Avaliação da eficiência do tratamento combinado de lixiviado com esgoto doméstico em estação de tratamento de esgoto.

Abstract

The leachate of municipal solid wastes landfills have a pollution potential that requires attention from public authorities, from universities, and private sector. Researches to leachate treatment considering its volume variation and organic charge has been developing in many places. Besides the efectiveness the researches have to conidered economic aspects. The combined biological treatment of leachate in sewage treatment plants seems to be a viable alternative. This work evaluated the combined treatment of leachate and sewage in a pilot scale plant of activated sludge, installed in the sewage treatment plant of Icaraí/Niterói (RJ). The study was developed with percentages of leachate from 0,5 to 2,5% in relation of sewage (volume/volume). In terms of COD load, the percentages were of 1,9 to 8,7% of load equivalent to added leachate. In the pilot scale the results showed an average COD reduction of 73%, with some results above 90%. Average values of remaining COD in the effluent of the pilot scalet varied from 43 to 134 mg/L. As regards the average removals of ammonia nitrogen, values from 80 to 97%. The reduction of organic matter in terms of DOC was 73%. Aerobic bench scale reactors were also run in order to evaluate possible interference in the development of biological sludge. Batch and continuous reactors were operated. The reactors did not indicate damage to biological sludge due to the adding of leachate in percentages of 0,5 to 2,5%. COD reductions above 80% were observed. The removals of ammonia nitrogen were higher in batch reactor (>80%). The obtained results demonstrate the technical feasibility of combined treatment and did not indicate negative interference for COD reduction, with the leachate rate utilized. Throughout the operation period of the pilot plant problems with sludge sedimentation were observed, but it seems interfere very few in the treatment performance.