Hu Jiangjun

Controlling the organic contamination strength of municipal wastewater with spirulina platensis

During a comparatively short period of time, fresh and marine eutrophication has become a large scale and world-wide problem. The effectiveness of nitrogen and phosphorus removal of the secondary efferent of sewage was tested, by means of spirulina platensis 439 and 972. The reactor was 1L and 2L beakers and operated under solar light at the temperature in the range of 28°C to 5°C, for four months. Water temperature and COD concentration were the primary factors to the removal efficiency of TN. The sound removal efficiency of TN was observed under spirulina platensis 439 and 972 from 10Chlµg/L to 30Chlµg/L, COD≤50mg/L, and hydraulic retention time (HRT) from 5d to 7d at temperature in the range from 25°C to 30°C. And the optimal balance between the removal efficiency of TN and the increase of TP was provided. The 439 and 972 removal efficiencies of total nitrogen were from 89% to 7% and from 82% to 6%, respectively under spirulina platensis of 20Chlµg/L, COD of 50mg/L, and at temperature in the range from 28°C to 5°C, for 6 days. The 439 and 972 removal efficiencies of total nitrogen were from 87% to 43% and from 82% to 41%, respectively under spirulina platensis of 20Chlµg/L, COD from 50mg/L to 140mg/L, at temperature 25°C, for 6 days. The removal efficiencies of TP were 5.8%∼15% and 3.1%∼10.6%, representatively when was joined spirulina platensis 439 and 972 in wastewater after 5 days. There had less removal efficiency of TP. And the TP concentration would reduce 3% or increase 16% by 439 and reduce 2% or increase 19% by 972 after 6 days. The removal efficiency of TN and TP using 439 were better than 972 under the same condition. There was higher TP concentration after 6 days if more spirulina platensis was joined. In one word, spirulina platensis could reduce the nitric and phosphorus pollution of point source and delay the fresh and marine eutrophication problem.