Treatment of agar waste expired by composting process

Abstract

Waste generated in the laboratories of higher education institutions (HEIs) is often considered hazardous due to its physicochemical characteristics, as well as other materials that represent a high organic load if inadequately disposed. The objective of this work, was to treat residual agar generated in the microbiology laboratories of the multifunctional building of the Academic Division of Biological Sciences (DACBiol), through traditional composting. To know the viability of the composting process, was worked with two compost piles made of 95.95 kg sludge and 141.5 kg plant residues (a total of 237.45 kg), to one of them (stack 1), 25 kg of waste agar was added. Physicochemical and analytical parameters were monitored for 63 days. A maximum temperature of 57.71±5.07 °C was obtained, in the agar cell and in the second cell of 50.23±4.30 °C. The initial pH values were 5.93±0.02 and 7.02±0.01, stabilizing at the end with values of 8.00 ± 0.07 and 7.95±0.11. The electrical conductivity presented final values of 6.87±0.46 dS m-1 and 3.02±0.09 dS m-1. Composting is an optional technology for the treatment of residual agar since the values of pH and temperature were not affected during the process, only a increase of electrical conductivity is presented. In addition, DACBiol, for having a certification in environmental quality and have a program of waste management of laboratories, must meet the objective of minimizing the generation of waste.