Composting and co‑composting of cofee husk and pulp with source‑separated municipal solid waste: a breakthrough in valorization of cofee waste

Authors

1 Bio- and Chemical Systems Technology, Reactor Engineering and Safety Department of Chemical Engineering, Leuven Chem & Tech, KU Leuven, Louvain, Belgium

2 Department of Horticulture and Plant Sciences, College of Agriculture and Veterinary Medicine, Jimma University, Jimma, Ethiopia

3 Department of Environmental Health Sciences and Technology, Jimma University, Jimma, Ethiopia

4 Materials and Process Engineering (iMMC-IMAP), Université catholique de Louvain, Louvain-la-Neuve, Belgium

5 Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria, South Africa

Abstract

Purpose In this study, the composting and co-composting potential of cofee husk and pulp with source-separated municipal solid waste (SSMSW) was investigated. Methods Cofee husk and pulp were mixed independently with SSMSW in diferent proportions (0, 33, 50 and 100%), and composted in triplicates with a total of 24 composting piles for 3 months. From each compost type, diferent physicochemical parameters were analyzed. In addition, the seed germination, growth and fresh head weight yield of each compost type were investigated on each matured compost type using cabbage seed (Brassica oleracea). Results The results indicate that the two cofee by-products can be composted alone or co-composted with SSMSW yielding very mature and stable compost. The results indicated that the addition of 1/4th of local soil (wt/wt) on C8 compost type yields the optimum fresh head weight of the cabbage among all feld experiments. In addition, when C8 compost type is mixed with local soil in 3:1 ratio, it could yield an optimum fresh head weight of the cabbage (572±10 g/kg of compost). This could be due to the relatively higher concentration of total nitrogen in the C8 compost sample. Conclusions Generally, the fnal compost can be served for unrestricted type of agricultural purposes. Thus, co-composing of cofee husk and pulp with SSMSW can alleviate the multidimensional problems of rural and urban dwellers.

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