Ammonia Nitrogen Research Articles

Integrated plant physiology, transcriptomics, and metabolomics reveal tobacco root growth and nicotine synthesis responses in tobacco exposure to different nitrogen forms

Tobacco (Nicotiana tabacum L.) is one of the world’s most economically important crops, with nicotine content being a crucial factor in determining its quality and economic value. By integrating plant physiology with transcriptomics and metabolomics analyses, we gained insight into the regulation of nicotine synthesis and metabolism in tobacco seedlings under different forms of nitrogen supply. Our findings revealed that ammonium nitrogen promotes nitrogen transformation in the root system of tobacco seedlings but inhibits root growth, whereas nitrate nitrogen inhibits biochemical processes but enhances root growth. Additionally, we observed that nitrate nitrogen facilitates the NAD + pathway in nicotine biosynthesis but inhibits the polyamine pathway, whereas ammonium nitrogen has the opposite effect. Overall, our comprehensive analysis indicates that the co-application of ammonium nitrate is conducive to nicotine synthesis. These results not only contribute to identifying key genes and metabolites involved in nicotine synthesis, but also provide a theoretical basis for establishing efficient regulation theories and pathways for tobacco's nitrogen utilization. Furthermore, they offer scientific support for future efforts aimed at regulating tobacco nicotine synthesis.Graphical

Simultaneous Measurement of Total Ammonia Nitrogen and Free Ammonia via Integrated Electrochemical Acidification─Optode Flow Cell.

The accurate measurement of total ammonia nitrogen (TAN) and free ammonia is crucial for various environmental, biomedical and industrial applications. We present a novel integrated system combining electrochemical water splitting with ammonia optodes to simultaneously measure TAN and free ammonia. Water electrolysis induces localized pH shifts, altering the ammonia speciation in the sample solution: an increase in pH near the cathode leads to conversion of NH4+ to NH3, enabling the measurement of TAN. Concurrently, a decrease in pH near the anode reduces the NH3 concentration to zero, enabling real-time zero calibration. In areas unaffected by these pH changes, the optode readout can effectively measure free NH3. The system demonstrates a measurement range of 0-300 mg·L-1 for both TAN and NH3, with a complete measurement cycle requiring only 6 min. The method was validated through the analysis of urine samples, showcasing its potential for real-time monitoring in clinical and environmental settings. The electrochemical speciation shifting allows for precise TAN measurement, while the zero-point calibration provided by the anode enhances the method's robustness and reliability. Overall, this study introduces a versatile and efficient approach for the simultaneous determination of TAN and NH3, offering significant improvements in speed and operational simplicity.

Characteristics and Mechanisms of Simultaneous Quinoline and Ammonium Nitrogen Removal by a Robust Bacterium Pseudomonas stutzeri H3

The discharge of organic and inorganic nitrogenous pollutants in wastewater leads to eutrophication and disrupts the ecological balance. Therefore, the pressing need for an effective treatment method has become increasingly evident. A robust bacterium Pseudomonas stutzeri H3 capable of simultaneous organic and inorganic nitrogen removal was isolated from the activated sludge in the coking wastewater treatment system. The optimal conditions for the simultaneous removal of ammonium nitrogen and quinoline were as follows: C/N ratio of 15–20, initial pH of 7–8, culture temperature of 30 °C, and shaking speed of 150–300 rpm. At 200 mg/L ammonium nitrogen and 100 mg/L quinoline, strain H3 achieved above 90% of removal efficiency, exhibiting excellent simultaneous nitrogen removal capabilities. The outstanding nitrogen removal efficiencies in the presence of quinoline and different inorganic nitrogen sources further confirmed the simultaneous organic and inorganic nitrogen removal capability of strain H3. The whole genome sequencing and nitrogen metabolic intermediates determination of strain H3 were performed to elucidate the gene function annotations, nitrogen removal function genes, and nitrogen metabolic pathways. The findings provide a promising pathway to treat the organic and inorganic nitrogenous pollutants in wastewater.

Determination of leachate leakage around a valley type landfill and its pollution and risk on groundwater

This paper investigates leachate leakage of a typical valley-type landfill in South China and health risk of groundwater pollution. Through geophysical detection on landfill, chemical analysis of 19 parameters such as pH, total dissolved solids (TDS), total hardness (TH), potassium permanganate index (CODMn), ammonia nitrogen (NH3–N), sulfate (SO42−), chloride (Cl−), fluoride (F−), nitrate (NO3–N), nitrite (NO2–N), and heavy metals (Hg, Fe, Mn, Cu, Zn, Cr, Pb and Cd) in groundwater, and model simulation, the prediction of pollution resource and risk level is achieved. This aggregated approach aims to effectively manage and control groundwater contamination and public health risks from the source. The results of transient electromagnetic method showed that four leakage areas of impermeable layer were existed in the landfill, with an area of 336.8 m2 and a depth of 15–22 m. The chemical analysis and pollution assessment revealed that groundwater at ZK01 and ZK04 were heavily polluted, ZK02 and ZK03 were slightly polluted, and ZK05 was non-polluted. Water quality of points ZK01–04 exceeded the standard value of Class III water in the Groundwater Quality Standard (GB/T 14,848-2017), and the main excessive parameters are pH, NH3–N, Mn and Fe. The landfill leakage, rock weathering dissolution and water–rock interaction possibly were the main sources of groundwater pollution through correlation analysis (CA) and principle component analysis (PCA). Numerical simulation based on the RBCA (Risk-based Corrective Action) model thought Mn and NO3–N had adverse non-carcinogenic effects o human health risk. Assuming that no pollution control measures are taken, the average increase rate of hazard index (HI) for pollutants within the past 20 years was between 0.04 and 0.08/a, and the average expansion rates of the risk area were 341–432 m2/a. The expansion rates of risk area along the groundwater runoff were 1.6–3.8 m/a, drinking water safety downstream of main pollution source runoff is the focus of protection.

Water Quality Assessment and Aeration Optimization of Wastewater Aeration Tanks Based on CFD Coupled with the ASM2 Model

High energy consumption and low aeration efficiency remain significant challenges in wastewater treatment. This study introduces a computational method that integrates the activated sludge model with Fluent (2021) to comprehensively simulate the internal operations of aeration tanks, enabling accurate modeling of biochemical mass transfer processes. Hydraulic retention times were analyzed using streamlined patterns, while low-velocity flow regions were identified across cross-sectional planes. The study systematically evaluated key water quality indicators, including dissolved oxygen, chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), and ammonium nitrogen (NH4+-N), across the aeration tank. A novel metric was proposed to quantify purification efficiency per unit aeration volume. Four optimized aeration schemes were designed and tested, incorporating microbubble aeration to improve flow dynamics. The optimized schemes achieved a 28% reduction in aeration energy while maintaining purification efficiency losses for COD, TP, TN, and NH4+-N below 8%. An alternative scheme reduced aeration volume by 16%, limiting efficiency losses to 5.5%. This work offers practical insights into optimizing wastewater treatment systems, providing data-driven strategies for enhancing energy efficiency and meeting stringent effluent standards.

Urbanization Gradients Affect Occurrence and Distribution of Antibiotic Contamination in the Baixi Reservoir and Yongjiang Estuary, China.

Urbanization has promoted the development of human society, but is often accompanied by environmental pollution. To investigate the extent to which differing levels of urbanization might affect antibiotic heterogeneity and distribution in the aquatic environment, we contrast the Yongjiang Estuary, an area of intense urbanization, with the Baixi Reservoir- whose hinterland is much less urbanized. We found that antibiotic residues in Baixi Reservoir and Yongjiang Estuary were significantly different due to urbanization gradient. 14 antibiotics were detected in Yongjiang Estuary with an average concentration of 0.74 ng/L, and the dominant classes being was macrolides. 13 antibiotics were detected in Baixi Reservoir with an average concentration of 0.12 ng/L, and the dominant class being tetracyclines. Total nitrogen, total suspended particulate matter and dissolved organic carbon (DOC) were found to have strong effect on the concentration of quinolones in Baixi Reservoir. However, salinity, ammonia nitrogen, DOC and chloride ion concentration were found to have strong effect on the concentration of quinolones in Yongjiang Estuary. DOC was the common factor affecting the concentration of antibiotics. This study provides data which reveal the distribution characteristics of antibiotics under different urbanization level and elucidates the risks posed by antibiotics resistance associated with rapid urbanization occurring in China and throughout the developing world.

A study of surface water quality using organic pollution indices: comparative characteristics and educational opportunities

ABSTRACT This study sets out to examine a variety of approaches to the assessment of organic pollution and to consider the potential application of the results in the educational process of students specializing in the environment. Water samples from the Styr River were collected and analysed for physicochemical parameters such as nitrate ions (NO3-), ammonium nitrogen (N-NH3), phosphate ions (PO43-), dissolved inorganic nitrogen, chemical oxygen demand, biochemical oxygen demand in 5 days, and dissolved oxygen from 2018 to 2022. Four different equations for calculating the OPI were used to determine the levels of organic pollution. Statistical methods, including Pearson correlation, multiple linear regression, partial least-squares regression, principal component analysis (PCA), and network analysis (NA), were applied to analyse the data. The study revealed variations in OPI levels depending on the methodology used. The different equations provided varying degrees of pollution classification, from ‘pure’ to ‘contaminated’ and from ‘none’ to ‘moderate’. Seasonal trends were observed, with higher organic pollution levels in summer and lower levels in winter. PCA and NA helped identify key variables contributing to organic pollution. The OPI levels varied across different methods, with some methods showing stable pollution levels and others showing periodic fluctuations.

Hydrogel beads as slow-release NH4 + fertilizer and reducing S and Fe in soil acidity: alginate-poly(acrylic acid)-carboxymethyl cellulose-oleic acid

A study was conducted on slow-release NH4 + fertilizer (SRNH4F) embedded in a hydrogel bead matrix consisted of sodium alginate, poly(acrylic acid), and carboxymethyl cellulose, both without (SPC-A) and with (SPC-B) the incorporation of oleic acid. The results demonstrated that SPC-B exhibited higher specific surface area, pore volume and a greater abundance of COOH functional groups. Swelling behavior analysis indicated that all samples achieved their highest swelling in NaOH solution. The SRNH4F release studies revealed that the inclusion of oleic acid significantly reduced NH4 + release, enabling more controlled NH4 + ion delivery in water, while also contributing to reduced CO2 emissions from soil, consistent with the observed trends in soil organic carbon levels. Furthermore, the treatment with hydrogel beads resulted in a significant increase (p ≤ 0.05) in soil available phosphorus, soil cation exchange capacity, exchangeable calcium, and available ammonium nitrogen. The immobilization rates in soil were satisfactory, reaching up to 93.36% for sulfur and 88.33% for iron with SPC-B. This technique demonstrated multifunctionality in improving nutrient management and mitigating environmental pollution.

Micro-doping tin-bismuth on modification of Co3O4 electrocatalyst and degradation of ammonia nitrogen.

Micro-doping tin-bismuth on modification of Co3O4 electrocatalyst and degradation of ammonia nitrogen.

Producing high-quality and safe whole-plant quinoa silage through selecting variety and harvest time

The great potential of whole-plant quinoa (WPQ) as a forage crop has been recognized in recent years. In this study, we investigated the effects of variety and harvest time on the fermentation characteristics, bacterial community, and hygienic quality of WPQ silage. Five varieties (Hongxin, Mengli1, SL577, SL2860, SL923) were grown across five separate experimental fields, with harvest occurring after 90 days (H1), 105 days (H2), or 120 days (H3). The samples were ensiled to evaluate their fermentation characteristics and bacterial composition. Hygienic quality was assessed using the Tax4fun2 and BugBase tools for potential pathogenicity and antimicrobial resistance prediction. The variety significantly influenced (P < 0.05) all fermentation variables (including pH, lactic acid, acetic acid, propionic acid, ethanol, and ammonia nitrogen), while harvest time affected pH and the contents of acetic acid, propionic acid, and NH3-N (P < 0.05). An interaction between variety and harvest time was detected (P < 0.05) for all fermentation variables. Based on the flieg’ score index, silage quality increased for Mengli1 (5.20–54.8), SL577 (36.7–71.5), and SL923 (34.9–77.0) with delayed harvest time, while silage quality decreased for Hongxin (52.1–41.4) and SL2860 (78.4–63.6). Compared to other silages, Hongxin silages exhibited greater differences in bacterial community composition between harvest times (indicated by higher PERMANOVA R2-value). Tax4fun2 and BugBase analyses revealed that delaying harvest time significantly increased (P < 0.05) the relative abundances of pathogenic and antibiotic-resistant KEGG pathways ("Infectious disease: bacterial invasion" and "Drug resistance") and harmful microbes associated with potential pathogenicity and antimicrobial resistance in Hongxin silages. This study highlights the importance of variety and harvest time in producing high-quality, safe WPQ silage, which is beneficial for ensuring the safety in our food supply chain.

Recycled wheat straw biochar enhances nutrient-poor soil: Enzymatic kinetics of carbon, nitrogen, and phosphorus cycling.

Recycled wheat straw biochar enhances nutrient-poor soil: Enzymatic kinetics of carbon, nitrogen, and phosphorus cycling.

Soil characteristics and bacterial community characteristics of shelterbelts of different tree species in black soil region of China

To understand how surface soil characteristics and bacterial communities are affected by the establishment of farmland shelterbelts. Five types of shelterbelts in the mid-west of Heilongjiang Province China were selected for the study. The physicochemical characteristics and bacterial diversity of Populus×xiaohei monoculture (X), Larix gmelinii monoculture (L), Pinus sylvestris monoculture (Z), Pinus sylvestris and Larix gmelinii mixed forest (ZL), and Fraxinus mandshurica and Larix gmelinii mixed forest (SL), as well as in fallow land (CK), were measured and analyzed, respectively. Soil physicochemical characteristics and bacterial diversity (via high-throughput sequencing) were analyzed across 0–20 cm depths. Results showed that shelterbelts significantly altered soil characteristics: X increased moisture, ammonium nitrogen, and microbial biomass nitrogen but reduced aeration. ZL exhibited the highest bacterial richness and enhanced water-holding capacity, aeration, and nutrient retention (total organic carbon, nitrogen, phosphorus). ZL outperformed monocultures in promoting soil health, with available potassium (0–10 cm) and pH (10–20 cm) identified as key drivers of bacterial community variation. Unique genera like Krasilnikovia and Rubrobacter dominated shelterbelt soils, reflecting species-specific effects. Shelterbelts induced surface accumulation of nitrate-nitrogen, potassium, and microbial biomass carbon. Overall, Pinus sylvestris and Larix gmelinii mixed forests optimized soil structure, microbial diversity, and nutrient cycling, underscoring their ecological benefits for sustainable agroforestry. This study highlights the critical role of mixed forest shelterbelts in enhancing soil health and microbial biodiversity, which are essential for sustainable land management practices in the black soil region of China.

Influence of a Combination of Glycerol Polyethylene Glycol Ricinoleate and Bi-Distilled Oleic Acid in Powder Form on Growth Performance, Nutrient Digestibility, Excreta Nitrogen and Liver Fatty Acid Profile of Broilers Fed Reduced-Energy Diets

The present study aimed to evaluate the effects of an emulsifier in powder form composed of glycerol polyethylene glycol ricinoleate and bi-distilled oleic acid on the growth performance, nutrient digestibility, excreta nitrogen and liver fatty acid profile of broilers fed reduced-energy diets. A total of 720 male ROSS 308 chicks were divided into four homogeneous groups (9 pens/20 chicks per group): positive control (PC), negative control (NC, −70 kcal/kg of AME), EMUL1 and EMUL2 fed an NC diet + 250 and 500 mg/kg of emulsifier. Body weight, average daily gain, average daily feed intake and feed conversion ratio (FCR) were evaluated. Excreta were collected at 24 and 42 d directly from polyethylene trays and pooled to determine the apparent total tract digestibility of dry matter, crude protein, ether extract and gross energy. The apparent metabolizable energy (AME, AMEn) and nitrogen ammonia in excreta were determined. Performances were improved in EMUL1 and EMUL2 during the trial (p &lt; 0.05). The digestibility of nutrients in EMUL1 and EMUL2 was increased in comparison to NC and PC (p &lt; 0.05). Excreta nitrogen ammonia was reduced by EMUL2 at 42 d (p &lt; 0.05). Glycerol polyethylene glycol ricinoleate and bi-distilled oleic acid in powder form modulated liver fatty acid profiles, enhancing oleic acid content in EMUL1 chickens (p &lt; 0.05), while γ-linolenic acid and arachidonic acid were enhanced in EMUL2 (p &lt; 0.05). Based on the findings, it is recommended to administer solidified glycerol polyethylene glycol ricinoleate and bi-distilled oleic acid in diets with reduced energy content for appreciable advantages in terms of growth through higher nutrient digestibility and better hepatic fatty acid composition.

Water quality and diarrhoeagenic Escherichia coli detection in surface Pampean aquatic systems.

Many surface water systems are impacted by point source pollution from sewage discharges and industrial wastes, as well as diffuse pollution from agriculture and livestock farming, inducing a potential biohazard to human, animal, and environmental health. This study aimed to determine the presence of diarrhoeagenic Escherichia coli (DEC) pathotypes and their antibiotic resistance, as well as the bacteriological, physical, and chemical water quality conditions in two Pampean peri-urban rivers (Rojas and Salado rivers, Buenos Aires, Argentina) used for recreation. Additionally, we explored the impact of the surrounding land use on the water quality. In the Rojas (R) and Salado (S) rivers, wastewater discharges from treatment plants increased nutrient content and coliform abundances at specific sampling sites (R2 and S3) and downstream (R3 and S4, respectively). Coliform abundances correlated with ammoniacal nitrogen concentrations, both exceeding recreational use guidelines. Out of 36 samples positive for DEC virulence factors, 11 DEC strains were isolated (5 enteroaggregative, 3 enteropathogenic, 1 shigatoxigenic-stx1/stx2, 1 shigatoxigenic-stx2, 1 hybrid enteroaggregative-enterotoxigenic). Six strains were resistant to one or more antibiotics. Our results suggest that differences in E. coli pathotypes between the two rivers and the water quality of each sampling site are linked to the surrounding land use, evidencing both diffuse and point source pollution.

Prediction of Water Quality Index of Island Counties Under River Length System—A Case Study of Yuhuan City

In order to cope with the extremely difficult challenges of water pollution control, China has widely implemented the river chief system. The water quality monitoring of surface water environment, as a solid defense line to safeguard human health and ecosystem balance, is of great importance in the river chief system. As a well-known island county in China, Yuhuan City holds even more precious water resources. Leveraging machine learning technology to develop water quality prediction models is of great significance for enhancing the monitoring and evaluation of surface water environment quality. This case study aims to evaluate the effectiveness of six machine learning models in predicting water quality index (CWQI) and uses SHAP (Shapley Additive exPlans) as an interpretability analysis method to deeply analyze the contribution of each variable to the model’s prediction results. The research results show that all models exhibited good performance in predicting CWQI, and as the number of significantly correlated variables in the input variables increased, the prediction accuracy of the models also showed a gradual improvement trend. Under the optimal input variable combination, the Extreme Gradient Boosting model demonstrated the best prediction performance, with a root mean square error (RMSE) of 0.7081, a mean absolute error (MAE) of 0.4702, and an adjusted coefficient of determination (Adj.R2) of 0.6400. Through SHAP analysis, we found that the concentrations of TP (total phosphorus), NH3-N (ammonia nitrogen), and CODCr (chemical oxygen demand) have a significant impact on the prediction of CWQI in Yuhuan City. The implementation of the river chief system not only enhances the pertinence and effectiveness of water quality management, but also provides richer and more accurate data support for machine learning models, further improving the accuracy and reliability of water quality prediction models.

The impact of the river chief system on transboundary water pollution

The River Chief System (RCS) in China plays a crucial role in addressing transboundary water pollution (TWP), which is vital for achieving the Sustainable Development Goal of "clean water." This study examines the static and dynamic effects of the RCS on TWP using a difference-in-difference-in-differences (DDD) model and manually collected RCS data from 104 counties between 2007 and 2020. The results show that the RCS significantly reduces chemical oxygen demand (COD) by 15.9% and ammonia nitrogen (NH3-N) by 22.9% in border counties, though it has no notable impact on dissolved oxygen (DO). Additionally, RCS intensity contributes to a 13.8% reduction in COD. However, no sustained dynamic effects are observed for COD or NH3-N reduction over time. Several robustness checks confirm the validity of these findings. Heterogeneity analysis indicates that the RCS’s impact is more pronounced in counties with higher economic development, upstream locations, lower initial pollution levels, and younger local government leaders. This study not only provides critical insights for water resource management in China but also offers international relevance for addressing TWP governance challenges in transboundary water bodies.

Effect of Essential Oil on Growth Performance, Rumen Fermentation and Nutrient Digestibility of Hu Sheep

Background: Plant essential oil is used as a feed additive instead of antibiotics, but there is little research on its application in ruminants. Therefore, it is very necessary to study the effects of essential oil on growth performance, rumen fermentation and nutrient digestibility of Hu sheep. Methods: 96 weaned male Hu sheep, weighing 17.69±0.20 kg, were randomly divided into 3 groups (control, 300 mg/kg and 600 mg/kg essential oil), with 4 replicates per group and 8 sheep per replicate. The pre-feeding period was 10 days and the full trial period was 61 days. Result: The results showed that the final weight of Hu sheep increased significantly (P less than 0.05) and the rumen liquid ammonia nitrogen decreased significantly (P less than 0.05) in the 600 mg/kg essential oil group when compared with the control group. The addition of essential oil to the diet had no significant effect on the rumen pH, volatile fatty acids and the digestibility of various nutrients. In conclusion, the diet addition of 600 mg/kg essential oil was better than 300 mg/kg for weaned Hu sheep performance, which can improve the growth performance and reduce the ammonia nitrogen of the rumen fluid. Essential oil can be added to Hu sheep feed as a good feed additive.

Coupled Effects of Water Depth, Vegetation, and Soil Properties on Soil Organic Carbon Components in the Huixian Wetland of the Li River Basin

Wetland ecosystems are essential to the global carbon cycle, and they contribute significantly to carbon storage and regulation. While existing studies have explored the individual effects of the water depth, vegetation, and soil properties on the soil organic carbon (SOC) components, a comprehensive study of the interactions between these factors is still lacking, particularly regarding their collective impact on the composition of the SOC in wetland soils. This paper focused on the Huixian Wetland in the Li River Basin. The variations in the SOC and its fractions, namely dissolved organic carbon, microbial biomass carbon, light fraction organic carbon, and mineral-associated organic carbon, under different water depths and vegetation conditions were examined. Additionally, the effects of the water depth, vegetation, and soil properties (pH and bulk density, total phosphorus (TP), total nitrogen (TN), ammonium nitrogen (NH4-N), and nitrate nitrogen (NO3-N)) on the changes in the SOC and its components were quantified. Specific water depth–vegetation combinations favor SOC accumulation, with Cladium chinense at a water depth of 20 cm and Phragmites communis at 40 cm exhibiting a higher biomass and higher SOC content. The SOC components were significantly and positively correlated with plant biomass, TP, TN, and NH4-N. The coupling of water depth, vegetation, and soil properties had a significant effect on the SOC components, with the coupling of water depth, vegetation, and soil properties contributing 74.4% of the variation in the SOC fractions. Among them, water depth, plant biomass, and soil properties explained 7.8%, 7.3%, and 6.4% of the changes, respectively, and their interactions explained 25.6% of the changes. The coupling of the three significantly influenced the changes in the SOC components. Optimal water level management and the strategic planting of wetland vegetation can enhance the carbon storage capacity and increase the SOC content. This research offers valuable insights for effectively managing wetland carbon sinks and soil carbon reserves.

Integration of Bio-Enzyme-Treated Super-Wood and AIE-Based Nonwoven Fabric for Efficient Evaporating the Wastewater with High Concentration of Ammonia Nitrogen

The treatment of ammonia nitrogen wastewater (ANW) has garnered significant attention due to the ecology, and even biology is under increasing threat from over discharge ANW. Conventional ANW treatment methods often encounter challenges such as complex processes, high costs and secondary pollution. Considerable progress has been made in employing solar-induced evaporators for wastewater treatment. However, there remain notable barriers to transitioning from fundamental research to practical applications, including insufficient evaporation rates and inadequate resistance to biofouling. Herein, we propose a novel evaporator, which comprises a bio-enzyme-treated wood aerogel that serves as water pumping and storage layer, a cost-effective multi-walled carbon nanotubes coated hydrophobic/hydrophilic fibrous nonwoven mat functioning as photothermal evaporation layer, and aggregation-induced emission (AIE) molecules incorporated as anti-biofouling agent. The resultant bioinspired evaporator demonstrates a high evaporation rate of 12.83kgm-2h-1 when treating simulated ANW containing 30wt% NH4Cl under 1.0 sun of illumination. AIE-doped evaporator exhibits remarkable photodynamic antibacterial activity against mildew and bacteria, ensuring outstanding resistance to biofouling over extended periods of wastewater treatment. When enhanced by natural wind under 1.0 sun irradiation, the evaporator achieves an impressive evaporation rate exceeding 20kgm-2h-1. This advancement represents a promising and viable approach for the effective removal of ammonia nitrogen wastewater.

Denitrification efficiency and biofilm community succession in a bidirectional alternating influent biofilter.

Biofilters are widely used for nitrogen removal in wastewater treatment. This study developed a bidirectional alternating-influent biofilter to reduce clogging and enhance nitrogen removal. Alternating influent utilized biofilm on the media as a denitrification carbon source. With initial ammonium, nitrate, and total nitrogen concentrations of 8.49±0.30, 12.52±0.20, and 19.89±0.79 mg/L, the forward influent achieved ammonium, nitrate, and total nitrogen removal efficiencies of 81.6%, 66.8%, and 71.2%, increasing by 13.3%, 3.0%, and 4.8% at the effluent. Reverse influent further boosted nitrate and total nitrogen removal by 14.0% and 5.5%. The natural DO gradient under conventional influent conditions was simulated, and the nitrogen removal mechanism and treatment effect, mainly nitrification and denitrification, were discussed. Microbial analysis showed that endogenous carbon in the biofilm, derived from decaying cells and EPS, reduced clogging risk. Significant changes in bacterial count, EPS content, and microbial abundance were observed across influent directions, with Proteobacteria, Bacteroidetes, and Pseudomonas increasing under reverse flow. These results indicate that bidirectional alternating influent can significantly improve nitrogen removal and reduce clogging, offering an effective optimization for wastewater treatment.