Nitrogen In Wastewater Research Articles

Performance and microbial communities of denitrification using construction waste as filler for nitrate removal

The increasing amount of construction waste generated by the construction industry is causing serious pollution to the environment. In our research, the feasibility of construction waste as filler for denitrification was investigated. The physical and chemical properties of ceramic pellet and construction waste were compared and analyzed using scanning electron microscopy and Fourier transform infrared spectroscopy characterization. In addition, the ability of construction waste to treat high concentrations of nitrogenous wastewater was investigated and the structure of the extracellular polymer and microbial community was analyzed. The results showed that the removal rates of NO3--N and COD of construction waste were stable at 98% and 60%, and the biofilm in the construction waste reactor is more hydrophobic and denitrification-related microorganisms are more advantageous. Experimental results demonstrate that construction waste was feasible as a filler for denitrification filters, and this study also achieve the purpose of treating waste with waste.

Study on adsorption of ammonia nitrogen by sodium-modified kaolin at calcination temperature.

Natural kaolin (NK) is not used as a material for removal of ammonia nitrogen in wastewater because of its low ammonia adsorption capacity. In this study, sodium-modified kaolin adsorbent (NaCK) with high ammonia nitrogen adsorption capacity was prepared by NaOH modification of calcined NK, which was developed to address this problem. The adsorption properties were evaluated by batch static adsorption test. The results showed that when the initial concentration of ammonia nitrogen was 10 mg/L, pH = 8, and dosage of adsorbent was 1 g/L, the adsorption capacity of NaCK-600 for ammonia nitrogen was the best, reaching 6.23 mg/g, which was 34.6 times higher than that of NK (0.18 mg/g). Batch static adsorption test combined with adsorption kinetics, adsorption isothermal, and characteristic data showed that NaCK prepared at different temperatures had different adsorption mechanisms. Batch static adsorption test data of NaCK-600 was in good agreement with the pseudo-second-order model and Langmuir model, and the main mechanism of its adsorption of ammonia nitrogen was the ion exchange of NH4+ and Na+ in NaCK. After the third cycle, the removal rate of NaCK-600 was still up to 76.44%, which indicates that NaCK-600 has considerable potential for removal of ammonia nitrogen in wastewater and provides a new way for the application of kaolin in removal of ammonia nitrogen.

Isolation, Identification and Characterization of Denitrifying Phototrophic Bacteria from Marine and Aquaculture Wastewater

Denitrifying bacteria occur primarily in the soil and play an important role in the nitrogen cycle and wastewater treatment. This study investigated the possibility of isolating denitrifying phototrophic bacteria from marine and aquaculture wastewater. The denitrifying ability of isolates was examined through their utilization of inorganic nitrogen and nitrate reductase test. The photosynthetic capability of the isolates was determined by detecting the photosynthetic pigments (bacteriochlorophyll and carotenoid). Molecular characterization of the isolates was carried out by the amplification of 16S rRNA gene. Forty-five different isolates were obtained and photosynthetic pigments were detected in 12 (8 from marine and 4 from aquaculture). Four of the isolates were found to grow on both inorganic nitrate and nitrite as the sole carbon source. Molecular characterization has shown that the isolates are denitrifying bacteria and the relationship between isolates and other denitrifying bacteria has been established by the construction of the phylogenetic tree. Hence denitrification and denitrifying bacteria can occur in both marine and aquaculture wastewaters.

Feasibility of bio-filter in treating low strength nitrogen wastewater under adverse temperatures

As a promising nitrogen removal technology, anammox still faces the bottlenecks of low temperatures, low substrates, and large wastewater flow in mainstream. This study investigated the feasibility of anammox bio-filter (A-BF) as advanced nitrogen removal unit for sewage treatment in low temperature climates. Results showed when treating 7 mg-NH4+-N·L−1 and 10 mg-NO2--N·L−1 wastewater, A-BF achieved 71.8 ± 5.6 % and 60.10 ± 10.31 % of total nitrogen removal efficiency (TNRE) under nitrogen loading rate (NLR) of 1.20 ± 0.30 kg-N m−3 d−1, within 0.3 h at 25 and 7.5 °C, respectively, based on ＜8 mg L−1 effluent. Further analysis showed that A-BF performance was recovered with TNRE of 71.8 ± 5.6 % when back to 25 °C after collapsing with TNRE of 24.30 ± 15.73 % at 5 °C. Dominant Candidatus Brocadia in anammox bacteria (AnAOB) (3.59–6.24 %) contributed to higher 0.22 and 0.46 g-N·g-VSS−1·d−1 biomass activity at 25 °C. This study provided possible and low-carbon strategy for advanced nitrogen removal.

One-Step Hydrothermal Preparation of a Corncob-Derived Porous Adsorbent with High Adsorption Capacity for Urea in Wastewater: Sorption Experiments and Kinetics Study.

With rapid industrial development, the massive generation of nitrogenous wastewater poses a serious threat to both human beings and the ecosystem. Bio-based adsorbents are considered promising adsorption materials for many applications. However, their complex preparation procedures, large energy consumption, and difficulty of microstructure control hinder their practical applications. In this study, a new corncob-derived porous adsorbent (CPA) with excellent urea adsorption capacity in wastewater was prepared by the one-step hydrothermal process. The effects of the hydrothermal process conditions on the urea adsorption capacity of the CPA were evaluated and optimized using the response surface methodology, and a kinetic analysis of the CPA was also carried out. Our findings showed that the adsorption process of urea by the adsorbent followed the Langmuir isotherm and pseudo-second-order kinetic models. The high adsorption capacity for urea was attributed to the abundant porous structure and the hydrogen bonds formed between the adsorbent and the amine group in urea, which made it more conducive to the adsorption of urea. Therefore, we believe that CPA could be a promising adsorbent for urea removal in wastewater.

Additional Treatment of Nitrogen and Phosphorus Using Natural Materials in Small-Scale Domestic Wastewater Treatment Unit

The conventional wastewater treatment methods only remove up to 80% of total nitrogen (N) or phosphorus (P) from wastewater, so additional facilities are needed. This article describes a newly created other wastewater treatment unit (NCU) that increases the effectiveness of P and N removal of the small-scale biological wastewater treatment plant. This work aims to evaluate the capacity of simultaneous elimination from wastewater nitrogen (NH4-N, NO3-N) and phosphorus (PO4-P) by adsorption. NCU was filled with the sorbent material zeolite (clinoptilolite) and OCS (Fe, Mn, Ca oxides coated sand). After treatment in the main plant, wastewater flows through the NCU without using electric power. A compact system consisting of a main treatment plant and the NCU worked for 4 months, as the harmonized European Standard EN 12566-7 recommended. The NCU unit reduced PO4-P, NH4-N, and NO3-N concentrations in the effluent (74–98%, 52–99%, and 50–98%, respectively). In general, the small-scale system treated wastewater did not contain more than 1 mg/L phosphorus concentration and not more than 10 mg/L nitrogen concentration. This study demonstrates that treatment in NCU is an ecological and environmentally friendly method suitable for decentralized wastewater treatment.

The evolution of nitrogen transformation microorganism consortium under continued manganese domestication conditions

Manganese redox-stimulated bioremediation of nitrogen wastewater is receiving increasing attention. However, the nitrogen metabolic capacity and community evolution during manganese-mediated nitrogen transformation process under continued manganese domestication conditions are ambiguous. In this study, nitrogen- metabolizing microbial consortiums were incubated with synthesized Mn-humic acid complex (Mn-HA) for one month (M1), three months (M2) and six months (M3), respectively. During the Mn-HA incubation period, Bio-MnOx accompanying with bacterial consortiums (MnOB consortiums) with high TIN removal capacities were obtained. The TIN removal rates in M1, M2 and M3 were 0.220, 1.246 and 4.237 mg·L−1·h−1, respectively, which were 15.961, 90.006 and 1550.006 times higher than CK (Control Check group, no Mn-HA added group) (0.014 mg·L−1·h−1), respectively. Functional genes (amoA, AMX and narG) were most abundant in M3, which was associated with the highest nitrogen removal rate in M3. MnOB1 (bacterial consortium in M1), including Geobactor, Geothrix, Anaeromyxobacter and Bacillus, may be responsible for the Mnammox-NDMO (MnOx reduction coupled to ammonium oxidation – nitrate/nitrite-dependent low-valent Mn oxidation) process. MnOB3 (bacterial consortium in M2) enriched nitrifying bacteria Ellin6067, and denitrifying bacteria Denitratisoma, which dominated nitrogen transformation. MnOB6 (bacterial consortium in M3) enriched denitrifiers Denitratisoma, nitrifiers Ellin6067 and potential anammox bacteria SM1A02, Candidatus_Brocadia. Combined with the reduced abundance of Nitrospirae, a short-cut partial nitrification and denitrification (PND) or partial nitrification, denitrification and anammox (PNDA) could occurred in M2 and M3. It is suggested that community may have evolved into an energetically efficient short-cut nitrification, denitrification and anammox consortium to replace the full-range nitrification and denitrification community in M1 and CK under the continued manganese domestication conditions. Enhanced metabolic pathways of hydroxylamine oxidation and the nitric oxide reduction may confirm that PND or PNDA occurred in M2 and M3.

Acceleration of nitrogen removal performance in a biofilm reactor augmented with Pseudomonas sp. using polycaprolactone as carbon source for treating low carbon to nitrogen wastewater

Heterotrophic nitrification-aerobic denitrification (HN-AD) process was achieved in a moving bed biofilm reactor after 180-days acclimation using PCL as carbon source for low C/N wastewater treatment. A novel HN-AD strain, JQ-H3, with ability of PCL degradation was augmented to improve nitrogen removal. TN removal efficiencies of 82.31%, 90.05%, and 93.16% were achieved in the augmented reactor (R2), at different HRTs of 24 h, 20 h, and 16 h, while in the control reactor (R1), the TN removal efficiencies were 59.24%, 74.61%, and 76.68%. The effluent COD in R2 was 10.17 mg/L, much lower than that of 42.45 mg/L in R1. Microbial community analysis revealed that JQ-H3 has successfully proliferated with a relative abundance of 4.79%. Relative abundances of functional enzymes of nitrogen cycling remarkably increased due to bioaugmentation based on the analysis of PICRUSt2. This study provides a new approach for enhancing nitrogen removal in low C/N sewage treatment via the HN-AD process.

The iron cycling mediated by a single strain Shewanella oneidensis MR-1 and its implication for nitrogen removal

Microbially mediated nitrate-reducing Fe(II) oxidation (NRFO) process has been recognized as an effective route for removing nitrogen in wastewater. However, the need for continuous dose of iron blocks NRFO technology to be scaled up. Microbial iron cycling can improve iron utilization efficiency, but whether it can be mediated by a single strain remains elusive. Here, Shewanella oneidensis strain MR-1 was employed to mediate Fe redox process with the subsequent addition of Fe(III), nitrate, and lactate under anaerobic conditions. Fe(II) kinetic curve showed that strain MR-1 could efficiently reduce Fe(III) with a reduction rate of 2.55 mmol·L−1·d−1, producing a great amount of Fe(II). After nitrate addition, strain MR-1 mediated the NRFO process. Fe(III) reduction and NRFO constituted Fe cycle, indicating that strain MR-1 successfully carried out Fe redox cycling. It is noted that two iron redox cycles were achieved, but the second cycle was weaker. That is, about 86.7 % of total iron was reduced in the first cycle, but only 4.6 % was reduced in the second cycle. As nitrate reduction is the key process for iron cycling, the unsustainability should be related to nitrate reduction inhibition. The possible mechanisms were investigated, revealing that nitrate reduction was inhibited by cell encrustation and nutrient shortage. These findings expand the understanding of microbial iron cycle and provide a new microbial iron cycling model. This will help to improve the biological wastewater treatment technology based on NRFO process.

Preparation of PVDF/TMKH‐550 composite membrane and its adsorption performance for ammonia nitrogen wastewater

AbstractIn order to reduce the agglomeration of tourmaline, silane coupling agent (3‐aminopropyl)‐triethoxysilane (KH‐550) was used to modify tourmaline. Then the modified tourmaline particles were added to the polyvinylidene fluoride (PVDF) casting solution by blending, and a series of PVDF/TMKH‐550 composite membranes were prepared by Nonsolvent Induce Phase Separation (NIPS). The results showed that the agglomeration of tourmaline could be reduced by modification. With the increase of TMKH‐550 nanoparticles content, the removal efficiency of ammonia nitrogen wastewater increased gradually. For PVDF/TMKH‐550 composite membranes, the results showed that the addition of TMKH‐550 nanoparticles improved the hydrophilicity, porosity, and pore size of the membrane, and increased the permeation flux. The removal efficiency of the composite membrane on ammonia nitrogen solutions could reach 75.40%, The pH and conductivity of deionized water after membrane filtration were tested. At 0.2 MPa, it was found that both pH and conductivity increased. The above results showed that tourmaline can not only activate water bodies but also remove pollutants in water.

Replacing Mineral Fertilizer with Nitrified Human Urine in Hydroponic Lettuce (Lactuca sativa L.) Production

Source-separated, nitrified, and decontaminated human urine constitutes a promising plant fertilizer that contains a large share of the nitrogen and phosphorus in household wastewater, and other plant nutrients. However, human urine contains high levels of sodium and chloride that can affect salt-sensitive greenhouse crops. Replacing mineral fertilizer with nitrified urine fertilizer could reduce the environmental impact of lettuce production in hydroponic systems, if marketable yield, appearance, and produce quality are not affected. In the present study, a treatment combination of a nitrified urine fertilizer and mineral fertilizers was used to grow lettuce through the nutrient film technique. This was compared to a conventionally fertilized control treatment. No significant differences were observed regarding yield, phenotype, and contents of nitrate, heavy metals, phenolic acids, and chlorophyll in leaf tissue. Calcium content was significantly reduced and sodium was elevated in nitrified urine treatment. For the elements nitrogen, phosphorous, and potassium, a saving of 48%, 13%, and 15% was calculated, respectively. The calculated carbon footprint from the total fertilizer production was reduced by 34.25%, caused by the nitrified urine treatment. Based on these results, a nutrient solution composed of nitrified urine fertilizer combined with mineral fertilizer may be a promising alternative for growers to produce lettuce with a reduced environmental impact without loss of plant quantity and quality.

Application of Hydrogen-Based Denitrification: Simultaneous Removal of Nitrate and Reactive Black 5 Dye from Textile Wastewater Containing Organic Matter

In this study, a hydrogen-based denitrification (HD) reactor was used to investigate the simultaneous treatment of nitrogen and decolorization in textile wastewater contaminated with organic matter. The reactor operated in two phases: without and with organic matter. Despite the short hydraulic retention time, the HD system successfully removed all pollutants, including nitrate, nitrite, reactive black-5 dye and chemical oxygen demand. The unhindered treatment efficiency for nitrogen and decolorization in the presence of organic pollutants was observed. With the addition of organic matter, the nitrogen removal efficiency increased slightly from 85% to 90–100%, and the decolorization rate doubled from 25% to 50–60%. Organic matter played a crucial role in stimulating heterotrophic bacteria during biological denitrification and acted as a carbon source facilitating biological denitrification and azo bond cleavage during dye degradation. Despite the generation of toxic byproducts and changes in the dominant microbial community, the treatment efficiency remained stable and improved. This approach offers a promising solution for enhancing treatment efficiency in textile wastewater, providing a cost-effective and environmentally friendly option for developing countries to treat wastewater before discharge.

Insight into response characteristics and inhibition mechanisms of anammox granular sludge to polyethylene terephthalate microplastics exposure

Currently, in-depth understanding of response characteristics and mechanisms of anammox process under microplastics (MPs) stress remains quite limited. This study investigated the influence of 0.1–1.0 g/L polyethylene terephthalate (PET) on anammox granular sludge (AnGS). Compared with the control, 0.1–0.2 g/L PET did not significantly affect the anammox efficiency, while the anammox activity decreased by 16.2% at 1.0 g/L PET. Integrity coefficient and transmission electron microscopy analysis demonstrated that the strength and structural stability of the AnGS became weaken following exposure to 1.0 g/L PET. With the PET increasing, the abundance of anammox genera and genes related to energy metabolism and cofactors and vitamins metabolism decreased. The reactive oxygen species generated in the interaction between microbial cells and PET resulting in cellular oxidative stress was responsible for inhibiting anammox. These findings give novel insights into the anammox behavior in biological nitrogen removal systems treating PET-loaded nitrogenous wastewater.

Applications of autotrophic ammonia oxidizers in bio-geochemical cycles

Nitrogen is essential for life and to produce food. Still, nitrogen loss of the unused nitrogen in wastewater, air, freshwater, and oceans has caused nitrogen pollution, which impacts the environment and leads to eutrophication, climate change, biodiversity loss, and ozone depletion. It also causing cardio respiratory issues in humans. Anthropogenic activities such as food processing, fertilizer production, mining, and other impacting the global biogeochemical nitrogen cycle. Autotrophic ammonia-oxidizing microbial moieties such as ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), and anaerobic ammonia-oxidizing bacteria (AnAOB) are being extensively used to remove nitrogen (present in the ammonia and ammonium forms). The conventional nitrogen removal process, “nitrification and denitrification,” has been highly used in wastewater treatment plants by employing a various bacterial communities. Since it required high organic compounds and an energy-intensive process, new strategies were being developed to reduce carbon footprint. “Anammox,” “Feammox,” and “Comammox” are a few processes that utilize specific bacterial moieties and do not require organic carbon. Among these, Anammox has become the most potential nitrogen removal system. In various studies, the combined Anammox and partial nitrification (PN/A) have shown the maximum nitrogen removal rate (NRR). This review discusses the applications of autotrophic ammonia oxidizers in agriculture, wastewater treatment plants, and engineered ecosystems. We have also addressed various stress impacts on ammonia oxidizers.

Pangenome-driven insights into nitrogen metabolic characteristics of Citrobacter portucalensis strain AAK_AS5 associated with wastewater nitrogen removal.

Nitrogen metabolism in the genus Citrobacter is very poorly studied despite its several implications in wastewater treatment. In the current study, Citrobacter portucalensis strain AAK_AS5 was assessed for remediation of simulated wastewater supplemented with different inorganic nitrogen sources. Combination of (NH4)2SO4 with KNO3 was the most preferred for achieving high growth density followed by (NH4)2SO4 and KNO3 alone. This was in agreement with highest ammonical nitrogen removal of 92.9% in the presence of combined nitrogen sources and the corresponding nitrate nitrogen removal of 93% in the presence of KNO3. Furthermore, these removal capacities were validated by investigating the uniqueness and the spread of metabolic features through pan-genomic approach that revealed the largest number of unique genes (2097) and accessory genes (705) in strain AAK_AS5. Of the total 44 different types of nitrogen metabolism-related genes, 39 genes were associated with the core genome, while 5 genes such asgltI,nasA,nasR,nrtA,and ntrCuniquely belonged to the accessory genome. Strain AAK_AS5 possessed three major nitrate removal pathwaysviz., assimilatory and dissimilatory nitrate reduction to ammonia (ANRA & DNRA), and denitrification; however, the absence of nitrification was compensated by ammonia assimilation catalyzed by gene products of the GDH and GS-GOGAT pathways. narGHIJ encoding the respiratory nitrate reductase was commonly identified in all the studied genomes, while genes such as nirK, norB, and nosZ were uniquely present in the strain AAK_AS5 only. A markedly different genetic content and metabolic diversity between the strains reflected their adaptive evolution in the environment thus highlighting the significance of C. portucalensis AAK_AS5 for potential application in nitrogen removal from wastewater.

Responses of microalgae under different physiological phases to struvite as a buffering nutrient source for biomass and lipid production

Microalgae cultivation for biodiesel production is promising, but the high demand for nutrients, such as nitrogen and phosphorus, remains a limiting factor. This study investigated effects of struvite, a low-cost nutrient source, on microalgae production under different physiological phases. Changes in element concentrations were determined to characterize the controllable nutrient release properties of struvite. Results showed that nutrient elements could be effectively supplemented by struvite. However, responses of microalgae under different growth stages to struvite varied obviously, achieving the highest biomass (0.53 g/L) and the lowest (0.32 g/L). Moreover, the microalgal lipid production was obviously increased by adding struvite during the growth phase, providing the first evidence that struvite could serve as an alternative buffering nutrient source to culture microalgae. The integration of microalgae cultivation with struvite as a buffering nutrient source provides a novel strategy for high ammonia nitrogen wastewater treatment with microalgae for biodiesel production.

Feasibility of low-intensity ultrasound treatment with hydroxylamine to accelerate the initiation of partial nitrification and allow operation under intermittent aeration

Partial nitrification is a key aspect of efficient nitrogen removal, although practically it suffers from long start-up cycles and unstable long-term operational performance. To address these drawbacks, this study investigated the effect of low intensity ultrasound treatment combined with hydroxylamine (NH2OH) on the performance of partial nitrification. Results show that compared with the control group, low-intensity ultrasound treatment (0.10 W/mL, 15 min) combined with NH2OH (5 mg/L) reduced the time required for partial nitrification initiation by 6 days, increasing the nitrite accumulation rate (NAR) and ammonia nitrogen removal rate (NRR) by 20.4% and 6.7%, respectively, achieving 96.48% NRR. Mechanistic analysis showed that NH2OH enhanced ammonia oxidation, inhibited nitrite-oxidizing bacteria (NOB) activity and shortened the time required for partial nitrification initiation. Furthermore, ultrasonication combined with NH2OH dosing stimulated EPS (extracellular polymeric substances) secretion, increased carbonyl, hydroxyl and amine functional group abundances and enhanced mass transfer. In addition, 16S rRNA gene sequencing results showed that ultrasonication-sensitive Nitrospira disappeared from the ultrasound + NH2OH system, while Nitrosomonas gradually became the dominant group. Collectively, the results of this study provide valuable insight into the enhancement of partial nitrification start-up during the process of wastewater nitrogen removal.

Performance of short-cut denitrifying phosphorus removal and microbial community structure in the A2SBR process

ABSTRACT Acclimatization of short-cut denitrifying polyphosphate accumulating organisms (SDPAOs), metabolic mechanism, and operating parameters were analyzed to investigate the performance of the anaerobic/anoxic sequencing batch reactor (A2SBR) process. The high-throughput sequencing technology was employed to explore the microbial community structures of activated sludge systems. The experimental results illustrated that SDPAOs were successfully enriched with three-phase inoculation for 36 days. The removal rates of TP and NO2 −-N were 93.22% and 91.36%, respectively, under the optimal parameters of a pH of 7.5, an SRT of 26 days, a temperature of 24 ℃ and a COD of 200.00 mg·L−1 using acetate as the carbon source. In the anaerobic stage, 82.20% external carbon source was converted into 88.78 mg·g−1 PHB, and the removal rate of NO2 −-N in the anoxic stage was characterized by ΔNO2 −-N/ΔPHB, anoxic ΔP/ΔPHBeffective was 0.289, which was higher than anaerobic ΔP/ΔCODeffective of 0.203. Ignavibacterium and Povalibacter with significant phosphorus removal ability were the dominant bacterial genera. The nitrogen and phosphorus removal could be realized simultaneously in an anaerobic/anoxic sequencing batch reactor. Therefore, this study provided an important understanding of the removal of nitrogen and phosphorus from low-carbon nitrogen wastewater.

Acid leaching–extraction–circulation process based on Mo(VI) coordination with H3PO4 to efficiently extract molybdenum from different components of molybdenum calcine

Ammonia nitrogen wastewater generated during the ammonia decomposition of molybdenum calcine causes serious environmental pollution. To address this issue, a novel acidic leaching–extraction–circulation process is proposed to efficiently extract molybdenum (Mo) from different molybdenum calcine components (MoO2, MoO3, and CaMoO4). This process differs from traditional alkali leaching methods as it relies on the coordination of Mo(VI) with H3PO4 to yield soluble H3PMo12O40 while adding sulfuric and nitric acids to achieve the efficient one-step leaching of complex raw ores. The addition of sulfuric acid not only enhances the oxidation of nitrate ion, effectively leading to the co-leaching of MoO2, which cannot be directly complexed by phosphoric acid, but also results in the decomposition of molybdophosphoric heteropoly acid into H3PO4 for cyclic leaching, thus reducing the production cost. Since most of the Mo in acidic lixivium is present as MoO22+ due to the depolymerization of H3PMo12O40, the acidic extractant P507 is employed to extract Mo in the organic phase via cation exchange with MoO22+. The H+ released during the extraction hinders the conversion of MoO22+ to PMo12O403– and regenerates sulfuric acid in the raffinate, which can be reused in cyclic leaching. This study provides an effective and environmentally friendly approach for the industrial extraction of Mo.

Domestication and pilot-scale culture of mixed bacteria HY-1 capable of heterotrophic nitrification-aerobic denitrification

To further investigate the potential of heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria for practical applications, the HN-AD mixed bacteria HY-1 were enriched and domesticated in this study. After five generations of domestication, the mixture was able to remove 98% of ammonia nitrogen (400 mg/L) and 81.9% of mixed nitrogen source (nitrate, nitrite). Changes in community structure in the domestication process of mixed microorganisms were studied using 16S rDNA-seq. The results indicated an increase in the abundance of Acinetobacter from 16.9% to 80%. The conditions for the expanded culture of the HY-1 were also optimized. Moreover, A pilot-scale expanded reactor with a capacity of 1000L was constructed, and the HY-1 was successfully expanded from 0.1L to 800L. The community structures of the HY-1 remained stable after the expanded culture, with Acinetobacter as the dominant species. Moreover, the HY-1 demonstrated adaptability to actual high ammonia nitrogen wastewater and showed potential for practical application.