Lodo gerado na estação de tratamento de água Tamanduá, Foz do Iguaçu, PR, como aditivo em argilas para cerâmica vermelha: Parte II: incorporação do lodo em mistura de argilas para produção de cerâmica vermelha Sludge generated in the water treatment plant Tamanduá, Foz do Iguaçu, PR, as an additive in clay for red ceramic: Part II: incorporation of sludge mixed with clay to produce red ceramic

A pesquisa contempla nesta segunda etapa, misturas binárias entre as argilas da Cerâmica Santa Rita e da Cooperativa de Artesões de Foz do Iguaçu, PR, em diferentes porcentagens peso, para confecção de corpos de prova por prensagem uniaxial, sinterizados nas temperaturas de 950 e 1050 ºC, e analisados pelos ensaios tecnológicos de cerâmica vermelha. Nas composições entre as argilas que apresentaram melhores desempenhos no processamento, incorporaram-se proporções de 4, 8, 12 e 16% de lodo visando agregar o resíduo a massa. Identificou-se nos resultados da produção de blocos estruturais de 6 furos pelo processo de extrusão que, 8% é o máximo de lodo a ser adicionado na massa cerâmica, onde não foi identificado trincas e deformações, com contração linear na ordem de 8,6%, absorção de água de 24,6% e resistência à compressão de 42,6 kgf/cm², em conformidade com as normas para produção de cerâmica vermelha para revestimento (tijolos).<br>The research addresses this second stage, binary mixtures of clays Ceramic Santa Rita and the Cooperative of Artisans from Foz do Iguaçu, PR, in different weight percentages, for making specimens by uniaxial pressing, sintered at temperatures of 950 and 1050 ºC, and analyzed by technological tests of red ceramic. In compositions among the clays that were better at processing, proportions of 4, 8, 12 and 16% of the waste sludge were added in order to add mass. It was identified in the results of the production of building blocks 6-hole extrusion process by which 8% is the maximum of sludge to be added to the ceramic body, which was not identified cracks and deformations with linear shrinkage in the order of 8.6% water absorption of 24.6% and compressive strength of 42.6 kgf/cm² in accordance with the standards for the production of red ceramic coating (bricks)

Assessment of a multistage system based on electrocoagulation, solar photo-Fenton and biological oxidation processes for real textile wastewater treatment

The performance of a multistage treatment system for textile wastewater was investigated in this study. The processes of electrocoagulation (EC), photo-Fenton oxidation, and activated sludge biological degradation were integrated in batch mode. The integrated treatment system performance was assessed according to three response variables: dissolved organic carbon (DOC), chemical oxygen demand (COD) and biodegradability index. Based on preliminary tests, the EC-based wastewater treatment was suitable as the first stage of the integrated treatment system, followed by the photo-Fenton process. A lab photo-reactor was used to assess the influence of photo-Fenton variables on the process performance. Based on the better lab photo-Fenton reactor conditions, the improvement of some biological indicators related to the organics biodegradability of treated wastewater was investigated in a pilot-scale photoreactor. An activated sludge-based biological reactor at lab-scale was used as a final treatment stage, in order to achieve the legislated limits for discharge into water bodies. Partial degradation of the organic pollutants was achieved by the EC process, with a 36% reduction in COD. In the second treatment stage, a 70% biodegradability index was attained by setting the photo-Fenton reaction conditions at 100 mg Fe2+ L-1, pH 2.8, 12 mM H2O2 and 6.9 kJ L-1 accumulated energy. Finally, a residual COD of 139 mg O-2 L-1 was achieved at the outlet of the biological process, which is below the maximum limit established by the Portuguese legislation

Insights into solar photo-Fenton process using iron(III)-organic ligand complexes applied to real textile wastewater treatment

The treatment of a real textile wastewater was accomplished using a conventional photo-Fenton reaction and mediated by different ferric-organic ligand complexes, performed in lab and pilot scale photoreactors irradiated by simulated and natural solar radiation, respectively. The textile wastewater presents a dark-blue colour, alkaline pH, a high organic content (COD = 1239 mg O-2 L-1; DOC = 408 mg C L-1) and moderate biodegradability (BOD5/COD = 0.16). The conventional solar-photo-Fenton reaction showed limited efficiency in the mineralization of the textile wastewater, which is characterized by a fast initial dissolved organic carbon decay in the absence of light, mainly attributed to the formation of ironorganic pollutants complexes with a low solubility at acidic pH values, leading to iron precipitation, followed by a very slow reaction rate under UV-visible light associated to (i) low amounts of dissolved iron and (ii) low photoactivity of the iron precipitates. The addition of the organic ligands, such as oxalic acid, citric acid and EDDS, enhanced significantly the photo-Fenton reaction, avoiding the formation of ironorganic pollutants complexes, and consequently increase of the quantum yield for ferrous ions production through the photodecarboxylation of ferric-organic ligands complexes. The catalytic activity of the iron-organic ligand complexes increased in the following order: Fe(III)-EDDS < Fe(III)-citrate < Fe(III)-oxalate. All the tested processes mediated by ferric-organic ligands complexes contributed to an effective decolourization and mineralization, but the most efficient system was the photo-Fenton-ferrioxalate reaction with an optimum catalyst concentration of 100 mg Fe3+ L-1, pH 2.8, temperature of 30 degrees C leading to complete decolourization and 69.1% mineralization after less than 8.8 kJuv L-1. An enhancement of the wastewater biodegradability was observed during the photo-Fenton-ferrioxalate reaction

Performance evaluation of different solar advanced oxidation processes applied to the treatment of a real textile dyeing wastewater

The performance of different solar-driven advanced oxidation processes (AOPs), such as TiO2/UV, TiO2/H2O2/UV, and Fe2+/H2O2/UV-visible in the treatment of a real textile effluent using a pilot plant with compound parabolic collectors (CPCs), was investigated. The influence of the main photo-Fenton reaction variables such as iron concentration (20-100 mg Fe2+ L-1), pH (2.4-4.5), temperature (10-50 °C), and irradiance (22-68 WUV m-2) was evaluated in a lab-scale prototype using artificial solar radiation. The real textile wastewater presented a beige color, with a maximum absorbance peak at 641 nm, alkaline pH (8.1), moderate organic content (dissolved organic carbon (DOC) = 129 mg C L-1 and chemical oxygen demand (COD) = 496 mg O2 L-1), and high conductivity mainly associated to the high concentration of chloride (1.1 g Cl- L-1), sulfate (0.4 g SO 4 2 - L- 1), and sodium (1.2 g Na+ L-1) ions. Although all the processes tested contributed to complete decolorization and effective mineralization, the most efficient process was the solar photo-Fenton with an optimum catalyst concentration of 60 mg Fe2+ L-1, leading to 70 % mineralization (DOCfinal = 41 mg C L-1; CODfinal < 150 mg O2 L-1) at pH 3.6, requiring a UV energy dose of 3.5 kJUV L-1 (t30 W = 22.4 min; (Formula presented.); (Formula presented.)) and consuming 18.5 mM of H2O2. (c) 2014 Springer-Verlag Berlin Heidelberg