title: Organic biowastes blend selection for composting industrial eggshell by-product: experimental and statistical mixture design.
abstract: Composting is one of the technologies recommended for pre-treating industrial eggshells (ES) before its application in soils, for calcium recycling. However, due to the high inorganic content of ES, a mixture of biodegradable materials is required to assure a successful procedure. In this study, an adequate organic blend composition containing potato peel (PP), grass clippings (GC) and wheat straw (WS) was determined by applying the simplex-centroid mixture design method to achieve a desired moisture content, carbon: nitrogen ratio and free air space for effective composting of ES. A blend of 56% PP, 37% GC and 7% WS was selected and tested in a self heating reactor, where 10% (w/w) of ES was incorporated. After 29 days of reactor operation, a dry matter reduction of 46% was achieved and thermophilic temperatures were maintained during 15 days, indicating that the blend selected by statistical approach was adequate for composting of ES.
authors.affiliation: Cernas - Natural Resources, Environment and Society Research Centre, Coimbra College of Agriculture of Polytechnic Institute of Coimbra, Bencanta 3040-316 Coimbra, Portugal. msoares@esac.pt
authors.forename: Micaela A R
authors.initials: MA
authors.lastname: Soares
authors.forename: Sandra R
authors.initials: SR
authors.lastname: Andrade
authors.forename: Rui C
authors.initials: RC
authors.lastname: Martins
authors.forename: Margarida J
authors.initials: MJ
authors.lastname: Quina
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Quinta-Ferreira
mesh_terms: D000818:Animals; D001673:Biodegradation, Environmental; D002118:Calcium; D002645:Chickens; D004528:Egg Shell / Q000737:chemistry*; D004785:Environmental Pollutants; D019649:Food Industry; D007220:Industrial Waste; D018547:Plant Stems; D006109:Poaceae; D059027:Recycling / Q000379:methods*; D012987:Soil; D011198:Solanum tuberosum
chemical_list: D004785:Environmental Pollutants; D007220:Industrial Waste; D012987:Soil; D002118:Calcium