Influência das condições de aplicação do carvão ativado pulverizado na eficiência de remoção de matéria orgânica no tratamento de água em ciclo completo

Abstract

Currently, there is a significant concentration of organic materials in watercourses and / or water reservoirs that receive domestic hazards and non-permitted industrial effluents, which suffer prolonged drought damage and what are the natural conditions caused by natural chemicals. The consequences can be the eutrophication of water bodies, with the occurrence of blooms, which lead to problems such as taste and odor, increased formation of unwanted decoration by-products, interferences in the water treatment process, increased consumption of chemicals, in addition to corrosion of the supply system units. Most water treatment systems, including those with full cycle technology, without removing organic materials. One of the alternatives used in ETAs to remove organic material is adsorption on pulverized activated carbon (CAP), a practice that is easy to install in existing ETAs. The implantation of an adsorption unit prior to the rapid mixing and the use or not of the pre-oxidation, should be studied before the installation of adsorption processes in WTPs, since longer contact times and pre-oxidation conditions, can enhance the adsorption with reduction in both coal consumption and sludge generation, in addition to ensuring greater operational safety of the system by removing organics compounds and providing quality treated water. In this context, the present work aimed to investigate the influence of the contact time, dosage and type of pulverized activated carbon on the efficiency of the adsorption of organic matter in raw water submitted to the water treatment process in full cycle under conditions with and without the pre-oxidation of water. The evaluation was carried out using 5 types of CAPs of mineral, vegetable and animal origin. CAPs of plant origin had an influence on contact time and dosage in the removal of organic matter, measured in total organic carbon, that is, greater dosage and contact times brought better results. Dosages of 30 mg/L and contact time of 25 minutes obtained the best results, reaching removal efficiencies in the order of 90% and TOC concentration below 3,0 mg/L. Pre-oxidation with chlorine did not prove to be advantageous in removing organic matter, and it was evident that the guarantee of the best cost-benefit in removing organic matter with the use of activated carbon and pre-oxidation with chlorine, requires testing preliminary.