Study On Partial-nitrification/ANAMMOX Coupled Process For Landfill Leachate

Leachate generated from landfill contains high concentrations of ammonium and organiccompounds, varies significantly in composition and flow rate, thus making its treatmentenergy-gobbling and highly expensive. Combined partial-nitrification/ANAMM OX processwithout adding carbon source, does not produce alkali, without any secondary pollution etc,which so far is the most economical, and efficient biological nitrogen removal process.However, the PN-ANAMMOX technology has not yet been fully investigated; The reason areboth ammonia oxidation bacteria (AOB) and ANAMMOX bacteria (AnAOB) are slowgrowers, and are susceptible to the variation in wastewater compositions and operationalconditions, thus resulting in a slow reactor startup and a difficult process control and afrequent instability in operation.Relevant experimental study is carried out for studying process control of ANAMMOXPN units, meanwhile, examining the rules of the process control on combiningPN-ANAMMOX. The main conclusions obtained were showed as follows.(1) By using endpoint pH control in a sequencing batch reactor (SBR), partial nitritationof landfill leachate was achieved. Optimal effluent NO2--N/NH4+-N molar ratio is controlledby endpoint pH. At specific endpoint pH, the higher concentration of ammonia nitrogeninfluent contains, the higher NO2--N/NH4+-N molar ratio effluent contains. effluentNO2--N/NH4+-N molar ratio is affected by each period of influent flow rate, at specificinfluent condictions, lower influent flow rate cause higher effluent NO2--N/NH4+-N molarratio.(2)Do research on performance ANAMMOX fed up with synthetic wastewater. Bycontrolling HRT and influent total nitrogen (TN), the maximum of nitrogen removalrate(NRR) of ANAMMOX reactor is7.67.6kg/m3/d. The pH and conductivity can be theperformance indicators of ANAMMOX reactor. The reduction of conductivity betweeninfluent and effluent has a good linear relationship with TN removal rate, which can grasp thenitrogen removal efficiency of reactor through conductivity in a timely manner. The kineticsof ANAMMOX describes υmax=9.41kg/m3/d, KB=6.57kg/m3/d.(3) ANAMMOX-UASB use the PN unit effluent as influent at combinedPN-SBR/ANAMMOX-UASB process. There are four phases according to the nitrogenremoval performance of ANAMMOX-UASB, at stable high nitrogen rate phase ofANAMMOX-UASB, ammonia nitrogen removal rate is88.4±7.2%, nitrite nitrogen removalrate is92.6±7.3%, TN removal rate is82.1±7.5%, the nitrogen loading rate is1.90±0.0.57kgN/m3/d, the max ammonia nitrogen removal rate is95.95%, max nitritenitrogen removal rate is99.50%, max TN removal rate is89.67%, max nitrogen removal rate(NRR) is3.02kgN/m3/d.