Body size: A hidden trait of the organisms that influences the distribution of antibiotic resistance genes in soil.

Body size is a key life-history trait of organisms, which has important ecological functions. However, the relationship between soil antibiotic resistance gene (ARG) distribution and organisms' body size has not been systematically reported so far. Herein, the impact of organic fertilizer on the soil ARGs and organisms (bacteria, fungi, and nematode) at the aggregate level was analyzed. The results showed that the smaller the soil aggregate size, the greater the abundance of ARGs, and the larger the body size of bacteria and nematodes. Further analysis revealed significant positive correlations of ARG abundance with the body sizes of bacteria, fungi, and nematodes, respectively. Additionally, the structural equation model demonstrated that changes in soil fertility mainly regulate the ARG abundance by affecting bacterial body size. The random forest model revealed that total phosphorus was the primary soil fertility factor influencing the body size of organisms. Therefore, these findings proposed that excessive application of phosphate fertilizers could increase the risk of soil ARG transmission by increasing the body size of soil organisms. This study highlights the significance of organisms' body size in determining the distribution of soil ARGs and proposes a new disadvantage of excessive fertilization from the perspective of ARGs.

Evaluation of the effect of a novel substrate that is composed of landfill-mined-soil-like-fractions on plant growth and heavy metal accumulation.

In the pursuit of a safe, low-cost, and sustainable method for the reuse of landfill-mined-soil-like-fractions (LFMSFs), pot experiments were conducted using seven growth substrates consisting of LFMSFs, tea residue, and peat for the cultivation of Photinia × fraseri. Six of the substrates had 40 %:60 %, 60 %:40 %, and 80 %:20 % volume ratios of LFMSFs to tea residue or peat, and one substrate consisted entirely of LFMSFs. The physicochemical properties of the substrate, growth parameters of the plants, and heavy metal content in the different pots were determined after one year of growth. The results indicated that the physicochemical properties of the substrate, that was composed of a mixture of LFMSFs and tea residue showed a significant improvement in organic matter, nitrogen, phosphorus, and potassium. However, there was also an increase in the salt and heavy metal contents when compared with those of peat. The plant growth in the LFMSF and tea residue substrate was slightly lower than that in the LFMSF and peat mixture. Notably, the best plant growth and environmentally friendly effects were observed when LFMSFs were added at 40 %. Additionally, most of the heavy metals were primarily removed from the substrate through the leaves of the seedlings, with the heavy metal contents being relatively low. In conclusion, LFMSFs as a cultivation substrate, represent a practical approach for reutilization, which could contribute to the reduction of reliance on traditional resources.

Pathogen resistance in soils associated with bacteriome network reconstruction through reductive soil disinfestation.

Reductive soil disinfestation (RSD) is an effective bioremediation technique to restructure the soil microbial community and eliminate soilborne phytopathogens. Yet we still lack a comprehensive understanding of the keystone taxa involved and their roles in ecosystem functioning in degraded soils treated by RSD. In this study, the bacteriome network structure in RSD-treated soil and the subsequent cultivation process were explored. As a result, bacterial communities in RSD-treated soil developed more complex topologies and stable co-occurrence patterns. The richness and diversity of keystone taxa were higher in the RSD group (module hub: 0.57%; connector: 23.98%) than in the Control group (module hub: 0.16%; connector: 19.34%). The restoration of keystone taxa in RSD-treated soil was significantly (P < 0.01) correlated with soil pH, total organic carbon, and total nitrogen. Moreover, a strong negative correlation (r = -0.712; P < 0.01) was found between keystone taxa richness and Fusarium abundance. Our results suggest that keystone taxa involved in the RSD network structure are capable of maintaining a flexible generalist mode of metabolism, namely with respect to nitrogen fixation, methylotrophy, and methanotrophy. Furthermore, distinct network modules composed by numerous anti-pathogen agents were formed in RSD-treated soil; i.e., the genera Hydrogenispora, Azotobacter, Sphingomonas, and Clostridium_8 under the soil treatment stage, and the genera Anaerolinea and Pseudarthrobacter under the plant cultivation stage. The study provides novel insights into the association between fungistasis and keystone or sensitive taxa in RSD-treated soil, with significant implications for comprehending the mechanisms of RSD. KEY POINTS: • RSD enhanced bacteriome network stability and restored keystone taxa. • Keystone taxa richness was negatively correlated with Fusarium abundance. • Distinct sensitive OTUs and modules were formed in RSD soil.

Contributions of carbon source, crop cultivation, and chemical property on microbial community assemblage in soil subjected to reductive disinfestation.

In agricultural practice, reductive soil disinfestation (RSD) is an effective method for eliminating soil-borne pathogens that depends heavily on carbon source. However, knowledge regarding the assembly of soil microbial communities in RDS-treated soils amended with different carbon sources after continuous crop cultivation is still not well-characterized. RSD treatments were performed on greenhouse soil with six different carbon sources (ethanol, glucose, alfalfa, wheat bran, rice bran, and sugarcane residue), which have different C:N ratios (Org C/N) and easily oxidized carbon contents (Org EOC). After RSD, two consecutive seasons of pepper pot experiments were conducted. Then, the effects of carbon source property, crop cultivation, and soil chemical property on soil microbial community reestablishment, pathogen reproduction, and crop performance were investigated in the RSD-cropping system. Variation partition analysis indicated that carbon source property, crop cultivation, and soil chemical property explained 66.2 and 39.0% of bacterial and fungal community variation, respectively. Specifically, Mantel tests showed that Org C/N, crop cultivation, soil available phosphorus and potassium were the most important factors shaping bacterial community composition, while Org C/N, Org EOC, and crop cultivation were the most important factors shaping fungal community composition. After two planting seasons, the number of cultivable Fusarium was positively correlated with Org EOC, and negatively correlated with soil total organic carbon, Fungal Chao1, and Fungal PC1. Crop yield of complex-carbon soils (Al, Wh, Ri and Su) was negatively affected by Org C/N after the first season, and it was highest in Al, and lower in Et and Su after the second season. Overall, Org EOC and Org C/N of carbon source were vitally important for soil microbe reestablishment, Fusarium reproduction and crop performance. Our findings further broaden the important role of carbon source in the RSD-cropping system, and provide a theoretical basis for organic carbon selection in RSD practice.

Physicochemical properties and risk assessment of perishable waste primary products.

Fertilization has become one of the most important ways to recycle perishable waste. In order to reveal the effect of the nutrient of the perishable waste primary products on the market and the possible impact of their application, 136 perishable waste primary products were sampled in nine cities in Zhejiang province, China. The result shows that these products have high nutrient content (average nutrient content was 5.00%). However, the conductivity (7.19 mS/cm) total soluble salt content (12.07%), and grease content (5.99%) were too high. The excessive salt and grease may cause harm to soil and crops, and become the main limiting factors for the fertilizer utilization of perishable waste. Heavy metal content of most of the samples met current commercial organic fertilizer standards, except that lead and chromium content of some samples exceeded the limit standard. Toluene, ethylbenzene, m & p-xylene were generally detected in the samples. These toxic and harmful substances have brought risks to the safe use of perishable waste into fertilizers.

Assessing Pb-Cr Pollution Thresholds for Ecological Risk and Potential Health Risk in Selected Several Kinds of Rice.

The expected typical gley moist paddy soil was collected in Zhejiang Province, China, and conventional (XS 134 and JH 218) and varieties of hybrid (YY 538 and CY 84) rices were used for a pot experiment. The effects of exogenous heavy metals lead (Pb) and chromium (Cr) on rice growth and the accumulation of heavy metals in the grains were studied. The results show that heavy metal concentrations in soil and rice grains have significant correlations, and Pb and Cr significantly (p < 0.05) inhibited the rice growth (plant height and panicle weight). The potential ecological hazard index (RI) of heavy metals in the soil was 4.88−6.76, which belongs to the grade of "slight ecological hazard", and Pb provides a larger potential ecological hazard than Cr in the studied region. The thresholds for potential health risks and ecological risks for Pb and Cr were lower than the "Control Standards for Soil Pollution Risk of Agricultural Land (Trial)" (GB15618-2018, China). This work provides the basis for soil pollution control for Pb and Cr and the selection of rice cultivars from Pb and Cr accumulated soils.

Optimization of vegetable waste composting and the exploration of microbial mechanisms related to fungal communities during composting.

The application of additives to regulate the microbial functional composition during composting has attracted much research attention. However, little is known about the succession and role of the fungal community in the laboratory-scale composting of vegetable waste supplemented with pig manure and microbial agents. The purpose of this study was to identify effective additives for improving vegetable waste composting performance and product quality, and to analyze the microbial community succession during composting. The results showed that the combined addition of pig manure and microbial agents (T2 treatment) accelerated the pile temperature increase, enhanced total organic carbon degradation (23.36%), and promoted the maturation of the compost. Furthermore, the T2 treatment increased the activities of most enzymes, reshaped the microbial community, and reduced the relative abundance of potential animal (1.60%) and plant (0.095%) pathogens. The relative abundance of Firmicutes (71.23%) increased with the combined addition of pig manure and microbial agents in the thermophilic stage. In the middle and late stages, Saccharomonospora, Aspergillus, and Thermomyces, which were related to C/N and total phosphorus, were enriched in the T2 treatment. Network analysis demonstrated that the complexity and stability of the fungal network were more evidently increased in the T2 treatment, and Saccharomonospora, Aspergillus, and Microascus were identified as keystone taxa. The keystone taxa associated with extracellular enzymes contributed significantly to compost maturation. These results provide a reference for the application of additives to improve compost safety in pilot-scale composting.

Disentangling the Effects of Physicochemical, Genetic, and Microbial Properties on Phase-Driven Resistome Dynamics during Multiple Manure Composting Processes.

Composting alters manure-derived antibiotic resistance genes (ARGs) to a certain extent, which is largely dependent upon the composting phase, manure type, microbial phylogeny, and physicochemical properties. However, little is known about how these determinants influence the fate and dynamics of ARGs as well as the mechanisms underlying the ecological process of ARGs during composting. Here, we investigated the temporal patterns of ARGs and their correlations with a series of physicochemical, genetic, and microbial properties during pilot-scale composting of chicken, maggot, bovine, and swine manure. We detected 237 ARGs, 71 of which were co-occurring across all four composting processes and accounted for >80% of the sum of resistome abundance. In support of this ARG co-occurrence, variance partition analyses demonstrated that the manure type explained less resistome variations (5.6%) than the composting phase (21.6%). During the phase-driven resistome dynamics, ARGs showed divergent variations in abundance, and certain beta-lactams and multidrug ARGs were consistently enriched across multiple manure composting processes. Correlation analyses all led to the conclusion that the divergent ARG variations during composting were attributable to the unequal effects of physicochemical properties, mobile elements, and succession of indigenous microbiota, whereas antibiotic residues' effects were marginal. Ultimately, this study determines the relative importance of various key determinants in the phase-driven divergence of ARGs during multiple manure composting processes and demonstrates a clear need to evaluate risks posed by enriched ARGs toward their receiving environments.

The process of biotransformation can produce insect protein and promote the effective inactivation of heavy metals.

An experiment was performed to study the inactivation effect of aerobic composting on heavy metals in maggot, pig and chicken manures. After composting, Cu mainly occurred in the oxidizable (OXI) fraction with a percentage distribution above 54%. Zn and Cd mainly existed in the bioavailable factor (BF), which has strong activity, with percentage distributions greater than 88.3% and 82.7%, respectively. Cr and Pb mainly existed in the stable residual (RES) fraction with a percentage distribution of approximately 50%. The aerobic composting process had a clear inactivation effect on heavy metals. For maggot manure compost in particular, the inactivation effects of Cu, Cr, Zn, Cd, and Pb were very good throughout the composting process, and the inactivation effect of Pb reached 54.42%. In addition, the process of biotransformation by housefly maggots promoted the conversion of fulvic acid (FA) to humic acid (HA) in pig manure, and the final increase in HA/FA after maggot manure composting was the largest among the different types of manure and beneficial to the inactivation of heavy metals. Compounds containing -CH3 and -CH2 groups were reduced, and aromatic structures were enhanced. Moreover, a maggot yield equivalent to 13.2% of the fresh pig manure was achieved during the process of biotransformation. The correlation analysis results showed that moisture content was an important factor affecting the inactivation rates of heavy metals in the three manure composts. Our results highlight that the process of biotransformation by housefly maggots can promote composting maturity and the inactivation of heavy metals, and produce a large amount of insect protein, yielding beneficial ecological and economic benefits.

[Degradation Characteristics of Antibiotics During Composting of Four Types of Feces].

The widespread use of antibiotics in feed results in a large number of antibiotic residues in feces. Composting technology can degrade these residual antibiotics. A pilot-scale aerobic composting device was used to analyze the antibiotic residues and composting degradation characteristics of four types of feces (maggot manure, chicken manure, pig manure, and cow manure). Results showed that sulfonamides (SAs), fluoroquinolones (FQs), tetracycline (TCs), and macrolides (MAs) were the main antibiotics, and different type of feces had different dominant antibiotics. The contents of FQs and oxytetracycline (OTC) were none on the seventh day of the compost, and their degradation rates were the fastest. After composting, the degradation rate of doxycycline (DOX) in the four types of fecal composts was more than 85%. Meanwhile, the degradation rates of SAs in chicken, pig, and cow manure composts were also more than 80%, which was much lower in the one in maggot manure compost. MAs were only found in maggot manure, and the degradation rate was 70.79% after composting. Correlation analysis indicated that the water content and bulk density were the most important environmental factors affecting the degradation rates of antibiotics in the four types of fecal composts.

Health risk assessment of heavy metal pollution in a soil-rice system: a case study in the Jin-Qu Basin of China.

A regional field survey of a total of 109 pairs of soil and rice samples was conducted to evaluate the health risks posed by heavy metals in the Jin-Qu Basin, China. The studied soils are characterized by acid (pH in mean level of 5.5), carbon rich (soil organic matter in mean of 33.6 g kg-1) and mainly contaminated by Cd (42.2% samples exceeded the standard value of 0.3 mg kg-1 (GB15618-2018)). The spatial distributions of Cd, Pb and Zn exhibited similar geographic trends. 34% and 30% of the rice samples containing Cd and Pb exceeded the threshold value of 0.2 mg kg-1 (GB2762-2017), respectively. The risk estimation of dietary intake had a target hazard quotient value of Cd of 0.918 and a hazard index value for rice consumption of 2.141. Totally, Cd and Pb were found to be the main components contributing to the potential health risks posed by non-carcinogenic effects for local inhabitants.

Utilization of gibberellin fermentation residues with swine manure by two-step composting mediated by housefly maggot bioconversion.

The ecological disposal of gibberellin fermentation residues (GFRs) is urgently needed. This study explored a new method of direct GFR utilization with swine manure at different substitution proportions (0%, 20%, 40%, and 60%) using two-step composting mediated by housefly maggot bioconversion. Regarding maggot bioconversion, substitution of GFRs accelerated the temperature increase and water content decrease, slowed the pH increase, and enhanced the maggot conversion rate. Among the proportions, 20% GFR substitution had the highest maggot conversion rate of 15.15%. During the composting stage, GFR substitution promoted the initial temperature increase and the water content decrease and maintained a relatively low pH. However, only 20% substitution promoted the maturity of compost. The degradation rates of the gibberellin residue were all higher than 97% in the treatments with GFRs after two-step composting. High-throughput sequencing analysis showed that GFR substitution had significant effects on the microbial community structure during the whole process. However, the change in the microbial community was similar to that of conventional composting. Therefore, this innovative approach is feasible for GFR resource utilization, and substitution below 20% for swine manure is recommended.

The bioaccessibility of iodine in the biofortified vegetables throughout cooking and simulated digestion.

Biofortification of crops with exogenous iodine is a novel strategy to control iodine deficiency disorders (IDD). The bioaccessibility of iodine (BI) in the biofortified vegetables in the course of soaking, cooking and digestion, were examined. Under hydroponics, the concentration of iodine in leafstalks of the celery and pakchoi increased with increasing exogenous iodine concentration, 54.8-63.9% of the iodine absorbed by pakchoi was stored in the soluble cellular substance. Being soaked in water within 8 h, the iodine loss rate of the biofortified celery was 3.5-10.4% only. More than 80% of the iodine in the biofortified celery was retained after cooking under high temperature. The highest BI of the biofortified vegetables after digestion in simulated gastric and intestinal juice amounted to 74.08 and 68.28%, respectively. Factors influencing BI included pH, digestion duration, and liquid-to-solid ratio. The high BI of the biofortified vegetables provided a sound reference for the promotion of iodine biofortification as a tool to eliminate the IDD.

Iodide and iodate effects on the growth and fruit quality of strawberry.

BACKGROUND: Iodine deficiency is an environmental health problem affecting one-third of the global population. An iodine biofortification hydroponic experiment was conducted to explore the iodide and iodate uptake characteristics of strawberry plants, to measure the dosage effects of iodine on plant growth and to evaluate the influence of I- or IO3- application on fruit quality. RESULTS: After biofortification, the iodine contents of the fresh strawberry fruits were 600-4000 µg kg-1 , covering the WHO dietary iodine allowance of 150 µg · day-1 for adults. The iodine uptake of the strawberry plants increased with increasing I- or IO3- concentration of the culture solution. At the same iodine concentration, the iodate uptakes of various plant organs under I- treatments were apparently more than those under IO3- treatments. Low-level exogenous iodine (I- ≤ 0.25 mg L-1 or IO3- ≤ 0.50 mg L-1 ) not only promoted plant growth and increased biomass per plant, but also improved fruit quality by enhancing the vitamin C and soluble sugar contents of the strawberry fruits. Nevertheless, excessive exogenous iodine inhibited plant growth and reduced biomass per plant. IO3- uptake apparently increased the total acidity and nitrate content of the fruits, reducing the quality of the strawberry fruits. Conversely, I- uptake obviously decreased the total acidity and nitrate content of the strawberry fruits, improving the fruit quality. CONCLUSION: The strawberry can be used as a target crop for iodine biofortification. Furthermore, applying an appropriate dose of KI can improve the fruit quality of the strawberry plants. © 2016 Society of Chemical Industry.

[Effects of Thermophilic Composting on Antibiotic Resistance Genes (ARGs) of Swine Manure Source].

To investigate the effects of thermophilic composting process on antibiotic resistance genes (ARGs) of swine manure source at a field scale, the abundance of four erythromycin resistance genes (ermA, ermB, ermC and ermF), three ß-lactam resistance genes (blaTEM, blaCTX and blaSHV) and two quinolone resistance genes (qnrA and qnrS) were quantified by quantitative PCR ( qPCR) during the composting process. The results suggested that the erm genes' copy numbers were significantly higher than those of the bla and qnr genes in the early stage of composting (P < 0.01). The maximum abundance of erm genes was ermB (9.88 x 108 copies · g⁻¹), following by ermF (9.4 x 108 copies · g⁻¹). At the end of the composting process, bla and qnr genes were at low levels, while erm genes were still at high levels. Even through ermF was proliferated comparing with the initial copies. These results indicated that thermophilic composting process could not effectively remove all ARGs. For some ARGs, compost may be a good bioreactor resulting in their proliferation. Application of composting products on farmland may cause transference of ARGs.

Analysis of volatile organic compounds in compost samples: A potential tool to determine appropriate composting time.

Changes in volatile organic compound contents in compost samples during pig manure composting were studied using a headspace, solid-phase micro-extraction method (HS-SPME) followed by gas chromatography with mass spectrometric detection (GC/MS). Parameters affecting the SPME procedure were optimized as follows: the coating was carbon molecular sieve/polydimethylsiloxane (CAR/PDMS) fiber, the temperature was 60°C and the time was 30min. Under these conditions, 87 compounds were identified from 17 composting samples. Most of the volatile components could only be detected before day 22. However, benzenes, alkanes and alkenes increased and eventually stabilized after day 22. Phenol and acid substances, which are important factors for compost quality, were almost undetectable on day 39 in natural compost (NC) samples and on day 13 in maggot-treated compost (MC) samples. Our results indicate that the approach can be effectively used to determine the composting times by analysis of volatile substances in compost samples. An appropriate composting time not only ensures the quality of compost and reduces the loss of composting material but also reduces the generation of hazardous substances. The appropriate composting times for MC and NC were approximately 22days and 40days, respectively, during the summer in Zhejiang.

Housefly maggot-treated composting as sustainable option for pig manure management.

In traditional composting, large amounts of bulking agents must be added to reduce the moisture of pig manure, which increases the cost of composting and dilutes the N, P and K content in organic fertilizers. In this study, maggot treatment was used in composting instead of bulking agents. In experiment of selecting an optimal inoculum level for composting, the treatment of 0.5% maggot inoculum resulted in the maximum yield of late instar maggots, 11.6% (maggots weight/manure weight). The manure residue became noticeably granular by day 6 and its moisture content was below 60%, which was suitable for further composting without bulking agents. Moreover, in composting experiment with a natural compost without maggot inoculum and maggot-treated compost at 0.5% inoculum level, there were no significant differences in nutrient content between the two organic fertilizers from the two treatments (paired Student's t15=1.0032, P=0.3317). Therefore, maggot culturing did not affect the characteristics of the organic fertilizer. The content of TNPK (total nitrogen+total phosphorus+total potassium) in organic fertilizer from maggot treatment was 10.72% (dry weight), which was far more than that of organic fertilizer made by conventional composting with bulking agents (about 8.0%). Dried maggots as feed meet the national standard (GB/T19164-2003) for commercial fish meal in China, which contained 55.32 ± 1.09% protein; 1.34 ± 0.02% methionine; 4.15 ± 0.10% lysine. This study highlights housefly maggot-treated composting can be considered sustainable alternatives for pig manure management to achieve high-quality organic fertilizer and maggots as feed without bulking agents.

Rapid production of maggots as feed supplement and organic fertilizer by the two-stage composting of pig manure.

A two-stage composting experiment was performed to utilize pig manure for producing maggots as feed supplement and organic fertilizer. Seven-day composting of 1.8 ton fresh manure inoculated with 9 kg mixture of housefly neonates and wheat bran produced 193 kg aging maggots, followed by 12 week composting to maturity. Reaching the thermophilic phase and final maturity faster was characteristic of the maggot-treated compost compared with the same-size natural compost. Upon the transit of the maggot-treated compost to the second stage, the composting temperature maintained around 55 °C for 9 days and the moisture decreased to ~40%. Moreover, higher pH, faster detoxification and different activity patterns for some microbial enzymes were observed. There was a strong material loss (35% water-soluble carbon and 16% total nitrogen) caused by the maggot culture in the first stage. Our results highlight a higher economic value of pig manure achieved through the two-stage composting without bulking agents.

Evaluation of iodide and iodate for adsorption-desorption characteristics and bioavailability in three types of soil.

Adsorption-desorption of iodine in two forms, viz., iodide (I(-)) and iodate (IO (3) (-) ), in three types of soil were investigated. The soils were: red soil developed on Quaternary red earths (REQ)- clayey, kaolintic thermic plinthite Aquult, Inceptisol soil (IS) and alluvial soil (AS)-Fluvio-marine yellow loamy soil. The isothermal curves of iodine adsorption on soils were described by Langmuir and Freundlich equation, and the maximum adsorption values (y (m)) were obtained from the simple Langmuir model. As compared with the iodide, the iodate was adsorbed in higher amounts by the soils tested. Among three soils, the REQ soil adsorbed more iodine (I(-) and IO (3) (-) ) than the IS and AS. The distribution coefficient (K (d)) of iodine in the soils decreased exponentially with increasing iodine loading concentration. Desorption of iodine in soil was increased correspondingly with increasing adsorption values. The REQ soil had a greater affinity for iodine than the IS and AS at the same iodine loadings. In the pot experiment cultivated with pakchoi (Brassica chinensis L.) and added with two exogenous iodine sources, the iodide form was quickly taken up by pakchoi and caused more toxicity to the vegetable. The rate of iodine loss from soil was higher for iodide form as compared with the iodate. The iodine bioavailability was the highest but the persistence was the weakest in AS among the three soils tested, and the REQ soil showed just the opposite trend to that of the AS soil. This study is of theoretical importance to understand the relationship between iodine adsorption-desorption characteristics and their bioavailability in different soils and it also has practical implications for seeking effective alternatives of iodine biofortification to prevent iodine deficiency disorders.

[Effect of aeration intensity on the nitrogen and phosphorus removal performance of AOA membrane bioreactors].

The ability of simultaneous phosphorus and nitrogen removal of sequencing batch membrane bioreactor run in anaerobic/oxic/ anoxic mode (AOA MBR) was examined under three aeration intensities [2.5, 3.75 and 5.0 m3 x (m2 x h)(-10]. The results showed that the averaged removals of COD were over 90% at different aeration intensities. And the higher aeration intensity was, the more ammonia nitrogen removal rate achieved. The removal rates of NH4(+) under the three aeration intensities were 84.7%, 90.6% and 93.8%, respectively. Total nitrogen removal rate increased with the increasing aeration intensity. But excessive aeration intensity reduced TN removal. The removal rates of TN under the three aeration intensities were 83.4%, 87.4% and 80.6%, respectively. Aeration intensity affected the denitrifying phosphorus ability of the AOA MBR. The ratio of denitrification phosphorus removal under the three aeration intensities were 20%, 30.2% and 26.7%, respectively.