Task1.1. Recovery of sewage scum and monitoring of sewage scum
With the aim of evaluating the feasibility of the operations, several samples will be up-taken from differently dimensioned WWTPs, located in different parts of Italy (north, center and south). The seasonability will be also studied along the project time. One sample per season will be up-taken and characterized in these two years from Torino (SMAT), Rome (ACEA) and Bari (AQP), from three representative WWTPs. Total solids, volatile solids, ashes, lipid content and characterization (glycerides, free fatty acids and soaps), free fatty acid profile, cellulose content, metal profile, FTIR, Mineral oil (C10-C40), DEHP and NPEO will be monitored.

Task1.2. Separation of GRFSS from CRFSS
The separation of GRFSS will be performed using a well consolidated solvent-free technology based on a centrifugation of a thermochemically pretreated SS. The effect of the addition of mineral acid (HCl or H2SO4) and the operating temperature will be studied, in terms of recoverability and purity of the two main phases: GRFSS and CRFSS. Both the phases will be chemically characterized, and, for CRFSS, the biological stabilization should be checked and necessarily achieved.

Task1.3. Enzymatic hydrolysis
Wet CRFSS, as obtained from Task1.2 will be hydrolyzed using commercial cellulases, namely Trichoderma Reesei, for the obtainment of a liquid glucose broad to be used in WP2 fermentations. In fact, due to the provenience of the cellulosic stream, prevalently toilet paper, no further pretreatments should be necessary to obtain glucose. The hydrolytic step will be optimized in terms of operative temperature, CRFSS and enzymatic load. Residual solids will be recovered, analyzed, and possibly tested in anaerobic digestion to produce biomethane (Task2.3), while the liquid phase will be eventually ultra-filtered for the recovery and reuse of enzymes in new cycles of hydrolysis of fresh CRFSS. The sugar broad could be concentrated up to 20-30 g/L.