Effect of initial C/N ratio on composting of two‐phase olive mill pomace, dairy manure, and straw

Abstract

Composting plants should be operated at a high degradation rate in order to lower their capital and operational costs. Initial C/N ratio is one of the most influential factors on the composting process. This study aimed to determine the impacts of initial C/N ratio on operational composting parameters of two‐phase olive mill pomace with separated dairy manure. Five initial C/N ratios ranging from 29.43 to 43.33 were examined using fifteen 100 L cylindrical reactors. The highest decomposition rate was estimated at 0.02 day−1 with the C/N ratio of 34.49. The maximum relative heat generation was obtained with the C/N ratio of 36.07. The C/N ratio of ≅33 reduced the composting cost of process‐based total airflow supplied per dry matter and organic matter loss. The maximum throughput capacity was obtained when the compost blend had the C/N ratio of ≅37.24. It was concluded that operating the composting of two‐phase olive mill waste, separated dairy manure, and straw with the boundary of the initial C/N ratios between 33 and 37 was recommended.

Method for C/N ratio estimation using Mask R-CNN and a depth camera for organic fraction of municipal solid wastes

“…The estimated total carbon to nitrogen ratios of the waste samples was calculated by Equation ( 12) where the measured volumes V were calculated by Equation (11). While the ground truth values were calculated by Equation ( 12) using volumes V′ calculated by Equation (15).…”

“…Composting is a bioconversion process that converts biodegradable waste to nutrient-rich products which can be used as biofertilizer to enhance the fertility of the soil [5,6] , biopesticides to manage plant diseases, and bioremediation to stabilize heavy metals in the contaminated soil [7][8][9] . During the transformation of organic waste in the composting process, carbon and nitrogen are the most vital nutrients for microorganisms to build cell structures and acquire metabolic energy [10] , and the initial Carbon to Nitrogen ratio (C/N) of feedstock is one of the crucial factor influencing degradation rate and nutrients losses, which can be adjusted with different bulking agent [11][12][13] .…”