In order to address the issues of complex processes and high infrastructure and operational costs in simultaneous nitrogen and phosphorus removal, a heterotrophic nitrifying strain NP3 exhibiting simultaneous nitrogen and phosphorus removal capabilities was isolated from activated sludge in this study. Strain NP3 was identified as Pseudomonas stutzeri by 16S rRNA sequence analysis, and its nitrogen and phosphorus removal characteristics and mechanisms were investigated. It was showed that strain NP3 was able to utilize ammonium, nitrate, and nitrite as the sole nitrogen source for efficient nitrogen and phosphorus removal under aerobic conditions. The accumulation of intermediate products during the reaction process was minimal, and nitrogen and phosphorus were primarily removed through assimilation. The growth and metabolic rates followed the order: NH₄⁺-N >NO₂⁻-N >NO₃⁻-N. Under the optimal growth conditions of sodium citrate as the carbon source, C/N=10, T=30℃, pH =7, and r=160r/min, the maximum removal rates of ammonia nitrogen and phosphate were almost 100%. Furthermore, successful amplification of denitrification and polyphosphate genes (nosZ, nirS, ppk) further confirmed the simultaneous nitrogen and phosphorus removal capability of strain NP3. X-ray Photoelectron Spectroscopy (XPS) analysis demonstrated that the functional groups on the extracellular polymeric substances(EPS) surface could adsorb different forms of phosphorus such as C-PO₃/P-C, PO₄^3-/HPO₄^2-, acting as phosphorus transfer stations.³¹P nuclear magnetic resonance (NMR) results further indicated that there was a large effect of EPS on phosphorus fugitive morphology, with pyrophosphate being the main phosphorus species in the presence of EPS, whereas orthophosphate and orthophosphate diester were the major phosphorus forms after EPS extraction.

Advanced oxidation processes (AOPs) represent a widely adopted approach for eliminating organic pollutants from water bodies. Nevertheless, conventional AOPs grapple with several challenges, notably including inadequate electron interactions, interference from macromolecular substances, constrained mass transfer processes, and moderate efficiency levels. To overcome these limitations, the employment of a spatial confinement strategy, which entails the construction of tailored nanoscale reactors, has emerged as a promising solution to substantially bolster oxidation efficiency. The spatial confinement strategy offers several key advantages: (1) optimize the migration of protons and charges; (2) alter molecular structures and molecular dynamics; and (3) create new active sites. This strategy is commonly integrated into processes such as Fenton oxidation, persulfate oxidation, photocatalytic oxidation, ozonation, and electrochemical oxidation. This paper summarizes the implementation and analytical methods of spatial confinement, outlines its three major functions, reviews its applications in various oxidation processes, and evaluates its effects at both microscopic and macroscopic levels. Furthermore, future directions for the development of spatial confinement in advanced oxidation are discussed.

Based on field data from 2019 to 2022 in the South Tiaoxi River Watershed in the upper reaches of the Taihu Lake Basin, redundancy analysis (RDA) and non-parametric breakpoint analysis (nCPA) were employed to analyze the relationships between riverine nitrogen (N) concentrations and landscape pattern indices at different buffer scales, and identity the critical landscape threshold ranges affecting the river nitrate (NO₃^--N) concentration. The results showed that the total nitrogen (TN) concentration in the South Tiaoxi River exceeded the Class V surface water quality standard, with NO₃^--N as the predominant N pollutant. During the wet season, the concentrations of TN, dissolved total nitrogen (DTN), NO₃^--N, and dissolved organic nitrogen (DON) were significantly higher than those in the dry season, whereas ammonium nitrogen (NH₄⁺-N) concentrations were lower. N concentrations were lower in the upstream compared to downstream. The landscape pattern indices in the buffer zones of 400m and 200m explained the largest variance in river N concentrations during the wet and dry seasons, respectively (89.49% and 90.97%). Based on the identified key thresholds of landscape pattern indices for significantly reducing the risk of NO₃^--N pollution in the watershed, the following suggestions are provided: the proportion of farmland, construction land, and Shannon diversity index (SDHI)in the buffer zone of 400m should be controlled within 0.25%, 1.75%, and 0.77, respectively; and the proportion of farmland and edge density (ED) in the buffer zone of 200m should be kept within 0.5% and 39m/hm², simultaneously with the proportion of forest area exceeding 91.0%.

In the present study, Manganese oxide octahedral molecular sieve (OMS-2_PS) was synthesized using K₂S₂O₈ and(CH₃COO)₂Mn·4H₂O via a solid-phase method. The physicochemical properties of OMS-2_PS were analyzed via X-ray diffraction(XRD), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The performance of persulfate activation by OMS-2_PS for degrading organic contaminants was examined. This study also investigated the effect of various parameters, including dosage of OMS-2_PS, PS concentration, and initial pH, on AO7 removal efficiency. Moreover, the mechanism of PS activation by OMS-2_PS was explored. The results showed OMS-2_PS was successfully synthesized via a solid-phase method, which exhibits a nanorod structure. OMS-2_PS could activate PS to degrade organic contaminants. The use of 50mg/L AO7,1.0g/L OMS-2_PS, and 2.0mmol/L PS led to the AO7 removal and mineralization rates of 97.4% and 50.1%, respectively. Ion coexistence experiments demonstrated that AO7 removal was considerably inhibited by Cl⁻, NO₃⁻, and CO₃²⁻, while HA had almost no effect on it. The free radical quenching experiments and electron paramagnetic resonance (EPR) analysis indicated ·OH and SO₄^•−were the primary active oxygen species in the OMS-2_PS/PS system, and ·OH played the dominant role in the AO7 degradation. XPS analysis revealed Mn(IV) and lattice oxygen on the surface of OMS-2_PS were the main active sites for PS activation. Based on experiment results, a potential activation mechanism of PS by OMS-2_PS was proposed that PS combined with OMS-2_PS through the hydroxyl groups on the surface of OMS-2_PS, and then PS reacted with the active sites on the surface of OMS-2_PS to produce active oxygen species. In addition, The OMS-2_PS/PS system effectively removed AO7 from different water bodies, and also degraded efficiently other pollutants including bisphenol A, naphthalene, and tetracycline, indicating that the OMS-2_PS/PS system have a bright application prospect in environmental pollution control.

This study applied umbrella-shaped modified basalt fiber (MBF) bio-carrier to an integrated fixed-film activated sludge system to investigate the performance of MBF bio-nest in wastewater treatment and N₂O emission reduction. The effect of dissolved oxygen (DO) on N₂O reduction in the bio-nest was investigated by changing the DO concentration. The results showed that under the same operating conditions, TN removal efficiency was increased by 63.87% and N₂O emission was reduced by 77.76% in the bio-nest system compared with the sequencing batch activated sludge bioreactor. According to the 16sRNA sequencing results, a variety of functional microregions existed within MBF bio-nests, with a high diversity of microbial populations. Saccharibacteria genera incertae sedis were the main carbon-removing bacteria in the reactor, and heterotrophic nitrification-aerobic denitrification(HN-AD) genera were the main nitrifying bacteria, which did not emit N₂O during the nitrification process. Denitrification genera were dominated by conventional heterotrophic denitrification bacteria (HDN) in the inner and middle layers of the bio-nest (17.42%,23.02%), and HN-AD bacteria in the outer layer of the bio-nest and suspended sludge (29.70%, 27.53%). Aerobic/anoxic/anaerobic genera were distributed in all layers of the bio-nest, and denitrification genera had higher relative abundance in the MBF bioreactor than in the SBR, which facilitated denitrification and mitigated the accumulation of intermediate products, reducing N₂O emissions. The MBF bio-nest reactor had the highest TN removal rate of 86.64%±1.14% and the lowest N₂O emission of (0.78±0.83) mg N₂O/g TN when the DO concentration was 2.5mg/L (M2). The bio-nest microbial genus categories were basically the same in each DO gradient, but differed in their relative abundance. In M2, HN-AD bacteria were the main nitrifying functional bacteria in the reactor(the relative abundance of the layers from inside to outside was 44.24%, 61.34%, and 36.16%), which was conducive to N₂O reduction; HDN were the main functional bacteria in the M2reactor, with moderate relative abundance of 20.17%, 12.00%, and 21.20% from inside to outside layers; the concentrations of NO₂^--N and NO₃^--N in the effluent were (0.011±0.002) and (1.65±0.46)mg/L; denitrification was carried out completely, which was conducive to the reduction of N₂O emissions.

To address the issue of insufficient polarization of auxiliary electrodes (AEs) in magnetically assembled electrodes, five types of magnetically assembled electrodes were constructed using five different AEs: CNT/Fe₃O₄、Fe₃O₄/MnO₂、Fe₃O₄/Co₃O₄、Fe₃O₄/RuO₂, and ferrocarbon particles (FC). This study examined the effects of tourmaline on the electrochemical performance of each electrode and its impact on wastewater treatment efficiency. The results demonstrate that tourmaline can significantly enhance the polarization process of AEs, increase the active surface area of the electrodes by up to 28.47%, improve the degradation efficiency of simulated acid red G wastewater by up to 108.06%, and enhance the mineralization efficiency of real petrochemical wastewater by up to 10.61%.

To investigate the impact and mechanisms of the "23·7" heavy rainstorm event on groundwater quality in the Mentougou Plain area, the area at the foothills of the Yongding River was selected as the study area. By comparing the alterations in groundwater and surface water quality before and after the rainstorm, and integrating hydrogeochemical modeling with microbial characterization, we analyze the underlying causes. The results showed that the average concentrations of Ca²⁺ and HCO₃^- in the groundwater increased by 9.75% to 14.68%, while those of Cl^-, SO₄^2-, F^-, total Fe, and total Mn decreased by 26% to 86.92% after the rainstorm, consistent with the trend in surface water. It suggested that the variation in groundwater chemistry was primarily driven by the infiltration of affected surface water. However, the trends in K⁺, dissolved oxygen (DO), redox potential (Eh), and NO₃^--N in groundwater are opposite to those in surface water, indicating that groundwater chemistry changes were not solely the result of simple physical mixing with surface water. The reverse simulation results using PHREEQC indicate that under the influence of the rainstorm, the evolution of groundwater chemistry is regulated by a combination of physical mixing and dilution, mineral dissolution and precipitation, denitrification, and sulfate reduction. Specifically, physical mixing and dilution account for 15.82% of the alterations. Based on it, the silicate minerals dissolution increases the Ca²⁺ concentration, while the dissolution of silicate and evaporite minerals, in combination with cation exchange, helps maintain Na⁺ balance. The infiltration of rainwater and the decomposition of organic matter increase the HCO₃^- concentration. The denitrification and sulfate reduction decrease NO₃^- and SO₄^2- concentrations. Notably, the heavy rainstorm exacerbated the dilution and diffusion of high-concentration Fe contamination around the Shougang Industrial Park. Although dilution reduced the peak concentration of Fe exceeding the standard from 89.5mg/L to 25.4mg/L, the number of locations where Fe exceeded the standard increased from one to four, accounting for 66.67% of the total. Meanwhile, this process significantly promoted the enrichment of Fe(Ⅱ)-dependent autotrophic denitrifying bacteria in the groundwater, enhancing the denitrification rate and significantly reducing the concentration of NO₃^--N in the groundwater.

This study aimed to explore the accumulation of MGEs by wetland plants in the treatment of rural sewage using a soil ecological infiltration system. Thus, the changes in the integrase gene intI1and transposase gene tnpA-04 in the vegetative parts of the wetland plant Iris were investigated before and after treatment. The results showed that, over a 60d operational period, the soil ecological infiltration system achieved average removal rates of ammonia nitrogen and chemical oxygen demand from rural sewage of 88.50% and 75.17%, respectively. The average height and fresh weight of the Iris increased by 3.63% and 43.45%, respectively. The concentration of MGEs in the plant increased by 1.67ng/g, with intracellular accounting for 68.26%. Forthermore, the abundance of the tnpA-04 gene was found to be 37.86% higher than that of the intI1gene, which demonstrated a higher propensity for transfer within the vegetative parts of Iris. The bioconcentration ability for MGEs in the plant's vegetative parts followed the order: stem >root > leaf. Moreover, variations in soil properties significantly influenced the plant's ability to accumulate MGEs (P < 0.05). This study suggests that wetland plants can effectively accumulate MGEs from rural sewage, thereby reducing the risk of antibiotic resistance gene dissemination.

This study aimed to investigate the mitigating effect and regulatory mechanism of humic acid (HA) on the physicochemical properties and pollutant treatment performance of aerobic granular sludge (AGS) under prolonged stress induced by graphene (G) and oxide graphene (GO). The results demonstrated that the optimal dosage of HA (10mg/L) significantly enhanced the physicochemical characteristics of AGS, and improved the pollutant treatment performance of the AGS reactor (R2 (1.0mg/L G) and R3 (1.0mg/L GO)). At the 75^th day, in R3, there was an obviously increase in average particle size of AGS from 1224.1µm to 1407.5µm, while in R2it increased from 1313.0µm to 1461.3µm. Simultaneously, the enhancement of AGS physicochemical properties led to a respective increase of 2.3% and 7.6% in TN removal efficiency for R2 and R3. The introduction of HA resulted in a significant reduction in the levels of reactive oxygen species (ROS), lactate dehydrogenase activity, catalase activity, and superoxide dismutase activity in R2 and R3. This suggested that HA can effectively bind with accumulated ROS within cells to further mitigate oxidative stress levels induced by G and GO. The addition of HA also effectively alleviated the excessive secretion of extracellular polymeric substances (EPS) in AGS, resulting in a decrease in the content of aromatic proteins and tyrosine-like substances within EPS. Consequently, this led to a more compact and denser AGS particle structure in R2 and R3. Ultimately, the changes in Zeta potential of G and GO (before and after the addition of HA) indicate that the incorporation of HA can enhance the initial potential values of G and GO, thereby augmenting the repulsive effect between G/GO and microorganisms, reducing direct contact between microorganisms and G/GO, thus effectively mitigating the toxic effects exerted by G and GO on microorganisms.

To clarify the temporal and spatial variation patterns of methane emissions from landfills and their influencing mechanisms, a case study was conducted at a municipal solid waste landfill in Qingdao. The static chamber method was used to measure the diurnal dynamics of methane emission fluxes across different seasons. The results indicate significant seasonal variations in methane emission fluxes from the landfill, with the highest emissions occurring in winter at (115.67±65.34) mmol/(m²·h) and the lowest in summer at (61.51±74.57) mmol/(m²·h). The diurnal methane emission fluxes also varied markedly between seasons, with summer fluxes exhibiting a bimodal curve and autumn and winter fluxes showing a unimodal curve. Correlation analysis revealed that methane emission fluxes were significantly related to atmospheric pressure, air temperature, relative humidity, wind speed, soil temperature, and soil relative humidity. In summer and autumn, methane emission fluxes showed a significant positive correlation with atmospheric relative humidity and a negative correlation with air temperature, whereas the opposite was true in winter.