title: Life cycle assessment of animal feeds prepared from liquid food residues: a case study of rice-washing water.
abstract: Life cycle assessment (LCA) was used to compare the greenhouse gas (GHG) emissions and energy consumption of three methods used to produce animal feed from concentrated rice-washing water (CRW) and disposing of the rice-washing water through wastewater treatment. Four scenarios were compared using LCA: (i) producing concentrated liquid feed by centrifugation (CC) of CRW with wastewater treatment and discharge of the supernatant, (ii) producing concentrated liquid feed by heating evaporation (HC) of CRW, (iii) producing dehydrated feed by dehydration (DH) of CRW, and (iv) wastewater treatment and discharge of nonconcentrated rice-washing water (WT). The functional unit (FU) was defined as 1 metric ton of rice washed for cooking or processing. Our results suggested that the energy consumptions of CC, HC, DH, and WT were 108, 322, 739, and 242 MJ per FU, respectively, and the amounts of GHG emissions from CC, HC, DH, and WT were 6.4, 15.8, 45.5, and 22.5 kg of CO equivalents per FU, respectively. When the produced feed prepared from CRW was assumed to be transported 200 km to farms, CC and HC still emitted smaller GHGs than the other scenarios, and CC consumed the smallest amount of energy among the scenarios. The present study indicates that liquid feed production from CRW by centrifugation has a remarkably reduced environmental impact compared with the wastewater treatment and discharge of rice-washing water.
authors.affiliation: National Agriculture and Food Research Organization, Ibaraki, Japan. aogino@affrc.go.jp
authors.forename: Akifumi
authors.initials: A
authors.lastname: Ogino
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Ishida
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Ohmori
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yamashita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yokoyama
authors.forename: Kenji
authors.initials: K
authors.lastname: Tatsugawa
authors.forename: Satoru
authors.initials: S
authors.lastname: Ijiri
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kawashima
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D003246:Conservation of Energy Resources / Q000379:methods*; D019649:Food Industry; D007220:Industrial Waste; D012275:Oryza; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical
chemical_list: D007220:Industrial Waste; D014874:Water Pollutants, Chemical; D014867:Water