Impact of Natural Microorganisms on the Removal of COD and the Cells Activity of the Chlorella sp. in Wastewater

In the treatment of wastewater containing only chemical oxygen demand (COD) byChlorellasp., the cell activity and proliferation ability ofChlorellasp. decreased with the culture time, which affected the removal of COD in wastewater. To solve these problems, theChlorellasp.–natural microorganism symbiosis system was prepared. The system was used to explore how natural microorganisms affect the cell activity and the proliferation ability ofChlorellasp. in wastewater. In the treatment of COD byChlorellasp., the removal rate of COD decreased from 45.47% to 28.88%, with a decrease in the cell activity and proliferation ability ofChlorellasp. In theChlorellasp.–natural microorganism symbiotic system, the removal rate of COD reached 45.75%. With the introduction of natural microorganisms, the circulation of CO2and O2betweenChlorellasp. and natural microorganisms promoted photosynthesis and respiration, which enhanced the cell activity ofChlorellasp. Under the condition that the dosage of natural microorganisms was between 1% and 6%, the concentration ofChlorellasp. was close to the logarithmic growth phase, which maintained the proliferation ability ofChlorellasp. At the same time, the natural microorganisms grew and proliferated in wastewater containing only COD through preying onChlorellasp.Keywords:Chlorellasp.;natural microorganisms;symbiosis system;cell activity;predation