Research On Methods Of Activated Sludge Nitrosation And Denitrificat Phosphorus Removal

This experiment is based on continuous-flow two-sludge nitrification denitrifying phosphorus removal system, at the acclimation stage, the processing object is ideal artificial water without carbon source, realize to start the enrichment of nitrification bacteria rapidly; treat simulated domestic wastewater as processing object, domesticate the nitrification denitrifying phosphorus accumulating bacteria by three stage method, domesticate the phosphorus accumulating bacteria by anaerobic/aerobic alternate running, through anaerobic/anoxic/aerobic alternate operation to domesticate nitrification denitrifying phosphorus accumulating bacteria, gradually shorten the aerobic time and prolonged hypoxia time in this stage, in the anoxic phase adding nitrite, anaerobic/anoxic alternate operation, strengthening nitrification denitrifying phosphorus accumulating bacteria.When the two kinds of bacteria are domesticated mature, connecting the two-sludge system;The results of continuous-flow two-sludge nitrification denitrifying phosphorus removal system show that, treatment effect of the real life sewage with this system is very good, for COD, total phosphorus and ammonia nitrogen the average removal rate is respectively77.51%,88.19%and72.67%. Through long-term experiments, we discovery that for sewage treatment the optimal C/N ratio of the system is3.0-5.0, the C/N ratio is too high or too low will affect the nitrogen and phosphorus efficiency of the effluent. At the same time, the effluent of the system will be effected by the sludge reflux ratio, the ammonia in the effluent is4-20mg/L, it is a little high, so the process can not achieve complete removal of nitrogen, which is the main disadvantage of two sludge system. When the beyond sludge reflux ratio is0.35-0.43, the removal effect will be better, if the beyond sludge reflux ratio is too high,it will affect the ammonia removal efficiency of the effluent,but if it is too low,it will affect the ammonia nitrogen and TP removal efficiency of the effluent. When the C/P ratio is11.8,it will up to the best treatment effect.The hydraulic retention time of post aeration tank should not be too long, post aeration time is adjusted to20min, can guarantee the system a good TP, TN and COD removal effect, after a period of operation, the system operational status and sludge are both in good condition.By the synchronizing intermittent test and static beaker test on influence of anaerobic phosphorus release with different carbon source,it is found that when the carbon source is sodium acetate, phosphorus release amount and the release rate is the biggest, followed by sodium propionate, the worst is using glucose as carbon source. With glucose as carbon source, almost can not observe phosphorus release phenomenon, even with phosphorus absorption phenomenon. Study of the NO2-/NO3-concentration ratio found that, when the NO2-/NO3-concentration is3.33, the removal rate of COD, total phosphorus is the best, the average removal rate is87.41%and91%. the domesticated nitrification denitrifying phosphorus accumulating sludge has a high tolerance limit of nitrite nitrogen, when the nitrite nitrogen concentration is40mg/L, will begin to inhibite the nitrification denitrifying phosphorus accumulating bacteria.Using traditional isolation and identification technology of bacteria, for the mixed liquid of hypoxia reacto, in nitrification denitrification bacteria and phosphorus accumulating bacteria medium using mixing plate method to isolate and identificate strain, and then do nitrification denitrification absorption of phosphorus test on the enrichment of single bacteria strains, screening the strain with nitrification denitrifying phosphorus uptake capacity. By means of experiments obtain5denitrifying bacteria strain with obvious denitrification effection, belong to Klebsiella, Bacillus (2), Enterobacteriaceae, Moraxella and Bacillus, and5phosphorus accumulating bacteria,belong to Enterobacteriaceae (2), Pantoea, Paracoccus, Staphylococcus. Through the absorption of phosphorus test and special staining found that the isolated7strains of nitrification denitrifying phosphorus accumulating bacteria all with different extent denitrifying phosphorus uptake ability. The phosphorus absorption of genus unit cell of Pantoea, Bacillus, Paracoccus, Klebsiella, Staphylococcus, Enterobacteriaceae and Moraxella bacteria are decreased, respectively, they are1.98×10-11mg/cfu1.64×10-1mg/cfu/1.43×10-11mg/cfu、1.13×10-1mg/cfu、9.59×10-12mg/cfu、7.72×10-12mg/cfu and6.28×10-12mg/cfu; special staining test shows that, at the polyphosphate granules in the vivo of anaerobic stage nitrification denitrifying phosphorus accumulating bacteria gradually decreased, PHB particles increased significantly; at the anoxic phase PHB content decreased, in the vivo of organism the polymeric phosphate (Poly-p) increased. In the10strains the amount of Enterobacteriaceae are the highest, there are3lines, accounted for30%of the total; there are2Bacillus strain, accounting for20%of the total; the rest of the Klebsiella, Pantoea, Paracoccus, Staphylococcus and Moraxella bacteria is1strain, respectively.