This study investigated the adsorption of leachate on filter paper with adsorbent poder (coal of açaí and red mud) and the adsorption of leachate previously filtered and then adsorbed on adsorption column with granular fixed bed (coal of açaí). The charcoal used is of vegetal origin generated by a thermo-catalytic cracking process of açaí stone (Euterpe Olerácea), impregnated with sodium hydroxide 2 mol.L-1 (NaOH). The açaí cores were collected from commercial establishments located in the Guamá neighborhood in the municipality of Belém-PA. The leachate was collected at the Central of Processing and Treatment of Urban Waste - CPTR in periods considering the seasonality of the region. It was obtained that for the physical-chemical characterization of the crude leachate the seasonality interferes in the concentrations of the leachate. The mean values of the BOD5/COD ratio indicate that the leachate has recalcitrant elements and low biodegradability characteristics. With the use of the red mud in the preliminary adsorption tests it was concluded that it is an environmental liability to be considered for treatment of leachate by adsorption, since it reduced the total solids concentration. In the preliminary adsorption tests carried out in a series batch and in the column adsorption tests also in the series the acaí coal leaching occurred in the effluent to be adsorbed, thus increasing the concentration of total solids in the final effluent. After adsorption tests in the adsorption column, pH, alkalinity and total solids values increased, however, COD and chloride concentrations decreased. The control chart graphs, for the variation of the COD concentration over time, showed that the adsorption processes were kept under the control according to the method. The mass adsorption of 1000 g of filtered leachate presented the best percentage of removal efficiency for COD, with 75%. The adsorption isotherm model that was best fitted to the experimental data after linearization was the Freundlich model, with R2 of 0.9985. However, by this model the adsorption isotherm was considered as unfavorable, that is, at high solute concentrations the coal does not perform favorable adsorption. The results obtained denote the technical viability of leachate treatment by the use of açaí coal impregnated with 2 mol.L-1 NaOH and crude red mud.
|
