Growth of Chlorella vulgaris and nutrient removal in the wastewater in response to intermittent carbon dioxide

Xiaoning Liu, Kezhen Ying, Guangyao Chen, Canwei Zhou, Wen Zhang, Xihui Zhang, Zhonghua Cai, Thomas Holmes, Yi Tao

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Abstract

In this study, Chlorella vulgaris (C. vulgaris) were cultured in cell culture flask supplied with intermittent CO 2 enriched gas. The impact of CO 2 concentration (from 1% to 20% v/v) on the growth of C. vulgaris cultured in domestic wastewater was exploited in various perspectives which include biomass, specific growth rate, culture pH, carbon consumption, and the removal of nitrogen and phosphorus compounds. The results showed that the maximum microalgal biomass concentration, 1.12 g L −1 , was achieved with 10% CO 2 as a feed gas. At 20% CO 2 the growth of C. vulgaris suffered from inhibition during initial 1.5 d, but acclimated to low pH (6.3 in average) with relatively higher specific growth rate (0.3–0.5 d −1 ) during subsequent culture period. After the rapid consumption of ammonium in the wastewater, an obvious decline in the nitrate concentration was observed, indicating that C. vulgaris prefer ammonium as a primary nitrogen source. The total nitrogen and phosphorus decreased from 44.0 mg L −1 to 2.1–5.4 mg L −1 and from 5.2 mg L −1 to 0–0.6 mg L −1 within 6.5 d under the aeration of 1–20% CO 2 , respectively, but no significant difference in consumed nitrogen versus phosphorus ratio was observed among different CO 2 concentration. The kinetics of nutrients removal were also determined through the application of pseudo first order kinetic model. 5–10% CO 2 aeration was optimal for the growth of C. vulgaris in the domestic wastewater, based on the coupling of carbon consumption, microalgal biomass, the nutrients removal and kinetics constants.

Original languageEnglish (US)
Pages (from-to)977-985
Number of pages9
JournalChemosphere
Volume186
DOIs
StatePublished - Nov 1 2017

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All Science Journal Classification (ASJC) codes

  • Pollution
  • Chemistry(all)
  • Health, Toxicology and Mutagenesis
  • Environmental Engineering
  • Environmental Chemistry

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