Avaliação da remoção de matéria orgânica carbonácea em filtros anaeróbios tratando lixiviado de resíduos sólidos urbanos

Abstract

Urban solid wastes (USW) have become one of the greatest problems of our time. The amount and variety of materials discarded, the population growth in cities and the rise of per capita generation have made their management increasingly complex. Disposal of these wastes in the environment is done in landfills. However, the use of this disposal method is attached to potential environmental impacts, a main one being leachate generation. The generation and discharge of leachate into the environment are a matter for concern because of its composition, since it contains different compounds, some of them with a high potential for pollution. It is essential to identify technological alternatives for leachate treatment units that will render compatible low costs, efficient treatment and compliance with the country's sanitary standards. This research studied anaerobic biological filters intending to obtain the efficiency of carbonaceous organic matter removal in the units. The filters installed for research operate with two main supports: recycled ground concrete and concrete block. The inflow of leachate was varied: ascending and descending flows, seeking to identify the optimal operational conditions to apply in landfills installed in Brazilian municipalities. Filters using concrete blocks as a support medium showed more biofilm formation, both in direct mass determinations, and in the analyses of proteins and microbial counts. The predominant morphologies in biofilm were bacilli, cocci, sarcines, filaments and spirilla. The efficiency of organic matter removal in the anaerobic filters operated with ascending flow of leachate was 61% and 56% for recycled ground concrete and block, respectively. The operation of filters with an ascending inflow was the best choice for all seasons of the year, when dealing with organic matter removal. The results obtained with ascending flow filters indicate greater mixture in the system, since in the descending flow there is the difficulty of homogeneous distribution of leachate, and more bottom sludge formation in the filters studied.