| The nitrogen cycle in nature is broken by the destruction of human activities on naturalecological systems, and nitrogen concentration in water is getting too high. So it is necessaryto work on the experimental and full-scale research of the treatment of high-ammoniaconcentration wastewater. Though the traditional nitrogen removal processe(nitrification-denitrification processe) can achieve the purpose of normal nitrogen removal, itcan't meet the requirement of treatment of the high-ammonia concentration wastewaterbecause of the weakness of the traditional nitrogen removal processe such as complexity onprocess, large power consumption, weakness of impact resistance, organic carbon addition,high operating cost. Therefore, it is necessary to study on new nitrogen removal processewhich is efficient and has low energy consumption. The partial nitritation-anaerobic ammoniaoxidation (ANAMMOX) has the advantages of low power consumption, no organic carbonaddition, less sludge production and low operating cost, plenty of investigators are workingon this process, and have brought out a lot of results.Nitritation reactor and ANAMMOX reactor were start up in SBR and UASB reactorrespectively, and the influence factors were studied, such as DO, pH, nitrogen loading rateand so on. Then the combined process of the two reactors was operated by synthetic ammoniawastewater. The main results were as follows:(1) On the basis of nitrification, NO－2-N accumulation was quickly obtained bydecreasing DO to0.8~1.3mg·L-1, and nitritation was achieved in68days while NO－2-Naccumulation was more than84%. Nitrite-oxidizing bacteria (NOB) were inhibited at low DOconcentration, nitritation could be achieved by controlling DO concentration. This studyshowed that nitritation was start up and operated stablely when DO was at0.5~1.3mg·L-1,moreover, NO－2-N accumulation was at a high level.(2) When an operation period was8hours, aeration flow was100L·h-1, NH4+-Nconcentration was300~350mg·L-1, CODCrwas300mg·L-1, partial nitritation was achievedby using half-alkalinity, while the ratio of NH4+-N/NO－2-N was around1:1.40. (3) When NH－4+-N and NO2-N concentration were165mg·L-1and220mg·L-1respectively, HRT was73hours, ANAMMOX reactor was start up in39days, while NH4+-Nand NO－2-N concentration were both below5mg·L-1, and the removal efficiency were bothmore than90%. In154days, NH4+-N and NO－2-N concentration were around250.4mg·L-1and320.7mg·L-1respectively, HRT was2.7hours, the removed nitrogen loading was morethan4.8kg TN/m-3d-1after raising nitrogen loading of ANAMMOX reactor by raisingnitrogen concentration of influent and shortening HRT. Futhermore, the topmost removednitrogen loading was4.883kg TN/m-3d-1in the day of133.(4) The combined process of nitritation and ANAMMOX was operated by syntheticammonia wastewater, when CODCrwas300mg·L-1, the removal efficiency of CODCrwasmostly more than88%. After the combined process was stable, NH4+-N and NO－2-Nconcentration were around132.3mg·L-1and173.6mg·L-1respectively in the effluent of thenitritation reactor, and NH4+-N and NO－2-N concentration were around3.9mg·L-1and6.1mg·L-1respectively in the effluent of ANAMMOX reactor when NH4+-N concentrationin the inlfuent of the combined process was aroud350mg·L-1, treated water was21L·d-1. Theaverage removal efficiency of total nitrogen was85.4%.(5) The effect of the combined process was limited by the ratio of NO－2-N/NH4+-N inthe influent of ANAMMOX reactor. When NO－2-N/NH4+-N was at1.26~1.45, the removalefficiency of total nitrogen was above80%, and NH4+-N and NO－2-N concentration were bothbelow10mg·L-1; When NO－2-N/NH4+-N was at1.1~1.26, the removal efficiency of totalnitrogen was still81.5%, but there was a certain amount of NH4+-N accumulation; When NO2－-N/NH4+-N was around1.0, nitrogen removal effect is significantly worse, NH4+-N wasaccumulated rapidly, the NH4+-N concentration in the effluent reached highly at130mg·L-1,and NO－2-N concentration get higher as the same. |
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