BACTERIOLOGICAL EVALUATION IN EXPERIMENTAL LANDFILL CELLS: THE CO-DISPOSAL OF HOUSEHOLD SOLID WASTE AND HEALTHCARE SOLID WASTE

This work aimed to study the effects of co-disposal of household solid waste (HHSW) and healthcare solid waste (HCW) on the microbiota of the leachate generated in experimental landfill cells. To this end, three waste containment units were built, differentiated by the percentage of HHSW and HCW: HHSW cell (100% household solid waste), HCW cell (100% healthcare solid waste) and COD cell (cell simulating co-disposal containing 98% HHSW and 2% HCW). Volume, temperature, pH and evaluation of the leachate's microbiota from the cells were monitored over 810 days of confinement. Culture-dependent methods (quantitative analysis of environmental contamination indicators and investigation in enterobacteria and Staphylococcus aureus), antimicrobial susceptibility patterns, and inhibitory activity were evaluated for microbiota monitoring. The microbiological characterization of the leachates from the cells showed no statistically significant differences in total coliforms, Escherichia coli, enterococci and Pseudomonas aeruginosa densities during the period evaluated. Enterobacteria of medical importance were identified in the leachates from the three cells: E. coli, Klebsiella pneumoniaea, Enterobacter sp and Proteus mirabilis. After 810 days of confinement, the leachates showed no antimicrobial activity against S. aureus, P. aeruginosa and Salmonella enterica serovar Choleraesuis. Statistical analysis of antimicrobial resistance patterns revealed significant similarities among the three cells. The results suggest no significant differences in the behavior of experimental landfills containing HHSW and HCW concerning the presence of pathogenic microbiota.