title: Boosting methane generation by co-digestion of sludge with fruit and vegetable waste: Internal environment of digester and methanogenic pathway.
abstract: The effects of anaerobic co-digestion of waste-mixed sludge with fruit and vegetable waste (FVW) on the methane generation of a mesophilic digester was investigated. Organic loading rates (OLR) were 1.46kgVS/m(3)day, 2.1kgVS/m(3)day and 2.8kgVS/m(3)day. Increase in the OLR due to FVW co-digestion caused modification of the internal environment of the digester, mainly in terms of N-NH4 (mg/L). Corresponding microbial populations were investigated by metagenomic high-throughput sequencing. Maximum specific bio-methane generation of 435 NLCH4 per kgVS feed was achieved for an OLR of 2.1kgVS/m(3)day, which corresponded to a biomethane generation per kgVS removed of about 1700 NLCH4. In these conditions the methanogenic pathway was dominated by aceticlastic Methanosaeta and hydrogenotrophic/aceticlastic Methanoscarcinae. Ammonia concentration in the digester resulted a key parameter for enhancing syntrophic acetate oxidation, enabling a balanced aceticlastic and hydrogenotrophic/aceticlastic methanogenic pathway.
authors.affiliation: LAR Laboratory - Dipartimento di Ingegneria, Via G. Duranti 93, 06125 Perugia, Italy. Electronic address: francesco.dimaria@unipg.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Di Maria
authors.affiliation: LAR Laboratory - Dipartimento di Ingegneria, Via G. Duranti 93, 06125 Perugia, Italy.
authors.forename: Martino
authors.initials: M
authors.lastname: Barratta
mesh_terms: D000641:Ammonia / Q000737:chemistry; D000693:Anaerobiosis; D001105:Archaea; D001673:Biodegradation, Environmental; D019149:Bioreactors; D004867:Equipment Design; D005638:Fruit / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008697:Methane / Q000032:analysis / Q000737:chemistry*; D017020:Methanosarcina; D010100:Oxygen / Q000737:chemistry; D012037:Refuse Disposal / Q000379:methods; D017422:Sequence Analysis, DNA; D012722:Sewage; D014675:Vegetables / Q000737:chemistry*
chemical_list: D012722:Sewage; D000641:Ammonia; D008697:Methane; D010100:Oxygen
keywords: Ammonium; Anaerobic co-digestion; Fruit and vegetable waste; Methane; Microbial population; Sludge