Experiment Study On Removal Of Nitrogen And Phosphorus From Sewage Using Anew Technology:Algae Biofilm Process

Using algae film remove the nitrogen and phosphorus in the wastewater, which have an important application prospect in prevent the water eutrophication. In this paper, Chlorella pyrenoidosa, Anabaena flosaquae and Scenedesmus obliquus used as target algae and a preponderant one would be screened. Build a reactor which consists of water tank, peristaltic pump, algae films, plate sedimentation tank and ultrafiltration device; manufacture the algae with the preponderant algae; Do the dynamic experiments which use the simulated water and the actual water from the South Lake in the condition of room temperature and light intensity of 3000-45001x of continuous illumination. The treatment effects of effluents, feasible and stable of the system have been verified in this process system. The main results summarized as follows:(1)In the optimization experiments of algae strains, the biomass of Chlorella pyrenoidosa, Anabaena flosaquae and Scenedesmus obliquus were 25.23%,25.23% and 36.45%, respectively. The results which combined the removal effects of N, P in artificial sewage by all of the three algae showed that Scenedesmus obliquus and Anabaena flosaquae have more obviously superiority in growth and removal efficiency.(2)The results of dynamic simulated municipal sewage experiment with a HRT of 6 days indicated that the removal ratios of TN, NH4+-N, TP and COD, on average, were 93.16,89.83%,96.16% and 90.22%, respectively. The average effluent concentration of TP, TN, NH4+-N and COD were 0.41 mg·L-1,2.36 mg ·L-1,1.34 mg·L-1 and 54.3 mg·L-1, reapectively; the turbidity of effluent lowewed to 2 degrees; the algae from the sewage could be completely filtering by the sedimentation tank and ultrafiltration system; the average temperature in the reactor was more 5.0 degrees Celsius higher than the room.(3)The results of actual water experiment showed that an unknown algae was emerged, compared with the FWAC(Freshwater Algae culture collection) by microscopy, found that it was most likely to be a haematococcus pluvialis.(4)The results of dynamic actual water experiment with a HRT of 4 days manifested that the average effluent concentration of TP, TN, NH4+-N and COD were,0.04 mg·L-1,0.65 mg·L-1,0.20 mg·L-1 and 29.80 mg·L-1, respectively; the removal ratios of TP, TN, NH4+-N and COD, on average, were 90.42%, 77.39%,91.47% and 52.61%, respectively; the pH and DO concentration in the reactor were 10.38 and 12.8 mg·L-1, basically maintain over 10.12 and 10.1 mg ·L-1; in addition, the average temperature in the reactor is more 4.0 degrees Celsius higher than that in the room.