Lodos ativados com adição de carvão ativado no tratamento combinado de lixiviado de aterro sanitário e esgoto doméstico

Abstract

The inappropriate management of leachate can cause negative environmental impacts, in order to compromise the availability and quality of natural resources, reason of to their complex composition and high polluter potential. One of the alternatives for the treatment of landfill leachate is its combined treatment with domestic sewage in sewage treatment plants, although higher proportions of the leachate in the sewage could compromise the efficiency of the process. This study aimed to evaluate the efficiency of the combined treatment of landfill leachate and domestic sewage in biomass and activated carbon systems. For this, were used sequential batch reactors in lab-scale and two types of activated carbon - granular (GAC) and pulverized (PAC). The work consisted of two stages, among them they are: the tests where the reactors were fed with different mixtures of leachate/synthetic sewage (0, 2, 5 e 10%) and concentrations of GAC (0, 2, 4 e 6 g/L) operating with residence times 23h and sludge ages 28 days; and tests where the reactors were fed with a mixture of 5% leachate/sewage; fixed a PAC concentration of 6 g/L and were operated on with differents HRT of 23, 16 and 8 hours and sludge ages of 28, 28, and 17 days, respectively. It has been evaluated, the difference between the two types of carbon regarding COD removal efficiency, in the following configurations: fixing the concentration of carbono (6 g/L) and the percentage of leachate in the feed (5% v/v), for the batch time of 23 h and sludge age of 28 d. For the first step, it was possible to verify that the COD removal efficiency was higher in the reactors containing GAC and biomass when comparedes to the reactor containing only biomass. And along this stage of the experiment it was possible to observe that after the increase of leachate concentration in the feed there was a significant drop in COD removal efficiency. In the evaluation of the PACT® process, it was verified that the reactor with HRT of 23 h was the one that presented the best COD and color removal efficiencies the process, 79 and 44%, respectively. In the comparative tests between the two types of carbon, the PAC system proved to be much more efficient in the removal of COD, presenting an average efficiency of 79% when compared to the GAC system (63%).