Caracterização do chorume produzido no aterro da Muribeca-PE.

Abstract

This dissertation aimed at characterising the leachate produced in a landfill known as Muribeca, which is situated in the city of Jaboatao dos Guararapes in Pernambuco. One should draw attention to the fact the leachate under study was produced in cells whose waste was filled approximately 16 years ago (CI and C2), as well as in more recent cells, which were filled about 4 years ago (C3 and C4), in two different points along the landfill (P2 and P21), where the leachate flowed, in the open air, into the Leachate Stream. The latter received the leachate and unloaded it into the Muribequinha River. Last but not least, three other points were chosen for the sake of investigation (P-C, P-D and P21), in which it was possible to find concentrated leachate, diluted leachate and the leachate that flows from the ponds which constitute the Leachate Treatment Station, respectively. With a view to carry out the present study, it was necessary to make use of data, which was collected from March 1996 to August 2002, of the following physical and chemical parameters: pH, alkalinity, total and volatile solids, BOD, QOD, clorets and heavy metal (cadmium, lead, cobalt, copper, chrome, manganese and zinc). Concerning the microbiological parameters, fecal and total coliforms were studied. In order to collect the leachate in the cells, while borings were carried out, piezometers (collection wells) were installed in different depths -Standard Penetration Test- (Cl:5, 15 and 18m; C2: 15m; C3 and C4:10m). The collection in the other points was superficial. The results were analyzed in association with pluviometric precipitation (rain fall). An afterwards, the effect of the collection depth and the age of the cell on the parameters quoted above was compared. Statistical analyses were used for the physical and chemical parameters of Muribeca Landfill cells. The correlation matrix method was elaborated to establish the level of significance between these parameters and the pluviometric precipitation (rainfall). The Kruskal-Wallis (SOKAL & Rolhf 1981) Method was used with a view to verify if the variation of the parameters was similar among different cells. The other cells (CI and C2) present lower values to the different parameters (BOD: CI between 59 and 2.673mg/l; C2 between 469 and 6.683mg/l and QDO: CI varied between 679 and 12.071mg/l and C2 between 3975 and 16.50mg/l). Concerning the newer cells (C3 and C4) the values were: (BOD :C3 between 147 and 4.552 e C4 between 2.680 and 18.850mg/l; QDO: C3 between 6.694 and 16.100mg/l and C4 between 6250and 37.900mg/l. The reason for this variation lies in the fact that the first ones were in an advanced process of organic-matter degradation, since several parameters of quality (pH, BOD, QOD, among others) are influenced by the age of the filled waste. Generally speaking, as the process of decomposition advances, the pH rises up to the average of 8,0 and both BOD and QOD decrease, presenting a BOD quotient of about 0,2 for the more stabilized matter. Fluctuation of these values was also observed. The points P2 and P21 presented lower values of BOD (P2 between 134 and 3.316 mg/1 and P21 between 22 and 1.295 mg/1) and QOD (P2 between 1.236 and 5.959mg/l and P21 between 170 and 5.985). This variation must have been due to the dilution caused by the rain. The pints P-C, P-D and P-A showed higher values than in P- 2 and P-21, when it comes to pH, Clorets, cadmium, cobalt, copper, chrome and zinc. On the other hand, these values were lower than in the piezometers. As the samples were collected in the pen air, leachate was found more diluted than in the cells, but in a less advanced stage of dilution than in the Leachate Stream. The Kruskal- Wallis Test revealed that cells with the same age and collection depth presented similar behavior to the parameters analyzed, whereas the group of cells with different ages and collection depths did not. In the correlation matrix, it was observed that the greater the number of collection wells studied, the higher the number of significant correlations. Knowledge of the composition of the landfill leachate is very important if one wishes to know the degree of contamination and to predict the impact this may have on the environment. Furthermore, this knowledge is essential when it comes to choosing the best form of treatment.