Integrated Process Of Anaerobic-Oxic Phosphorus Removal And Anaerobic Ammonium Oxidation Nitrogen Removal For Urban Sewage Regeneration

Urban sewage has been internationally recognized as valuable city's "secondresources", while the research, development and application of the integrated processfor regeneration of municipal wastewater is very important for alleviating the watercrisis, restoring or maintaining the healthy cycle of cultural water. In biologicalwastewater treatment process, in order to solve the contradictions and competitionsessentially between the nitrogen removal bacteria and phosphorus removal bacteria,the removal of phosphorus and nitrogen can be considered separately. Currently,anaerobic-oxic process is the most economical and reliable for biological phosphorusremoval, while for biological nitrogen removal, anaerobic ammonium oxidationundoubtedly owns more significance for sustainable development.For the integrated reclamation process of municipal wastewater includinganaerobic-oxic biological phosphorus removal and shortcut nitrification-anaerobicammonium oxidation (ANAMMOX), the problem of activated sludge bulking issolved, and the reactor's fast recovery techniques are determined through adjustingthe operation parameters of phosphorus removal reactor. Through the analysis on themechanism characteristics for the reaction of shortcut nitrification and ANAMMOX,the main effect factors for biological autotrophic denitrification reaction aredetermined, and the main technical means of ANAMMOX reaction for municipalwastewater with low ammonia are put forward. Nitrogen and phosphorus removalbacteria from the integrated process are coupled, and the reactor's runningperformance is explored, thus providing basis information for the optimization ofintegrated process.The primary content and innovations of this research work are as follows:(1) The low dissolved oxygen control is the main way for the partialnitrosation of municipal wastewater For nitrosation system of biofilter, the DOconcentration in the biofilm system can be controlled well through the approach ofcombination of aeration in the water column of upper part of the filter and inner loopdevice carrying DO. At the same time, the pH value of treated water can be improved,which is more conductive to the enrichment and growth of ammonia-oxidizingbacteria. Under the intermittent running conditions for the notrosation biofilter, theconcentration change of NH4+-N, NO2--N and NO3--N all have the dynamics characterof zero-order reaction, while the change trend of the ratio between NO2--N andNH4+-N shows a quadratic variation. Accordingly, the suitable hydraulic retentiontime (HRT) for partial nitrosation should be controlled between 9.05 to 13.58 hoursunder the experimental conditions.(2) The fast startup of ANAMMOX biofilter for municipal wastewater withlow ammonia and room temperature is achieved The domestication and rapid expansion process of ANAMMOX bacteria should be experienced for the startup ofbiofilter reactor inoculated ANAMMOX bacteria, which includes 30 days for thedomesticated time, and 75 days for the rapid amplification time. The biofilm reactortaking bioactivity volcanic ceramic as filter media is recognized as the carrier for theenrichment and amplification of ANAMMOX bacteria. In the reactor startup process,the gas production quantity, the changes of biofilm color, the nitrogen transformationand the pH value etc., can be recognized as the important symbol for demonstratingthe characteristics of the phases of domestication and multiplication.(3) The phosphate effect mechanism for the running performance ofANAMMOX biofilter is put forward There is a reversible inhibition effect on theANAMMOX reaction for municipal wastewater with room temperature and lowammonia through increasing the phosphate concentration in the influent. When the TPconcentration is more than 10 mg/L, some crystal sediments such asMgNH4PO4·6H2O (MAP) will begin to form in the filter, which may fill the pore ofANAMMOX biofilter and block the normal delivery of ANAMMOX reactionsubstrate, thus resulting in the significant decreasing of nitrogen removal load. Thenitrogen removal load can be restored to 88.8% of the original ability in two daysthrough the union of stopping adding the phosphate, reducing the pH value inshort-term and backwashing.(4) The method of simultaneous nitrosation-ANAMMOX in SBR isestablished In the process of simultaneous nitrosation-ANAMMOX for municipalwastewater treatment in SBR suspended activated sludge reactor, for DO, 1 mg/L canbe recognized as the end sign for the SBR reaction cycle under the system runningconditions of no more than 0.3 mg/L according to the cycle variation of DO, ORP andpH. At lower temperatures, the activity of anammox bacteria is difficult to be raised.Given the actual situation of urban sewage treatment works, the appropriateincreasing of the biomass density for ANAMMOX bacteria is a feasible approach forimproving the effect of nitrogen removal by ANAMMOX process compared to thetwo ways of raising temperature and adding non-aeration term.(5) The startup of CANON biofilter is realized under the conditions ofmunicipal wastewater with low ammonia and room temperature Controlling DOcan be recognized as the main control factor for the biofileter's startup ofnitrosation-ANAMMOX for urban wastewater in the conditions of room temperatureand low ammonia nitrogen. The DO concentration in the biofilm system can becontrolled well through the union approach of aeration in the upper water of biofilterand the inner loop device carrying DO in the treated water. In intermittent operatingconditions, the whole reaction cycle can be real-time controlled according to thechanges of pH value.