Carbon-based materials boost the anaerobic treatment of slaughterhouse wastewater

Carbon-based materials were tested as methanogenic boosters to enhance the anaerobic treatment slaughterhouse wastewater, which included an organic xerogel (OX) doped with graphene oxide, a peach stone carbon (PSC), and a monolithic whey carbon (MWC). Enhanced treatment by the carbon-based boosters was evident in terms of organic matter removal and methane production rate, which was globally reflected on a superior methanogenic conversion efficiency as compared to the unamended control. OX appeared as the best methanogenic booster increasing up to 77 % and 12 % the methane production rate and organic matter removal, respectively. The obtained results suggest that hydrolysis and acidification of the complex wastewater were the limiting steps during the treatment of this industrial effluent. This observation is consistent with the higher production of ammonium, derived from protein hydrolysis, which occurred in bioreactors amended with carbon-based materials, as compared to the unamended control. Several changes in the relative abundance of key microbial taxa occurred; particularly, members of the bacterial families Synergistaceae and Anaerolineaceae, as well as the archaeal Methanolinea and Proteiniclasticum genera, increased significantly in the presence of OX. The synthesized materials are proposed to improve the performance of anaerobic treatment systems dealing with complex wastewaters.