This study explored the interactions between alkaline hydrothermal pretreatment (AHPT) operational conditions temperature (°C), NaOH concentration (M) and residence time (min) on the compositional characteristics of the solid (SH) and liquid hydrolysate (LH) obtained from AHPT of sugarcane bagasse (SCB), empty fruit bunch (EFB) and agave bagasse (AB). The experimental design was carried out with a three factors five levels (−훼, −1, 0, 1, and +훼) central composite rotatable design. Response variables for the liquid hydrolysate included glucose, xylose and arabinose content. Whereas the effects on the solid hydrolysate were evaluated with delignification and solids recovery (%). Biogas production and in situ biogas upgrading by co digestion of SH and NaOH rich LH was evaluated against mono digestion of raw and treated fibers. Therefore, methane production and methane content in the biogas were also considered response variables. Compositional characteristics were fiber dependent. Glucose, xylose and arabinose were found in SCB and AB LHs whereas for EFB LH cellobiose was also detected. A significant (p-value <0.05) linear interaction between treatment temperature and glucose release was found for SCB and AB. EFB showed significant (p-value <0.05) a quadratic interaction between temperature and retention time with glucose release. Arabinose presented a significant (p-value <0.05) linear positive interaction with temperature and NaOH concentration in all fibers. Delignification of SCB had a significant (p-value <0.05) negative correlation with the coupled effect of temperature and NaOH concentration. Solids recovery showed a significant (p-value <0.05) negative interaction with temperature and NaOH concentration for all fibers. Methane production from SCB hydrolysates co digestion presented significant (p-value <0.05) interaction with NaOH concentration and retention time. EFB hydrolysates co digestion presented a significant (p-value <0.05) interaction with temperature and NaOH concentration. Methane content in biogas presented a significant (p-value <0.05) linear interaction with temperature and NaOH concentration. No energy gain from pretreated SCB was observed. A maximum energy gain of 3.5MJ Kg-1 for pretreated empty fruit bunch. Agave bagasse presented a maximum net energy gain of 4.8 MJ Kg-1.Keywords: Empty fruit bunch; sugarcane bagasse; agave bagasse; hexoses; pentoses; lignin degradation.

In this work, the effects of the addition of a cationic polymer ADIFLOC KD 451 (ADIPAP, France) in the performance of a decentralized Anaerobic Membrane Bioreactor (AnMBR) pilot plant treating 1.5 m3 blackwater per day was studied. To this end, on-line sludge filterability characterizations were performed following the Delft Filtration Characterization (DFC) method. Likewise, a Supervisory Control and Data Acquisition (SCADA) system was used to measure and record the variations in transmembrane pressure (TMP). Polymer addition resulted in the modification of the biomass properties such as increased particle size measured as d50 from 19.49µm to 32.85µm and lower colloidal particles concentration. The combined effect of these changes influenced the fouling cake layer development rate. The preceding resulted in lower TMP in the pilot plant which indicates that higher operational fluxes can be achieved due to flux enhancer addition.