The Research Of Removing P From Wastewater By Making Use Of Algae

With the developing of socio-economy and the improving of people living standard, our country enhanced the emission standard of municipal wastewater processing factory (TP<0.5mg/L), so the traditional phosphorus removal technology could no longer meet the demands. Because of the physiological function of alga -absorbing nutrients such as nitrogen and phosphorus, the way of applying alga to deal with wastewater is beginning to rise slowly. Applying alga to process wastewater is a new technology of wastewater treatment. It accord to the principle of ecology. It not only protect environment but also save energy.The experiment researched on the effect of applying attached algae growing on the bottom of fountain to remove nitrogen and phosphorus in wastewater on the condition of aeration mixing. The operation way was the following: aeration mixing in SBR reactor(10L), 30W light shining, temperature keeping at 20℃, water conned rapidly, aeration (6h), precipitate (1h), drainage (4L), leisure. The contents of NH₃-N and TP in synthetic wastewater were changed from17.08 mg·L^-1,4.33 mg·L^-1 to 3.75 mg·L^-1,0.17 mg·L^-1 respectively. The removal rates of NH₃-N and TP were up to 78.04% and 96.07%. The pH was changed from 7.60 to 7.95. Under the preconditions that the algal growth is natural, the rate of phosphorus removal will be increased with the raise of concentration of NH₃-N, temperature, intensity of illumination, and slant acid pH.The experiment also found that the attached algae system wasn't a single algae system, but algae - bacterium symbiotic system. Therefore, this system also has a high removal rate of COD. The COD was changed from 190.8 mg·L^-1 to 23.86 mg·L^-1. The removal rate of COD was up to 87.49%.Compared with the early algal nutrients treatment technology - high rate algal pond and immobilized algal, making use of attached algae formed processing system similar to the activated sludge treatment system not only have the effect of algae absorbing nitrogen and phosphorus, but also have the effect of bacterium removing organism. It is concluded that this processing system have the potential for wastewater treatment.