Avaliação da eficiência de wetland construído como unidade de polimento de efluente de tratamento secundário de lixiviado por lodos ativados

Abstract

One of the challenges in the implementation of landfills is to treat the leachate generated adequately and release it into the environment within the standards established by law. The pollution potential of the leachate is connected mainly to the high organic load values which leads to reduction the available oxygen (used in the degradation of organic matter) into waterways, damaging the fauna and flora in the media. The objective of this study was to evaluate the constructed wetland as a polishing treatment system for a secondary effluent of a leachate treatment plant of municipal solid waste landfill in the metropolitan area of Rio de Janeiro. Above the specific and non-specific collective parameters also were performed a fractionation membrane separation process and testing toxicity. The results show that the wetland has a positive action as polishing unit reflected in the reduction of turbidity parameters (84%), COD (19%), ammonia (30%) and total solids (3%), reducing the environmental impacts of the leachate. However, the quality of the final effluent is in above the benchmarks of environmental control and shows the need for a secondary effluent of better quality. The results also showed that high inert COD values of both the influent (average of 85%) and in the effluent (average of 93,5%) of wetland indicate that these leachates are refractory nature confirmed by low biodegradability values in the influent (average of 20,5%) and effluent (average of 5%) of wetland. The fractionation membranes showed that the influent and effluent wetland have larger contributions molecules in the fraction> 10 kDa. The toxicity tests with Aliivibrio fischeri showed that the influent and effluent of the wetland have acute toxicity, which were lower in the range with smaller molecules.