Next Article in Journal
“BalSim”: A Carbon, Nitrogen and Greenhouse Gas Mass Balance Model for Pastures
Next Article in Special Issue
Biochemical Hydrogen Potential Tests Using Different Inocula
Previous Article in Journal
Study on Factors Affecting the Agricultural Mechanization Level in China Based on Structural Equation Modeling
Open AccessArticle

Biofuel Production and Phosphorus Recovery through an Integrated Treatment of Agro-Industrial Waste

1
Department of Environmental and Chemical Engineering, University of Calabria, Via P. Bucci cubo 44B, 87036 Arcavacata di Rende (CS), Italy
2
Department of Sustainability; Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), P. Enrico Fermi 1, 80055 Portici (NA), Italy
3
Department of Engineering; University of Campania “Luigi Vanvitelli”, Via Roma 29, 81031 Aversa (CE), Italy
4
Department of Informatics, Modelling, Electronics and Systems Engineering, University of Calabria, Via P. Bucci cubo 39C, 87036 Arcavacata di Rende (CS), Italy
*
Author to whom correspondence should be addressed.
Sustainability 2019, 11(1), 52; https://doi.org/10.3390/su11010052
Received: 30 October 2018 / Revised: 16 December 2018 / Accepted: 18 December 2018 / Published: 21 December 2018
(This article belongs to the Special Issue Advances in Biorefining of Biowaste)
The present study aimed to develop an integrated treatment of agro-industrial waste for biofuel (biogas and syngas) production and for phosphorus recovery. In the first step, an anaerobic digestion (AD) process was carried out on two different mixtures of raw agro-industrial residues. Specifically, a mixture of asparagus and tomato wastes (mixture-1) and a mixture of potatoes and kiwifruit residues (mixture-2) were investigated. The results proved that the properties of mixtures notably affect the evolution of the digestion process. Indeed, despite the lower organic load, the maximum biogas yield, of about 0.44 L/gCODremoved, was obtained for mixture-1. For mixture-2, the digestion process was hindered by the accumulation of acidity due to the lack of alkalinity in respect to the amount of volatile fatty acids. In the second step, the digestates from AD were utilized for syngas production using supercritical water gasification (SCWG) at 450 °C and 250 bar. Both the digestates were rapidly converted into syngas, which was mainly composed of H2, CO2, CH4, and CO. The maximum values of global gasification efficiency, equal to 56.5 g/kgCOD, and gas yield, equal to 1.8 mol/kgTS, were detected for mixture-2. The last step of the integrated treatment aimed to recover the phosphorus content, in the form of MgKPO4ˑ6H2O, from the residual liquid fraction of SCWG. The experimental results proved that at pH = 10 and Mg/P = 1 it is possible to obtain almost complete phosphorus removal. Moreover, by using the scanning electronic microscopy, it was demonstrated that the produced precipitate was effectively composed of magnesium potassium phosphate crystals. View Full-Text
Keywords: anaerobic digestion; biogas; biomass; magnesium potassium phosphate; supercritical water gasification anaerobic digestion; biogas; biomass; magnesium potassium phosphate; supercritical water gasification
Show Figures

Figure 1

MDPI and ACS Style

Siciliano, A.; Limonti, C.; Mehariya, S.; Molino, A.; Calabrò, V. Biofuel Production and Phosphorus Recovery through an Integrated Treatment of Agro-Industrial Waste. Sustainability 2019, 11, 52.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop