Desempenho do Reator Anaeróbio Horizontal com Chicanas no tratamento da manipueira em fases separadas e estabilização do pH com conchas de sururu

Abstract

The industrial processing of cassava generates various solid waste and wastewater whose impact on the environment can be quite significant if no appropriate treatment. The manipueira is a wastewater generated during the pressing of cassava for production of flour or washing of cassava for starch extraction and purification. It hás high concentration of organic matter, around 70g.L-1, and toxic effect due to the presence of cyanide that can reach 400mg.L-1. Therefore, it is the residue of greater impact to the biota. An efficient alternative for the treatment of this waste is anaerobic digestion. The anaerobic treatment, although it needs mechanisms to stabilize the pH because the rapid acidification of manipueira, has been occupying space in the industrial plants backed by research that confirms its potential to reduce COD and cyanide and for optimization of the conversion of organic matter to biogas (carbon dioxide, CO2, and methane, CH4). This predominance has been possible due to the development of new configurations of systems where the central units are anaerobic reactors. The reactors are cheap, more compact, more efficient and promote the production and use of biogas which can be introduced in the production process to supply the industrial energy demand. This work investigates the use of Anaerobic Horizontal Reactors with Chicane (RAHC) at bench scale for the treatment of manipueira with pH stabilized by shells of sururu. The RAHC was designed from changes in the Anaerobic Horizontal Reactor of Fixed Bed (RAHLF), a tubular highrate reactor that allows the retention of a large immobilized mass of microorganisms attached in a fixed support. The system used was composed of two reactors in series to promote the separation of phases. The substrate used in the work was produced from samples collected at home flour installed in Microregion Producer of Arapiraca, Alagoas, Brazil. Were developed activities for characterization of effluents and system monitoring during 288 days through physical-chemical laboratory analysis. The performance was evaluated through periodic analysis of COD, volatile acids, total alkalinity, pH, solids, total nitrogen and phosphorus to manipueira diluted to 5%, 10% and 20%. The stabilization of pH was conducted by formation of a fixed bed with shells of sururu in the acidogenic reactor. The shells of sururu were adequate to the pH control. The results confirmed the adequacy of RAHC to the manipueira treatment. The system with 5% and 10% of manipueira obtained maximum COD reduction of 95%. With the system operating at 20% of manipueira, was overload indicated by a significant drop in efficiency and destabilization of the pH. The results lead to a promising alternative for the manipueira anaerobic treatment with control of pH by use of the shells of sururu.