Growth condition study of algae function in ecosystem for CO2 bio-fixation.

Algae niche play a crucial role on carbon cycle and have great potential for CO(2) sequestration. This study was to investigate the CO(2) bio-fixation by the high rate pond (HRP) to mimic the algae function of nature. All the reactors can keep CO(2) consumption efficiencies over 100%. The statistical analyses proved HRPs were close to the natural system from all the growth conditions. The HRP could show the "natural optimization as nature" to perform as well as the artificial reactor of continuously stirred tank reactor (CSTR). In the nutrition study, the carbon mass balance indicated CO(2) was the main carbon source. Accordingly, the HRPs can keep a neutral pH range to provide dissolved oxygen (DO), to promote total nitrogen (TN)/total phosphorous (TP) removal efficiencies and to demonstrate self-purification process. Furthermore, the observations of different nitrogen species in the reactors demonstrated that the major nitrogen source was decided by pH. This finding logically explained the complex nitrogen uptake by algae in nature. Consequently, this study took advantage of HRP to explore the processes of efficient CO(2) uptake with the corresponding growth condition in the ecosystem. Those results contributed the further understanding of the role of CO(2) bio-fixation in nature and demonstrated HRP could be a potential ecological engineering alternative.