Análise comparativa do lixiviado bruto gerado em um aterro sanitário e o acumulado em uma lagoa de tratamento por evaporação natural.

Abstract

Solid waste, when grounded, goes through biodegradation processes that generate byproducts that cause damage to the environment and the health of the population. Among these by-products is leachate, a highly polluting liquid with a diverse composition including inorganic salts, heavy metals and high concentrations of total ammonia nitrogen, biodegradable and refractory organic matter, and xenobiotic organic compounds. Therefore, in order to prevent environmental degradation, leachate must be collected and properly treated before being released into the environment. One of the main challenges in leachate treatment is the variability of the composition of this effluent, requiring in some cases the association of two or more treatment techniques. The case study was carried out at the Sanitary Landfill in Campina Grande-PB (ASCG), which adopts as a treatment for the generated leachate, an accumulation lagoon, natural evaporation and effluent recirculation to the Landfill cells. Thus, this study aims to compare the raw leachate, the generated in ASCG and the accumulated in a treatment lagoon for natural evaporation. For this purpose, the pH, Total Ammonia Nitrogen (TAN), Total Alkalinity (TA), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), heavy metals and phytotoxicity contents of the crude leachate collected in the pipeline's Entrance of Lagoon and leachate collected inside the Naturally Evaporating Lagoon. Thus, it was found that the pH, iron, lead and zinc of Lagoon leachate were in accordance with the legislation that establishes standards for the discharge of effluents. The only indicator that showed a reduction behavior of its concentrations was TAN, however, according to the temperature and pH of the leachate, the presence of free ammonia, which is toxic, was verified. Even with the reduction of TAN concentrations, there was an increase in the phytotoxicity of the leachate in Lagoon, when compared to the raw leachate, which indicates that, despite reducing TAN concentrations, the natural evaporation technique does not reduce the effluent phytotoxicity because this technique is not efficient in reducing heavy metal concentrations. In the current ASCG project, it isn't foreseen the release of the effluent generated in receiving bodies, however, it’s important to emphasize that for this release to occur, the implementation of a more efficient treatment technique is necessary.