Preliminary assessment of storage and conservation time of liquid waste from biogas plants for subsequent application to crops

Abstract

Biogas effluent is an organic product obtained from the anaerobic biodigestion of organic substrates under controlled humidity, pH and temperature conditions. In Cuba, this process is generally carried out using the ecological treatment of solid organic waste from collection centers and swine excreta, in order to obtain electricity and apply its benefits in agricultural practices. Taking into consideration the large amount of liquid effluents generated as a residual product of the swine biogas plants, they were stored for a period of 12 months at room temperature in 3 and 5 liter plastic bottles to determine the stability of the nutrients. The preserved samples of the liquid effluent were evaluated every 3 months with a portable multiparametric equipment model KPSD8, determining temperature (^oC), Electrical Conductivity (EC) (mg/cm), salinity (g/l), Total Soluble Salts (SST) (g/l), density (g/l), pH, oxygen (mg/l), oxygen saturation (%). The physicochemical parameters studied behaved in a stable manner; however, after the sixth month these parameters began to vary slightly, which may be related to the aging of the sample. This result may indicate the possibility of storing this product for at least 6 months without losing its characteristics; however, it is recommended to continue these studies to determine the stability of macro and micronutrients