Potencial de contaminação do solo após processo de compostagem em pátio não impermeabilizado

Abstract

The aim of this study was to analyze soil leaching at 0,2 and 0,5 meters deep through inspection of chemical elements (nitrate, sodium, potassium, and phosphor) contained in the slurry found in composting piles of food waste from university restaurants. The research was conducted at the Federal University of Lavras. The composting piles were built based on the carbon to nitrogen (C:N) ratio of each material to be composted. These materials constituted of food scraps from the university restaurant at the Federal University of Lavras, sludge from a sewage treatment plant, wood shavings/sawdust and guinea grass (Panicum maximum Jacq cv Colonião). Four treatments were evaluated as described: T1 (guinea grass, food waste from the university restaurant and water); T2 (guinea grass, food waste from the university restaurant, sludge and water); T3 (wood shavings/sawdust, food waste from the university restaurant and water) and T4 (wood shavings/ sawdust, waste from the university restaurant, sludge and water). After 120 days, sodium concentration increased in T1, T2, T3 and T4 due to the presence of food waste from the university restaurant in all treatments. The potassium concentration was higher in T1 and T2 at 0.20 m, due to the presence of grass. There was no increase in nitrate at 0.2 m, after 120 days. However, this mineral had high concentrations at 0.5 m in T2 and T4 because of the presence of sludge in the treatment composition. Thus, waterproofing the soil becomes necessary to avoid contamination of the water table because of nitrate leaching in low layers.