Application of an integrated methodology for the synthesis of water networks and wastewater treatment in the pulp and paper industry / Aplicação de uma metodologia integrada para síntese de redes de água e tratamento de efluentes na indústria de papel e celulose

The increase in the costs of water and wastewater treatment makes it relevant to develop tools that allow the efficient use of water in the industry, aiming at reduce costs and respecting the disposal limits imposed by the legislation. Thus, the objective of this work is to apply an integrated methodology for the synthesis and analysis of water networks and industrial wastewaters, combining the Wastewater Sources Diagram (WWSD) method with the results of the Water Sources Diagram (WSD) to the data representative of the pulp and paper industry. A case study considering the relevant contaminants present in the wastewaters from this process was carried out. The wastewater treatment network generated with the WWSD reduced the need for wastewater treatment by 35.20%, allowing lower costs and environmental impacts. 

The Role of Coagulation-flocculation in the Pretreatment of Reverse Osmosis in Power Plant

The objective of this work is to simulate pretreatment steps on a laboratory scale with the purpose of producing a higher quality permeate for feed reverse osmosis process. Pretreatment steps involved in this work are a combination of physical and chemical processes, such as coagulation-flocculation, sand filtration, and microfiltration. Samples of seawater next to Itaqui thermoelectric power plant in Maranhão, State of Brazil, powered by coal, were collected and characterized. The characterization indicated high levels of turbidity, which is unusual for seawater, indicating the need of pretreatment to reverse osmosis. The combination of polyaluminum chloride dosages of 30 mg/L and 0.3 mg/L of Nalclear 8,173 anionic polymer allowed the reduction of turbidity values to below 1 Nephelometric Turbidity Unit (NTU). The use of coagulation and microfiltration membranes provided values of silt density index next to 3, while with sand filter, the silt density index values were higher than 4

Tratamento de águas de refrigeração com peróxido de hidrogênio

Hydrogen peroxide and chlorine are compared as possible disinfectants for water-cooling circuits. To this purpose, samples taken from the cooling system of a steel making plant were treated (at 25ºC and pH values of 5.5 and 8.5) with varying amounts of the two oxidizing agents (0.0 mg/L, 2.0 mg/L and 6.0 mg/L). The results were evaluated through bacterial counting and measurement of corrosion rates upon AISI1020 carbon steel coupons. Bacterial removal and corrosion effects proved to be similar and satisfactory for both reagents

ESTUDO DE TRATAMENTO DE EFLUENTE DE SERVIÇO DE SAÚDE PARA REDUÇÃO DE CUSTOS ECONÔMICOS E IMPACTOS AMBIENTAIS

As universidades e instituições de pesquisa geram cerca de 1% dos resíduos químicos perigosos no mundo, sendo, muitas delas, da área de saúde. Para que esses resíduos sejam tratados como efluente é necessária a adequação às legislações ambientais de disposição final de resíduos de serviço de saúde e lançamento de efluentes. O objetivo deste estudo é apresentar uma proposta de tratamento de efluente de laboratório de assistência à saúde, por meio de processos oxidativos avançados (POA). Utilizou-se efluente gerado de equipamento de análise, Labmax 240 Premium, o qual realiza testes bioquímicos e imunoquímicos de sangue e soro humano, oriundo do Laboratório de Diagnóstico, Ensino e Pesquisa do Centro de Saúde Escola Germano Sinval Faria (ENSP/Fiocruz). Para tratamento do efluente, foram comparadas as seguintes alternativas: peróxido de hidrogênio (H2O2), fotólise (UV), H2O2/UV, reagente de Fenton e foto-Fenton. Entre todos os POA estudados, o reagente de Fenton apresentou os melhores resultados nas condições de concentração molar de oxidante 3:1 (H2O2:DQO) com adição única; razão mássica de catalisador Fe2+ foi 5:1 (H2O2:Fe2+) e pH 2,0. As eficiências de remoção foram de DQO de 73,4%, de demanda bioquímica de oxigênio (DBO) de 46%, de turbidez de 90,1%, ocorrendo consumo total do oxidante (H2O2) e geração de 2.126 mg/L de lodo, de modo que o efluente final se adequou à legislação ambiental. A análise econômica verificou uma economia de 71,8% no custo total em relação à disposição praticada, incineração, o que a torna viável e indica que o método utilizado gera menores impactos ambientais globais

Synthesis and characterization of zero-valent iron nanoparticles supported on SBA-15

This paper aims to synthesize zero-valent iron nanoparticles (nZVI) supported on SBA-15 nanosilica. The nanosilica generate in the system by polymer reaction with hydrochloric acid under controlled temperature. After, the iron nanomaterial was obtained by sodium borohydride reduction as described in this work. Afterward the synthesis of the nanoparticles contained iron supported on silica SBA-15, the material was characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, zeta potential and X-ray fluorescence spectroscopy. The results indicated that nanomaterial obtained was in nanometric scale, by TEM results, and showing characteristic peaks at EDS results, with 11.9% iron and 14.0% silicon content, respectively, and containing 73.0% and 27.0% of their respective oxides through X-ray fluorescence spectroscopy. The isoelectric potential of the sample was around 2.0, close to the value reported for silica, due to the higher percentage of silica in the sample when compared to iron. The obtained material can be used, for some cases, as an possible alternative, to the Fenton reaction for the degradation of xenobiotic compounds or other applications in the groundwater and wastewater treatments

Nickel sorption using Bioclastic Granules as a sorbent material: equilibrium, kinetic and characterization studies

The present study evaluated the potential of bioclastic granules (BG) from Lithothamnium calcareum algae as a sorbent material for the removal of Ni(II) from aqueous solutions, through experimental batch tests. Relevant sorption process variables were evaluated, such as pH (2–7), particle size (<38–300 μm), initial sorbent concentration (0.5–3.0 g L−1), initial metal ion concentration (5–500 mg L−1) and contact time (5–240 min). The data set regarding the uptake of metal ions at equilibrium was well-fitted to the Langmuir isotherm model (R2 0.957), with a qmax of 54.9 mg g−1 and kL 0.014 L mg−1. The kinetic data were better fitted to the pseudo-second order kinetic model (R2 of 0.994), with qeq of 21.74 mg g−1 and k2 of 0.028 g mg−1 min−1. Characterization of BG before and after the sorption tests in the presence of Ni(II) ions was conducted by X-ray fluorescence analysis (XRF), BET surface area, X-ray diffraction (XRD), zeta potential and electron microscopy scanning (SEM-EDS). Keywords: Wastewater treatment, Sorption, Nickel, Calcareous alga