Sustainable management of peel waste in the small-scale orange juice industries: A Colombian case study

Appropriate waste management in emerging economies like Colombia should be an asset for the overall sustainability. In the Orange Peel Waste case, incineration and Anaerobic Digestion are challenging solutions for the orange juice agro-industrial sector for avoiding the landfill, which is the conventional practice. However, these alternatives should be assessed in order to determine their feasibility. This paper aims to understand if incineration and Anaerobic Digestion are potential alternatives to landfill form a techno-economic and environmentally perspective. To this aim, a comparative Life Cycle Assessment was carried out in four scenarios. In the first scenario coal and landfill are used as source energy and landfill disposal in the actual orange juice process. In the second scenario, the peels are incinerated to avoid landfill and reduce the need for coal. The third scenario includes the valorization of the peels by means of Anaerobic Digestion which produces biogas for the plant energy requirements. In the fourth scenario, apart from the energy from biogas, the digestate becomes a fertilizer for use in the orange crops. The results revealed that scenario III and IV are environmentally friendly options compared to Scenario I, but they incur higher costs than Scenario II. Carbon footprint found that 1.55 kg of CO2 are saving when coal substitution is reduced from 0.493 kg in SI to 0.279 kg in SII. Therefore, Scenario II is more suitable for the Colombian socioeconomic reality since Scenario II is not only techno-environmentally achievable, but also economically feasible. The methodology used in this case study could be applied to other countries or small and medium scale technologies and could also be useful for the scientific community, enterprises and policy-makers.