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Nutrient removal and biogas upgrading by microalgal strains cultured in anaerobic digested starch wastewater

Cheng, Bin, Ge, Zhigang, Zhang, Hui, Zhao, Yongjun, Sun, Shiqing, Hu, Changwei
Journal of chemical technology and biotechnology 2016 v.91 no.12 pp. 3028-3034
Chlorella vulgaris, biogas, biomass, chemical oxygen demand, microalgae, nitrogen content, phosphorus, pollutants, starch, wastewater
BACKGROUND: In this study, the microalga Chlorella vulgaris (FACHB‐38) was cultivated in pure (3122.5 mg L⁻¹ chemical oxygen demand (COD)) and diluted anaerobic digested starch wastewater (ADSW; 313.2, 622.8, 935.7, 1248.5, and 1558.9 mg L⁻¹ COD). This study mainly aimed to compare algal growth and tolerance with various dilutions of ADSW, as well as determine nutrient removal efficiency and role of biogas upgrade. RESULTS: Chlorella vulgaris cultured in ADSW with 935.7 mg L⁻¹ COD yielded a maximum total biomass of 3.39 ± 0.27 g L⁻¹ (dry weight) and pollutant removal efficiencies of 79.04% ± 5.71% COD and 73.19% ± 6.98% total nitrogen (TN). The contents of C, N, and P in biomass remained constant at 48.93–50.12%, 8.76–9.94%, and 0.74–0.98%, respectively, among all dilutions. High total phosphorus (TP) removal efficiency was observed in treatments with 1248.5–1558.9 mg L⁻¹ COD. The most appropriate dilutions for biogas upgrade were 935.7 and 1248.5 mg L⁻¹ COD. CONCLUSION: The optimal effect of nutrient removal and biogas upgrading can be obtained by appropriate control of ADSW dilution in influents. © 2016 Society of Chemical Industry