title: Cultivating Chlorella sp. in a pilot-scale photobioreactor using centrate wastewater for microalgae biomass production and wastewater nutrient removal.
abstract: This study is concerned with a novel mass microalgae production system which, for the first time, uses "centrate", a concentrated wastewater stream, to produce microalgal biomass for energy production. Centrate contains a high level of nutrients that support algal growth. The objective of this study was to investigate the growth characteristics of a locally isolated microalgae strain Chlorella sp. in centrate and its ability to remove nutrients from centrate. A pilot-scale photobioreactor (PBR) was constructed at a local wastewater treatment plant. The system was tested under different harvesting rates and exogenous CO(2) levels with the local strain of Chlorella sp. Under low light conditions (25 μmol·m(-2)s(-1)) the system can produce 34.6 and 17.7 g·m(-2)day(-1) biomass in terms of total suspended solids and volatile suspended solids, respectively. At a one fourth harvesting rate, reduction of chemical oxygen demand, total Kjeldahl nitrogen, and soluble total phosphorus were 70%, 61%, and 61%, respectively. The addition of CO(2) to the system did not exhibit a positive effect on biomass productivity or nutrient removal in centrate which is an organic carbon rich medium. The unique PBR system is highly scalable and provides a great opportunity for biomass production coupled with wastewater treatment.
authors.affiliation: Bioproducts and Biosystems Engineering Department, University Of Minnesota, 1390 Eckles Ave, Saint Paul, MN 55108, USA.
authors.forename: Min
authors.initials: M
authors.lastname: Min
authors.forename: Liang
authors.initials: L
authors.lastname: Wang
authors.forename: Yecong
authors.initials: Y
authors.lastname: Li
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mohr
authors.forename: Bing
authors.initials: B
authors.lastname: Hu
authors.forename: Wenguang
authors.initials: W
authors.lastname: Zhou
authors.forename: Paul
authors.initials: P
authors.lastname: Chen
authors.forename: Roger
authors.initials: R
authors.lastname: Ruan
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism; D002708:Chlorella / Q000378:metabolism*; D058086:Microalgae / Q000378:metabolism*; D058433:Photobioreactors / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D002245:Carbon Dioxide