Compare Of Enrichment And Metabolism Characteristics Between Denitrifying Phosphorus Removal Bacteria And Traditional Phosphorus Accumulating Organisms

In the traditional aerobic phosphorus-accumulating organisms (PAOs) and denitrification phosphorus-accumulating organisms (DNPAOs) enrichment systems, in order to investigate characteristics of PAOs metabolism and determine the best kind of carbon source for biological phosphorus removal, three kinds of carbon sources were used for investigating their effect on phosphorus removal speed, phosphorus removal efficiency and characteristics of biologic metabolism.In the traditional PAOs enrichment SBR (sequencing batch reactor) systems, three different carbon sources were added separately to examine phosphorus release and uptake characteristics. Results showed that the order of 3 types of carbon source according to the rate of phosphorus removal is: sodium acetate (99.5%) > sodium propionate (93.4%) > glucose (91.5%). When sodium acetate is the sole carbon source, system's effluent quality is the best one and sodium acetate is the best carbon source for biological phosphorus removal. At the end of anaerobic period, the order of 3 types of carbon source according to the amount of anaerobic phosphorus release is: sodium acetate (37.8mg/L) > sodium propionate (33.0mg/L) > glucose (31.6mg/L), according to the concentration of phosphorus in effluent: sodium acetate (0.04mg/L) < sodium propionate (0.53mg/L) < glucose (0.67mg/L). The order of three kinds of carbon source according to amount of aerobic uptake phosphorus is: sodium acetate (44.9mg/L) > sodium propionate (40.5mg/L)> glucose (38.9mg/L). Sodium acetate leads the largest amount of uptake phosphorus. When the carbon source induced the largest anaerobic average release speed, it leads the largest average uptake phosphorus speed, the order of 3 types of carbon source according to the amount of anaerobic-induced is: Vsodium acetate (7.6mgP/L.h) > Vsodium propionate (5.4mgP/L.h) > Vglucose (4.6mgP/L.h), order according to the average speed of phosphorus uptake caused by three carbon source is: Vsodium acetate (15.0mgP/L.h) > Vsodium propionate (13.5mgP/L.h) > Vglucose (13.0mgP/L.h).Under anaerobic condition, synthesis amount PHB (poly-β-hydroxybutyrate) by sodium acetate in PAOs enrichment system is highest and amount of anaerobic phosphorus release is largest too. Moreover, the concentration of phosphorus in effluent is lowest. Under conditions of three kinds of carbon source, order according to amount of anaerobic PHB synthesis is: sodium acetate (69.3mgPHB/gMLSS) > sodium propionate (55.8mgPHB/gMLSS) > glucose (31.5mgPHB/ gMLSS). When sodium acetate, sodium propionate and glucose as the sole carbon source, differences of characteristic metabolic of PHB are as follows: three types of carbon sources systems in the anaerobic system period, amount of synthesis PHB is liner with the phosphorus released amount. When sodium acetate is the carbon source, the amount of anaerobic synthesis PHB and the amount of uptake phosphorus has the best linear correlation and the quality of effluent is best. As the glucose metabolically ways are more complex, the anaerobic amount of synthesis PHB and anaerobic phosphorus released has less relevance.In the DNPAOs enrichment SBR systems, three different carbon sources were added separately to examine phosphorus release and uptake characteristics. Results showed that during anaerobic period, the amount of anaerobic phosphorus release and the speed of phosphorus release are related to the situation of carbon utilization, during anaerobic period, when the amount of carbon removal is larger, the amount of phosphorus release is higher and speed of phosphorus release is faster. During anaerobic period the order of different carbon source according to the amount of anaerobic phosphorus release is as follows: sodium acetate (29.6mgP/L) > sodium propionate (18.0mgP/L) > glucose (12.4mgP/L), and the amount of average phosphorus release speed is as follows: sodium acetate (7.4mgP/L) > sodium propionate (4.5mgP/L) > glucose (3.1mgP/L). The best carbon source which induced anaerobic phosphorus release is sodium acetate. Phosphorus removal efficiencies has nothing to do with the largest speed of phosphorus release and the largest speed of phosphorus uptake is only related with the average speed of anaerobic phosphorus release phosphorus uptake. When glucose is the sole carbon source, during anaerobic period the amount of COD removal is the less one, and the remaining carbon which is taken into anoxic period will influence on denitrifying phosphorus removal. The reason may be complicated with glucose complex metabolism pathway. Under conditions of three different carbons source, during anoxic period DNPAOs will break down carbon and translate it into inner carbon source PHB. Then, the Poly-p particle uptake phosphate from wastewater, meantime, the synthesis of glycogen is prepared for the next cycle of denitrifying phosphate. The speed of anaerobic PHB synthesis by sodium acetate is largest, followed by glucose, the lowest is sodium propionate. In different kinds of carbon source systems, the anoxic PHB decomposition speed by sodium acetate is largest and sodium propionate is the secondly, the smallest is glucose. The carbon source which induced a higher maximum PHB anaerobic synthesis speed, can not lead a higher anoxic maximum decompositions speed. The quality of effluent only relate to average anaerobic PHB synthesis speed and anoxic average PHB decomposition speed, but have nothing to do with the maximum anaerobic PHB synthesis speed and anoxic maximum PHB decomposition speed, also, a faster anaerobic average synthesis speed of PHB will lead a faster anoxic average synthesis speed. Under condition of three kinds of carbon source, glycogen anaerobic maximum synthesis speed and anoxic maximum synthesis speed has no correlation, the average speed of anaerobic decomposition of glycogen and anoxic average speed of synthesis is also very poor correlation, the maximum anaerobic decomposition speed is higher will not induce the fastest anoxic synthesis speed faster. Results showed tha: in three different kinds of carbon source DNPAOs enrichment systems, the fastest anaerobic glycogen degradation speed has nothing to do with the maximum anoxic synthesis speed, also the average glycogen degradation speed has poor relationship with average anoxic synthesis speed. A faster average degradation speed did not induce a faster anoxic synthesis speed.By comparison between PAOs and DNPAOs, it was found that in three different carbons source DNPAOs enrichment sludge systems, all of the systems show that the amount of anaerobic released phosphorus, speed of anaerobic phosphorus release are lower than that in PAOs enrichment systems. But their qualities of effluent are all meet the criteria, and DNPAOs systems are able to get simultaneous denitrifying and phosphorus removal. Based on this point, DNPAOs has more advantages than PAOs for biological nutrient removal.