Treatment Of Highly Loaded Ammonia-nitrogen Wastewater By Moving-bed SBR

In this paper, the moving-bed SBR system is established to deal with ammonia-nitrogen wastewater by optimizing the process operating parameters. Membrane biological quantity, the evolution mechanism of species and community structure are investigated by microbiology molecular techniques. The main research contents are shown as follows:(1) The performance of moving-bed SBR system dealing with ammonia wastewater:Under the condition of NH4+-N100mg/L, COD decreasing from400mg/L to200mg/L gradually, the NH4+-N removal rate of system R1(25%packing fill rate) and R2(13%packing fill rate) are well. In running process, the nitrite accumulation and denitrification all appear in the moving bed SBR system. Moreover, there is a positive relationship between the fill rate and the two phenomenons. The higher COD concentration is conductive to denitrification and not to the accumulation of nitrite.(2) The microbial phase analysis results of moving bed SBR systemResults of scanning electron microscopy (SEM) on different periods of the suspended filler bio-film show that Brevibacterium occupy a major position in the original sludge. In early running stage, there is tan flocculent film on packing surface with loose structure. In the middle of running, a dense yellow-brown bio-film forms on the filler surface. Electron microscopy observation shows that Bacillus and Coccus are enrichment, gathering into a mass. Filamentous bacteria wrapped in microbial shape gradually are blurred. Back-end bio-film color is deepened. More intensive bacteria observed by electron microscopy shows that bio-films have already reached quite mature stage.Research the composition and diversity of microbial communities in the system using PCR-DGGE. The results show that the bacteria species are rich in the reactor and the main kind is the Proteobacteria genus. Most of the bacteria belong to aerobic heterotrophic bacteria, and a small part is facultative anaerobe. There are5bands having the function of reduction for nitrate and nitrite. The main ammonia-oxidizing bacteria in the reactor is Nitrosomonas. Three of them belong to Nitrosomonas European, while the others are non-cultivated.(3) Study of influencing factors of running for moving bed SBR system shows that:The NH4+-N removal rates under the conditions of four carbon sources (ethanol, sodium acetate, glucose and sucrose) didn’t have significant difference. When sodium acetate as the carbon source, TN remove rate was the highest. Under the condition of NH4+-N100mg/L, the NH4+-N removal rate decreases with the increase of COD concentration while COD was in100-400mg/L.But the NH4+-N removal rates were all above99%. The higher the organic concentration is, the greater the TN removal rate. Ammonia concentration in the range of30-50mg/L, the removal efficiency is better. Generally speaking, after five hours of reaction, the removal is nearly100%. The degradation of ammonia in the concentration of15-60mg/L follows the first order reaction kinetics.