Desnitrificação em sistemas de lodo ativado.

Abstract

For sizing activated iodine system with nutrient removal, several factors must be considered when optimizing the project. A good alternative for activated iodine systems projects in tropical countries, such as Brazil, is the introduction of one or more anoxic reactors, since nitrification is an almost inevitable factor under the present temperature and oxygen availability conditions in these systems. The main process that takes place in anoxic phases is called denitrification and is able to reduce costs with up to 20% aeration, recover the alkalinity lost in nitrification and still remove the organic matter and nitrogen from the liquid phase efficiently. The objective of this study was to determine the denitrification capacity of the Bardenpho and UCT systems, to evaluate the kinetics of the denitrification process, and to verify the metabolic behavior of heterotrophic bacteria generated in activated iodine systems when submitted to aerobic and anoxic environments (via nitrate and nitrite) with soluble and particulate substrates, by comparing the rate of oxygen consumption and the rate of equivalent oxygen consumption. The denitrification via nitrate to particulate material the UCT system behaved a little better. This same trend occurred using nitrite as the final electron acceptor. The rates of nitrate-equivalent oxygen and oxygen consumption were similar (Bardenpho anoxic: 51 mg / L / h, aerobic: 51 mg / L / h) and, (University of Cape Town, anoxic: 36 mg / L / h; In order to optimize these systems, the removal of nitrogen should be a relevant factor, since it was confirmed that besides the removal of this nutrient, matter can be removed with the same efficiency as an aerobic reactor.