Felipe Corrêa Veloso dos Santos

Freshwater parameters in the state of Rio Grande do Sul, southern Brazil, and their influence on fish distribution and aquaculture

Este estudo analisou a relacao entre varios parâmetros de qualidade da agua (pH, dureza, alcalinidade, turbidez, ferro e manganes durante 16 anos) com a distribuicao de peixes e piscicultura no estado do Rio Grande do Sul, Brasil. O pH ficou em media em uma faixa neutra (6,5-7,5), mas valores maximos e minimos atingiram niveis nao apropriados para a piscicultura em algumas cidades. Os valores de alcalinidade foram baixos (exceto na regiao sudoeste do estado), o que poderia contribuir para oscilacoes no pH. Dureza, turbidez, ferro (exceto na regiao proxima a cidade de Cacapava do Sul) e manganes ficaram dentro de niveis aceitaveis para a piscicultura, mas a turbidez ocasionalmente elevou-se a niveis fora dessa faixa aceitavel e os piscicultores devem ter algum mecanismo para reduzi-los. Em conclusao, de forma geral a qualidade da agua do Rio Grande do Sul pode ser considerada adequada para a aquicultura, mas os piscicultores devem conhecer metodos para corrigir a turbidez, como a utilizacao de sulfato de calcio.

Mechanical Viability of Replacement of Sand by Ground Glass in Concrete

The objective of this work was to evaluate the mechanical feasibility and applicability of the replacement of sand by ground glass in the manufacture of concrete. For this, the characterization of the materials that compose the concrete was performed, as well as the glass reused from bottles longnecks, which was the material adopted in this research as a sustainable alternative. After the characterization of the materials according to the applicable national standards, concrete samples were run with different percentages of sand replacement by glass (5%, 10% and 50%) and a concrete without glass as a reference sample. For each concrete, specimens were molded, which passed through the curing process and were tested at compression rupture at the ages of 7 and 28 days. With the results obtained by the rupture of the test specimens, statistical analyzes were carried out to deterRecebido em 26/09/2016 Aceito em 02/05/2017 RECEN 19(1) p.46-55 jan/jun 2017 DOI:10.5935/RECEN.2017.01.04 UCKER, F. E. e SANTOS, F. C. V. mine the differences between the means, and the Tukey test was applied at the 5% level of significance. Thus, it was possible to observe that the partial substitution of sand by glass in the concrete is mechanically viable, since it produces similar and even superior results regarding the compressive strength, considering that it is an easily obtainable, non-returnable material, requiring disposal Adequate, in addition to the increasing need for improvement in the sustainable techniques of concrete production in civil construction.

AVALIAÇÃO DOS SISTEMAS DE REUTILIZAÇÃO DA ÁGUA DE LAVAGEM DOS FILTROS DE UMA ESTAÇÃO DE TRATAMENTO DE ÁGUA: ESTUDO DE CASO

This article presents a study of technical and economic feasibility of recirculation of washing water filters Water Treatment Plant City Goianesia -GO. Through laboratory tests the raw water and filtered water washing water after use in the filter was determined that the wash water could be used for recirculation in the system, it is necessary to make one settling tank, which was calculated so that the total volume would supply flushing of all the filters for one day and one lift was designed to pump water to enter the system. After technical analysis confirm that there is feasibility for the deployment of the system was made an economic analysis if the investment to be made for the implementation of the system would be economically feasible and what would be the period when there is water utility (SANEAGO) could profit in deployment. After the economic evaluation of the best alternative is concluded that ETA for the relevant recirculating water from the washing of filters is both economically and technically feasible. The return on investment with the implementation of this system will be 14 years and 9 months for the worst case scenario analysis (based financing from BNDES to 13.5 % and considering only the savings of pumps.

APROVEITAMENTO DO LODO GERADO EM SISTEMA DE DECANTAÇÃO PARA O TRAÇO DE CONCRETO NÃO ESTRUTURAL

In order to destination for the sludge generated from washing concrete mixers trucks for concrete producers, we evaluated its use in place of part of the fine and coarse sand in the trace of conventional concrete. For this, two types of sludge, type 01 experiments 5 and 10% substitution of sand by the mud were used, and the type sludge 02 substiuida with sand in proportions of 5, 10, 25 and 50% by sludge rotated at each stroke. It then emerged the compressive strength of the specimens of each trait. The trace obtained witness resistance at 28 days of 19.70 MPa. Also at 28 days to 01 Lodo, the heaters were 5% to 17.80 MPa and 16.40 MPa for 10% replacement. For Sludge 02, the resistances at 28 days were 21.65 MPa for 5%, 10% to 23.03 MPa, 19.23 MPa for 25% and 50% to 18.18 MPa.