Deliverable D1.5 "Enhanced stabilization processes"

This report is focussed on different strategies to enhance anaerobic digestion processes by adding either a sludge pre-treatment method (ultrasounds or hybrid disintegration) or a post-treatment (aerobic or thermophilic digestion in dual stage). The investigated processes were: i) a dual stage mesophilic/thermophilic anaerobic digestion, with or without ultrasounds pre-treatment; ii) a batch mesophilic/thermophilic anaerobic system, with hydrodynamic cavitation pre-treatment and iii) sequential anaerobic/aerobic digestion process. A deeper knowledge of the identity and function of the microbial components would therefore allow to better control the biological processes. In order to enhance the efficiency of FISH identification, 16S rRNA gene clonal approach was also employed finalized to generate novel FISH probes and to further refine the analysis. The main scope of these activities was to investigate sustainable options to enhance anaerobic digestion in order to improve biosolids quality in terms of stability, dewaterability and hygienization by maximizing contemporarily energy recovery. The identification of the microorganisms involved in the different metabolic steps of the anaerobic digestion will be also evaluated in order to understand population dynamics and improve the methane production.