Potential of Sustainable Concept for Handling Organic Waste in Tunisia

Nour El Houda Chaher, Safwat Hemidat, Qahtan Thabit, Mehrez Chakchouk, Abdallah Nassour, Moktar Hamdi and Michael Nelles
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Nour El Houda Chaher: Department of Chemical and Process Engineering, National Engineering School of Gabes, University of Gabes, Gabes 6029, Tunisia
Safwat Hemidat: Department of Waste and Resource Management, Faculty of Agricultural and Environmental Sciences, University of Rostock, 18051 Rostock, Germany
Qahtan Thabit: Department of Waste and Resource Management, Faculty of Agricultural and Environmental Sciences, University of Rostock, 18051 Rostock, Germany
Mehrez Chakchouk: Department of Biological and Chemical Engineering, National Institute of Applied Sciences and Technology, University of Carthage, Tunis 1080, Tunisia
Abdallah Nassour: Department of Waste and Resource Management, Faculty of Agricultural and Environmental Sciences, University of Rostock, 18051 Rostock, Germany
Moktar Hamdi: Department of Biological and Chemical Engineering, National Institute of Applied Sciences and Technology, University of Carthage, Tunis 1080, Tunisia
Michael Nelles: Department of Waste and Resource Management, Faculty of Agricultural and Environmental Sciences, University of Rostock, 18051 Rostock, Germany

Sustainability, 2020, vol. 12, issue 19, 1-31

Abstract: Nowadays, Tunisia is seeking to implement cost-efficient and sustainable solutions in relation to the treatment of organic waste which, at up to 65%, makes up the largest proportion of total waste generated in the country. Therefore, an efficient tool for decision makers is needed to provide a clear approach about the potential of organic waste as well as the treatment concept, which can be adapted based on technical requirements and local conditions. Results revealed that there is a high variation in terms of the nature of the collected biowaste, which affects the selection of the adopted bioprocess for each geographical zone of the study area. Three main categories of biowaste are produced along the coastline of Tunisia: food waste (FW) (102.543 t/a); green waste (GW) (1.326.930 t/a); and cattle manure (CM) (1.548.350 t/a). Based on the results of similar projects and laboratory-scale research work, anaerobic and aerobic digestion were examined. Regarding aerobic digestion, the monitoring of several physicochemical parameters ascertained that the co-composting of FW and GW at different ratios (GW: FW = 100:0, 75:25, 50:50, and 25:75) allowed the production of a stable and mature compost. A highly qualified end-product was generated from each trial categorized as a finished compost of class V with reference to German Standards of compost. Regarding the anaerobic process, different feedstock mixtures (FW:CM = 0:1, 1:1, 2:1, and 3:1) were prepared to feed semi-continuous anaerobic reactors. However, a significant improvement in the process development was recorded for digesters including a higher fraction of FW, which produced 0.846 L N /kg VS in as the maximum biogas production. Therefore, biological treatments of food waste and different co-substrates seems to be a suitable technique for Tunisia in terms of waste management, environmental, and energy aspects. However, the evaluation of the efficiency of the proposed biological treatments was also verified by a draw-up of a technical and economic feasibility analysis. Although the cost–benefit estimations proved that the profits from both the compost and biogas plants would be very modest, the feasibility of such sustainable projects should not only be evaluated on an economic basis, but also by taking into account socio-environmental considerations including decreasing environmental threats, providing work opportunities, increasing incomes, stimulating public awareness as well as reducing the operating costs linked to landfilling.

Keywords: biowaste; mapping; biological treatment; technical model; cost-benefits; Tunisia (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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