Comparison of the evolution of physicochemical and microbial characteristics of the wastes, those most commonly generated in Algeria during composting

Abstract

Purpose This paper focuses on monitoring the behavior of five different types of waste and humus during composting to see the impact of the nature of the substrate on the process and the quality of mature compost. Method Green waste, coffee waste, household waste (Fraction of the household waste which having dimensions smaller than 8 mm) and humus were collected separately from different areas of Oran city, western Algeria, composted in windrows of 2 m long, 1 m wide, and 0.5 m high each for 150 days during the winter and spring period (2019-2020). The physicochemical parameters and characteristics were determined on the one hand, and on the other hand, the evolution of the microflora was monitored. Results The results show a correlation between the parameters of each substrate. Furthermore, it was found that green waste, coffee waste, and household waste can give the best quality of compost if the process conditions are respected (maintenance of C/N ratio and moisture level). However, small waste and very small waste can also be used to amend green areas and public gardens. The results also showed that the concentration of pathogenic microorganisms such as Salmonella and Shigella did not exceed the NFU44-051 standard. Conclusion The findings support the industrialization of waste valorization by composting as an effective technique for waste reduction given the current situation and encourage investors and promote the industrialization of waste recovery by composting in Algeria.