Author(s): Oliveira, João Vítor ; Duarte, T. ; Costa, J. C. ; Cavaleiro, Ana Júlia ; Pereira, M. A. ; Alves, M. M.
Date: 2017
Persistent ID: http://hdl.handle.net/1822/47230
Origin: RepositóriUM - Universidade do Minho
Project/scholarship: info:eu-repo/grantAgreement/FCT/5876-PPCDTI/126270/PT ; info:eu-repo/grantAgreement/FCT/5876/147337/PT;
Subject(s): Anaerobic co-digestion; Sewage sludge; Lipid rich waste; Wastewater treatment plant; Design of Experiments
Redirection of sewage sludge in wastewater treatment plants (WWTP) from landfilling or incineration to biological treatment, for instance anaerobic digestion, has become a part of the current global environmental, economic and regulatory issues. A statistical approach, based on a design of experiments, was adopted in order to assess methane production from the anaerobic co-digestion of mixed sewage sludge (MS) with crude glycerol (cGly) and waste frying oil (WFO). The effect of three factors MS concentration, co-substrate concentration, and fraction of cGly (xcGly) in a mixture (w/w) of cGly and WFO on biochemical methane potential (BMP) and the maximum initial methane production rate (kCH4) was assessed by a Central Composite Design Circumscribed. In the absence of a co-substrate, MS digestion reached a BMP of (294 ± 6) L kg-1 (L of methane at standard temperate and pressure (STP) conditions per kg of VS of waste added) and a kCH4 of (64 ± 1) L kg-1 d-1 (L of methane at STP conditions per kg of VS of waste added and per day), with a biodegradability of (56 ± 1) %. After optimization, MS and co-substrate concentrations of 4.64 g L-1 and 8.77 g L-1, respectively, with xcGly of 0.8 were defined as the condition to simultaneously boost BMP (91 %) and kCH4 (250 %). An WWTP would be able to save 36.2 k in electricity per 1 000 m3 of sewage sludge produced, if the selected co-digestion conditions were applied, rather than digesting only the sludge.
This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462), the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte. The authors also acknowledge the financial support of the FCT (ESF) through the grant given to João V. Oliveira (SFRH/BD/111911/2015). Research of A.J. Cavaleiro was supported by the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement No 323009.
info:eu-repo/semantics/publishedVersion
