Study On Denitrifying Phosphorus Removal And Denitrification In SBBR With Adding Polyurethane Carriers

Recently, nitrogen and phosphorus removal is a hot spot in the wastewater treatment field at home and abroad. New technologies were put forward to emerge in endlessly application with techniques of shortcut nitrification and denitrification, simultaneous nitrification and denitrification, phosphorus bacteria uptake phosphorus. While, there were few processes can achieve to remove the nitrogen and phosphorus in the same reactor. In order to solve the biological treatment process contradictions between the denitrification and phosphorus removal, the study combined the denitrifying dephosphatation technology to deal with the nitrogen and phosphorus removal in the SBBR.This study used simulation sewage as the research object and polyurethane as the carriers, through two kinds of operation modes, the experiment studied the denitrifying dephosphatation in the SBBR, even focused on the phosphorus removal.During three months, the system achieved to cultivate the denitrifying phosphorus bacteria from the macroscopy under the anaerobic/anoxic(An/A) conditions. TP average removal rate was 81.32% in the end of domestication. And the experiment also got the operation cycle under An/A conditions: anaerobic stirring (including water time) (120min) - anoxic (240min) - precipitation (30min)– drainage(5min) - standby (85min). The experiment studied the influence factors of denitrifying dephosphatation under An/A conditions, and the results showed that: When COD concentration was 150mg/L(NaAc/propionic acid=2), TP concentrations were below 5.44mg/L, pH was 7~7.5 in the influent, temperature was 25℃, nitrate concentration was about 65mg/L or nitrite concentration was about 20mg/L in the beginning of the anoxic influent, the average removal rates of COD, TP and TN pollutants in the SBBR system were respectively 88.14%, 94.59% and 64.40%, the effluents all met theⅠA standards.During one month, the system achieved to cultivate the phosphorus bacteria from the macroscopy under the anaerobic/aerobic/anoxic(A/O/A)(adding the carbon source in the beginning of the aerobic condition) conditions. TP average removal rate was 81.36% in the end of domestication. And the experiment also got the optimal operation cycle under A/O/A (adding the carbon source in the beginning of the aerobic condition) conditions: anaerobic stirring (including water time) (90min)– aerobic(90min) - anoxic(120min) - precipitation(30min)– drainage(10min) - standby(140min). The experiment studied the influence factors of denitrifying dephosphatation under A/O/A(adding the carbon source in the beginning of the aerobic condition) conditions, and the results showed that: When COD concentrations were 102.35~300mg/L in the influent, TP concentrations were 3.65~12.22mg/L, ammonium concentration was about 30mg/L, the COD concentration was about 110mg/L in the beginning of the aerobic condition, the average removal rates of COD, TP and TN pollutants in the SBBR system were respectively 93.50%, 96.46% and 98.92%, the effluents all met theⅠA standards.Compared the two kinds of operation modes in SBBR, the results showed that: An/A and A/O/A(adding the carbon source in the beginning of the aerobic condition) operation modes all had a better phosphorus removal and COD removal effects. While it need lower carbon source in An/A conditions, and the other had a better nitrogen removal performance.The experiment further studied the microcosmic system in microbiology, the results showed that: the system isolated three strains named 1#, 3# and 5#, they all had store phosphorus performance, Gram's staining were negative. Through the nitrate reduction experiments confirmed that the above three strains had nitrogen removal performance, and their average denitrification rates were respectively 75.82%, 78.26% and 62.48%.