Scholarlink

<p>Nitrate contamination in groundwater poses significant health risks, underscoring the need for effective bioremediation strategies. This study assesses the nitrate removal and CO₂ fixation efficiencies of two microalgae species, <i>Chlorella vulgaris</i> and <i>Scenedesmus</i> sp., cultivated in batch monocultures and mixed cultures. The goal was to reduce nitrate concentrations below the 10&#xa0;mg/L NO₃<sup>–</sup>-N standard within a short hydraulic retention time (HRT), while minimizing the formation of undesirable byproducts. Initial results showed that <i>Chlorella vulgaris</i> monoculture achieved a biomass productivity of 0.12&#xa0;g/L/d and a NO₃<sup>–</sup>-N removal rate (NRR) of 10&#xa0;mg/L/d, whereas <i>Scenedesmus</i> sp. reached 0.19&#xa0;g/L/d and 12.7&#xa0;mg/L/d, respectively. Mixed cultures outperformed monocultures, with an NRR of 13.2&#xa0;mg/L/d over 73&#xa0;h, effectively lowering nitrate-nitrogen concentrations below 10&#xa0;mg/L. The highest CO₂ fixation rate (R<sub>CO2</sub>) in mixed culture was 0.39&#xa0;g/L/d, surpassing monoculture rates of 0.21 and 0.36&#xa0;g/L/d for <i>Chlorella vulgaris</i> and <i>Scenedesmus</i> sp., respectively. However, released COD as an undesirable byproduct peaked at 45&#xa0;mg/L in mixed cultures. Different inoculation ratios of <i>Scenedesmus</i> sp. to <i>Chlorella vulgaris</i> (1:1, 2:1, and 1:2) were tested at equal total cell densities. The 2:1 ratio favoring <i>Scenedesmus</i> sp. Increased biomass productivity to 0.22&#xa0;g/L/d and NRR to 13.6&#xa0;mg/L/d, with an R<sub>CO₂</sub> of 0.41&#xa0;g/L/d. In contrast, the 1:2 ratio yielded 0.187&#xa0;g/L/d biomass productivity and 12.5&#xa0;mg/L/d NRR. These results show that optimizing species ratios in mixed microalgal cultures enhances nitrate removal and CO₂ fixation, providing a fast, effective method for bioremediation of groundwater.</p> Graphical abstract <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Optimizing Mixed Cultures of Chlorella vulgaris and Scenedesmus Sp. for Enhanced Nitrate Removal and CO2 Fixation in Groundwater Bioremediation

  • 期刊论文

  • 发表日期：

    2025年9月4日

查看全文
  • Fariba Rezvani

摘要

Nitrate contamination in groundwater poses significant health risks, underscoring the need for effective bioremediation strategies. This study assesses the nitrate removal and CO₂ fixation efficiencies of two microalgae species, Chlorella vulgaris and Scenedesmus sp., cultivated in batch monocultures and mixed cultures. The goal was to reduce nitrate concentrations below the 10 mg/L NO₃–-N standard within a short hydraulic retention time (HRT), while minimizing the formation of undesirable byproducts. Initial results showed that Chlorella vulgaris monoculture achieved a biomass productivity of 0.12 g/L/d and a NO₃–-N removal rate (NRR) of 10 mg/L/d, whereas Scenedesmus sp. reached 0.19 g/L/d and 12.7 mg/L/d, respectively. Mixed cultures outperformed monocultures, with an NRR of 13.2 mg/L/d over 73 h, effectively lowering nitrate-nitrogen concentrations below 10 mg/L. The highest CO₂ fixation rate (RCO2) in mixed culture was 0.39 g/L/d, surpassing monoculture rates of 0.21 and 0.36 g/L/d for Chlorella vulgaris and Scenedesmus sp., respectively. However, released COD as an undesirable byproduct peaked at 45 mg/L in mixed cultures. Different inoculation ratios of Scenedesmus sp. to Chlorella vulgaris (1:1, 2:1, and 1:2) were tested at equal total cell densities. The 2:1 ratio favoring Scenedesmus sp. Increased biomass productivity to 0.22 g/L/d and NRR to 13.6 mg/L/d, with an RCO₂ of 0.41 g/L/d. In contrast, the 1:2 ratio yielded 0.187 g/L/d biomass productivity and 12.5 mg/L/d NRR. These results show that optimizing species ratios in mixed microalgal cultures enhances nitrate removal and CO₂ fixation, providing a fast, effective method for bioremediation of groundwater.

Graphical abstract