Biological Phosphorus Removal And Recovery By The Combined Medium Anaerobic/Aerobic Biofilter System

Phosphorus is the essential nutrient element in the organisms in nature, and also be thedecisive factor of causing eutrophication. The anaerobic/aerobic biofilter has the characteristicsof compact, high efficiency, convenient management, and it is a new technology that accordswith our city development in china. This research adopts the combined packing anaerobic/aerobic biofilter (AABF) to treat municipal wastewater with low carbon (C) to P ratio (C/P=11),and biofilter is filled with lava-quartz sand double-deck as carrier to be attached bymicroorganism, comparative analysis of the biological phosphorus removal efficiency ofcombined and single medium AABF was made at the stage of hanging membrane and stableoperation; The paper study the influence of carbon source regulation-phosphorus recovery(CSR-PH) mode on the quantity of phosphorus accumulating organisms (PAOs), the PHBinduced ability and biological phosphorus accumulating ability; The magnesium potassiumphosphate (MKP) crystallization method is used to produce high concentration phosphorusrecovery liquid, and the phosphorus recovery efficiency is calculated. The main research resultsare as follows:①The film-hanging speed and attached biomass on combined packing are superior to thoseon single packing; The COD removal efficiency reaches more than74%, ammonia nitrogenremoval efficiency reached more than94%and total phosphorus removal efficiency fluctuates inthe range of28.98%~52.99%at the hanging membrane stage of the combined packing anaerobic/aerobic biofilter; The finished time of hanging film on combined packing is25days, and thaton single packing is30days; The total phosphorus removal efficiency is80.21%in lava-quartzsand combined packing AABF, and its TP removal efficiency is obviously better than that is75.38%in quartz sand single packing AABF. Adding biological cotton Between the lava rockand quartz sand packing layer, and it improves the phosphorus removal performance of the whole system effectively. The appropriate influent ammonia concentration range is24~36mg/Lin combined packing AABF. The addition of3.64mg/L magnesium ion and4.62mg/L potassiumion can make combined packing biological aerated filter keep the optimal phosphorus removalstate; The COD removal in the combined packing AABF mainly occurred on the lava rock layer,and the total phosphorus removal mainly develop on the bottom of packing layer (0~300mm)and central layer (300~600mm). The COD and TP removal efficiency of the whole packing layerin the combined packing AABF is significantly better than that in the single AABF.②The biofilm of combined biofilm biofilter contains abundant phosphorus at the biologicalphosphorus accumulating stage: Using the combined packing is advantageous to form biofilmwith good performance that can accumulated phosphorus; The anaerobic phosphorus release rateand aerobic phosphorus uptake rate of backwashing biofilm in combined packing AABF are3~7mg P/(g VSS hour). In the phosphorus accumulating period, a lot of PHB in PAOs body canaccelerate PAOs aerobic phosphorus uptake rate; The fluctuation of Influent carbon sourceconcentration will affect the characteristic of the biofilm, and increasing carbon source is helpfulto improve the phosphorus release and uptake characteristic of biofilm reasonably whenbiological phosphorus accumulating reaches saturated.③Reasonable carbon source adding and chemical phosphorus recovery methods canimprove the phosphorus recovery efficiency of the whole system at the phosphorus recoverystage: This experiment adopts the continuous circulating type to supplement influent carbonsource that is advantageous to save influent carbon source and phosphorus recovery time.Carbon source regulation-phosphorus recovery mode and regular influent carbon sourcesupplement can make biofilm accumulating a large amount of PHB, and high concentrationphosphorus released liquid is produced that is conducive to the subsequent formation of MKPprecipitation, and also improve the removal efficiency of wastewater phosphorus and otherinorganic salts. The carbon source supplement cycle is10days, and shortening supplementalcarbon addition cycle reasonably can effectively improve the phosphorus recovery efficiency;During using the MKP crystallizing way to recovery the supernatant of anaerobic highphosphorus produced by AABF, the optimal pH was10, the optimal Mg:K:P is1.5:0:1, and theoptimal initial phosphorus concentration is above80mg/L; The long-term operation results of AABF system shows that the global phosphorus recovery efficiency can reach43%.