RESOURCE RECOVERY FROM WASTEWATER WITH A THERMOPHILIC TECHNOLOGY FOR SEWAGE SLUDGE REDUCTION

Today, 1.7 Earths would be needed to satisfy humanity's demand for resources and ecological services in just one year. Minimizing the exploitation of feedstocks and developing a functional recovery of resources in every field, reducing the accumulation of waste, become indispensable. Wastewater treatment plants (WWTPs) are often negatively known to produce biological sewage sludge, a waste whose final fate is increasingly technically and socially debated. This work proposes a technology for the reduction of biological sewage sludge production, a thermophilic aerobic/anaerobic membrane biological reactor (TAMR). The aim can be achieved by (i) prevention in the water line, treating industrial wastewater or aqueous waste with low production of thermophilic sludge; (ii) minimization in the sludge line, directly treating the biological sludge (thickened only or thickened and digested) already produced by WWTPs. Regardless of the approach, TAMR presents two types of residues: an aqueous permeate rich in carbon and nitrogen, and a surplus thermophilic biological sludge in smaller quantities. In this work, after (i) the analysis of high performances on various polluting parameters (COD, surfactants, etc.), and (ii) the process optimization through statistical data processing and study on thermophilic sludge rheology; examples of reuse of TAMR residues have been reported. After the recovery of the nitrogen by stripping, the permeate can be used as an external carbon source in denitrification; while the thermophilic sludge meets the quality requirements for recovery in agriculture. Furthermore, thermal energy production was investigated for future energy recovery at the WWTPs.