title: Effects of hydraulic retention time on cultivation of indigenous microalgae as a renewable energy source using secondary effluent.
abstract: Secondary effluent from wastewater treatment plants is suitable media for cultivating microalgae as a renewable energy source, and hydraulic retention time (HRT) control in culture is important to conduct well-planned outdoor indigenous microalgae cultivation with secondary effluent. This study revealed cultivation characteristics under various HRT by continuous 6-month experiments. In addition, effects of HRT on cultivation were determined by a mathematical model that described indigenous microalgae growth. Cultivated biomass mainly consisted of Chlorophyceae and its detritus regardless of HRT, and 5.93-14.8g/m(2)/day of biomass yield was obtained. The cultivated biomass had a stable higher heating value of 16kJ/g. Sensitivity analysis of the model suggests that HRT control had great effects on biomass yield, and 2-3days of HRT were recommended to obtain maximum biomass yield under certain weather conditions (temperature: approximately 12-25°C and solar radiation: approximately 8-19MJ/m(2)/day).
authors.affiliation: Materials and Resources Research Group, Innovative Materials and Resources Research Center, Public Works Research Institute, 1-6 Minamihara, Tsukuba, Ibaraki 3058516, Japan. Electronic address: yu-takabe@pwri.go.jp.
authors.forename: Yugo
authors.initials: Y
authors.lastname: Takabe
authors.affiliation: Recycling Research Team, Materials and Resources Research Group, Public Works Research Institute, 1-6 Minamihara, Tsukuba, Ibaraki 3058516, Japan.
authors.forename: Taira
authors.initials: T
authors.lastname: Hidaka
authors.affiliation: Recycling Research Team, Materials and Resources Research Group, Public Works Research Institute, 1-6 Minamihara, Tsukuba, Ibaraki 3058516, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Tsumori
authors.affiliation: Materials and Resources Research Group, Innovative Materials and Resources Research Center, Public Works Research Institute, 1-6 Minamihara, Tsukuba, Ibaraki 3058516, Japan.
authors.forename: Mizuhiko
authors.initials: M
authors.lastname: Minamiyama
mesh_terms: D018533:Biomass; D000460:Chlorophyta; D003246:Conservation of Energy Resources / Q000379:methods; D058086:Microalgae / Q000254:growth & development*; D008962:Models, Theoretical; D059205:Renewable Energy; D062065:Wastewater / Q000737:chemistry*; D060753:Water Quality
chemical_list: D062065:Wastewater
keywords: Hydraulic retention time; Indigenous microalgae; Mathematical model; Outdoor cultivation; Secondary effluent