Tatiane Benvenuti

Water quality assessment of the Sinos River – RS, Brazil

Worldwide environmental pollution is increasing at the same rate as social and economic development. This growth, however, is disorganized and leads to increased degradation of water resources. Water, which was once considered inexhaustible, has become the focus of environmental concerns because it is essential for life and for many production processes. This article describes monitoring of the water quality at three points along the Sinos River (RS, Brazil), one in each of the upper, middle and lower stretches. The points were sampled in 2013 and again in 2014. The water samples were analyzed to determine the following physical and chemical parameters plus genotoxicity to fish: metals (Cr, Fe, Al), chemical oxygen demand, biochemical oxygen demand, chlorides, conductivity, total suspended solids, total phosphorous, total and fecal coliforms, pH, dissolved oxygen, turbidity, total Kjeldahl nitrogen nitrate and ammoniacal nitrogen. Genotoxicity was tested by exposing individuals of the species Astyanax jacuhiensis to water samples and then comparing them with a control group exposed to water from the public water supply. The results confirmed the presence of substances with genotoxic potential at the sample points located in the middle and lower stretches of the river. The results for samples from the upper stretch, at P1, did not exhibit differences in relation to the control group. The physical and chemical analyses did not detect reductions in water quality in the lower stretch, as had been expected in view of the large volumes of domestic and industrial effluents discharged into this part of the river.

Integrated Environmental Assessment of streams in the Sinos River basin in the state of Rio Grande do Sul, Brazil.

The deterioration of environmental quality in the Sinos River basin is directly associated with the impacts of intense industrialization and urbanization. An integrated environmental assessment (IEA) was conducted in July and September of 2012, in areas along the sources of the EstânciaVelha/Portão, Pampa and Schmidt streams using physical, chemical and biological methods. The water in the three sampling sites was not proper for human consumption, presented a low toxic contamination index (TCI) and mesotrophic characteristics. One site was included in Class 4, and two, in Class 3, according to current legislation. The rapid assessment protocol (RAP) indicated a natural environmental condition for habitat diversity and environmental impact in the three sites. The Tradescantia pallida (Rose) D.R. Hunt var. purpurea Boom biomarker showed water genotoxicity in two of the sites. The integrated diagnosis of water quality in these streams is fundamentally important to ensure the sustainable management of water resources and their multiple uses, as well to estimate their contribution to pollution in this river basin.

Concentrations of PM2.5-10 and PM2.5 and metallic elements around the Schmidt Stream area, in the Sinos River Basin, southern Brazil

This research aimed to evaluate the air quality, by determining the concentrations of PM2.5-10, PM2.5 and the metallic elements Al, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn and Hg in the leaf part of ryegrass (Lolium multiflorum) in an area close to Schmidt Stream, at the lower section of Sinos River Basin (SRB), in a research campaign of six months, from October 2013 to March 2014. The particles collected in the PM sampling were analyzed by Scanning Electron Microscopy (SEM) combined with Energy Dispersive X-ray Spectrometry (EDS), in order to study their morphology and chemical composition. The mean concentration of PM2.5-10 was 9.1 µg m(-3), with a range of 2.2 µg m(-3) to 15.4 µg m(-3) and the mean concentration of PM2.5 was 4.7 µg m(-3), with a range of 1.9 µg m(-3) to 8.2 µg m(-3). Concentrations of metallic elements, especially Pb, Cr and Zn, were classified as Class 4 (very high pollution levels), according to the classification proposed by Klumpp et al. (2004). Chemical and morphological analysis of PM revealed the presence of particles of biological origin, soot (Cr, Fe, Ni, Zn, Cd, Hg and Pb), salts (KCl) and soil resuspension (Al and Si). The integrated study methodology, employing environmental variables, such as PM and ryegrass, can be of help in the preparation of wide-ranging environmental diagnoses, in addition providing information needed to develop precautionary measures designed to minimize the effects of atmospheric pollution that takes into consideration the environments supportive capacity and environmental quality.

Electrodialysis Treatment of Nickel Wastewater

The galvanic processes are one of the main activities contributing to metal discharges into the environment. A large volume of wastewater is generated that contains a high load of salts and metals and it must be treated to recover the chemicals and water and save resources. Nickel is a toxic metal and causes various health problems. According to environmental regulations across the world, nickel concentrations in effluents must be controlled on an acceptable level before the discharge into the environment. The removal of metals by conventional treatment (chemical precipitation) not only does not result in a final effluent with a nickel concentration below the acceptable limit, but it also generates a large volume of galvanic sludge, a hazardous waste material. Several treatment processes have been suggested for the removal of nickel from rinse water, such as electrochemical techniques. This chapter presents the application of electrodialysis (ED) as an alternative that can contribute to comply with legal environmental standards and enable the recovery and reuse of water and chemicals in the nickel electroplating process, helping to minimize the environmental impact associated with the water consumption and generation of waste in the galvanic industry.

Toxicity effects of nickel electroplating effluents treated by photoelectrooxidation in the industries of the Sinos River Basin

The Sinos river Basin is an industrial region with many tanneries and electroplating plants in southern Brazil. The wastewater generated by electroplating contains high loads of salts and metals that have to be treated before discharge. After conventional treatment, this study applied an advanced oxidative process to degrade organic additives in the electroplating bright nickel baths effluent. Synthetic rinsing water was submitted to physical-chemical coagulation for nickel removal. The sample was submitted to ecotoxicity tests, and the effluent was treated by photoelectrooxidation (PEO). The effects of current density and treatment time were evaluated. The concentration of total organic carbon (TOC) was 38% lower. The toxicity tests of the effluent treated using PEO revealed that the organic additives were partially degraded and the concentration that is toxic for test organisms was reduced.

Analysis of different current density conditions in the electrodialysis of zinc electroplating process solution

ABSTRACT The use of currents below and above the limiting one for the treatment by electrodialysis of a solution prepared as a surrogate of a rinse water of the acid zinc electroplating processes was studied. The ionic transport behavior was evaluated by chronopotentiometry. The limiting current values were obtained through current–voltage curves. The trials performed with different current densities showed that the electrodialysis removed at least 98% of the contaminants without insoluble species precipitation on membrane surfaces. The water reuse is possible after electrodialysis treatment with current densities above the limiting one and considering a demineralization rate of 60%.

Tratamento de efluentes de eletrodeposição de níquel por fotoeletrooxidação

Considering the growing concern about effluent toxicity, generated by the pres ence of metals and the occurrence of new organic pollutants, this study applied an advanced oxidation process (AOP), denominated the photo-electro-oxidation (PEO), for polishing after the effluent passed through the conventional wastewater treatment from the metal finishing industry that often does not satisfactorily remove metals and organic additives. PEO associated organic additive degradation with nickel removal. A synthetic wastewater, whose composition is similar to a nickel bath containing additives, was evaluated. Employing a Ti anode coated with 70%TiO 2 /30%RuO 2 under an incidence of UV radiation from a mercury vapor lamp of 250 W and a stainless steel cathode, 2.5 L of wastewater were treated in a 1.6 L reactor, at a flow rate of 1L.min -1 . Applying different current densities, there was a reduction of up to 83% COD and removal of Ni above 90%. The cytotoxicity assays indicated that PEO did not generate more toxic intermediates because there was no increase in the toxic effect when the solutions were compared before and after PEO.