Study On SHARON-ANAMMOX Process For Treatment Of Ammonium Wastewater

In recent years,with new theoretical development of biological nitrogen removal, people have developed a new variety of effective biological nitrogen removal processes,such as short-cut nitrification and denitrification,simultaneous nitrification and denitrification,and anaerobic ammonium oxidation(ANAMMOX),etal.When the single-reactor high activity ammonia removal over nitrite(SHARON)process was achieved in a sequencing batch reactor(SBR)and the nitrogen loading rates of ANAMMOX process in a anaerobic rotating biological contactor(ARBC)was improved for matching up to the accumulative quantity of nitrite in the effluent of SBR,the combination of SHARON and ANAMMOX process for the treatment of ammonium influents was studied.The results were showed as follows:1.Inoculated with common aerobic sludge,the SHARON process was achieved working at temperatures around 28℃,pH ranged between 7.0 and 8.0,maintaining the dissolved oxygen(DO)under 1 mg·L^-1and working with ammonium concentration of 150 mg·L^-1in SBR.The accumulative ratio of nitrite was achieved above 0.8 and the nitrogen loading rates were up to 0.26kgNm^-3day^-1and 0.077kgNkg^-1volatile suspended solids(vss)day^-1,respectively,after 20 days'opetation.From the study of ammonium consumption process,when the maximum ammonium oxidation rate was 0.0126mgNmg^-1vss h^-1,it was observed that pH began to decrease from 7.88 to 7.0 and then it starts to increasing until reaching the value of 7.74,accordingly,the DO was below 0.1 mg·L^-1during the first 3 hours and then it began to increase until reaching the maximum value of 5 mg·L^-1.With the microscope,it was observed that the floc of sludge was small and the bacteria with the shape of bacillus were gram negative.The ammonium oxidation bacteria(AOB)and nitrite oxidation bacteria (NOB)was present in a quantitative ratio of 10³:1 from the most possible number (MPN). 2.The stable operation of SHARON process was carried out working with ammonium concentration ranged between 150 mg·L^-1and 250 mg·L^-1.The ammonium elimination and the accumulative ratio of nitrite were achieved above 90%and 85%, respectively.The ammonium loading rate was up to 0.129kgNkg^-1vss day^-1.The MLVSS was reached 3600 mg·L^-1and the SVI was maintained at 70mL·g^-1.The color of the floc was changed to yellow white.3.In the period of ANAMMOX stable operation,when HRT was reduced from 24h to 16h and the concentration of nitrite and ammonium were 80 mg·L^-1,the ammonium average removal rate was reduced from 90%to 86%and the nitrite removal rate remained above 99,9%.The total nitrogen loading rate increased from 0.178 to 0.275kgNm^-3day^-1.When HRT remained at 24h,the total nitrogen loading rate increased from 0.225 to 0.445kgNm^-3day^-1by increasing the concentration of ammonium and nitrite.Working with the nitrite concentration of 210 mg·L^-1,the inhibition of nitrite concentration was detected in ARBC and the ammonium,nitrite and total nitrogen elimination decreased from 95.%,97%and 92%to 85%,87% and 82%,respectively.The color of the sludge was brown red and the bacteria with the shape of bacillus was gram negative by.the microscope.Some coccus was found gathered together on the surface of the granule sludge by scanning electron microscope.4.In the period of combined process operation,combination of SHARON and ANAMMOX process for the treatment of ammonium influents was studied when the quantity of nitrite removal in ARBC matched up to the accumulative quantity of nitrite in the effluent of SBR.Research results show that the SHARON process was achieved working with ammonium concentration ranged between 250 mg·L^-1and 300 mg·L^-1and working at temperatures around 28℃,pH ranged between 7.0 and 8.0, maintaining the dissolved oxygen(DO)under 1 mg·L^-1.The accumulative ratio of nitrite was achievedabove 85%and the ammonium loading rate was up to 0.133kgNkg`(-1)vss day^-1.The complete autotrophic nitrogen removal could be achieved when the effluent of SHARON process mixed ammonium was used for the influent of ANAMMOX process working at temperatures around 40℃.The ammonium,nitrite and total nitrogen elimination were above 86%,97%and 90%,respectively.The total nitrogen loading rate was 0.488kgNm^-3day^-1.