Treatment Of High Ammonia Wastewater By Partial Nitrification And Anaerobic Ammonia Oxidation

Partial Nitrification（PN）and Anaerobic Ammonium Oxidation（Anammox）,as emerging biological denitrification processes in recent years,have the advantages of low energy consumption,small sludge production and high denitrification efficiency,and have good application in the treatment of high ammonia nitrogen wastewater represented by farm wastewater.It has a good application prospect in the treatment of high ammonia nitrogen wastewater represented by farming wastewater.In this study,we firstly investigated the optimal parameters during the start-up and operation of the nitrification process in a sequencing batch activated sludge reactor（SBR）,and the changes of denitrification performance of the anaerobic ammonia oxidation system under different organic carbon source conditions in an upflow anaerobic sludge bed reactor（UASB）.The combined process of partial nitrosation and anaerobic ammonia oxidation was used to investigate the nitrogen removal performance of the combined process of anaerobic digestion,partial nitrosation and anaerobic ammonia oxidation in treating high ammonia nitrogen wastewater.During the experiment,high-throughput sequencing technology was used to observe the changes of microbial community succession in the nitrification reactor,and the changes of fluorescent substances in the reactor effluent were monitored by using parallel factor analysis combined with three-dimensional fluorescence technology.The main research contents and conclusions are as follows.1.The experimental results showed that the injection of hydroxylamine as an inhibitor effectively shortened the start-up time of the nitrosation reactor,and the stable accumulation time of nitrite nitrogen was shortened from the traditional 30 days to 23 days.When the temperature was 32℃,the dissolved oxygen concentration was 0.5 mg/L,and the influent COD concentration was less than or equal to 150 mg/L,the nitrite nitrogen accumulation in the nitrification reactor was the best,and the effluent concentrations of ammonia nitrogen and nitrite nitrogen at this stage were 31.68 mg/L and 78.28 mg/L,respectively.The effluent nitrite nitrogen concentration decreased significantly when the COD concentration exceeded 150 mg/L.2.The nitrosation reaction temperature was regulated to 15℃,20℃and 30℃,and the ammonia nitrogen concentration in the effluent was 67.21 mg/L,41.25 mg/L and 20.63mg/L after stable operation,corresponding to 52.78%,72.23%and 85.88%of ammonia nitrogen removal and 21.25 mg/L,67.59 mg/L and 80.29 mg/L of nitrite nitrogen removal,respectively.The nitrite nitrogen concentrations were 21.25 mg/L,67.59 mg/L,and 80.29mg/L,respectively;among them,higher nitrite nitrogen accumulation could be achieved in the effluent at 25℃and 30℃under normal high temperature conditions;the low temperature of 15℃severely inhibited the activity of ammonia oxidizing bacteria（AOB）and stronger activity of nitrite oxidizing bacteria（NOB）,resulting in poor nitrite nitrogen accumulation.3.When the concentration of hydroxylamine in the feed water was 5 and 10 mg/L,the nitrite nitrogen concentration in the system was accumulated in a large amount,and the highest nitrite nitrogen effluent concentration reached 85.52 mg/L,and the nitrite nitrogen accumulation rate was 93.06%.When the concentration of hydroxylamine was higher than10 mg/L,the accumulation rate of nitrite nitrogen was stabilized at 96.45%and did not change significantly.4.Different concentrations of organic carbon sources were added to the feed water of the successfully started and stably operated UASB anaerobic ammonia oxidation reactor to investigate the performance of the anaerobic ammonia oxidation bacteria and heterotrophic denitrifying bacteria in the reactor for synergistic denitrification under different organic shock loads.The best denitrification performance of the coupled system was achieved when the organic carbon source concentration was 120 mg/L,and the highest total nitrogen removal rate was 93.71%.When the organic carbon source concentration was greater than120 mg/L,the anaerobic ammonia oxidizing bacteria gradually lost their competitive advantage,the total nitrogen removal rate gradually decreased,and the denitrification performance of the coupled system gradually deteriorated.5.After both the nitrosation reactor and the anaerobic ammonia oxidation reactor were operated stably,they were treated in series with high ammonia nitrogen simulated wastewater,and the effluent of the nitrosation reactor was directly used as the feed water of the anaerobic ammonia oxidation reactor,so that the NO₂^--N/NH₄⁺-N ratio in the nitrosation effluent gradually approached the theoretical value.It was found that when the NO₂^--N/NH₄⁺-N of anaerobic ammonia oxidation influent was 1.44 and COD/NH₄⁺-N was1.01,the total nitrogen and COD concentrations of the effluent were kept at low levels,and the combined process had good treatment effect.The highest total nitrogen removal rate of the combined process reached 81.52%.The results showed that the removal rates of ammonia nitrogen and COD were kept at high levels when the combined process treated the actual farming wastewater,but after the anaerobic digestion treatment,there were still some hard-to-degrade organic substances in the water body that could not be degraded and utilized by the subsequent anaerobic ammonia oxidation reactor.6.Three-dimensional fluorescence spectroscopy combined with parallel factor analysis was used to analyze the composition and changes of fluorescent substances in the reactor effluent and during operation.The results were as follows:under organic load impact,the anaerobic ammonia oxidation reactor effluent contained three main fluorescent fractions,namely protein-like substances,fulvic acid-like substances,and humic acid-like substances.High-throughput sequencing of the sludge in the nitrosation reactor showed that the relative abundance of Nitrosomonas spp.reached up to 26.9%after successful start-up.Figure[39]table[18]reference[101]...