Performance of CO2 concentrations on nutrient removal and biogas upgrading by integrating microalgal strains cultivation with activated sludge. (15th February 2016)

• Record Type: Journal Article
• Authors: Sun, Shiqing; Ge, Zhigang; Zhao, Yongjun; Hu, Changwei; Zhang, Hui; Ping, Lifeng
• Is Part Of: Energy. Volume 97(2016)
• Page Start: 229
• Page End: 237
• Publication Date: 2016-02-15
• Subjects: Algal-bacterial processes -- CO2 removal -- H2S removal -- Macromolecular and elemental composition -- Nutrient removal; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2015.12.126
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: In this work, a cooperative algal-bacterial system that efficiently upgrade biogas, simultaneously reduce the biogas slurry nutrient, and exhibits high biomass productivity, was developed. The method about removing H2 S and CO2 from biogas by three microalgal strains ( Chlorella vulgaris, Scenedesmus obliquus, and Neochloris oleoabundans ) mixed with activated sludge using biogas slurry as nutrient medium. A CO2 concentration of 45% (v/v) was considered optimum to support CO2 and H2 S removals of 74.11%–80.57% and 99.04%–99.42%, respectively. At the CO2 concentration of 45%–55%, the mixed culture containing S. obliquus and C. vulgaris efficiently removed COD (chemical oxygen demand) and TP (total phosphorus), respectively. The mixed culture containing S. obliquus demonstrated high N removal efficiency at CO2 concentration of 45%. Biomass productivity increased at increasing CO2 concentration in a certain range, with a maximum of 0.177 g L −1 d −1 at CO2 concentration of 45% (v/v) for the mixed culture containing S. obliquus, whereas the C, N, and P biomass contents remained constant at 46.73%–52.31%, 7.59%–9.08%, and 0.91%–1.08%, respectively. This study showed the potential of the combination of alga and bacteria to serve as a treatment for nutrient removal and biogas upgrading in algal-bacterial processes. Highlights: Nutrient, CO2, and H2 S were efficiently removed in algal-bacterial processes. The mixed culture containing Scenedesmus obliquus achieved the best combined effects. Activated sludge supported a superior biogas slurry treatment performance. The peak carbohydrate content of containing S. obliquus was 75.24% under 55% CO2 . Maximum biomass productivity of 0.177 gL −1 d −1 was recorded under 45% CO2 .