Solar Drying to Reduce Pathogens In Biosolids In Arid Regions

Abstract

Utilization of landfilling and ocean dumping for biosolids disposal is declining due to environmental and monetary concerns. Biosolids are suitable for use as a soil amendment for various crops and native vegetation. Therefore, it may be beneficial to integrate soil into cultivated soil or mine tailings. However, biosolids from wastewater treatment plants inherently contain elevated numbers of pathogenic microorganisms. Therefore, the efficacy of cost-effective methods to reduce pathogens to accepted levels was evaluated in solar drying beds in La Paz County, Arizona. The research demonstrated that biosolids could be effectively treated during warm, dry periods, as biosolids were converted from Class B to Class A microbial quality within two weeks during the summer of 2004. However, alternatives must be utilized for rainy, cold seasons. Also, public opinion and outreach cannot be ignored as important factors to consider in the future of biosolids treatment and reuse.