Co-composting of eggshell waste in self-heating reactors: Monitoring and end product quality

• Published in: Bioresource technology Vol. 148; pp. 293 - 301
• Main Authors: Soares, Micaela A.R., Quina, Margarida M.J., Quinta-Ferreira, Rosa M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2013; Elsevier
• Subjects: Animals; Applied sciences; Biological and medical sciences; Biological treatment of sewage sludges and wastes; Biotechnology; Biotechnology - instrumentation; Biotechnology - methods; Byproducts; Composting; Egg Shell - chemistry; Environment and pollution; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Hot Temperature; Humans; Humidity; Hydrogen-Ion Concentration; Industrial applications and implications. Economical aspects; Industrial eggshell waste; Nitrogen - analysis; Organic Chemicals - analysis; Oxygen - analysis; Pollution; Reactors; Recycling; Risk; Sanitation; Self-heating potential; Soil - chemistry; Soil improver; Spreading; Volatilization; Waste Products - analysis; Wastes; Industrial eggshell waste; Composting; Self-heating potential; Soil improver; Soils; Industrial waste; Production quality; Surveillance; Egg shell; Self heating; Reactor
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2013.08.151

•Eggshell waste (ES) recycling in self-heating composting reactors was investigated.•Potato peel, grass clippings and rice husks were the starting composting materials.•ES incorporation did not affect the self-heating capacity of the mixture.•Nitrogen losses were enhanced by ES during thermophilic period.•A calcium-rich marketable compost for soil application was obtained. Industrial eggshell waste (ES) is classified as an animal by-product not intended to human consumption. For reducing pathogen spreading risk due to soil incorporation of ES, sanitation by composting is a pre-treatment option. This work aims to evaluate eggshell waste recycling in self-heating composting reactors and investigate ES effect on process evolution and end product quality. Potato peel, grass clippings and rice husks were the starting organic materials considered. The incorporation of 30% (w/w) ES in a composting mixture did not affect mixture biodegradability, nor its capacity to reach sanitizing temperatures. After 25days of composting, ES addition caused a nitrogen loss of about 10gNkg−1 of initial volatile solids, thus reducing nitrogen nutritional potential of the finished compost. This study showed that a composting mixture with a significant proportion of ES (30% w/w) may be converted into calcium-rich marketable compost to neutralize soil acidity and/or calcium deficiencies.