Optimization For Treatment Of High Ammonia-Nitrogen And Organic Concentration Wastewater With AB-BSBR

The degradation of relatively high concentration ammonia with high COD wastewater were studied,the start-up and degradation of NH4+-N and NO2--N in AB-ASBR reactor were explored and the factors which affected the degradation performance in this task were analyzed.The study mainly include three aspects: the removal rate of NH4+-N and NO2--N when chemical oxygen demand existed;optimal operation of degrading high concentration organic sewage water by AB-ASBR,the main parameters were:the stirring frequencies of adsorption and regeneration period in reactor A,the reaction period in reactor B and flocculant quantity of polyacrylamide (PAM);the impact on COD to NH4+-N and NO2--N.The AB-ASBR reaction was successfully started-up175days later before a stable operation, when NH4+-N and NO2--N contents in the influent were550mg/L and320mg/L. The removing rates achieved92%and95%respectively.Compared with NO2--N, anaerobic sludge has stronger absorption ability than to adsorb NH4+-N. Firstly, the activated sludge has a larger specific surface area and possess preferable physical adsorption performance.Secondly, activatedsludge was composed of a large number of microbial cells and extracellularpolymer system, therefore, the negative surface potential and high adsorptionactivity were possessed.Therefore the adsorption of NH4+-N was a process ofion exchange adsorption, also known as chemical adsorption. Moreover, lowH/D increased the contacting area of the sludge and the liquid, provided properphysisorption and chemisorption environment, and accelerated the adsorptiveprocess.The stirring frequencies of adsorption and regeneration period in reactor A,the reactive period in bioreactor B, flocculant dosage of polyacrylamide (PAM)were optimized by orthogonal and single-factor experiments when the inflowCOD was7500mg/L. Primary and secondary sequence of parameters was thestirring frequencies of adsorption period in reactor A, the stirring frequencies ofreaction period in reactor B, the stirring frequencies of regeneration period inreactor A and flocculant dosage of PAM. The obtained parameters were:thestirring frequency of adsorption period in reactor A was chosen as20s/2min, thestirring frequency of reaction period in reactor B was7min/h, the stirringfrequency of regeneration period in reactor A was4min/h, and the flocculantdosage was15mg/L.The COD concentrations in the inflow were increased ranging from7500mg/L to10000mg/L when AB-ASBR was operated steadily. The COD inthe effluent was below100mg/L under totally anaerobic condition. The transformation rules of ammoina-N and nitrite-N in the reactor were investigated as the COD concentration was8000mg/L,9000mg/L and10000mg/L respectively.Statistics signified that the higher influent concentration of COD, the higher effluent ammonia-N concentration. While when it came to nitrite, inverse results were obtained.