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Occurrence of endocrine disrupting compounds in water sources of Belo Horizonte Metropolitan Area, Brazil.

Endocrine disrupting compounds (EDCs) have attracted the attention of the scientific community because of the effects of EDCs on aquatic fauna and the potential threat they pose to human health. There are a handful of papers on the monitoring of EDCs in Brazilian surface waters, hence this research was aimed at assessing, by using liquid chromatography coupled to mass spectrometry (LC–MS), the presence of 17β‐estradiol, 17α‐ethynylestradiol and 4‐nonylphenol in surface waters used for supplying the Belo Horizonte Metropolitan Area, Minas Gerais state, Brazil. The one‐year monitoring period of three water sources showed that 4‐nonylphenol was detected in all samples in a concentration range of 44 to 1918 ng L−1, whilst the natural and synthetic estradiols were hardly detected (only in ∼15% of samples) and always in low concentrations (2 to 54 ng L−1). Samples of partially treated water, collected in three water treatment plants before the chlorination step, showed that the steps of prechlorination, flocculation–sedimentation and sand filtration did not efficiently remove the EDCs studied.

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.

CONTRIBUTION TO THE STUDY OF MEASURES FOR THE REDUCTION OF APPARENT WATER LOSS IN URBAN AREAS

En Brasil, el promedio de las perdidas de facturacion de las empresas operadoras de los servicios de agua es de aproximadamente 36%. Este valor advierte acerca de la necesidad de mejorar la eficiencia de los servicios, especialmente en lo que se refiere a las perdidas aparentes, que pueden representar mas de 50% del total. Tomando en cuenta dicho aspecto, en este estudio se evaluo la influencia de la clase metrologica y del tiempo de servicio de los hidrometros en la sub medicion, por medio de estudio a escala piloto y de banco. Los resultados mostraron reduccion significativa de las perdidas aparentes debido a la sustitucion de hidrometros clase B por los C, y su viabilidad economica. Ademas, se pronuncio acerca de la interferencia del uso de reservorios y sobre la influencia de la politica arancelaria en los resultados financieros de las operadoras y en el consumo de los usuarios.

Recirculação de água de lavagem de filtros e perigos associados a protozoários

This paper presents the results of (i) the characterization of the filter backwash water (FBW) of Vicosa University water treatment plant; (ii) trials of FBW clarification in sedimentation columns, with and without polymer application; (iii) trials of FBW recycling in a pilot plant, under variable conditions of recycling flow rates (5 to 20% of the raw water flow - RW) and of the influent water (RW + FBW) turbidity (12.1 to 257.3 uT). Around 101 Giardia spp. cysts and Cryptosporidium spp. oocysts per liter were found in the FBW. The results of sedimentation columns and recycling trials demonstrated that FBW clarification using polymers contributes to minimize hazards related to the introduction of Giardia cysts and Cryptosporidium oocysts.

Solução oxidante gerada a partir da eletrólise de rejeitos de dessalinizadores de água

This work carried out studies about the use of the electrolysis process to produce oxidant solutions from water desalinators wastes for water disinfection. The experiment was conducted in laboratory scale. Three oxidant solutions were generated by electrolysis from wastes of water desalinators that presented concentrations of 1.7 x 103 mg, 5.5 x 103 mg and 10.2 x 103 mg of Cl-/L.The electrolysis process lasted eight hours and the following parameters were monitored every hour: pH, electrical conductivity, temperature, total chlorine. It was observed that the production of chlorine is directly related to chloride concentration; the average content of chlorine of the oxidant solutions generated from the desalinators wastes was 0.10%, 0.24% and 0.27% m/m.