Antonio Teixeira de Matos

ASSESSMENT OF WATER SYSTEMS FOR CONTAMINANTS FROM DOMESTIC AND INDUSTRIAL SEWAGES

The State of Minas Gerais represents one of Brazils most outstanding mining resources. The contamination of river waterfrom kaolin processing activities may be harmful to people inthe way of slow but chronic poisoning. On the other hand, the discharge of untreated or inadequately treated domestic sewage into aquatic environments can also cause deleterious effects to the health. However, no reliable figures are available for pollutant occurrences in river water. This draws attention to thevery precarious situation that exists with respect to pollutionby organic and inorganic toxic wastes, especially with respect to humans and fauna in all its expressions. Thus, with the purpose of establishing a preliminary report to trace out industrialisation outcomes, samples of river water, vegetation and fish were collected and analysed to detect pollutant inputs.The concentration of metals was determined in suspended particle,vegetation and fish, while those of nitrite, nitrate, phosphateand chloride were determined in river water samples. The concentration of dissolved oxygen (DO) was measured in river water at the time of collection. Chemical oxygen demand (COD) and biochemical oxygen demand (BOD) were also determined. Metalinputs in the samples analysed appeared to be related to effluentdischarges into the rivers. The suspended particles showed highconcentrations (in mg kg-1) of zinc (62 600) and aluminium(559 000), while vegetation samples collected near rivers wereheavily contaminated with iron (7680). The fishes examined werecontaminated with chromium (1.5 mg kg-1). In general, the concentrations of nitrite, nitrate, chloride, phosphate and BOD in river water were lower than the maximum values established bythe Brazilian Environmental Standards.

Competitive Adsorption of Zinc, Cadmium, Copper, and Lead in Three Highly- Weathered Brazilian Soils

Abstract Equilibrium adsorption experiments on zinc (Zn), cadmium (Cd), copper (Cu), and lead (Pb) were conducted in three horizons of two Ultisols and one Oxisol with and without liming, from Vicosa‐MG (Brazil). Equilibrium solutions were applied as a “cocktail”; containing 700 mg L‐1 of Zn, 20 mg L#lb1 of Cd, 200 mg L‐1of Cu, and 300 mg L‐1 of Pb and its dilutions of 1:5 and 1:20. After shaking, the mixture was centrifuged, the supernatant collected and the pH and the concentrations of metals in the mixture were determined. Soil order, soil horizon, and liming had significant effects on the metal adsorption. Some important changes in the adsorption characteristics of the metals, especially in Zn and Cd, were observed due to competition between the different cations present in the solution. Also, desorption of Zn and Cd was observed with an increasing concentration of the solution. The adsorption data for Zn and Cd did not fit the linear, Langmuir, Freundlich, and Temkin isotherm equations for most situa...Abstract Equilibrium adsorption experiments on zinc (Zn), cadmium (Cd), copper (Cu), and lead (Pb) were conducted in three horizons of two Ultisols and one Oxisol with and without liming, from Viçosa‐MG (Brazil). Equilibrium solutions were applied as a “cocktail”; containing 700 mg L‐1 of Zn, 20 mg L#lb1 of Cd, 200 mg L‐1of Cu, and 300 mg L‐1 of Pb and its dilutions of 1:5 and 1:20. After shaking, the mixture was centrifuged, the supernatant collected and the pH and the concentrations of metals in the mixture were determined. Soil order, soil horizon, and liming had significant effects on the metal adsorption. Some important changes in the adsorption characteristics of the metals, especially in Zn and Cd, were observed due to competition between the different cations present in the solution. Also, desorption of Zn and Cd was observed with an increasing concentration of the solution. The adsorption data for Zn and Cd did not fit the linear, Langmuir, Freundlich, and Temkin isotherm equations for most situations, as these equations do not consider the possibility of a decrease in the amount of metal adsorbed with increasing metal competition for the adsorption sites. Due to the competition with other metals, the equations, which offered the best fit for Zn and Cd, were quadratic polynomial models. On the other hand, for Cu and Pb, the equations, which showed the best fit were linear, Langmuir, and Temkin, for different situations. The reasons for this behavior were related to the strong competitive forces for the adsorption sites presented by these two metals.

Características químicas de solo submetido ao tratamento com esterco líquido de suínos e cultivado com gramíneas forrageiras

In this study, the effect of intensive swine liquid manure (SLM) application was evaluated through the overland flow method, on chemical characteristics of a Yellow-red Podzolic soil (Ultisol) cultivated with four forage species: Amazonian kikuyu grass (Brachiaria humidicola (Rendle) Schweick), signal grass (Brachiaria decumbens Stapf), coastcross bermudagrass (Cynodon dactylon (L.) Pers.) and Tifton 85 bermudagrass (Cynodon spp.) were evaluated. SLM was applied in plots of 4m2 and with 5% slope, during four months, at an average equivalent to 800 kg ha-1d-1 of biochemical oxygen demand (BOD5). Soil samples were collected at 0-0,20 m depth, in the beginning and at the end of the experiment. The result showed the increase of the P, K, Na and Zn concentrations while the Mg and Cu concentrations decreased and Ca continued unaltered. The acidity, sum of bases and CEC increased in the soil that received SLM, while the saturation of bases decreased. Due to the nourishiment accumulation, it is recommended to monitor the soil chemical characteristcs and underground water on the profile for evaluation of the enviromental contamination risks.

Effect of influent aeration on removal of organic matter from coffee processing wastewater in constructed wetlands

The aim of the present study was to evaluate the influence of aeration and vegetation on the removal of organic matter in coffee processing wastewater (CPW) treated in 4 constructed wetlands (CWs), characterized as follows: (i) ryegrass (Lolium multiflorum) cultivated system operating with an aerated influent; (ii) non-cultivated system operating with an aerated influent, (iii) ryegrass cultivated system operating with a non-aerated influent; and (iv) non-cultivated system operating with a non-aerated influent. The lowest average chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) removal efficiencies of 87, 84 and 73%, respectively, were obtained in the ryegrass cultivated system operating with a non-aerated influent. However, ryegrass cultivation did not influence the removal efficiency of organic matter. Artificial aeration of the CPW, prior to its injection in the CW, did not improve the removal efficiencies of organic matter. On other hand it did contribute to increase the instantaneous rate at which the maximum COD removal efficiency was reached. Although aeration did not result in greater organic matter removal efficiencies, it is important to consider the benefits of aeration on the removal of the other compounds.

Influência da aplicação de águas residuárias de suinocultura na capacidade de infiltração de um solo Podzólico Vermelho-Amarelo

This work was carried out at the Experimental Area of Hydraulics, Irrigation and Drainage of the Agricultural Engineering Department, at the Federal University of Vicosa, Vicosa, Minas Gerais, Brazil. The aim was to evaluate the influence of successive applications of swine wastewater, with different concentrations of total solids, on the infiltration capacity of a Yellow Red Podzol. The experiment was conducted in a completely randomized design with five treatments and three replications. The treatments consisted of applying water and swine wastewater with 2.4, 7.0, 16.3 and 26.9 g L-1 of total solid concentrations. Fifteen ring infiltrometers were installed in an area of 60 m2, which was divided in plots of 2 x 2 m dimensions. Four infiltration tests were performed at 15 day intervals in each plot. It was concluded that increasing the total solid concentration of swine wastewater caused a reduction of the soil infiltration capacity. In addition, it was observed that successive applications intensified this effect. The total solid concentration of wastewater was more important to reduce the soil infiltration capacity than the levels of sodium absorption ratio and salinity.

Influence of domestic and industrial waste discharges on water quality at Minas Gerais State, Brazil

The aquatic contamination from kaolin processing plants, as well as from untreated or inadequately treated municipal sewage, was evaluated in the Uba Stream and Vermelho Stream, at the Minas Gerais State, Brazil. With this purpose, samples of water, suspended material and vegetation were collected and analysed. The analyses involved the determination of the concentration of metals, nitrite, nitrate, chloride, phosphate, chemical oxygen demand and biochemical oxygen demand. The suspended material showed high concentrations (in mg kg-1) of Zn (2,400) and Fe (14,900), while the vegetation collected closed to the streams was heavily contaminated with Al (7,120). The concentrations of nitrite, nitrate and chloride in stream water were lower than the maximum values established by the Brazilian Environmental Standards. The phosphate and biochemical oxygen demand values exceeded 7 and 3 times respectively, the maximum concentrations for superficial water of satisfactory quality.

Produtividade e composição química do capim-Tifton 85 submetido a diferentes taxas de aplicação do percolado de resíduo sólido urbano

The issue of this study was to evaluate the effect of different rates of landfill leachate (LL) in productivity and chemical composition of Tifton 85 (Cynodon spp). The leachate was applied at rates of 0 (control), 250, 500, 750, 1,000 kg ha-1 d-1 of BOD5, for eight months. In the control treatment, not receiving the leachate, it was applied water from the public supply network being the water depth of application defined based on the Reference Evapotranspiration (ETo). The experiment was analyzed in a split plot, with five plots concentrations of BOD5 and the cuts the subplots in a randomized block design with four replications. The data were subjected to analysis of variance and regression. The dry matter yield, crude protein levels and concentrations of N, K, Na, Ca, Mg, Mn, Cd, Pb and Fe, in the aerial parts of the Tifton 85, increased with the application rates of the percolate. The concentration of N, P and Mn tended to decrease with the number of grass cuts; for Cd, Pb and Fe tended to stabilize after the 2nd or the 3rd cuts; and the Na increase after the 3rd cut. The K, Ca and Mg concentrations were unstable.

Plantio e desempenho fenológico da taboa (Thypha sp.) utilizada no tratamento de esgoto doméstico em sistema alagado construído

This study was carried out in under to evaluate the macrophytes (Typha sp) performance and nutrient removal by the same, cropped in four constructed wetlands (SACs), used in treating the domestic wastewater proceeding from septic tank. So, were evaluated vegetable organ and the following variables quantified in either wastewater and vegetable tissue: total nitrogen (N-total), total phosphorus (P-total), sodium (Na) and potassium (K). An average depth of 27.15cm were reached by roots, as well as a satisfactory development of Thypha sp., therefore making possible to beginning the operation of the system at four months after vegetation establishment. The system made possible the following removals of the aerial biomass: 1.69%, 1.64%, 4.94% and 0.74% from the contribution of N-total, P-total, potassium and sodium, respectively.

Remoção de sólidos em suspensão na água residuária da despolpa de frutos do cafeeiro em filtros constituídos por pergaminho de grãos de café submetido a compressões

The removal of suspended solids (SS) is fundamental to apply the wastewater from the coffee shrub cherry pulping (ARC) on agricultural crops fertigation. Among the available options for the removal of SS from ARC is the use of organic filters. This study was carried out to evaluate the influence of the compression degree on either volume reduction or parchment efficiency, when used as medium filter for the removal of suspended solids (SS) in ARC. In a first stage, some assays were conducted in which the testing sample of either triturated parchment (retained between the sieves with 2.5 and 3.0 mm) and non-triturated one (under the condition which it is produced) were submitted to different compressions to reducing the volume of the filtering columns down to 5; 10; 15; 20; 25 and 28%. At the second stage, test specimens were used as a filtering material of ARC in order to evaluate its capacity to remove SS found in this wastewater. The triturated parchment appeared to be more resistant to the compression, as well as provided higher efficiency in removing SS and ARC for the same volumetric reductions in the filtering material than the non-triturated parchment. Range reductions from 10 to 15% in the filter volume constituted by triturated parchment were enough to obtain satisfactory efficiencies in removing the SS from ARC, whereas for those filters constituted by non-triturated parchment the volume reductions should be above 25%.

Aquatic contamination of the Turvo Limpo river basin at the Minas Gerais state, Brazil

The aquatic contamination from the discharge of untreated or inadequately treated municipal sewage, as well as from husbandry, agriculture, and the disposal of municipal garbage, metallic scraps and civil architecture residues in the neighborhood of the Turvo Limpo River basin was evaluated. The water-courses examined were the Sao Bartolomeu Stream, Turvo Sujo River, and Turvo Limpo River, located in the Minas Gerais State, Brazil. Water samples were collected at the river-side in the dry season (July, August, and September 2005) and analyzed for evaluation of pollutant inputs. The pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), total phosphate, total ammonia nitrogen (NH3 + NH4+), nitrate and metal concentrations (Al, Ca, Cr, Cu, Fe, Mg, Ni, Pb, and Zn) in water samples were determined. The concentrations of these metals in the suspended solids were also determined. The suspended solids showed high concentrations of Zn (15,350 mg kg-1) and Pb (3,590 mg kg-1), while the stream water was enhanced with Al (1,480 µg L-1). The pH and the concentrations of BOD, total phosphate and total ammonia nitrogen in the water-courses were far from those established by the Brazilian Environmental Standards for Class 2 water. In all examined sites there was an increase in the nitrate concentration compared with that of a spring (site 1). The nitrate concentrations were below those of the total ammonia nitrogen, indicating that the nitrogen in the water-courses was mainly originated from recent sewage discharges, since did not occurred larger mineralization with the formation of nitrate ions.