A novel carbon emission evaluation model for anaerobic-anoxic-oxic urban sewage treatment.

The proposal of the dual carbon goal and the blue economy in China has sparked a keen interest in carbon emissions reduction from sewage treatment. Carbon accounting in urban sewage plants serves as the foundation for carbon emission reduction in sewage treatment. This paper re-evaluated carbon accounting in the operational processes for urban sewage treatment plants to develop a novel carbon emission evaluation model for anaerobic-anoxic-oxic treatment plants. The results show that the carbon emissions generated by non-carbon dioxide gases far exceed the carbon emissions from carbon dioxide alone. Moreover, the recycling of sewage leads to carbon emissions reduction that offsets the carbon emissions generated during the operation of the sewage plant. Also, the carbon emissions generated by sewage treatment plants are lower than those generated by untreated sewage. The findings and insights provided in this paper provide valuable references for carbon accounting and the implementation of low-carbon practices in urban sewage treatment plants.

First flush stormwater pollution in urban catchments: A review of its characterization and quantification towards optimization of control measures.

Identification, quantification, and control of First-Flush (FF) are considered extremely crucial in urban stormwater management. This paper reviews the methods for FF phenomenon identification, characteristics of pollutants flushes, technologies for FF pollution control, and the relationships among these factors. It further discusses FF quantification methods and optimization of control measures, aiming to reveal directions for future studies on FF management. Results showed that statistical analyses and Runoff Pollutographs Applying Curve (RPAC) fitting modelling of wash-off processes are the most applicable FF identification methods currently available. Furthermore, deep insights into the pollutant mass flushing of roof runoff may be a critical approach to characterizing FF stormwater. Finally, a novel strategy for FF control is established comprising multi-stage objectives, coupling LID/BMPs optimization schemes and Information Feedback (IF) mechanisms, aiming towards its application for the management of urban stormwater at the watershed scale.

Phosphorus removal from aqueous solution using a novel granular material developed from building waste.

In this study, a granular material (GM) developed from building waste was used for phosphate removal from phosphorus-containing wastewater. Batch experiments were executed to investigate the phosphate removal capacity of this material. The mechanism of removal proved to be a chemical precipitation process. The characteristics of the material and resulting precipitates, the kinetics of the precipitation and Ca2+ liberation processes, and the effects of dosage and pH were investigated. The phosphate precipitation and Ca2+ liberation processes were both well described by a pseudo-second-order kinetic model. A maximum precipitation capacity of 0.51 ± 0.06 mg g-1 and a liberation capacity of 6.79 ± 0.77 mg g-1 were measured under the experimental conditions. The processes reached equilibrium in 60 min. The initial solution pH strongly affected phosphate removal under extreme conditions (pH <4 and pH >10). The precipitates comprised hydroxyapatite and brushite. This novel GM can be considered a promising material for phosphate removal from wastewater.

High prevalence and diversity of viruses of the subfamily Gammaherpesvirinae, family Herpesviridae, in fecal specimens from bats of different species in southern China.

Several studies have reported the detection of herpesviruses (HVs) in bats. However, the prevalence and phylogenetic characteristics of HVs in bats are still poorly understood. To elucidate the epidemiological characteristics of bat HVs in southern China, 520 fecal samples from eight bat species were collected in four geographic regions of southern China. Of these samples, 73 (14.0 %) tested positive for HVs using nested polymerase chain reaction assay. Phylogenetic analysis revealed a high degree of molecular diversity of HVs in bats of different species from different geographic regions. Our study provides evidence for co-evolution of bats and HVs.

[Evolution of Water Quality and Characterization of Microbial Populations in Different Storage Forms of Roof Rainwater].

The safety and security of stored rainwater quality is the key to improve the efficiency of rainwater resources storage, and roof rainwater is the best scenario for rainwater storage and utilization. Through long-term monitoring of the evolution of water quality during the roof rainwater storage process, different storage materials （PE and glass） and different DO regulation modes （sealing and aeration） were constructed, and 16S rRNA microbial diversity sequencing and environmental factor correlation methods were used to characterize the changes in water quality under microbial metabolism during the rainwater storage process, as well as the potential risks of utilization and health. The results showed that the degradation of COD occurred mainly in the first 10 days of the storage process, and the nutrients were transformed mainly by microbial metabolism. There were differences in the characteristics of water quality changes under different water storage conditions, with traditional PE materials promoting the propagation of some pathogenic Xanthobacter, Alternaria, Stachybotrys, and Cladosporium, which were negatively correlated with DO and pH. Aeration was beneficial in reducing the abundance of bacteria and fungi, whereas the sealed water storage method was beneficial in inhibiting the growth of pathogenic bacteria such as Legionella.

[Identification and Derivation of Emerging Contaminants in the Roof Rainwater Confluence].

To identify emerging contaminants （ECs） in rainwater is a topic that has gradually received widespread attention. Rainwater resources, specifically urban roofs, play a crucial role in utilizing rainwater efficiently by understanding the occurrence and migration characteristics of pollutants in precipitation. This study selected a typical roof and studied the differences in rainwater quality and pollution occurrence at different collection stages during six rainfall events from March to May in 2023. Principal component analysis （PCA） and correlation analysis were used to explore the distribution, migration, and transformation of ECs in the collection process of roof rainwater. The findings revealed the presence of 44/54 ECs in wet deposition, dry and wet deposition, and roof runoff processes, with a total concentration range of 63.0 to 432.4 ng·L-1 and an average concentration of 166.8 ng·L-1. Notably, bisphenol A （BPA） exhibited the highest concentration, ranging from 14.7 to 265.6 ng·L-1, with an average concentration of 62.5 ng·L-1, followed by ofloxacin （OFX） and ethylhexyl methoxycinnamate （EHMC）, with detected concentrations up to 45.5 ng·L-1 and 44.8 ng·L-1. Dissolved organic matter （DOM）, nitrogen pollutants, and particulate matter were important factors affecting the occurrence characteristics of ECs, with a mantel correlation coefficient of up to 0.98 （P<0.01）. Based on the analysis of different rainfall events and collection stages, variations were observed in the accumulation pathways and contribution ratios of different pollutants. The wet deposition exhibited the highest content of ECs in the initial stage, whereas the dry and wet deposition and roof runoff processes displayed higher ECs content in the later stages. Additionally, the average ECs contribution rates of dry and wet deposition to roof runoff were 21.48% and 78.52%, respectively. Due to the influence of roof material and surface roughness retention performance, over 30% of ECs, including pharmaceuticals and personal care products （PPCPs）, endocrine-disrupting compounds （EDCs）, and pesticides, were deposited on the roof during the runoff collection. The results of this research can provide the theoretical foundation and technical support for the identification and control of ECs in urban roof runoff and for the safe storage of rainwater.

Nitrogen removal efficiency and mechanisms of an improved anaerobic-anoxic-oxic system for decentralized sewage treatment.

The unstable operation and poor effluent quality often associated with decentralized sewage treatment systems due to fluctuating water flows have garnered significant attention. In this study, a novel integrated process combining anoxic denitrification and simultaneous nitrification and denitrification was developed to address these challenges. The improved anaerobic-anoxic-aerobic system achieved average effluent concentrations of 20.83 mg/L and 4.63 mg/L for chemical oxygen demand and NH4+-N, with average removal rates of 91 % and 68 %, respectively. Moreover, the aerobic zone demonstrated an impressive efficiency of 40.8 % for simultaneous nitrification and denitrification. The key bacteria groups driving the system's performance were heterotrophic and aerobic nitrifying bacteria, which dominated the microbial populations. Overall, the system optimizes the traditional anaerobic-anoxic-aerobic process, providing an effective solution for fluctuating wastewater flows. It establishes a successful coexistence model for multiple microbial populations, highlighting its applicability for superior nitrogen removal performance, and reference for optimizing rural sewage treatment. TAKE HOME MESSAGE SENTENCE: The improved anaerobic-anoxic-aerobic system for fluctuating wastewater treatment has superior nitrogen removal performance depending on multiple microbial populations.

Evolution of water quality in rainwater harvesting systems during long-term storage in non-rainy seasons.

The development of rainwater utilization strategies has relied on rainwater harvesting (RWH) systems for centuries to alleviate the pressure on water resources. However, there are still significant knowledge gaps regarding the changes in water quality in RWH systems during long-term storage in non-rainy seasons. This study evaluated the water quality processes in RWH systems through static rainwater storage experiments for approximately 60 days. The results revealed that nutrients in rainwater accumulated in sediment during storage. Disturbance and redox conditions at the rainwater-sediment interface contribute to the release of sedimentary facies materials. The rainwater showed distinct DO stratification, with the biochemical reactions of sedimentary facies being the primary factor driving oxygen consumption. ORP and turbidity showed positive correlations with COD (r = 0.582; 0.572), TOC (r = 0.678; 0.681), TN (r = 0.452; 0.439), and NH4+-N (r = 0.502; 0.553) (P < 0.05). The regulation of water quality and extension of the usage cycle were identified as critical factors influenced by DO. In addition, bacteria share similar ecological niche preferences. These findings provide scientific evidence for the high-quality reuse of rainwater in decentralized RWH systems during long-term storage in non-rainy seasons.

Novel adaptive activated sludge process leverages flow fluctuations for simultaneous nitrification and denitrification in rural sewage treatment.

The fluctuating characteristics of rural sewage flow pose a significant challenge for wastewater treatment plants, leading to poor effluent quality. This study establishes a novel adaptive activated sludge (AAS) process specifically designed to address this challenge. By dynamically adjusting to fluctuating water flow in situ, the AAS maintains system stability and promotes efficient pollutant removal. The core strategy of AAS leverages the inherent dissolved oxygen (DO) variations caused by flow fluctuations to establish an alternating anoxic-aerobic environment within the system. This alternating operation mode fosters the growth of aerobic denitrifiers, enabling the simultaneous nitrification and denitrification (SND) process. Over a 284-day operational period, the AAS achieved consistently high removal efficiencies, reaching 94 % for COD and 62.8 % for TN. Metagenomics sequencing revealed HN-AD bacteria as the dominant population, with the characteristic nap gene exhibiting a high relative abundance of 0.008 %, 0.010 %, 0.014 %, and 0.015 % in the anaerobic, anoxic, dynamic, and oxic zones, respectively. Overall, the AAS process demonstrates efficient pollutant removal and low-carbon treatment of rural sewage by transforming the disadvantage of flow fluctuation into an advantage for robust DO regulation. Thus, AAS offers a promising model for SND in rural sewage treatment.

Comparison of genomic and amino acid sequences of eight Japanese encephalitis virus isolates from bats.

We compared nucleotide and deduced amino acid sequences of eight Japanese encephalitis virus (JEV) isolates derived from bats in China. We also compared the bat JEV isolates with other JEV isolates available from GenBank to determine their genetic similarity. We found a high genetic homogeneity among the bat JEVs isolated in different geographical areas from various bat species at different time periods. All eight bat JEV isolates belonged to genotype III. The mean evolutionary rate of bat JEV isolates was lower than those of isolates of other origin, but this difference was not statistically significant. Based on these results, we presume that the bat JEV isolates might be evolutionarily conserved. The eight bat JEV isolates were phylogenetically similar to mosquito BN19 and human Liyujie isolates of JEV. These results indicate that bats might be involved in natural cycle of JEV.

Comparison of the Effects on Bovine Serum Albumin Induced by Different Forms of Vanadium.

Various forms of vanadium coexist in vivo, and the behavior mechanism is different. An investigation of the separate and simultaneous binding of three vanadium forms with bovine serum albumin (BSA) was performed. VO(acac)2/NaVO3/VOSO4 bound to site I of BSA, and their binding constants were 4.26 × 105, 9.18 × 103, and 4.31 × 102 L mol-1 at 298 K, respectively. VO(acac)2 had the strongest binding ability to BSA and had the most influence on the secondary structure of BSA and the microenvironment of around amino acid residues. The effect of NaVO3 and VOSO4 coexistence on the binding of VO(acac)2 to BSA was therefore further investigated. Both NaVO3 and VOSO4 had an effect on the binding of VO(acac)2 and BSA, with NaVO3 having the most noticeable effect. NaVO3 interfered with the binding process of VO(acac)2 and BSA, increased the binding constant, and changed the binding forces between them. Competition and allosteric effect may be responsible for the change of binding process between VO(acac)2 and BSA in the presence of NaVO3/VOSO4.

A 5-Year Follow-Up Study to Explore Factors Associated with Rapid Kidney Function Decline Among Bus Drivers.

Background: Owing to the stressful occupational characteristics, bus drivers have been reported to have a higher risk of renal dysfunction. However, the related factors associated with rapid kidney function decline among bus drivers have not been explored in the existing literature. Therefore, our research aimed to investigate factors related with rapid kidney function decline, and to explore the correlation of baseline SUA (serum uric acid), longitudinal changes in SUA, and rapid eGFR (estimated glomerular filtration rate) decline for bus drivers. Methods: This was a five-year cohort study in Shenzhen, China, between 2017 and 2021. We included 832 bus drivers with normal kidney function at baseline. Study subjects were stratified into four quartiles of change in eGFR, and rapid eGFR decline was regarded as the highest (4th) quartile of ΔeGFR (eGFR in 2017-eGFR in 2021). Univariable and multivariable logistic regressions were conducted to explore factors affecting rapid eGFR decline. Results: The incidence of hyperuricemia among bus drivers was 37.7% in 2017 and 40.5% in 2021. The overall subjects had a median 5-year decrease in eGFR of 6.72 mL/min/1.73 m2, and individuals with increased SUA from normal to hyperuricemia group had the greatest decline of eGFR. Multivariate analysis showed bus drivers' age (Odds radio: OR, 1.04), elevated baseline eGFR (OR, 1.08), and SUA increase (OR, 1.38) were significantly associated with rapid eGFR changes. Conclusion: The high prevalence of hyperuricemia among bus drivers should warrant more attention from health professionals. Subjects' age, elevated baseline eGFR, and SUA increase were risk factors for rapid eGFR decline over 5-year. The findings can provide significant evidence for timely prevention and intervention to decrease the incidence of rapid renal function decline among bus drivers.

Acceptable risk assessment and management of environmental pollution emergency events base on distance model.

Existing environmental management regulations and assessment methods can help understand and relieve pollution problems greatly affecting the natural world. However, what is lacking is awareness and targeted recommendations for environmental pollution emergency events (EPEEs). Here we analyzed a total of 2164 EPEEs in China from 2000 to 2021 in terms of annual variations, spatial distributions, phases of regional development, and pollution sources. The findings showed that regional economies can have significant impacts on the occurrence of EPEEs. Regarding the four causes of pollution, the contribution from industrial sources was above 80 %, especially water pollution events, for which it accounted for 84 %. The probability of pollution events specifically relates to regional GDP and it was highest in those provinces with the highest GDP rankings, albeit there were marked differences in the industrial structure. In order to better manage EPEEs, an Environment-Emergency Distance Model (EEDM) is proposed. This model uses the Multidimensional psychological distance to quantitatively evaluate the acceptable public risk level after the occurrence of EPEEs. This method provides a basis for pollution prevention and remediation by visualizing the risk acceptable for the public and provides guidance for sustainable environmental development.

New conceptualization and quantification method of first-flush in urban catchments: A modelling study.

A major challenge for runoff pollution control lies in the quantification and identification of the first-flush. At present, there is a lack of reasonable theoretical methods to guide engineering practices. To remedy this deficiency, a novel method of cumulative pollutant mass vs. cumulative runoff volume (M(V)) curve simulation is proposed in this study. Subsequently, the first-flush phenomenon was redefined based on the M(V) curve simulation and demonstrate that the first-flush exists until the derivative of the simulated M(V) curve is equal to 1 (Ft' = 1). Consequently, a mathematical model for first-flush quantification was developed. The Root-Mean-Square-Deviation (RMSD) and Pearson's Correlation Coefficient (PCC), as objective functions, were used to evaluate the performance of the model and the Elementary-Effect (EE) method was used to analyze the sensitivity of the parameters. The results indicated the satisfactory accuracy of the M(V) curve simulation and first-flush quantitative mathematical model. The NSE values exceeding 0.8 and 0.938, respectively, were obtained by analyzing 19 rainfall-runoff data for Xi'an, Shaanxi Province, China. The wash-off coefficient "r" was demonstrably the most sensitive factor influencing the model performance. Therefore, interactions between "r" and the other model parameters should be focused on to highlight the overall sensitivities. Overall, this study posits a novel paradigm shift from the traditional dimensionless definition criterion to redefine and quantify first-flush, which has significant implications for urban water environment management.

The nonlinear correlation between the cardiometabolic index and the risk of diabetes: A retrospective Japanese cohort study.

Background: The cardiometabolic index (CMI) has been proposed as a novel indicator of cardiometabolic status. However, evidence on the relationship between CMI and diabetes mellitus (DM) risk was limited. Our study aimed to explore the relationship between CMI and DM risk among a large cohort of Japanese adults. Methods: This retrospective cohort study recruited 15453 Japanese adults without diabetes at baseline who underwent physical examinations at the Murakami Memorial Hospital between 2004 and 2015. Cox proportional-hazards regression was applied to evaluate the independent relationship between CMI and diabetes. Our study performed a generalized smooth curve fitting (penalized spline technique) and an additive model (GAM) to determine the non-linear relationship between CMI and DM risk. In addition, a set of sensitivity analyses and subgroup analyses were employed to evaluate the relationship between CMI and incident DM. Results: After adjusting for confounding covariates, CMI was positively related to the DM risk in Japanese adults (HR: 1.65, 95%CI: 1.43-1.90, P<0.0001). A series of sensitivity analyses were also employed in this study to guarantee the reliability of the findings. In addition, our study discovered a non-linear association between CMI and diabetes risk. CMI's inflection point was 1.01. A strong positive association between CMI and diabetes incidence was also discovered to the left of the inflection point (HR: 2.96, 95%CI: 1.96-4.46, P<<0.0001). However, their association was not significant when CMI was higher than 1.01 (HR: 1.27, 95%CI: 0.98-1.64, P=0.0702). Interaction analysis showed that gender, BMI, habit of exercise, and smoking status interacted with CMI. Conclusion: Increased CMI level at baseline is associated with incident DM. The association between CMI and incident DM is also non-linear. A high CMI level is associated with an increased risk for DM when CMI is below 1.01.

Photochemical behavior of constructed wetlands-derived dissolved organic matter and its effects on Bisphenol A photodegradation in secondary treated wastewater.

Free water surface flow (FWS) constructed wetlands (CWs) have been broadly applied for polishing secondary treated effluents. Dissolved organic matter derived from FWS CWs (WDOM) plays key roles in contaminants transformations. Conversely, photodegradation could shape the quantity and quality of WDOM, thereby affecting its roles in the photolysis of organic micropollutants (OMPs). Nevertheless, whether and how solar irradiation-induced photodegradation modify the properties of WDOM, and the effects of WDOM on the photodegradation of OMPs remain unclear. This study elucidates the photochemical behavior of two WDOM isolated from field-scale FWS CWs for effluent polishing under simulated sunlight irradiation using spectroscopic tools and high-resolution mass spectra. Furthermore, the roles of WDOM in the photodegradation of Bisphenol A (BPA), as a representative endocrine-disrupting compound (EDC), were comprehensively investigated. Solar irradiation was demonstrated to lower the molecular weight and aromaticity of WDOM, as well as weaken its light absorption. Ultrahigh-resolution mass spectra further confirmed that aromatic and unsaturated structures were susceptible to solar irradiation-induced photodegradation reactions. Subsequently, less aromatic and more saturated structures eventually formed under sunlight irradiation, consistent with the result from spectroscopic characterization. The reactive species produced from WDOM significantly enhanced the photodegradation of BPA with the kobs noticeably increasing 4-fold compared with the kobs for direct photolysis. Additionally, 3WDOM* was identified as the dominant reactive species leading to the photolysis of BPA in the presence of WDOM. These findings improve understanding of the phototransformation behavior of WDOM under sunlight irradiation and the roles that WDOM plays in the photochemical fate of coexisting OMPs in CWs treatment systems.

Assessment of plants radial oxygen loss for nutrients and organic matter removal in full-scale constructed wetlands treating municipal effluents.

Bidirectional cross flow wetlands with different plant species were set to investigate seasonal variation in radial oxygen loss (ROL) and its effects on COD and NH4+-N removal. Findings demonstrated a strong seasonal effect on the rate of ROL, with Arundo donax var.versicolor showing the highest ROL of 2.99 µmol·h-1·g-1. Additionally, ROL showed strong positive correlations with plant total biomass (P < 0.01), aboveground biomass (P < 0.01), height, maximum root length (P < 0.01), root porosity (P < 0.01), and removal efficiency of COD and NH4+-N (P < 0.01). Furthermore, high-throughput sequencing analysis of substrate samples from three wetland units planted with Thalia dealbata, Canna indica and Arundo donax var. versicolor revealedProteobacteria as the predominant rhizospheric phylum. Relative abundance of Alpha- and Gamma-Proteobacteria were higher in the Arundo donax var.versicolor samples due to its higher oxygen transport capacity. These results demonstrate that root properties are important determinants for selecting appropriate plants for constructed wetland.

Size distributions and heavy metal pollution of urban road-deposited sediments (RDS) related to traffic types.

Little is known about the particles attached on the surfaces of coarse (> 150 µm) road-deposited sediments (RDS), which are potential contributors of stormwater pollution. Therefore, the size distributions and heavy metal (including Cu, Pb, Zn, Cr, and Ni) pollution of RDS were evaluated taking these attached particles into consideration. Moreover, the relationships of RDS contamination with traffic types were further discussed. The results showed that < 22, 22-38.5, 38.5-150, > 150 µm RDS and attached particles accounted for 2.1 ± 1.8%, 8.5 ± 5.7%, 50.7 ± 6.8%, 38.6 ± 8.3%, and 2.0 ± 1.2% of total RDS mass, respectively. The size distributions of attached particles were comparable to that of representative stormwater particles, suggesting their great potential to contribute stormwater particles by desorption. The Zn pollution of attached particles was remarkable, which was significantly higher than that of both fine (< 150 µm) and coarse (> 150 µm) RDS. The Cu and Pb pollution were comparable to that of fine RDS, which were significantly higher than that of coarse RDS. Conversely, the Cr and Ni pollution were comparable to that of coarse RDS, which were significantly lower than that of fine RDS. Traffic types were found to be closely related with RDS contamination, and thus are indicative of specific RDS pollution. For example, electrombile in old residential area is indicative of abnormal Pb pollution due to past emissions of leaded gasoline; lorry is indicative of remarkable Zn pollution of > 22 µm RDS due to abrasion of tires and metallic substances. Accordingly, traffic type is accessible to identify the typical pollutants in RDS to promote effective RDS management.

Impacts of key factors on heavy metal accumulation in urban road-deposited sediments (RDS): Implications for RDS management.

Understanding of the impacts of key influential factors on RDS related heavy metal (HM) contamination is crucial for developing effective RDS management strategies to support the stormwater pollution mitigation. In this paper, three factors (i.e. traffic condition, slope of road and antecedent dry period) were considered to investigate their influences on the accumulation of RDS and adsorbed HMs. Positive correlations between truck and Zn/Ni content in RDS, car and Cu/Pb content in fine RDS, as well as bus and Cu content in coarse RDS were observed. Relative to sloping stretches, RDS from level stretches generally presented finer size distributions and aggravated HM contamination in fine fractions. Moreover, the fine RDS and adsorbed HMs increased significantly with the accumulation of RDS. Based on these findings, optimized RDS management strategies were proposed to enhance the removal of washable RDS in pollution hotspots. For example, tandem sweeping technologies, performing high efficiency in capturing fine particles, are suggested to be employed during the steady period of RDS accumulation, in order to reduce fine RDS effectively. The outcomes of this study provide useful reference for the source control of stormwater runoff pollution.

Current status and characteristics of urban landscape lakes in China.

Urban landscape lakes (ULLs) are important environmental elements in most cities. In order to understand the current situation of ULLs in China and formulate proper strategies to improve their landscape quality to meet public desire for water-front enjoyment, a study was conducted of 189 ULLs widely distributed in 26 provinces of China, based on existing data and field surveys. These ULLs were firstly categorized according to their topographic features, climatic zones, and water replenishment sources. Lake water quality was evaluated considering both single factors and a comprehensive pollution index (CPI). Results show that if the Chinese Surface Water Quality Standard was used as the sole criteria, about 60% of the ULLs investigated could not meet the lowest requirement. Excessive total nitrogen (TN) concentration was the most limiting factor especially when reclaimed water was the replenishment source. The differences in topographic and climatic conditions to a certain extent affected the availability of replenishment water sources but no significant correlation was identified with the single water quality factors or CPI. However, when public satisfaction was introduced in the evaluation of the ULLs' landscape effect, it was found that the water transparency in terms of Secchi Depth (SD) correlated well with people's appreciation of water landscape.