Wastewater Discharge Research Articles

Analysis of wettability and oil-water separation mechanism of superhydrophilic/underwater superoleophobic mesh based on capillary force model

The Frequent oil spills at sea and large discharges of oily wastewater spills seriously jeopardize the ecological environment and lead to an increasing shortage of water resources, so the oil/water separation has become a hot spot of global research. As opposed to the conventional separation method, the membrane separation has received wide attention because of its advantages of green environmental protection, low energy consumption and easy operation. In this paper, Cu(OH)2 mesh with superhydrophilic and underwater superoleophobic properties were prepared by in-situ growth method using purple copper mesh as the substrate. Scanning electron microscopy, x-ray photoelectron spectroscopy and contact angle tests were used to evaluate the surface morphology, chemical composition and wetting behavior of the mesh. The results showed that the water contact angle was 0° in air and the contact angle was 155.4° for oil droplets underwater. The membrane exhibited high separation efficiencies (99%) and separation fluxes (3.67-6.54×104 L·m-2·h-1) for the five tested oils under gravity drive. The wettability of the mesh was unaffected after 20 separation experiments. The surface wettability and the oil/water separation mechanism were analyzed using the capillary force-based separation model combined with the Young and Cassie-Baxter equations.

Long-term impact of wastewater effluent discharge on groundwater: Identification of contaminant plume by geochemical, isotopic, and organic tracers' approach

Infiltration of effluents from wastewater treatment plants (WWTP) into groundwater can be a source of Contaminants of Emerging Concern (CECs), such as pharmaceutical compounds, that are not fully removed during the treatment processes. A multi-tracer approach, based on hydrogeochemical, isotopic, and organic tracers, is applied in the Vistrenque Aquifer (Gard, France) to assess the dispersion of such unintentional plumes and its potential implication on groundwater quality for CECs in a small catchment area. In this area, a point source of WWTP effluent causes contaminant infiltration and unintentional transfer to the aquifer. This strong impact of an urban effluent was revealed from the Br/Cl ratio, boron concentrations and δ11B isotopic signature of the groundwater in the direct vicinity of the infiltration point. With increasing distance from that point, dilution with groundwater rapidly attenuates the urban signal from these hydrogeochemical and isotopic tracers. Nevertheless, a gadolinium anomaly, resulting from discharges of urban wastewater containing the contrast agents used for magnetic resonance imaging (MRI), highlights the presence of a wastewater plume further along the flow line, that comes with a series of organic molecules, including pharmaceutical residues. Monitoring persistent or reactive molecules along the plume provides a more detailed understanding of the transfer of CECs into groundwater bodies. This highlights the relevance of pharmaceutical compounds as co-tracers for WWTP plume delineation. The present multi-tracer approach for groundwater resource vulnerability towards CECs allows a more in-depth understanding of contaminant transfer and their fate in groundwater.

Analysis on the spatiotemporal evolutions of groundwater hydrochemistry and water quality caused by over-extraction and seawater intrusion in eastern coastal China

The over-extraction of groundwater has resulted in seawater intrusion and the southward migration of the saltwater interface, gradually deteriorating the groundwater quality in the Weibei Plain. In this research, groundwater samples were gathered from 46 monitoring wells for shallow groundwater during the years 2006, 2011, 2016, and 2021. The hydrochemical features of regional groundwater and the factors influencing the issue were subjected to statistical analysis. Additionally, the assessment of spatiotemporal variations in groundwater quality was conducted using the customized entropy-weighted water quality index (EWQI) method. The relationship between groundwater over-extraction and the southward intrusion of the saltwater interface was compared and analyzed. The results of this paper revealed that the Weibei Plain has been in a state of long-term over-extraction of groundwater from 2000 to 2021, with an average annual over-extraction of 118.49 million m3. The groundwater depression cone areas in the northern part of the study area increased from 3,247.37 to 4,581.34 km2 from 2006 to 2021, with the center of the cone experiencing a drop in groundwater level from −22 to −85 m. The saltwater interface shifted southward by 711.71 km2 from 2006 to 2021. In groundwater, the high concentrations of TH, TDS, and Cl− were primarily related to the seawater intrusion, while higher concentrations of NO3− were mainly determined by frequent agricultural production, industrial wastewater, and domestic sewage discharges. The groundwater hydrochemical types in the study area transitioned from predominantly HCO3·Ca-Mg type in 2006 to HCO3-Na type and SO4·Cl-Ca·Mg type in 2021 due to seawater intrusion. The results of PCA and HCA show the effects of seawater intrusion, human activities, and rock weathering on groundwater hydrochemistry. The evaluation results based on the EWQI revealed that the average value of the samples in 2021 was 101.36, which belonged to Class IV water quality standards, representing the poorest water quality among the 4 years. The southward migration of the saltwater interface led to the deterioration of groundwater quality in the groundwater depression cone areas, which gradually worsened from 2006 to 2021. The maximum increase in EWQI value was 174.68 during the period, shifting from Class III water quality to Class V water quality. Groundwater quality remained relatively better in the western and southern regions which were less affected or unaffected by seawater intrusion. The results of the study can provide a certain reference value for the sustainable management of groundwater resources and the management of groundwater pollution and seawater intrusion in the Weifang City area in the future.

Empirical analysis of the relationship between economic growth and environmental pollution based on VAR model: A case study of Hubei Province China

In this paper, the industrial three wastes from 1992 to 2018 in Hubei Province were collected as environmental indicators, and the per capita GDP was used as economic indicators. The study of Kuznets curve showed that industrial wastewater gradually decreased with economic growth, showing an inverted N shape; Both industrial emissions and solid waste will increase with the growth of per capita GDP, industrial waste gas shows a linear relationship, and industrial solids show an inverted U relationship. Then through the VAR model research, it is found that the response of industrial “three wastes” to per capita GDP growth in Hubei Province is positive in the short term. The long-term response of economic development in Hubei province to industrial waste gas and industrial solid waste discharge is positive and decreasing, but the short-term response to industrial wastewater discharge is negative. The variance decomposition analysis reveals that the primary environmental determinants influencing the current economic growth trajectory of Hubei Province are industrial wastewater, industrial waste gas, and industrial solid waste. Fluctuations in economic growth within Hubei Province demonstrate a stronger correlation with variations in emissions of industrial wastewater and industrial solid waste, while exerting comparatively less influence on changes in emissions of industrial waste gas.

Differential comparison of degradation efficiencies in urban environmental waters and effluents and with and without nanoparticles

DOM is an important component of water bodies and provides unimaginable vitality to the entire water body. This paper employed a filter configuration method to extract dissolved organic matter and sewage. In the control group, nanoparticles are added to set up a control group. The degradation efficiency of urban water bodies and sewage and their degradation efficiency in the presence or absence of nanoparticles was compared using a UV spectrophotometer and a photochemical reaction meter. By analyzing the degradation efficiency of DOC, we observed that the degradation efficiency of urban water is much higher than that of wastewater, and nanoparticles can increase the reaction rate. This effect is particularly pronounced in pond water, which can provide a reference for the standard of wastewater discharge and urban water management.

Confined growth of oxygen-vacancy rich TiO2-x nanoparticles with heterophase junction for high-efficiency photocatalytic water purification

Photocatalysis stands out as a promising technique for waste purification, but its practical application is limited by the insufficient generation of reactive oxygen species (ROS) over photocatalysts. Herein, we proposed a dual strategy for promoting ROS generation by the construction of oxygen-vacancy-rich TiO2-x confined on silica nanosheet (TiO2-x@S-A500). The surface-confinement effect arising from silica leads to the formation of TiO2 anatase/brookite heterophase junctions, thus enhancing the photogenerated charge separation. More importantly, the oxygen vacancies (Vo) introduced by silica-mediated reaction were spatially confined at the interface between silica and TiO2, which served as trap centers to capture photogenerated electrons, thus facilitating the O2 activation for generations of •O2– and 1O2. Eventually, TiO2-x@S-A500 exhibited enhanced photocatalytic performance for degrading phenolic pollutants under sunlight irradiation, with the degradation rate constant (k) for 4-chlorophenol that was 2.4 and 3 times higher than that of pure TiO2 and P25, respectively, and the toxicities for its intermediates were greatly reduced. Additionally, 180 mg/L of COD present in the real biologically pretreated coal gasification wastewater was degraded within 60 min to 45 mg/L, satisfying the Integrated Wastewater Discharge Standard of China.

Pollution levels and ecological risks of PPCPs in water and sediment samples of Danjiangkou Reservoir.

The concentrations and distribution patterns of three typical pharmaceuticals and personal care products (PPCPs) in water and sediment samples obtained from Danjiangkou Reservoir during two seasonal sampling periods were studied to determine their impact on water quality. The temporal and spatial variations in concentrations measured were analyzed and related to ecological risks with data obtained during the mean-flow period (in June) and the dry period (in November). We found a high detection rate of ketoprofen (KTP) in water samples from Danjiangkou Reservoir; the concentrations ranged from not detected (ND) to 46.80ng/L with the highest values measured in the Hanku tributary samples followed by the samples collected in the main body of Danjiangkou Reservoir. The KTP concentrations in the Danku tributary samples were the lowest measured in this study. In addition, the concentrations of KTP in the Shending River, Sihe River, Jianghe River, Guanshan River, and Jianhe River water samples were relatively high in the mean-flow period. The water sample detection rates and concentrations of triclosan (TCS) and triclocarban (TCC) were low in both the mean-flow period and the dry period. All three kinds of PPCPs were detected in the sediment samples with the concentrations of KTP, TCS, and TCC ranging from 0.76 to 7.89μg/kg, 0.01 to 0.59μg/kg, and 0.01 to 11.36μg/kg, respectively. Overall, the concentrations of the three measured PPCPs in the water and sediment samples were all relatively low compared to results reported in the recent literature. The dry period concentrations of PPCPs in the water samples were lower than the concentrations measured in the mean-flow period. However, dry period concentrations were higher in the sediment samples compared to those in the mean-flow period samples. Our interpretation of the spatial and temporal patterns of PPCPs in Danjiangkou Reservoir suggests that these compounds were likely mainly derived from wastewater discharge in the upper reaches of the reservoir. The risk quotient (RQ) method was used for an ecological risk assessment of the detected PPCPs in this study. We found that TCS in water and sediment posed medium ecological risks to algae at different times of the year. In view of the extreme importance of water safety in Danjiangkou Reservoir, the ecological risks of PPCPs require additional attention.

Adsorption of cyanide from Cassava wastewater using activated carbons derived from Raphia hookeri kernels: a comparison of in-situ and ex-situ activation

The rise in cyanide concentration in groundwater in many developing countries is linked to the indiscriminate discharge of cyanide-bearing wastewater from cassava processing industries. This research synthesized a super-active activated carbon (AC) from a novel biomass precursor, Raphia hookeri kernel, functionalized with phosphoric acid via in-situ and ex-situ methods. Morphological and functional characterizations were performed, and the influence of some key process variables on cyanide adsorption was also investigated for the two derived ACs to study the impact of the activation method used. The optimal conditions for cyanide adsorption for the in-situ and ex-situ–derived ACs were identified as pH 8, AC dose of 0.15 g, temperature of 40 °C, and initial cyanide concentration of 100 mgL−1 at different equilibrium times of 100 min and 120 min, respectively. The kinetic studies revealed that the pseudo-second-order kinetic model fitted the adsorption data better for the two ACs based on the high correlation coefficients (r2), suggesting that the adsorption process is chemisorption. The equilibrium studies showed that the in-situ-derived AC followed the Langmuir isotherm with a maximum adsorption capacity (qm) of 93.821 mgg−1 indicating monolayer adsorption for the in-situ-derived AC. The ex-situ-derived AC, however, followed the Sips isotherm with a maximum adsorption capacity (qm) of 79.381 mgg−1 indicating a heterogeneous surface for the ex-situ-derived AC. The ACs showed decreasing cyanide adsorption after five cycles but maintained significant adsorption capacity after desorption-adsorption cycles.

Novel activated NIR-II fluorescence/Ratio photoacoustic probe for dual-modality accurate imaging of palladium ions overload in mouse liver

Palladium contaminants can pose risks to human health and the natural environment. Once Pd2+ enters the body, it can bind with DNA, proteins, and other macromolecules, disrupting cellular processes and causing serious harm to health. Therefore, it becomes critical to develop simple, highly selective and precise methods for detecting Pd2+in vivo. Here, we have successfully developed the first activated second near‐infrared region fluorescence (NIR-II FL) and ratio photoacoustic (PA) probe NYR-1 for dual-modal accurate detection of Pd2+ levels. NYR-1 is capable of rapidly (< 60 s) and sensitively detection of Pd2+ in solution, providing switched on NIR-II FL920 and ratio PA808/PA720 dual-mode signal change. More notably, the probe NYR-1 was successfully used for non-invasive imaging of Pd2+ overload in mouse liver by NIR-II FL/Ratio PA dual-modality imaging technology for the first time. Thus, this work opens up a promising dual-modal detection method for the precise detection of Pd2+ in organisms and in the environment.

Water quality monitoring and modeling for an urban storm drainage channel in Thane, India.

The absence of a sewer system and inadequate wastewater treatment plants results in a discharge of untreated wastewater to the urban drainage channels and pollutes receiving waters. Field visits were carried out to observe water quality parameters such as dissolved oxygen (DO), biochemical oxygen demand (BOD), and chemical oxygen demand (COD) in an urban drainage system (Kolshet drain) in Thane City, Mumbai Metropolitan Region, India. Dye-tracing studies using rhodamine WT dye were used for computing the velocity, discharge, and dispersion coefficient of the drain. The data analysis shows that the BOD and COD values in the drain are higher than the permissible limits (30mg L-1 for BOD and 250mg L-1 for COD), which is not suitable for disposal to any receiving water body. Also, the DO was less than the permissible limit of a minimum of 3mg L-1 (for the survival of aquatic life). It is seen that the higher BOD load significantly reduced the DO throughout the drain. The Water Quality Analysis Simulation Program (WASP 8.32, 2019) developed by the US Environmental Protection Agency (USEPA) has been used for the simulation of the DO and BOD in the drainage channel. The model simulates an appropriate estimate of the expected variation of DO and BOD at points of interest. The modeling for the Kolshet drain is expected to enable better estimates of the wastewater parameters and the pollution transport in the drain for planning purposes.

Fabrication of a Janus Copper Mesh by SiO2 Spraying for Unidirectional Water Transportation and Oil/Water Separation.

Massive discharge of oily wastewater and frequent occurrence of offshore oil spills have posed an enormous threat to the socioeconomic and ecological environments. Janus membranes with asymmetric wettability properties have great potential for oil/water separation applications and have attracted widespread attention. However, existing Janus membranes still suffer from complex and costly manufacturing processes, low permeability, and poor recyclability. Herein, a novel and facile strategy was proposed to fabricate a Janus copper mesh with opposite wettability for unidirectional water transport and efficient oil/water separation. The hydrophilic side of the Janus copper mesh was prepared by coating it with Cu(OH)2 nanoneedles via a chemical oxidation method. The hydrophobic side was fabricated by coating it with hydrophobic SiO2 nanoparticles via a facile spraying method. The as-prepared Janus copper mesh showed asymmetric surface wettability, which can achieve unidirectional water transport and efficient oil/water separation with excellent recyclability, exhibiting great application potential for droplet manipulation and wastewater purification.

Wastewater Effluent from Outfalls in Kuwait Bay: A Threat to Recreational Water Quality

The implications of wastewater discharge into marine ecosystems are gravely concerning due to their ability to trigger a chain reaction of contaminants that pose severe risks to both humans and aquatic life. Kuwait Bay is no exception, with numerous wastewater outfalls posing a threat to the marine environment on its southern coasts. This study sought to extensively evaluate the recreational water quality adjacent to wastewater outfalls at five specified sites and compare the results according to the KEPA's (Kuwait's Environmental Public Authority) guidelines. Field measurements and laboratory analyses were conducted to gauge various parameters associated with water quality, such as nutrients, heavy metals, fecal bacterial indicators (FBI), and pharmaceutical compounds. The results of field measurements indicated that two locations had insufficient DO levels with values &lt; 4 mg/l below KEPA standards and brackish to saline water concerning Electrical conductivity (EC) measurements. However, the heavy metal results demonstrated mercury (Hg) pollution at all locations, whereas the nutrient data revealed significant PO4-P concentrations. Furthermore, EPA requirements were considerably exceeded for bacterial indicator counts (fecal coliforms, E. coli, and fecal streptococci), suggesting serious biological pollution at these locations and elevated concentrations of paracetamol and ranitidine have been detected in pharmaceutical compound analysis, particularly in location OC5. The study's findings emphasized the significance of periodic surveillance to ensure the ongoing improvement of water quality and public health in Kuwait's coastal zones and highlighted the dire need to address the extensive contamination by implementing measures to mitigate the dump of unprocessed wastewater into the sea.

Screening of pharmaceuticals and personal care products in the water environment of a region diversified in land use and urban development (Silesian Province, southern Poland)

This research aimed to assess the PPCP contamination of the water environment within the Silesian Province (southern Poland), where emerging contaminants are likely to occur due to urbanisation and industrialisation, especially in the central part of the voivodeship. An attempt was made to compare the PPCP occurrence in waters of areas that varied in land use and urban development, i.e. within the Upper Silesian Urban Area (USUA) and outside this region. The research was performed in selected areas of the province and involved sampling of raw and treated wastewater from four wastewater treatment plants (WWTPs), as well as surface water (9 samples) and groundwater (14 samples) in six pilot sites. In total, 102 PPCPs were analysed using the LC-MS/MS method. In the natural waters, physicochemical parameters were also measured, and the basic chemical composition of the samples was determined. In the wastewater samples, the number of detected substances and the total PPCP concentrations were up to 66 PPCPs and 1211.0 µg/L in influents, and up to 59 PPCPs and 174.1 µg/L in effluents. The values for the natural water samples were respectively up to 71 PPCPs and 172.2 µg/L in surface water, and up to 13 PPCPs and 1.5 µg/L in groundwater. The results revealed that wastewater discharges from WWTPs using conventional treatment methods serve as a significant source of PPCPs due to inefficient removal of the microcontaminants. The contamination level of the surface waters in terms of the PPCP occurrence and basic chemical composition was higher within the USUA, where rivers are recipients of wastewater discharges from WWTPs. The PPCP quantity in the groundwater samples did not vary greatly within and outside the USUA, likely due to hydraulic connection between rivers and aquifers or induced surface water infiltration that recharge aquifers in some of the selected areas.

Purification of graphite from spent carbon cathodes through the reduction of the mechanical entrainment of cryolite using polyaluminium chloride as a flocculant

Spent carbon cathodes (SCCs) generated during electrolytic aluminum production pose significant environmental hazards. To optimize resource utilization, flotation is used as an early process for the clean recovery of valuable graphite from waste cathodes. However, the mechanical entrainment in flotation restricts the further improvement of product purity, resulting in an increase in waste gas and wastewater discharge in the subsequent purification process. In this study, to increase the fixed carbon content of flotation products, flocculant was first applied to the flotation separation of SCCs, and polyaluminum chloride (PAC) was used to flocculate cryolite with high impurity content to reduce mechanical entrainment in the flotation process. Zeta potential measurements, particle size analysis, optical microscopy, and scanning electron microscopy confirmed the agglomeration of cryolite under the action of PAC. Additionally, the DLVO (Derjaguin, Landau, Verwey, and Overbeek) theory was used to estimate the interaction energy to further explain the mechanism underlying cryolite agglomeration. Interaction energy calculation revealed that the attraction energy between particles was dominant at the PAC concentration of 2000 mg/L. Flotation experiments indicated that under a constant pulp pH of 7.8, the absence of sodium silicate, and a stirring speed of 1200 rpm, mechanical entrainment decreased from 91.53 ± 1.53 g/L to 69.80 ± 1.90 g/L, and the carbon grade of the product increased from 83.07 ± 0.28% to 88.94 ± 0.30%. Overall, the proposed purification method provides a new approach for the efficient recovery of graphite in waste cathodes, which is of great significance for the sustainable development of graphite resources.

Batrachochytrium dendrobatidis and Hannemania mite’s relationships with Mexican amphibians in disturbed environments

The rapid transformation and pollution of ecosystems have severely impacted biodiversity. Specifically, anthropogenic activities have imposed adverse effects on amphibians, with evidence suggesting that these activities alter parasite and pathogen interactions within their hosts. To investigate these interactions in areas affected by different anthropogenic activities, our study focused on analyzing a pathogen and a parasite known to interact within the amphibian skin (spongy epidermis layer) and both compromising amphibian health: Batrachochytrium dendrobatidis (Bd), a fungus responsible for chytridiomycosis, a disease associated with massive population declines in amphibians and the Hannemania sp. mite in Mexico. Four sampling areas along the Sonora River were selected, representing different human activities: mining, livestock, wastewater discharge, agriculture, and one in an urban zone. We analyzed 135 amphibians across 10 anuran species. Among these, the most abundant species (Lithobates yavapaiensis) exhibited the highest prevalence of both pathogen and parasite (90.1% and 27.3%, respectively) and was significantly associated with the intensity of Bd-infection. The prevalence of Hannemania mites varied significantly across sampling sites as did Bd prevalence and infection load, with the highest Bd load found at the wastewater discharge site. A significant association between the intensity of Bd-infection and both mite abundance and amphibian species was observed when the sampling site was considered. Additionally, sites with Bd-positive individuals and Hannemania parasitism coincide with refractory elements characterized by mechanical or corrosion resistance. The persistence of these elements in the environment, along with the small particle size (&amp;lt;850 nm) found in sediments, poses a potential risk of internalization, bioaccumulation (e.g., Fe, Co, and Ti), and their transfer through the food chain. It is thus essential to consider monitoring environmental and biotic factors that modulate the relationships between parasites, pathogens, and amphibians if we are to propose conservation strategies adapted to disturbed environments.

Scenario-based assessment of fecal pathogen sources affecting bathing water quality: novel treatment options to reduce norovirus and Campylobacter infection risks.

Wastewater discharge and runoff waters are significant sources of human and animal fecal microbes in surface waters. Human-derived fecal contamination of water is generally estimated to pose a greater risk to human health than animal fecal contamination, but animals may serve as reservoirs of zoonotic pathogens. In this study, quantitative microbial risk assessment (QMRA) tools were used to evaluate the hygienic impact of sewage effluents and runoff water from municipalities and animal farms on surface and bathing waters. The human-specific microbial source tracking (MST) marker HF183 was used to evaluate the dilution of fecal pathogens originating from the sewage effluent discharge to the downstream watershed. As novel risk management options, the efficiency of UV-LED disinfection and wetland treatment as well as biochar filtration was tested on-site for the contamination sources. According to the dilution pattern of the MST marker HF183, microbes from wastewater were diluted (2.3-3.7 log10) in the receiving waters. The scenario-based QMRA revealed, that the health risks posed by exposure to human-specific norovirus GII and zoonotic Campylobacter jejuni during the bathing events were evaluated. The risk for gastroenteritis was found to be elevated during wastewater contamination events, where especially norovirus GII infection risk increased (1-15 cases per day among 50 bathers) compared with the business as usual (BAU) situation (1 case per day). The noted C. jejuni infection risk was associated with animal farm contamination (1 case per day, versus 0.2-0.6 cases during BAU). Tertiary treatment of wastewater with wetland treatment and UV-LED disinfection effectively reduced the waterborne gastroenteritis risks associated with bathing. Based on the experiences from this study, a QMRA-based approach for health risk evaluations at bathing sites can be useful and is recommended for bathing site risk assessments in the future. In case of low pathogen numbers at the exposure sites, the MST marker HF183 could be used as a pathogen dilution coefficient for the watershed under evaluation. The full-scale implementation of novel tertiary treatment options at wastewater treatment plants (WWTPs) as well as on-site runoff water treatment options should be considered for infection risk management at locations where scenario-based QMRA implies elevated infection risks.

Grey water footprint for evaluating Zefta wastewater treatment plant: a case study

ABSTRACT The numbers of wastewater treatment plants (WWTP) in Egypt are increasing, yet the general level of pollution associated with wastewater discharge after treatment has not been evaluated. Grey water footprint (GWF) was used to assess the effluent discharges from Zefta WWTP. GWF, before and after treatment, was calculated and followed up to determine its impact on the receiving freshwater body. 150 samples were collected and analysed for BOD5 to determine the optimum operating conditions. Averages values were DO = 2.2, SV30 = 500, SVI = 167, SA = 9.3 d, MLVSS = 2392 mg/L, f/m = 0.16, MLSS in RAS = 7922 mg/L, WAS = 140 m3/d and the HRT = 12 h. The removal efficiency of COD and TSS in the primary settling tank reached 39% and 69%, respectively. Average calculations of removal efficiency percentile reached 90-93%. Average freshwater quantities required to reduce pollutants in the receiving body stream were seasonally determined for Zefta WWTP as 5.3 × 107 m3/year. The average influent BOD5 was 376 mg/L, it was reduced to 47 mg/L in the effluent, wherever the Cmin is 6 mg/L and Cnat is 10 mg/L. Statistical analysis has shown a significant direct relation between ΔWFG,mef and WFG,ref reached 0.952 and a significant inverse relation with Cef −0.982. WFG,T has shown a significant direct relation with Cr 0.974. WFG,T– ref has shown a significant direct relation with Cr as 0.971 and WFG,T as 0.803. It can be concluded that ΔWF is effective in evaluating the efficiency of wastewater treatment and its effect on the quality of receiving water bodies.

Lanthanum(III) − 2,5 − Pyrazinedicarboxylate framework as an antibacterial adsorbent for highly efficient and selective capture of Pb(II) and Cd(II) from wastewater

Removing heavy metal ions and microorganisms from wastewater remains a persistent challenge in wastewater treatment. The development of a novel metal–organic framework (MOF), synthesized from 2,5-pyrazine-dicarboxylic acid and lanthanide (La(III), Ce(III), Pr(III)), targeting the concurrent remediation of heavy metal and bacterial pollutants in wastewater. La-PzDC demonstrated remarkable efficacy in removing Pb(II) and Cd(II), achieving maximum adsorption capacities of 697.72 mg g−1 and 398.26 mg g−1, respectively. La-PzDC achieved rapid adsorption equilibria—within 10 min for Pb(II) and 20 min for Cd(II), and conformed to the pseudo-second-order kinetics and Langmuir isotherm models. La-PzDC captured Pb(II) and Cd(II) from actual wastewater, and its residual levels met the relevant wastewater discharge standards. La-PzDC also exhibited excellent reusability and selectivity for Pb(II) and Cd(II). The adsorption mechanism through spectroscopic analysis and density functional theory (DFT) calculations, pinpointing coordination with oxygen and nitrogen-containing groups as a key factor. Significantly, La-PzDC achieves nearly 99 % bacterial elimination against E. coli and S. aureus. The above results indicated that La-PzDC has high selectivity, rapid removal capacity and excellent antibacterial activity, offering a new strategy for the dual challenge of heavy metal and bacterial contamination in wastewater treatment.

Research on the coordinated relationship between sewage resource utilization and economic research on the coordinated relationship between "dual-cycle" wastewater resource utilization and economic development

Dual-cycle wastewater resource utilization is aimed at improving the utilization rate of water resources and reducing the discharge of urban wastewater in order to increase the utilization rate of natural resources and achieve the circular utilization of water resources during urban development. Based on the dual-cycle concept, this study aims to explore the coordination between wastewater resource utilization and economic development in China, and understand the impact between the two. Literature research and data analysis are mainly used to analyze data from different provinces in China, making the research practically valuable. Through the analysis of data from five different provinces, it is found that the better the economic development of a province, the higher the importance attached to wastewater resource utilization. However, due to the impact of rapid economic development, the efficiency of wastewater resource utilization shows a slow trend. Conversely, inland provinces that attach importance to wastewater resource utilization, despite some shortcomings in economic development, have strong potential for economic development, which reflects the coordination between the two. The overall coupling degree between wastewater resource utilization and economic development in China is in a stable growth trend, showing a primary level of coordination. To achieve advanced or even superior coordination, further research on the coordination between wastewater resource utilization and economic development based on the dual-cycle concept is needed. This research aims to provide reference value for improving the coordination between wastewater resource utilization and economic development and discover the relationship between the two under different economic development conditions, where regions with higher economic development efficiency have higher wastewater resource utilization rates, but there is no obvious coordination. Therefore, the research focuses on studying the coordination between wastewater resource utilization rates and economic development in different economic development regions, innovating the content of coordination research.

Green synthesis of iron nanoparticles using Pistacia-atlantica leaf extract for enhanced removal of Cr(VI) from aqueous solution

The discharge of chromium-containing wastewater from various industries into aqueous environments is regarded as an important and challengeable matter due to its high toxicity. The application of conventional methods for eliminating this pollutant are often very expensive and difficult. Therefore, the adsorption process has been introduced as a desirable and effective method for removing chromium ions from aqueous media. In this research, iron nanoparticles (Fe-NPs) were synthesized using Pistacia-atlantica leaf extract as a reducing agent, then they were characterized by DLS, XRD, FT-IR, FESEM/EDS, and TEM techniques and its effectiveness to eliminate hexavalent chromium (Cr (VI)) from aqueous solutions was carried out. The capability of the batch adsorption procedure was assessed under different operational factors, such as initial pH, adsorbent dose and initial Cr (VI) concentration. Optimum adsorption conditions were determined at initial pH of 2, Cr (VI) concentration of 25 mg L−1 and adsorbent dose of 0.24 g L−1. Based on the obtained results, the highest removal efficiency (99.9%) by the adsorption process was occurred at pH of 2, concentration of 5 mg L−1 and 30 min of operational time. On the other hand, the results showed that the percentage of the pollutant elevated by increasing the contact time and amount of adsorbent dose, whereas that of was declined by increasing the initial concentration of Cr (VI). Besides, the experimental equilibrium data was evaluated by Langmuir, Freundlich, and Temkin isotherm models, and the outcomes revealed conformity with the Langmuir isotherm model. The Cr (VI) adsorption utilizing Fe-NPs adhered to a pseudo-first-order kinetic model. Eventually, thermodynamic studies demonstrated that the adsorption of Cr (VI) onto the surface of the Fe-NPs is endothermic and spontaneous.