, the inactivation of indicator bacteria and the formation of ozone disinfection byproducts in sanitary wastewater effluent. The applied ozone doses were 5, 8 and 10 mg.O3.L(-1), followed by chlorine doses of 10, 20 and 30 mg.L(-1), respectively. After the sequential ozone/chlorine process, the mean reduction in chemical oxygen demand ranged from 9 to 37%. Total coliform inactivation ranged from 1.59 to 3.73 log10, and E. coli was always <1 CFU 100 mL(-1). Ozonation resulted in the formation of aldehydes, which were not significantly impacted by the subsequent chlorine dose (P ≤ 0.05).


Assuntos
Cloro/farmacologia , Desinfecção/métodos , Ozônio/farmacologia , Esgotos , Anaerobiose , Análise da Demanda Biológica de Oxigênio , Brasil , Cloro/química , Escherichia coli/citologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Humanos , Concentração de Íons de Hidrogênio , Testes de Sensibilidade Microbiana , Ozônio/química , Esgotos/química , Esgotos/microbiologia , Microbiologia da Água , Purificação da Água/métodos
10.
Eng. sanit. ambient ; 20(2): 279-288, abr.-jun. 2015. tab, ilus
Artigo em Português | LILACS-Express | ID: lil-759312

RESUMO

O principal objetivo desta pesquisa foi estudar o processo de oxidação, a eficiência da inativação de coliformes e a formação de subprodutos da ozonização, associado com a desinfecção de efluente sanitário anaeróbio proveniente de um reator UASB. Tal evento foi realizado por meio da aplicação das dosagens de ozônio de 5,0 mg.O3.L-1+ 10 mg.Cl2.L-1 (ensaio 1); 8,0 mg.O3.L-1+ 20 mg.Cl2.L-1 (ensaio 2) e 10,0 mg.O3.L-1+ 30 mg.Cl2.L-1 (ensaio 3). Neste trabalho, utilizou-se efluente da Estação de Tratamento de Esgoto da Universidade de São Paulo, no Brasil. As reduções médias totais da demanda química de oxigênio para os efluentes ozonizados/clorados foram de 9, 32 e 37% para os ensaios 1, 2 e 3, respectivamente. A inativação dos coliformes totais variou de >5,7 até 6,4 log10 e >5,8 até >6,0 log10para Escherichia coli. A formação de aldeídos não sofreu mudanças significativas (p=0,05) para as dosagens e os tempos de contato aplicados após os ensaios de ozonização/cloração.


The main purpose of this research was to study the oxidation process, the coliform inactivation effectiveness, and the formation of ozone disinfection byproducts, which were associated with disinfection of the anaerobic sanitary wastewater effluent from a UASB reactor. Such event was performed with ozone applied at doses of 5.0 mg.O3.L-1+ 10 mg.Cl2.L-1 (essay 1); 8.0 mg.O3.L-1+ 20 mg.Cl2.L-1 (essay 2), and 10.0 mg.O3.L-1+ 30 mg.Cl2.L-1 (essay 3). The wastewater used in this research was generated at the Wastewater Treatment Plant of Universidade de São Paulo, in Brazil. The total mean decreases of the chemical oxygen demand for ozonized/chlorinated effluents were 9, 32 and 37% for assays 1, 2 and 3 respectively. The total coliform inactivation varied from >5,7 to 6,4 log10 and >5.8 to >6.0 log10 for Escherichia coli. The formation of aldehydes did not suffer any significant changes (p=0.05) for dosages and contact times applied after ozonation/chlorination assays.

11.
Ecotoxicology ; 23(9): 1803-13, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25213288

RESUMO

The toxic potential of four disinfectant agents (chlorine, ozone, peracetic acid and UV radiation), used in the disinfection of urban wastewater, was evaluated with respect to four aquatic organisms. Disinfection assays were carried out with wastewater from the city of Araraquara (São Paulo State, Brazil), and subsequently, toxicity bioassays were applied in order to verify possible adverse effects to the cladocerans (Ceriodaphnia silvestrii and Daphnia similis), midge larvae Chironomus xanthus and fish (Danio rerio). Under the experimental conditions tested, all the disinfectants were capable of producing harmful effects on the test organisms, except for C. xanthus. The toxicity of the effluent to C. silvestrii was observed to increase significantly as a result of disinfection using 2.5 mg L(-1) chlorine and 29.9 mg L(-1) ozone. Ozonation and chlorination significantly affected the survival of D. similis and D. rerio, causing mortality of 60 to 100 % in comparison to the non-disinfected effluent. In experiments with effluent treated with peracetic acid (PAA) and UV radiation, a statistically significant decrease in survival was only detected for D. rerio. This investigation suggested that the study of the ideal concentrations of disinfectants is a research need for ecologically safe options for the treatment of wastewater.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Desinfetantes/toxicidade , Animais , Brasil , Chironomidae/efeitos dos fármacos , Cloro/toxicidade , Cladóceros/efeitos dos fármacos , Desinfecção , Ecossistema , Monitoramento Ambiental , Água Doce/química , Ozônio/toxicidade , Ácido Peracético/toxicidade , Esgotos , Testes de Toxicidade , Raios Ultravioleta , Águas Residuárias/química , Peixe-Zebra
12.
Eng. sanit. ambient ; 18(3): 215-222, July-Sept/2013. tab, graf
Artigo em Português | LILACS-Express | ID: lil-690018

RESUMO

O objetivo do estudo foi avaliar a degradação do hormônio 17β-estradiol com doses de cloro e tempos de contato comumente utilizados em estações de tratamento de água. A aplicação de cloro levou a pequenas alterações na maioria das variáveis analisadas. A concentração inicial de 17β-estradiol influenciou a remoção pelo cloro, e observou-se que o aumento da dose de cloro aumentou a remoção do 17β-estradiol até a dose de 2 mg.L-1. A maior remoção de hormônio obtida foi de 99%, e a inativação dos microrganismos indicadores, E. coli e coliformes totais foi de até 5,6 log para valores de CT maiores que 14 mg.min.L-1 .


The purpose of this study was to evaluate the degradation of the estrogen 17β-estradiol at doses of chlorine and contact times commonly used in water treatment plants. The application of chlorine led to minor changes in most parameters examined. The initial concentration of the hormone affected the removal by chlorine and was observed that increasing the dose of chlorine increased the removal of 17β-estradiol until the dose of 2 mg.L-1. The highest removal of hormone obtained was 99%, and inactivation of the indicator microorganisms, E. coli and total coliform was up to 5.6 log for values of CT greater than 14 mg.min.L-1 .

13.
Environ Technol ; 32(11-12): 1401-8, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21970182

RESUMO

Water disinfection assays were carried out using ozone and chlorine in non-sequential steps--the individual method--and in sequential steps--the combined ozone/chlorine method. Escherichia coli strain ATCC 11229 was used as the indicator microorganism. For the assays using the individual method, the applied dosages of ozone were 2.0, 3.0 and 5.0 mg/L, and 2.0 and 5.0 mg/L of chlorine were used. For the assays applying the combined method, the dosages (dosage combination) were, in mg/L: 2.0 O3 + 2.0 Cl, 3.0 O3 + 2.0 Cl2, 5.0 O3 + 2.0 Cl2 and 2.0 O3 + 5.0 Cl2. The applied contact times were 5, 10, 15 and 20 minutes for the individual method as well as for the combined method. For all used dosages and contact times, E. coli inactivation was superior to the inactivation obtained in the individual method, indicating the occurrence of synergism for E. coli inactivation in the combined method.


Assuntos
Cloro/farmacologia , Desinfetantes/farmacologia , Escherichia coli/efeitos dos fármacos , Ozônio/farmacologia , Purificação da Água/métodos , Cloro/química , Desinfetantes/química , Viabilidade Microbiana/efeitos dos fármacos , Ozônio/química , Microbiologia da Água , Purificação da Água/instrumentação
14.
Chemosphere ; 84(11): 1535-41, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21700318

RESUMO

Estrogens are a class of micro-pollutants found in water at low concentrations (in the ng L(-1) range), but often sufficient to exert estrogenic effects due to their high estrogenic potency. Disinfection of waters containing estrogens through oxidative processes has been shown to lead to the formation of disinfection byproducts, which may also be estrogenic. The present work investigates the formation of disinfection byproducts of 17ß-estradiol (E2) and estrone (E1) in the treatment of water with ozone. Experiments have been carried out at two different concentrations of the estrogens in ground water (100 ng L(-1) and 100 µg L(-1)) and at varying ozone dosages (0-30 mg L(-1)). Detection of the estrogens and their disinfection byproducts in the water samples has been performed by means of ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with a triple quadrupole (QqQ) and a quadrupole-time of flight (QqTOF) instrument. Both E2 and E1 have been found to form two main byproducts, with molecular mass (MM) 288 and 278 in the case of E2, and 286 and 276 in the case of E1, following presumably the same reaction pathways. The E2 byproduct with MM 288 has been identified as 10 epsilon-17beta-dihydroxy-1,4-estradieno-3-one (DEO), in agreement with previously published results. The molecular structures and the formation pathways of the other three newly identified byproducts have been suggested. These byproducts have been found to be formed at both high and low concentrations of the estrogens and to be persistent even after application of high ozone dosages.


Assuntos
Estradiol/química , Estrona/química , Ozônio/química , Poluentes Químicos da Água/química , Cromatografia Líquida de Alta Pressão , Recuperação e Remediação Ambiental , Oxirredução , Espectrometria de Massas em Tandem
15.
Chemosphere ; 82(6): 789-99, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21087787

RESUMO

Estrogens constitute a recognized group of environmental emerging contaminants which have been proven to induce estrogenic effects in aquatic organisms exposed to them. Low removal efficiency in wastewater treatment plants results in the presence of this type of contaminants in surface waters and also even in finished drinking water. This manuscript reviews the environmental occurrence of natural (estrone, estradiol and estriol) and synthetic (ethynyl estradiol) estrogens in different water matrices (waste, surface, ground and drinking water), and their removal mainly via chemical oxidative processes. Oxidative treatments have been observed to be very efficient in eliminating estrogens present in water; however, disinfection by-products (DBPs) are generated during the process. Characterization of these DBPs is essential to assess the risk that drinking water may potentially pose to human health since these DBPs may also have endocrine disrupting properties. This manuscript reviews the DBPs generated during oxidative processes identified so far in the literature and the estrogenicity generated by the characterized DBPs and/or by the applied disinfection technology.


Assuntos
Desinfetantes/química , Desinfecção/métodos , Estrogênios/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Cloraminas/análise , Cloraminas/química , Cloro/análise , Cloro/química , Compostos Clorados/análise , Compostos Clorados/química , Desinfetantes/análise , Estradiol/análise , Estradiol/química , Estriol/análise , Estriol/química , Estrogênios/química , Estrona/análise , Estrona/química , Etinilestradiol/análise , Etinilestradiol/química , Óxidos/análise , Óxidos/química , Ozônio/análise , Ozônio/química , Esgotos/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Abastecimento de Água/análise
16.
Eng. sanit. ambient ; 10(2): 111-117, abr.-jun. 2005. tab
Artigo em Português | LILACS | ID: lil-415813

RESUMO

Foi realizado estudo comparativo em condições experimentais similares, entre hipoclorito de sódio e ácido peracético na desinfecção de água com elevada concentração de matéria orgânica. O conteúdo de carbono orgânico dissolvido (COD) variou de 4,652 a 30,13 mgC/L para a água de estudo bruta e após a desinfecção esses valores variaram de 5,105 a 26,16 mgC/L para os ensaios com cloro e de 15,89 a 32,78 mgC/L para os ensaios com ácido peracético. O desempenho dos dois desinfetantes foi avaliado segundo a inativação de três microrganismos indicadores, Escherichia coli ATCC 11229, colifagos e Clostridium perfringens ATCC 13124 que eram previamente cultivados e inoculados à água no momento do experimento. As concentrações aplicadas de cloro e ácido peracético foram de 2,0; 3,0; 4,0 e 5,0 mg/L e os tempos de contato de 5, 10, 15 e 20 minutos. Para 3,0 mg/L de cloro aplicado, obteve-se 3 log de inativação de E. coli em 20 minutos de contato, 2,92 log de inativação de fagos em 10 minutos e 2 log de inativação de C. perfringens em 15 minutos. Os resultados dos ensaios de desinfecção com ácido peracético indicaram efetiva inativação dos microrganismos indicadores empregados, mesmo na presença de elevada concentração de matéria orgânica. Para 5,0 mg/L de ácido peracético aplicado e 15 minutos de contato, inativações de E. coli maiores que 6 log, de fagos maiores que 5 log em 20 minutos e de C. perfringens maiores que 4 log em 10 minutos de contato foram alcançadas.


Assuntos
Águas Residuárias , Clostridium perfringens , Colífagos , Escherichia coli , Ácido Peracético , Hipoclorito de Sódio , Desinfecção da Água
17.
Eng. sanit. ambient ; 9(4): 335-342, out.-dez. 2004. ilus, tab, graf
Artigo em Português | LILACS | ID: lil-406809

RESUMO

Neste trabalho são apresentados resultados da aplicação da fotocatálise heterogênea utilizando dióxido de titânio imobilizado sobre placa de vidro, irradiado por luz solar, para desinfecção de esgoto sanitário secundário. Utilizou-se o efluente de um reator anaeróbio/aeróbio com leito expandido de carvão ativado que trata o esgoto do Campus da USP/São Carlos, e também de contribuições domésticas. Os experimentos foram do tipo batelada, com tempo de recirculação de 4 horas. As vazões estudadas foram 15, 22,5 e 30 L/h. Foram avaliadas as remoções de matéria orgânica (DQO e COT) e a inativação de microrganismos indicadores de contaminação fecal (coliformes totais, E. coli, Clostridium perfringens e colifagos).


Assuntos
Águas Residuárias , Clostridium perfringens/isolamento & purificação , Colífagos/isolamento & purificação , Estações de Tratamento de Águas Residuárias/métodos , Características de Águas Residuárias , Tratamento de Águas Residuárias , Desinfecção da Água
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