Giulia Massini

Biocides electrogeneration for a zero-reagent on board disinfection of ballast water

The feasibility of a quick electrochemical process for on board zero-reagent treatment of ballast water by anodic and cathodic production of oxidants was proposed. The process has been tested in the inactivation of the marine dinoflagellates Alexandrium minutum and A. taylori, both responsible for algal blooms and toxin-producing, and against the marine bacterium Pseudomonas aeruginosa, a Gram-negative pathogenic micro-organism. A complete inactivation of both dinoflagellates was quickly achieved with electro-generated active chlorine, while higher resistance to oxidising agents was verified for P. aeruginosa. A combined sequential treatment involving anodic oxidation followed by extended exposure time in the absence of current, and a final cathodic treatment was proposed. The cathodically electro-generated hydrogen peroxide contributed to the reduction of treatment time and the removal of residual species.

Combined bioaugmentation with anaerobic ruminal fungi and fermentative bacteria to enhance biogas production from wheat straw and mushroom spent straw

Bioaugmentation with anaerobic ruminal fungi and a pool of hydrogen-producing fermenting bacteria was tested on wheat straw (WS) and mushroom spent straw (MSS) with the aim of improving anaerobic digestion performance. Batch tests were set up to simulate a Bioaugmentation Anaerobic Digestion (BAD) treatment comparing single- (I-BAD) and two-stage (II-BAD) process configurations, at two reactor scales, 120 and 1200 ml (×10). In both cases, higher CH4 cumulative production was obtained in the II-BAD configuration on WS (65.1 ± 8.9 Nml and 922 ± 73.8 Nml respectively). The II-BADx10 tests allowed increasing CH4 production (≃290% and ≃330% on WS and MSS, respectively) when compared to the unaugmented condition. Final results highlighted the achievable advantages of the two stage configuration in terms of CH4 production enhancement. Microbial community investigations confirmed the efficiency of the bioaugmentation treatment and revealed that such a result was mainly related to the Methanosarcinales increase, mostly composed by Methanosaeta.

Bio-production of Hydrogen and Methane Through Anaerobic Digestion Stages

The anaerobic digestion (AD) is a widespread technology for the energetic valorization of organic wastes and the plants number is increasing both in industrialized and emerging countries. On the other hand, a low efficiency of the biogas production is still observed mainly due to the limited knowledge on the microorganism interactions and the lack of microbiological monitoring in the AD process. The energetic valorization of organic waste, producing both methane and hydrogen, can be increased by applying microbial ecology principles and exploiting the potential offered by functional microbial biodiversity.

Produzione biologica di idrogeno da scarti agroalimentari e zootecnici: ruolo della codigestione

In una prospettiva di produzione energetica il piu possibile diversificata e distribuita il biofueling rappresenta oggi un interessante opportunita. In questo ambito lo sviluppo di tecnologie volte alla produzione biologica di idrogeno attraverso l’utilizzo di rifiuti provenienti da industrie zootecniche e agroalimentari raggiunge il duplice obiettivo di produrre energia pulita e di ridurre gli impatti ambientali derivanti dallo smaltimento dei rifiuti stessi. L’idrogeno, per la sua elevata efficienza di conversione, rinnovabilita e natura non inquinante e considerato il vettore energetico del futuro. Lo scopo del presente lavoro e quello di studiare il processo di produzione d’idrogeno potenziale dal solo letame e in codigestione con scotta e glicerolo. La produzione biologica di idrogeno e stata studiata in reattori batch sottoposti ad agitazione e mantenuti a 37°C. Un primo set di esperimenti e stato condotto per valutare gli effetti della sterilizzazione sulle rese di produzione di idrogeno. I risultati hanno mostrato che il processo di sterilizzazione delle biomasse incrementa fino a tre volte la produttivita. Un secondo set di esperimenti e stato allestito per migliorare la produzione di idrogeno da letame tramite codigestione con scotta e glicerolo in differenti rapporti percentuali. I risultati hanno mostrato che la codigestione incrementa la resa dal 24% al 78%.