Suchergebnisse

About 245 thousand tones of municipal solid waste are collected daily in Brazil. Nearly 32 thousand tones of the collected amount are treated in sanitary landfill, which generates biogas and leachate as byproduct. The leachate resulting from sanitary landfill contains high concentration of carbonaceous and nitrogenized material. The crucial question is that the biodegradation of the carbonaceous material is difficult as long as the nitrogenized material is present in the form of ammoniacal nitrogen (NH4+), which compromises performance of biological treatment process. Therefore, a physical and chemical treatment of the leachate should be done before its biological treatment, especially for reduction of ammoniacal nitrogen concentration and for propitiating the realization of application of biological treatment. The treatment of leachate requires specific consideration, which is not needed for other types of waste. In the specific case in this study, where ammoniacal nitrogen concentration was about 2,200 mgN L-1 and the BOD5/COD ratio was 0.3, the study of ammonia stripping process was performed. Ammonia stripping process was studied in packed towers of 35 L capacity each and the parameters investigated were pH, ratio of contact area/leach volume and the aeration time. One of the parameters that influenced most in efficiency of ammonia stripping process was pH of the leachate since it contributes in conversion of ammoniacal nitrogen from NH4+ to NH3.

In Brazil, the per capita generation of municipal solid waste is approximately 0.80kg.hab-1.day-1, which implies daily production of 156 tons, whereas on average 50% of this quantity of waste is composed mainly of putrescible organic material that will contribute to the leachate generation process directly influencing the qualitative and quantitative aspects. Landfill leachate basically originates from the percolation process of different types of water and is considered a wastewater to cause in significant environmental impact on the environment, given in possession of high concentration of ammonia nitrogen, organic matter difficult to biodegradation, metals heavy and xenobiotics. The objective of this study was to evaluate the performance of a series of stabilization ponds, the treatment process conjugate of landfill leachate fresh more domestic sewage in the proportion of 1 plus 99% (volume percent), respectively. The experimental system consisted of four stabilization ponds in series, being a facultative pond, followed by three maturation ponds. The applied surface charge (λs) the series of stabilization ponds was 320 kgDBO5 . ha-1.day-1 with hydraulic retention time (HRT) of 17 days for the series. The average removal efficiency of BOD5 and ammonia was 69 and 86% respectively, while removing coliform efficiency always in the 99.9% threshold during the monitoring period was 220 days. Overall it can be concluded that treatment conjugate landfill leachate and sewage in stabilization ponds, in northeastern Brazil, is emerging as a promising technological alternative, given the comfortable area availability in northeastern Brazil, conditions climate favorable and the ponds system present low ratio cost / benefit when compared to other waste treatment systems of this nature.