Marcelo Libânio

Proposta de Índice de Qualidade para Água Bruta afluente a estações convencionais de tratamento

This paper has the objective of proposing a Raw Water Quality Index (RWQI) influent for the conventional water treatment plants that allow the comparison of the treatability of distinct surface water sources. The Delphi methodology was employed similarly to that employed for the development of Water Quality Index, in the beginning of the 1970s, with a panel composed by 24 specialists. According to the panel opinion, the RWQI was composed by eight water quality parameters usually monitored in a significant portion of Brazilian plants. Its application on five surface water sources allows the recommendation of its use as an additional tool for the assessment of the performance of water treatment plants operated by the Brazilian sanitation companies.

Avaliação do impacto da variação da renda no consumo domiciliar de água

Este trabalho objetivou avaliar o impacto que a alteracao da renda das familias exerce sobre o consumo de agua tratada fornecida pela concessionaria (no caso, a Companhia de Saneamento de Minas Gerias - Copasa) no municipio de Belo Horizonte, ao longo de um historico de 35 meses, abrangendo o periodo de agosto de 2003 a junho de 2006. Para tal, utilizaram-se dados da Pesquisa Mensal de Emprego (PME) do Instituto Brasileiro de Geografia e Estatistica (IBGE), englobando 3.100 domicilios e 10.200 moradores, e os consumos residenciais micromedidos dos 6 distritos operacionais da Copasa. Os dados foram observados em seus periodos de forma que houvesse a compatibilizacao cronologica entre os mesmos. Os resultados mostraram relacao intrinseca entre o consumo per capita e a renda mensal, balizados pelos graficos de dispersao e pelos significativos coeficientes de determinacao obtidos (superiores a 0,8), alem do prognostico de saturacao do consumo demonstrado para classes sociais economicamente mais favorecidas.

Avaliação da remoção de saxitoxinas por meio de técnicas de tratamento das águas de abastecimento

O objetivo do trabalho e avaliar a eficiencia da adsorcao com carvao ativado em po (CAP) e da cloracao de calcio na remocao de saxitoxinas. As saxitoxinas dispersas em agua destilada foram produzidas por meio da extracao de celulas viaveis de cianobacterias da especie Cylindrospermopsis raciborskii. Os ensaios foram realizados em equipamento de jar test adaptado e empregando-se tres tipos de CAP e hipoclorito de calcio. Os tempos de detencao aplicados foram de duas horas para adsorcao e 30 e 60 minutos para oxidacao. Os resultados evidenciaram que a eficiencia de remocao, para a adsorcao, esta intrinsecamente relacionada ao tipo de carvao e a dosagem empregada, obtendo maior eficiencia para o CAP de madeira. Para oxidacao, os dois tempos de contato e as dosagens avaliadas apresentaram eficiencia praticamente constante, da ordem de 80%, atendendo ao estabelecido pela Portaria 518.

Comparison between two forms of granular activated carbon for the removal of pharmaceuticals from different waters

ABSTRACT The aim of this study was to evaluate the performance of two forms of basic granular activated carbon (GAC), mineral (pH = 10.5) and vegetal (pH = 9), for the removal of three pharmaceuticals, as sulphamethoxazole (SMX), diclofenac (DCF) and 17β-estradiol (E2), from two different matrices: fortified distilled (2.4–3.0 mg L−1 and pH from 5.5 to 6.5) and natural (∼1.0 mg L−1 and pH from 7.1 to 7.2) water in a bench scale. The Rapid Small-Scale Column Test used to assess the ability of mineral and vegetal GAC on removal of such pharmaceuticals led to removal capacities varying from 14.9 to 23.5 mg g−1 for E2, from 23.7 to 24.2 mg g−1 for DCF and from 20.5 to 20.6 mg g−1 for SMX. Removal efficiencies of 71%, 88% and 74% for DCF, SMX and E2, respectively, were obtained at breakthrough point when using mineral GAC, whereas for the vegetal GAC the figures were 76%, 77% and 65%, respectively. The carbon usage rate at the breakthrough point varied from 11.9 to 14.5 L g−1 for mineral GAC and from 8.8 to 14.8 L g−1 for vegetal GAC. Mineral CAG also exhibited the best performance when treating fortified natural water, since nearly complete removal was observed for all contaminants in the column operated for 22 h at a carbon usage rate of 2.9 L g−1.

Remoção de microcistina-LR de águas eutrofizadas por clarificação e filtração seguidas de adsorção em carvão ativado granular

Conventional treatment process of natural waters with high densities of cyanobacteria and cyanotoxins usually presents low efficiency according to the present drinking water standard (maximum permissible value of 1.0 µg.L-1 of microcystin). Additional steps, such as activated carbon, commonly become necessary to achieve the maximum permissible value of microcystin (1.0 µg.L-1) set up by Brazilian Drinking Water Regulation 2914. In this context, the main objective of this work was to evaluate microcystin removal from natural waters by means of two granular activated carbons after clarification and sand filtration in bench scale. The results pointed out that the breakthrough happened in activated carbon with highest grain sizes in lower contact time (2 h) , when compared with that with smaller grain sizes. These results open the perspective of an application of the activated carbon in actual scale, assuring the treated water quality in compliance with the Brazilian Drinking Water Standards Regulation 2914.

Estudo da coagulação aplicada à filtração direta descendente

The present work compares several coagulants (alum, ferric chloride, ferric sulfate, and aluminum hydrochloride - each by itself or with cationic polymers) applied to in line downflowing direct filtration, as to their effectiveness in reducing apparent color, turbidity, and phytoplankton. The tests were carried out in static reactors and in a pilot unit, using natural water drawn from the reservoir of a water treatment plant. Coagulants used in dosages recommended for direct filtration yielded values of apparent color and turbidity that complied with Brazilian government regulations. There was no significant difference among them in either bench or pilot scale at a 95% reliability interval.

Proposição de um índice de qualidade de estações de tratamento de água ( IQETA )

O presente trabalho objetiva a proposicao de um Indice de Qualidade de Estacao de Tratamento de Agua (IQETA), aplicavel a estacoes de tecnologia convencional, que permita comparar o desempenho das estacoes por meio de uma metodologia que transcenda o simples atendimento ao padrao de potabilidade. A metodologia para a elaboracao do IQETA fundamentou-se basicamente na mesma utilizada para o desenvolvimento do IQA. A posterior aplicacao do IQETA a dez estacoes de portes distintos validou-o como ferramenta de avaliacao. Verificou-se clara tendencia das estacoes com melhor desempenho - produzindo agua filtrada de melhor qualidade, em termos de turbidez - serem contempladas com maiores valores para o IQETA, demonstrando a utilidade do indice como uma ferramenta capaz de auxiliar na administracao de sistemas de producao de agua para consumo humano.

Avaliação da remoção de fármacos e de desreguladores endócrinos em águas de abastecimento por clarificação em escala de bancada

EVALUATION OF REMOVAL OF PHARMACEUTICALS AND ENDOCRINE DISRUPTERS IN DRINKING WATER BY CLARIFICATION AT BENCH SCALE. In this work, the efficiency of clarification treatment (coagulation, flocculation and sedimentation) with polyaluminum chloride (PAC) and aluminum sulfate (SA) as coagulants was evaluated in the removal of 7 microcontaminants (diclofenac - DCF, sulfamethoxazole - SMX, ethinylestradiol - EE2, bisphenol-A - BPA, estradiol - E2, estrone - E1 and estriol - E3) in water of low and high turbidity. The clarification treatment led to poor removal rates (40% at most) for all microcontaminants except SMX which exhibited intermediate removal efficiency (67 to 70%). Overall, PAC application yielded better performance compared to SA.

Nova abordagem do Índice de Qualidade de Água Bruta utilizando a Lógica Fuzzy

For the performance evaluation of water treatment plants, the raw water quality presents significant relevance. In Brazil, the Index of Quality of Raw Water for Public Supply (IAP) and the Index of Quality of Raw Water (IQAB), developed according to deterministic models, can evaluate the treatability of natural waters. However, the IAP presents a high cost for actual implementation and the IQAB needs some adjustments related to the input parameters and grading criteria. Aiming at a non-deterministic model, able to deal with uncertain, nonlinearity of the parameters and expert knowledge, Fuzzy Logic was applied to a new approach of the IQAB. The Fuzzy Raw Water Quality Index (IQABF), in comparison with the original IQAB, presented more restrictive, more consistent and more flexible for future adjustments. Its application for six water sources of Southeast Region showed practically the same hierarchy in terms of the treatability in comparison with the original IQAB.

Response surface methodology applied to tropical freshwater treatment

ABSTRACT This paper presents the profits and disadvantages of the chemometrics approach instead of the one-factor-at-a-time (OFAT) coagulation diagram approach for tropical water physicochemical treatment. Central composite design associate to response surface methodology (CCD-RSM) is used to find the real best conditions for coagulant dosage and pH aiming at high-turbidity removal. The number of experiments needed to chemometrics model construction (12) is comparatively smaller than that used in the coagulation diagram (84), saving financial and environmental resources. Arguments for Water Treatment Plants (WTP) considering the replacement of coagulation diagram approach by the CCD-RSM approach in drinking water treatment are presented. Chemometrics models are all constructed on a free software platform, providing the best pH within the range 7.7–8.1, and the best coagulant dosage (polyaluminium chloride, PAC) between 2.0 and 3.1 mg Al2O3 L−1 (equivalent in mass). CCD-RSM provides a faster, lower-cost and more reliable alternative tool for WTP decision-making instead of the OFAT model, mainly for waters more affected by seasonal effects as can be seen in tropical and subtropical countries. GRAPHICAL ABSTRACT