Anaerobic digestion of solid agroindustrial waste in semi-continuous mode: Evaluation of mono-digestion and co-digestion systems

Journal Article · Sun Oct 15 04:00:00 EDT 2017 · Waste Management

DOI:https://doi.org/10.1016/J.WASMAN.2017.06.026· OSTI ID:22742132

Pellera, Frantseska-Maria; Gidarakos, Evangelos

Highlights: • Agroindustrial waste were co-digested with an artificial organic fraction. • Variations in organic loading rate and hydraulic retention time were studied. • Sequential feeding of the substrates based on their seasonality was investigated. • Co-digestion resulted in higher methane yields compared with mono-digestion. • Applying sequential feeding led to a more equilibrated system operation. - Abstract: The present study aimed at investigating the anaerobic digestion of four agroindustrial waste, namely cotton gin waste, winery waste, olive pomace and juice industry waste, in semi-continuous mode, conducting mono-digestion and co-digestion assays, using an artificial organic fraction sample as co-substrate. These assays were divided into two groups, in which different conditions were applied. Group I investigated the variation in two operational parameters, i.e. the organic loading rate (OLR) and the hydraulic retention time (HRT), while in Group II, the assays were fed with different substrates in a sequential order. Results showed more elevated specific methane yields for co-digestion assays compared with mono-digestion assays. Maximum yields were achieved at an OLR of 1.0 gVS/(L·d) and a HRT reduced to half of the initial. Further reduction of the HRT coupled to an increase of the OLR generally caused a significant decrease of specific methane yields, as well as one case of severe overloading, i.e. the mono-digestion of juice industry waste, which resulted in instability and ultimately system failure. Sequential feeding with different substrates led to a more equilibrated operation, especially for co-digestion systems, with higher specific methane yields being observed during the phases corresponding to winery waste and juice industry waste substrates. Overall more positive results were obtained in the cases in which the latter substrates were fed to the reactors at process startup.

• OSTI ID: 22742132
• Journal Information: Waste Management, Journal Name: Waste Management Vol. 68; ISSN WAMAE2; ISSN 0956-053X
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ANAEROBIC DIGESTION
LOADING RATE
METHANE
OPERATION
RETENTION
SOLID WASTES
SUBSTRATES
YIELDS