Estudos de caracterização, tratabilidade e condicionamento de lixiviados visando tratamento por lagoas

Abstract

The stabilized landfill leachate is characterized by high concentration of refractory organic matter, ammonium and toxic compounds. This can be an environmental problem due to its high pollutant potential. For the biological treatment it is necessary to adjust the initial conditions favorable to specific biotic grown, that is responsible for degradation of organic matter and nutrients. This can be obtained in the system start-up. The main aim of this study was to evaluate the tratability and conditioning of the stabilized landfill leachate by stabilization ponds during the start-up process and physical-chemical pre-treatment techniques. This research included the physical-chemical characterization of leachate, theproject, design and construction of stabilization ponds, the start-up evaluate and the proposal of the physical-chemical pre-treatment for the system. The evaluate of start-up was carried out in two step. In the first step, the results in bath scale showed that the start-up of the facultativeponds for treatment of recalcitrant leachate obtained greater performance when realized employing leachate diluted 10 times, with addition of 200 mg/L of sludge of the activated sludge reactor treating wastewater and with periodic loads of leachate after the formation of algae. However, theses results do not showed enough to real application, which wasconfirmed by demonstrative scale application. It is believed that theses results were due to low dissolved oxygen in the effluent. In this context, in the second step it was evaluated the introduction of forced aeration and the use of physical-chemical pre-treatment (Coagulation/Floculation, Advanced Oxidative Process, Adsorption by Activated Carbon)aiming color removal. The result showed that the aerated pond allowed the process viability, and the system presented stability next to the 56th day of the start-up, with average efficiency of soluble COD removal equal to 20% and low nutrients removal. On the physical-chemicalpre-treatments, the Advanced Oxidative Process was the most attractive. This technique allowed maximum removals of color and total COD of 90 and 80% respectively, in addition it removed mainly compounds with high molecular mass decreasing the inert COD and increasing the biodegradability of the leachate. In a nutshell the results in general formshowed that the stabilization ponds system was insufficient to the treatment of recalcitrant leachate, and the combination of physical-chemical process was adequate for the treatment of this kind of effluent.