Efficiency Physics and Chemistry in Different Sewage Treatment Systems in Environmental Contaminants Removal

The objective of this research was to evaluate the characteristics of two conventional treatment systems of sewage sludge production to estimate contamination removal efficiency and compare it with the Brazilian legislation. For that purpose, physicochemical parameters such as pH, phosphorus, potassium, metal ions, total solids, total fixed solids, total volatile solids, moisture, organic matter, and total organic carbon were determined. The results in relation to the sludge presented a pH close to neutral, and the concentration of phosphorus, potassium, and organic matter in the sludge of the system operated with an anaerobic sludge mantle reactor (RALF) was superior to that of the system operated with stabilization ponds (SPs). The concentrations of the metal ions in the RALF sludge were higher than those of the sludge in the drying bed; in the SPs these concentrations decreased during the treatment process. When comparing the wastewater treatment plants (WWTPs), the concentrations of the metal ions were higher in the RALF sludge, except Mn and Ni, and the Fe concentration was similar in both systems.