Treated Wastewater Effluent Research Articles

Temporal Concentrations of Quaternary Ammonium Compounds in Wastewater Treatment Effluents During the COVID-19 Pandemic, 2020-2021.

Quaternary ammonium compounds (QAC) are high production chemicals used in many commercial and household disinfection products. During the SARS-CoV-2 (COVID-19) pandemic, QACs were included on lists of COVID-19 disinfectants. Increased QAC use could lead to higher levels of QACs in wastewater treatment plant (WWTP) effluents, which could subsequently be released into the environment. To evaluate QACs in WWTP effluent, three WWTPs in the northeastern United States were monitored from May 2020 through August 2021. Target QACs included six benzylalkyldimethyl ammonium compounds (BAC), three dialkyldimethyl ammonium compounds (DADMAC), two ethylbenzylalkyldimethyl ammonium compounds (EBAC), and benzethonium. At least one QAC was detected in every sample with individual concentrations up to 1,600 ng L-1. BAC-C14 was detected most frequently, found in 93% of effluent samples; BAC-C12, BAC-C16, EBAC-C12 and EBAC-C14 were all detected in greater than 80% of samples. Few temporal patterns were observed in QAC concentrations with respect to weekly COVID-19 cases: at WWTP 2, DADMAC-C8:C10 and DADMAC-C10 were positively correlated, and DADMAC-C8 negatively correlated. There were several seasonal trends at WWTP 1, including significant differences of ƩDADMAC, which were higher in fall than summer; ƩBAC was higher during the fall than both spring and summer; and ƩQAC where higher during the fall than spring.

Utilizing electrooxidation for textile effluent wastewater treatment and simultaneous electrocatalytic hydrogen production: Transforming waste into energy and promoting water reuse in a circular economy context

Textile effluent wastewater poses a serious environmental risk because of its high concentration of pollutants, which include organic compounds, heavy metals, and dyes. The present study investigates the technical and economic feasibility of hybrid water electrolysis performances. Specifically, real textile effluent wastewater was utilised to examine simultaneous abatement and electrochemical hydrogen production. The treated water can be recycled in the textile mill, offering the benefits of trash-to-treasure and cost savings through the circular economy. In addition to reducing the environmental impact of textile wastewater, the synergistic approach seeks to maximise its potential for producing hydrogen as clean energy. Here, the commercially available stainless sheet was used as the anode in the electrochemical setup system and the two-dimensional Ti3C2TX MXene was used as the catalyst embedded cathode. The optimal electrode-electrolyte parameter settings resulted in an 83 % decrease in COD level and a degradation efficiency of about 88 %. The potential for widespread adoption in the textile industry is highlighted by the discussion of the economic viability and environmental advantages of using wastewater from textile effluents for pollutant degradation and hydrogen production. Hence, the energy estimation was looked at and estimated in order to evaluate the process viability. For instance, the hybrid electrolysis process uses a very small amount of electricity (0.825 kWh m−3 order−1) and has an apparent operating current (30 mA/cm2). This work could serve as a guide for the methodical assessment and choice of hybrid water electrolysis using actual wastewater. The electrode's recyclability and reuse were proven for possible commercial applications. The stability of the Ti3C2TX electrode over a wide pH range was investigated in order to produce hydrogen on a big scale at a reasonable cost.

Molecular insights into the degradation of organic matter from secondary swine wastewater effluent: A comparative study of advanced oxidation processes

Advanced oxidation processes (AOPs) are promising for the treatment of secondary swine wastewater effluents, however, the molecular-level understanding of effluent organic matter (EfOM) removal and transformation during AOPs is limited. This study employed molecular-level characterization based on Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and bulk characterizations to investigate these processes in various AOPs, including Cu-Fenton, UV-Cu-Fenton, Fenton, UV-Fenton, and UV/H2O2 treatments. Our findings revealed that the removal rates of dissolved organic carbon and EfOM molecules follow the sequence of UV-Fenton > Fenton > UV-Cu-Fenton > UV/H2O2 > Cu-Fenton, correlating with the rates of H2O2 decomposition during reactions. AOPs with faster H2O2 decomposition, indicative of higher reactive oxygen species generation, predominantly mineralize rather than transform EfOM. Linkage analysis highlighted oxygen addition and deamination as the primary transformation reactions, with variations in the dominance levels of these reactions across different AOPs. Recalcitrant molecule, particularly CHNO and CHO types, including low-molecular-weight carboxyl-rich alicyclic molecules, pose challenges in treatment. To enhance the efficacy of secondary effluent treatment, strategies focusing on the targeted removal of such recalcitrant EfOM should be developed. This study provided new insights into the selection and optimization of AOPs for secondary swine wastewater effluent treatment.

Effect of High-Rate Aeration in the Electrocoagulation Treatment of Pharmaceutical and Synthetic Textile Industrial Wastewater Effluents

Despite the extensive literature on the effects of implementing aeration in the electrocoagulation (EC) treatment of industrial wastewater, few studies evaluate the performance of this technique at high aeration rates. In this work, we present the outcomes derived from EC treatment of pharmaceutical and synthetic textile wastewater effluents in two lab-scale reactors with and without aeration, each equipped with different electrode combinations of aluminium and iron (Al/Al, Al/Fe, and Fe/Fe). In the non-aerated EC reactor, maximum chemical oxygen demand (COD) reductions of 56% and 80% were achieved for the pharmaceutical and textile effluents, respectively, with up to 100% removal of turbidity and colour with the Al/Al combination. The installation of high-rate aeration to prevent sludge accumulation on the electrode surface markedly reduced residence times and enhanced the COD removal in the pharmaceutical effluent. However, this implementation potentially reduced the process efficiency for thesynthetic textile effluent as prolonged operation led to flocculation breakdown and subsequent re-dissolution of the contaminants in the water.

By-product distribution and cytotoxicity assessment of ZnO-assisted photocatalytic degradation of reactive blue 250 dye

This research examined the effectiveness and feasibility of utilizing ultraviolet (UV) assisted photo-catalysis to treat wastewater effluents from textile production containing reactive blue 250 (RB 250) dye. Molecular oxygen and active species like O2•−, HO2•, H2O2 and •OH play crucial roles in the degradation process. Additionally, the degradation of dyes is influenced by several factors, including dye concentration, duration of UV irradiation, pH levels, concentration of H2O2, and the catalyst. The concentration of H2O2 and catalyst dose for the decolorization was studied at 0.6 mL and 0.5 g respectively. The discoloration was higher at low dye concentration, high H2O2 concentration, acidic conditions and high catalyst concentration. The maximum degradation (97 %) of RB 250 dye was obtained in the presence of zinc oxide nanoparticles within 90 min. The extent of decolorization of the dye was determined by UV–Vis spectroscopy. Fourier transform infrared spectroscopy (FTIR) was employed to analyze the changes in functionalities after degradation. The disappearance of characteristic peaks associated with specific groups within the dye molecule confirmed the extensive degradation of RB 250 dye. LCMS analysis was conducted to examine the intermediates and a mechanistic degradation pathway was subsequently proposed. The cytotoxicity of the irradiated dye samples was evaluated through a hemolytic test both pre and post-treatment. The findings suggest that the UV/H2O2/ZnO treatment represents a promising approach for effectively degrading RB 250 dye.

Microalgae to remove pharmaceutical and personal care products (PPCPs) from wastewater

Substances used for medicinal, cosmetic, hygiene, and health care objectives are included in the category of pharmaceuticals and personal care products (PPCPs). They are a major source of public concern because of their ubiquitous manufacturing, usage, and careless disposal of expired products into the environment. Many PPCPs, including antibiotics, analgesics, endocrine disruptors, and microbial/disinfecting agents, are commonly detected in freshwater systems, groundwater, and wastewater treatment effluents in amounts ranging from nanograms per liter to milligrams per milliliter. Additionally, these compounds frequently show persistence and accumulate in biological tissue, eventually finding their way into crops, vegetables, and drinking water supplies. Because many PPCPs are known to have the ability to upset ecosystems and/or provide health hazards, they are categorized as “emerging contaminants.” The research on the occurrence, fate, and possible health and environmental hazards related to PPCPs in both aquatic and terrestrial habitats is thoroughly reviewed in this work. It also covers reported cases of danger or health concerns in humans, although a full assessment may not be possible given the limitations of the data at hand. This review aims to provide a comprehensive and well-focused overview of the current understanding of bioremediation strategies for the removal of pharmaceuticals and personal care products (PPCPs), with an emphasis on the application of macroalgae, microalgae, and aquatic macrophytes. It examines the physicochemical properties of PPCPs and their potential risks to environmental and human health. Additionally, the review explores the potential and challenges associated with the broader application of biotechnologies employing algae and aquatic macrophytes. This includes research efforts to correlate the operational parameters of these biotechnologies with the primary mechanisms responsible for PPCP removal. In conclusion, algae and macrophytes present promising, eco-friendly solutions for wastewater treatment, significantly contributing to the mitigation of PPCP contamination.

Seasonally varying contributions of contemporaneous and lagged sources of instream total nitrogen and phosphorus load across the Illinois River basin

Quantifying nutrient sources in streams, their temporal and spatial variability, and drivers of that variability can support effective water resources management. Yet a lack of data and modeling capabilities has previously prevented comprehensive quantification across both space and time. Here a dynamic SPARROW (Spatially Referenced Regressions on Watershed attributes) model that accounts for a lagged delivery of nutrients to streams was developed and applied to simulate seasonal and source-specific total nitrogen (TN) and total phosphorus (TP) loads in streams across the Illinois River basin (IRB). Dynamic load predictions from 2000 through 2020 revealed that a third of the TN and a quarter of the TP instream load originated from non-point sources that were lagged in their delivery from land-application to streams by more than a season. This lagged mass was the largest overall TN source—which was estimated as a lagged expression of previous seasonal non-point sources including fertilizer, manure, atmospheric deposition and fixation, and urban land use. Treated wastewater effluent was the largest TP source exported from the basin, contributing 39 % of the TP load and 15 % of the TN load, and dominated the load in the upper Illinois River near Chicago. Loads in the lower river during this period, conversely, were attributed primarily to a mix of agricultural sources and their lagged fractions from headwater tributaries. Instream processes removed 10 % of the TN load while only 4 % of the TP load was removed during instream transport. With appropriate datasets, the models could be extended to other basins or time periods and used to forecast future seasonal nutrient loads.

Advanced electro-oxidation-adsorption process for chlorate removal from synthetic and municipal wastewater treatment effluents

This study evaluates a hybrid electro-oxidation-adsorption process for chlorate removal in wastewater treatment. Using a specialized reactor, we investigated the influence of operational parameters including current density, reaction time, granular activated carbon (GAC) dosage, electrode spacing, and pH. Optimal removal efficiency of 82.40 % was achieved under the following conditions: 75 A/m² current density, 5 min reaction time, 20 g/L GAC dosage, 2 cm electrode spacing, and a pH of 2. This method outperforms traditional adsorption and electrochemical oxidation, offering a promising solution for reducing chlorate-related environmental impacts.

Occurrence of Uncultured Legionella spp. in Treated Wastewater Effluent and Its Impact on Human Health (SCA.Re.S Project).

Wastewater treatment plants (WWTPs) provide optimal conditions for the environmental spread of Legionella. As part of the Evaluation of Sanitary Risk Related to the Discharge of Wastewater to the Ground (SCA.Re.S) project, this study was conducted to evaluate the presence of Legionella in WWTP effluent and in groundwater samples collected from two wells located downstream from the plant. The samples were analyzed to determine the concentrations of Legionella spp using the standard culture-based method and molecular techniques, followed by genomic sequencing analysis. Legionella was detected only with the molecular methods (except in one sample of effluent positive for L. pneumophila serogroup 6), which showed viable Legionella pneumophila and L. non-pneumophila through the use of free DNA removal solution in both the effluent and groundwater, with concentrations that progressively decreased downstream from the plant. Viable L. pneumophila appeared to be slightly more concentrated in warm months. However, no significant differences (p ≥ 0.05) in concentrations between cold and warm months were observed. A genotypic analysis characterized the species present in the samples and found that uncultured Legionella spp, as yet undefined, constituted the prevalent species in all the samples (range 77.15-83.17%). WWTPs play an important role in the hygienic and sanitary quality of groundwater for different uses. The application of Legionella control systems during the purification of effluents is warranted to prevent possible outbreaks of legionellosis.

Detection of Extended-spectrum β-lactamase-producing Klebsiella pneumoniae and Escherichia coli in wastewaters of Madurai, India

The present study aimed to determine the presence of Klebsiella pneumoniae and Escherichia coli with extended-spectrum β-lactamase (ESBL)s property from treated wastewater effluents. Treated effluent samples were collected from two major water treatment plants which located at Avaniyapuram and Sakkimangalam, Madurai, Tamil Nadu, India. Among the 51 isolates, 56.86 % represented E. coli (18 from Avaniyapuram and 11 from Sakkimangalam) and 43.14 % were K. pneumoniae (7 from Avaniyapuram and 15 from Sakkimangalam). Based on the ESBL propensity, E. coli was overrepresented in the present study. All the isolates turned positive for ESBL, while 5.88 % of K. pneumoniae and 7.84 % of E. coli were positive for carbapenemases. Further, K. pneumoniae isolates from both sites showed 100 % resistance to beta-lactams, with resistance to other antibiotics such as tetracycline and meropenem. E. coli isolates were 100 % resistant to ceftazidime and cefuroxime, and 88.9 % were resistant to amoxicillin/clavulanate and ceftriaxone. The MAR indices observed in the present study for E. coli and K. pneumoniae were above the threshold value of 0.2 suggested a high risk of environmental contamination. These findings highlighted the need for routine surveillance at appropriate intervals for the presence of ESBL producing pathogens and other MDR pathogens in the environment to provide proper clinical management, develop various counter measures and policies to address and halt the spread of such potential threats.

Natural vs. anthropogenic sources of N-Nitrosodimethylamine precursors in surface water

N-nitrosodimethylamine (NDMA) is a carcinogenic disinfection byproduct formed from reactions between dichloramine and organic nitrogen-containing precursors. It is unclear if NDMA precursors in surface water intakes originate in anthropogenic (i.e., wastewater) or natural sources. The Truckee River has a single point source release of treated wastewater effluent, making it an ideal system to study the relative importance of precursor sources. Three Lagrangian sampling events were conducted. NDMA formation potential (FP, a measurement of precursors) above the wastewater outfall indicated that the natural background of NDMA precursors was 2-28 ng/L. NDMA FP increased to 18-31 ng/L immediately downstream of the wastewater outfall, but decreased rapidly in a first order manner, and were not statistically different from the upstream samples in only ∼6 km. This suggests that the dominant source of NDMA precursors may be wastewater derived only near wastewater outfalls and deviates from the previous belief that wastewater-derived precursors are responsible for NDMA formation in drinking water sources located further downstream. Additionally, given the rapid loss of the wastewater precursors in this study, precursors which are slow to biodegrade/photolyze/adsorb to sediment are likely to be poor surrogates for the overall wastewater NDMA precursor pool. To understand temporal changes in the wastewater impact on environmental NDMA precursor loading, two 24-hour sampling events were conducted near (<3 km) the wastewater outfall and demonstrated that temporal changes in the NDMA precursors directly downstream of the wastewater outfall are directly linked to the wastewater flow contribution.

Experimental soil matrix, vortex and oil skimming technology as a tertiary treatment of wastewater effluent

Abstract Water is a necessary resource that must be carefully managed. Hazardous chemicals are produced with increased industrial activities and contamination has been detrimental to both people and the environment. An experimental investigation was performed to evaluate the efficiency of vortex technology, soil matrices, and oil skimmer separately for combination as a tertiary wastewater treatment in the design of a phytoremediation system. The objective of the study is to evaluate the performance of each component in removing oil and grease, reducing the concentration of ammonia, nitrate, and phosphate; quality control measures for dissolved oxygen, total dissolved solids, and chemical oxygen demand. One-way ANOVA, kinetics analysis, and adoption isotherm analysis were applied to determine the significance of the parameters. Analysis of results for the oil skimmer exhibited an efficiency of 96% in removing oil and grease after 5 hours of treatment. The vortex technology results were fluctuating with percentage removal of nitrates at 11% while ammonia with an initial concentration of 5.24 mg/L was reduced to 4.12 mg/L. Phosphate decreased after treatment from an initial of 0.87 mg/L to 0.809 mg/L. The analysis of pollutant concentration in the soil matrix after a 5-day period indicated a greater efficiency compared to the vortex technology in the removal of ammonia and phosphate. The ammonia concentration decreased from 18.7 mg/L and 21.4 mg/L to &lt;0.1 mg/L. Similarly, phosphate concentration decreased from 15.5 mg/L to 1.13 mg/L and from 32.5 mg/L to 0.948 mg/L. The research finding underscores the efficiency of the soil matrix in removing ammonia and phosphate but recommends the need for additional intervention to lower nitrate. Overall, the three technologies showed potential and greater efficiencies in mitigating wastewater streams resulting in a notable reduction in oil and pollutant concentrations.

Advanced nanocellulose-based electrochemical sensor for tetracycline monitoring

Antibiotics play a pivotal role in healthcare and agriculture, but their overuse and environmental presence pose critical challenges. Developing sustainable and effective detection methodologies is crucial to mitigating antibiotic resistance and environmental contamination. This study presents a cellulosic polymer-based electrochemical sensor by integrating TEMPO-oxidized cellulose nanofibers-polyethyleneimine hybrids (TOCNFs-PEI) with single-walled carbon nanotube networks (SWCNTs). Our research focuses on (i) conducting physicochemical and electrochemical studies of multifunctional SWCNT/TOCNFs-PEI architectures, (ii) elucidating the relationships between the material's properties and their electrochemical performance, and (iii) assessing its performance in detecting tetracycline concentrations in both controlled and more complex matrices (treated wastewater effluents). The limits of detection were evaluated to be 0.180 µmol L−1 (at the potential of 0.85 V) and 0.112 µmol L−1 (at the potential of 0.65 V) in phosphate-buffered saline solution, and 2.46 µmol L−1 (at the potential of 0.82 V) and 1.5 µmol L−1 (at the potential of 0.65 V) in the undiluted membrane bioreactor effluent sample, respectively. Further, the designed cellulosic polymer-based sensing architecture is compatible with large-scale production, paving the way for a new era of green, versatile sensing devices. These developments will significantly contribute to global efforts to alleviate antibiotic resistance and environmental contamination.

Living in mangroves: a syntrophic scenario unveiling a resourceful microbiome

BackgroundMangroves are complex and dynamic coastal ecosystems under frequent fluctuations in physicochemical conditions related to the tidal regime. The frequent variation in organic matter concentration, nutrients, and oxygen availability, among other factors, drives the microbial community composition, favoring syntrophic populations harboring a rich and diverse, stress-driven metabolism. Mangroves are known for their carbon sequestration capability, and their complex and integrated metabolic activity is essential to global biogeochemical cycling. Here, we present a metabolic reconstruction based on the genomic functional capability and flux profile between sympatric MAGs co-assembled from a tropical restored mangrove.ResultsEleven MAGs were assigned to six Bacteria phyla, all distantly related to the available reference genomes. The metabolic reconstruction showed several potential coupling points and shortcuts between complementary routes and predicted syntrophic interactions. Two metabolic scenarios were drawn: a heterotrophic scenario with plenty of carbon sources and an autotrophic scenario with limited carbon sources or under inhibitory conditions. The sulfur cycle was dominant over methane and the major pathways identified were acetate oxidation coupled to sulfate reduction, heterotrophic acetogenesis coupled to carbohydrate catabolism, ethanol production and carbon fixation. Interestingly, several gene sets and metabolic routes similar to those described for wastewater and organic effluent treatment processes were identified.ConclusionThe mangrove microbial community metabolic reconstruction reflected the flexibility required to survive in fluctuating environments as the microhabitats created by the tidal regime in mangrove sediments. The metabolic components related to wastewater and organic effluent treatment processes identified strongly suggest that mangrove microbial communities could represent a resourceful microbial model for biotechnological applications that occur naturally in the environment.

Comparative evaluation of spatiotemporal variations of surface water quality using water quality indices and GIS

AbstractThere is a need for a comprehensive comparative analysis of spatiotemporal variations in surface water quality, particularly in regions facing multiple pollution sources. While previous research has explored the use of individual water quality indices (WQIs), there is limited understanding of how different WQIs perform in assessing water quality dynamics in complex environmental settings. The objective of this study is to evaluate the effectiveness of three WQIs (Canadian Council of Ministers of the Environment (CCME), National Sanitation Foundation (NSF) and System for Evaluation of the Quality of rivers (SEQ-Eau) and a national water quality regulation in assessing water quality dynamics. The pilot study area is the Acısu Creek in Antalya City of Turkey, where agricultural practices and discharge of treated wastewater effluents impair the water quality. A year-long intensive monitoring study was conducted includig on-site measurements, analysis of numerous physicochemical and bacteriological parameters. The CCME and SEQ-Eau indices classified water quality as excellent/good at the upstream, gradually deteriorating to very poor downstream, showing a strong correlation. However, the NSF index displayed less accuracy in evaluating water quality for certain monitoring stations/sessions due to eclipsing and rigidity problems. The regulatory approach, which categorized water quality as either moderate or good for different sampling sessions/stations, was also found less accurate. The novelty of this study lies in its holistic approach to identify methodological considerations that influence the performance of WQIs. Incorporating statistical analysis, artificial intelligence or multi-criteria decision-making methods into WQIs is recommended for enhanced surface water quality assessment and management strategies.

Novel Crosslinked Anion Exchange Membranes Based on Thermally Cured Epoxy Resin: Synthesis, Structure and Mechanical and Ion Transport Properties.

Limitations in existing anion exchange membranes deter their use in the efficient treatment of industrial wastewater effluent. This work presents an approach to fabricating novel anion-conducting membranes using epoxy resin monomers like hydrophobic or hydrophilic diglycidyl ether and quaternized polyethyleneimine (PEI). Manipulating the diglycidyl ether nature, the quantitative composition of the copolymer and the conditions of quaternization allows control of the physicochemical properties of the membranes, including water uptake (20.0-330%), ion exchange capacity (1.5-3.7 mmol/g), ionic conductivity (0.2-17 mS/cm in the Cl form at 20 °C), potentiostatic transport numbers (75-97%), as well as mechanical properties. A relationship was established between copolymer structure and conductivity/selectivity trade-off. The higher the quaternized polyethyleneimine, diluent fraction, and hydrophilicity of diglycidyl ether, the higher the conductivity and the lower the permselectivity. Hydrophobic diglycidyl ether gives a much better conductivity/selectivity ratio since it provides a lower degree of hydration than hydrophilic diglycidyl ether. Different mesh and non-woven reinforcing materials were also examined. The developed membranes demonstrate good stability in both neutral and acidic environments, and their benchmark characteristics in laboratory electrodialysis cells and batch-mode dialysis experiments are similar to or superior to, commercial membranes such as Neosepta© AMX, FujiFilm© Type1, and Fumasep FAD-PET.

Textile Dye Decolorization Potential of Bacillus pumilus and Staphylococcus saprophyticus Isolated From Textile Industry Effluents

Textile dyeing industries are usually chastised for being big polluters due to the poisonous nature of most dyes, which endangers all kinds of life, including people. In this study, dye degrading bacteria were isolated from water and soil samples contaminated with textile dye taken from Batik palli in Narayanganj and the ability of five isolated bacteria including Staphylococcus saprophyticus, Bacillus pumilus, Micrococcus endophyticus, Pseudomonas mendocina, and Acinetobacter baumannii, to decolorize crystal violet (CV) dye was investigated. Among these, Bacillus pumilus decolorized 58% of CV at 250 ppm, while Staphylococcus saprophyticus decolorized 48% of CV, after 3 days of incubation at 37°C. We examined multiple temperature and pH conditions to determine the best parameters for CV dye decolorization. Bacillus pumilus boosted decolorization rates by 65.39% at 37°C and at pH 7.0, while Staphylococcus saprophyticus increased decolorization rates by 58.73%, at 37°C and at pH 5.0. Furthermore, extending the incubation period to 6 days enhanced decolorization rate in both isolates, with Bacillus pumilus increased from 58% to 65% and Staphylococcus saprophyticus increased from 48% to 58%. Nevertheless, the inclusion of co-substrates such glucose and yeast extract further boosting decolorization rate for both isolates, approximately tripling it. As a result, this study discovered indigenous bacteria capable of decolorizing CV dye, implying that they could be employed in the treatment of textile wastewater effluents. Bangladesh J Microbiol, Volume 40, Number 2, December 2023, pp 50-54

Transfer of heavy metals from soil to vegetables: A comparative assessment of different irrigation water sources

This study aimed to assess the transfer factor (TF) of heavy metals (HMs) from soil to commonly consumed vegetables irrigated with different water sources. The field study covered 36 m2 of agricultural land in Kermanshah province, Iran, divided into nine equal-sized plots. Coriander, basil, and radish were the three types of vegetables cultivated and subjected to irrigation over two months, utilizing three different water sources: treated wastewater effluent (TWE), river water (RW), and well water + nitrogen fertilizer (WWF). After the irrigation and harvesting stages, soil samples from the cultivation area and harvested vegetables were collected. These samples underwent analysis using the ICP-OES method to assess HM levels and subsequent calculation of the TF of HMs from soil to plants. The results revealed that the TF levels indicated plants' relatively weak response (TF < 1) to the absorption of HMs. For non-toxic elements (Mn, Fe, Zn, Cu, Ni), TF values were generally higher than those for toxic elements (Cd, As, Pb) across all three vegetable types and irrigation treatments. The study's findings suggest that the TF of HMs in the studied vegetables varied based on the irrigation source and vegetable type. Various factors, including the type of irrigation source and vegetable, influenced the TF of HMs, each having different impacts on the transfer rate of each HM. The study highlights the importance of monitoring irrigation water and soil quality to prevent the accumulation of HMs in cultivated vegetables, thereby mitigating potential risks to human health.

High-efficiency lanthanum-modified zeolite adsorbents for phosphorus control and algal suppression: Preparation, characterization and mechanistic insights

The use of lanthanum (La)-based materials for phosphate removal from water has received increasing attention. However, challenges remain to enhance phosphate (P) sorption capacities and remove P at low concentrations. In this study, lanthanum modified zeolite materials loaded with different lanthanum types were synthesized by hydrothermal method. Based upon preliminary screening of synthesized La-modified zeolite materials in terms of phosphate sorption capacity and La content, lanthanum chloride-modified zeolite (LZ) is chosen for further study. Specifically, for these materials, phosphate sorption kinetics and isotherm behavior, and solution matrix effects (solution pH, and ionic strength) are reported. The developed LZ has a high sorption capacity of 124.38 mg/g, which exceeds that of most La-based adsorbents currently available. P uptake by LZ was pH-dependent with the highest sorption capacities observed over a pH range of 3 ∼ 9. The presence of coexisting ions (Cl-, SO42-, HCO3–) does not significantly affect the adsorption capacity of LZ. In a real treated wastewater effluent with phosphate concentration of 1.92 mg/L and 0.155 mg/L, 0.1 g/L and 0.01 g/L of LZ efficiently reduced the phosphate concentration to below 0.01 mg P/L. Electrostatic attraction and inner-sphere complexation were identified as the sorption mechanisms of phosphate by LZ. The acute toxicity test confirms that the addition of LZ has no acute toxicity effect on aquatic organisms. However, LZ shows indirect and direct inhibitory effects on algae growth, which is beneficial for the control of eutrophic water. Moreover, the exhausted LZ can be easily regenerated with over 70 % adsorption capacity remained during five recycles. Overall, LZ shows great application potential, and this work provides new insights into the molecular-level mechanism of phosphate sequestration by LZ.

Sources of per- and polyfluoroalkyl substances in an arid, urban, wastewater-dominated watershed

Per- and polyfluoroalkyl substances (PFAS) enter surface waters from various sources such as wastewater treatment plants, fire-fighting sites, and PFAS-producing and PFAS-using industries. The Las Vegas Wash in Southern Nevada of the United States (U.S.) conveys wastewater effluent from the Las Vegas metropolitan area to Lake Mead, a drinking water source for millions of people in the U.S. Southwest. PFAS have previously been detected in the Las Vegas Wash, but PFAS sources were not identified. In this study, upstream wash tributaries, wastewater treatment effluents, and shallow groundwater wells were sampled in multiple campaigns during dry-weather conditions to investigate possible PFAS sources. Out of 19 PFAS, two short-chain PFAS—perfluoropentanoic acid (48 % of the total molar concentration) and perfluorohexanoic acid (32 %)—comprised the majority of PFAS loading measured in the Las Vegas Wash, followed by perfluorooctanoic acid (9 %). On a mass loading basis, the majority of total measured PFAS (approximately 90 %) and at least 48 % of each specific PFAS in the Las Vegas Wash likely entered via municipal wastewater effluents, of which the main source was likely residential wastewater. One of the drainage areas with a major civilian airport was identified as a potential source of relatively enriched perfluorosulfonic acids to a small wash tributary and shallow groundwater samples. Nonetheless, that tributary contributed at most 15 % of any specific PFAS to the mainstem of the Las Vegas Wash. Total PFAS concentrations were relatively low for the small tributary associated with an urban smaller airport and the lack of flow in the tributary channel immediately downgradient of an Air Force base indicates the smaller airport and base were unlikely significant PFAS sources to the Las Vegas Wash. Overall, this study demonstrated effective PFAS source investigation methodology and the importance of wastewater effluent as a PFAS environmental pathway.