[The characterization of biosolids produced by the San Fernando wastewater treatment plant in Itagui, Antioquia, Colombia].

ABSTRACT Objective This study was aimed at evaluating pertinent physicochemical and microbiological (bacteria and parasites) parameters regarding the biosolids produced by the San Fernando wastewater treatment plant (WWTP) in Itagui, Antioquia, Colombia. Methods Twelve samples were collected and evaluated every month from January to December during 2010. The chemical, physical and microbiological tests followed the protocol described in Colombian technical guideline 5167. The protocol described in Mexican official Norm 004 (with some modifications) was used for identifying helminth ova and assessing their viability. Results All samples proved positive for Ascarislumbricoides, viable ova count ranging from 4 to 22 eggs/2gTS. Both Salmonella and Enterobacteriawere detected in all samples evaluated, the latter having 3,000 colony forming unit (CFU)/g minimum concentration. Biosolid sample values met the heavy metal concentration requirement established by national guidelines. There was no statistical association between rainfall and the pathogen's presence in the biosolids. Conclusion Our results suggested that the biosolids being produced by the San Fernando wastewater treatment plant (WWTP) could be used as organic fertilizer; however they should be treated/sanitized to meet the stipulations in Colombian technical guideline 5167.