Chemical Characterization of Biosolids from Three Spanish WWTPs: Transfer of Organics and Metallic Pollution from Urban Wastewater to Biosolids.

The article investigates the production of biosolids in three Spanish wastewater treatment plants. Biosolids produced from the treatment of urban wastewater in Spain are usually intended for agricultural use. The quality of the generated biosolids was independent of both the amount of treated water and the treatment process applied. The reliable production of biosolids depends on the quantity of the suspended solids and the organic load influent to the treatment systems. The generated biosolids had the ability to concentrate the organic matter and metals from the wastewater up to 417 and 869 times.