Avaliação da técnica de evaporação para concentração de nutrientes na mistura de urina e cinza de madeira

Abstract

Human urine has great nutritional value, but in its constitution 96% is water, and in the other 4% are the nutrients. Such composition hinders the logistics of storage and transportation. Nitrogen is the most representative nutrient in the urine, being present in the form of urea, which after excretion goes through the degradation process triggered by the enzyme urease and results in the volatilization of the ammoniacal nitrogen. Thus the objective of this work is to evaluate the concentration of urine nutrients associated to wood ash from the reduction of moisture by the evaporation process. The concentration of nutrients was promoted by evaporation in a greenhouse using three drying temperatures, 50, 60 and 70oC, and to inhibit urease, four treatments T1 (5g of ash + 40 mL of urine), T2 (10g of ash + 40 ml of urine), T3 (15 g of ash + 40 ml of urine) and T4 (20 g of ash + 40 ml of urine). The results show a reduction of more than 90% of the initial volume of urine, maintaining up to 97.44% of the total nitrogen at a temperature of 50oC. On the other hand, in the temperature of 70oC, the preservation of the total nitrogen ranged from 3.2 to 7.9%. The concentration of nutrients in human urine associated with wood ash through the evaporation process represents an alternative to be considered to contribute to the insertion of urine into the fertilizer market.