Municipal Wastewater Samples Research Articles

Development of “water-lean” solvent-based air-assisted liquid–liquid microextraction; application in the extraction of some phenolic compounds from water and wastewater samples prior to GC-FID analysis

In the present study, an efficient, robust, and reliable air–assisted liquid–liquid microextraction procedure was introduced based on a “water-lean” solvents for the extraction and preconcentration of phenolic compounds from spring water and petrochemical, Songun mine, and municipal wastewater samples. For this purpose, various hydrophobic water-lean solvents composed of organic solvents consisting of carbon tetrachloride, dichloromethane, 1,1,2-trichloro-1,2,2-trifluoroethane, and chloroform with amines including n-butylamine, di-n-butylamine, iso-propylamine, n-hexylamine, diethylamine, pyridine, aniline, toluidine, and benzylamine) were prepared and they were used as the new extraction media. The selected compounds (phenol, 1-naphthol, 2-naphthol, 4- chlorophenol, o-cresol, 2-nitrophenol, and 2-nitroso-1-naphthol) were extracted from sample solution containing sodium chloride (5 %, w/v) using 200 µL of a water-lean solvent composed of dichloromethane: butylamine (1:1) by performing the sucking/injection cycles for four times. The effect of several parameters on the extraction efficiency of the method, consisting of type and volume of water-lean solvent, extraction numbers, pH, and ionic strength, were examined and optimized by “one-variable-at-one-time” strategy. High enrichment factors (315–420), respectable extraction recoveries (63–84 %), low limits of detection (0.23–0.56 ng mL−1) and quantification (0.77–1.86 ng mL−1), and broad linearity of the calibration curve (1.86–500 ng mL−1) demonstrated satisfactory performance of the present approach. The relative standard deviation for the extraction of 50 and 100 ng mL−1 of each phenol (n = 6) were ≤ 6.3 % for intra- and inter-day precisions. Eventually, the proposed method was efficaciously performed for extraction and determination of the selected analytes in various water and wastewater samples and phenol and 4-chlorophenol were found in the samples at ng mL−1 level.

Fast, Simple, and Sensitive Voltammetric Measurements of Acyclovir in Real Samples via Boron-Doped Diamond Electrode.

The voltammetric acyclovir (ACV) trace-level determination procedure has been introduced. This is the first time that a commercially available boron-doped diamond electrode (BDDE) coupled with differential-pulse voltammetry (DPV) has been used for this purpose. The commercially available BDDE is characterized by a short response time, low background current, and very good analytical parameters of ACV determination. Ultimately, DPV measurements using the BDDE in 0.075 mol L-1 PBS with a pH of 7.2 under optimized conditions achieved the lowest detection limit (LOD = 0.0299 nmol L-1) reported in the literature for voltammetric procedures. Moreover, it is highly resistant to the presence of various interfering agents and has been used to analyze pharmaceutical and municipal wastewater samples. The obtained results are consistent with measurements made using chromatographic reference methods.

Degradation of polyethylene terephthalate (PET) plastics by wastewater bacteria engineered via conjugation.

Wastewater treatment plants are one of the major pathways for microplastics to enter the environment. In general, microplastics are contaminants of global concern that pose risks to ecosystems and human health. Here, we present a proof-of-concept for reduction of microplastic pollution emitted from wastewater treatment plants: delivery of recombinant DNA to bacteria in wastewater to enable degradation of polyethylene terephthalate (PET). Using a broad-host-range conjugative plasmid, we enabled various bacterial species from a municipal wastewater sample to express FAST-PETase, which was released into the extracellular environment. We found that FAST-PETase purified from some transconjugant isolates could degrade about 40% of a 0.25 mm thick commercial PET film within 4 days at 50°C. We then demonstrated partial degradation of a post-consumer PET product over 5-7 days by exposure to conditioned media from isolates. These results have broad implications for addressing the global plastic pollution problem by enabling environmental bacteria to degrade PET.

A pioneering electrochemical sensor for the simultaneous determination of nitrofurantoin and furazolidone residues in food and municipal wastewater samples

In this study, a pioneering electrochemical sensor was developed for simultaneously determining nitrofurantoin (NFT) and furazolidone (FZD) residues in food and municipal wastewater samples. The sensor was prepared by integrating gold‑silver-alloy nanocoral clusters (Au-Ag-ANCCs) with zinc oxide nanoparticles (ZnO-NPs), carbon paste electrode (CPE) and polyethylene oxide (PEO) nanocomposites. The surface morphology and elemental compositions of Au-Ag-ANCCs/ZnO-NPs-CPE/PEO were characterized by FT-IR, XRD, SEM, EDX, EIS, and CV. The sensor showed exceptional performance over a wide linear range, from 1.0 pM to 250 μM for NFT and 0.9 nM to 360 μM for FZD. The detection and quantification limits were found to be 0.26 pM and 0.88 pM for NFT and 0.023 pM and 0.076 pM for FZD, respectively. In addition, the sensor exhibited excellent repeatability, reproducibility, selectivity, and long-lasting stability. When applied to the detection of AZM and ENF residues in poultry, fish, honey, dairy products and municipal wastewater, it exhibited excellent recoveries of 96.3–102.8% and relative standard deviations between 1.87% and 1.53%. In general, the developed sensor represents a significant advance in the fight against antibiotic residue pollution.

Removal of carbamazepine, sulfamethoxazole and aspirin at municipal wastewater treatment plant of Astana, Kazakhstan: paths to increase the efficiency of the treatment process

AbstractBACKGROUNDMedical substances are utilized around the world, and their accumulation in nature is a global concern. This work aimed to identify three priority pharmaceuticals discharged into the domestic sewage stream of Astana city (Kazakhstan). Samples of municipal wastewater were taken before and after the wastewater treatment plant (WWTP) over a period of 13 months. The performed experiments demonstrated that there are seasonal variations in the priority pharmaceuticals – carbamazepine (CBZ), sulfamethoxazole (SMX) and aspirin (ASP) – identified in the wastewaters.RESULTSThe non‐conventional WWTP of Astana city, which includes a sequence of treatment processes, showed 2–100% removal of these compounds with the following influent concentrations from the entering stream: 12.5–185.6 ppb (μg L−1) for CBZ, 2.6–51.2 ppb for SMX and 1.9–199.8 ppb for ASP. Laboratory‐scale experiments revealed that the application of the membrane separation technique, i.e. ultrafiltration, is able to provide improved removal of these pharmaceuticals. The removal of ASP, CBZ and SMX by phase inversion polyethersulfone and track etch (TE) polycarbonate membranes was investigated. Filtration with TE membrane demonstrated 39–97% removal of the primary pharmaceuticals from the wastewater.CONCLUSIONFiltration with TE membrane was recognized as an affordable and efficient supplementary treatment step. The addition of the TE separation process in the Astana WWTP could potentially improve the removal of the studied pharmaceuticals along with other medical substances. The reported results hold substantial significance, particularly for rapidly expanding urban centers and developing nations. This is especially crucial as there is a scarcity of data regarding the treatment of pharmaceuticals in municipal wastewater for these regions. © 2024 Society of Chemical Industry (SCI).

Characterization of cotinine degradation in a newly isolated Gram-negative strain Pseudomonas sp. JH-2.

Cotinine, the primary metabolite of nicotine in the human body, is an emerging pollutant in aquatic environments. It causes environmental problems and is harmful to the health of humans and other mammals; however, the mechanisms of its biodegradation have been elucidated incompletely. In this study, a novel Gram-negative strain that could degrade and utilize cotinine as a sole carbon source was isolated from municipal wastewater samples, and its cotinine degradation characteristics and kinetics were determined. Pseudomonas sp. JH-2 was able to degrade 100mg/L (0.56 mM) of cotinine with high efficiency within 5 days at 30 ℃, pH 7.0, and 1% NaCl. Two intermediates, 6-hydroxycotinine and 6-hydroxy-3-succinoylpyridine (HSP), were identified by high-performance liquid chromatography and liquid chromatograph mass spectrometer. The draft whole genome sequence of strain JH-2 was obtained and analyzed to determine genomic structure and function. No homologs of proteins predicted in Nocardioides sp. JQ2195 and reported in nicotine degradation Pyrrolidine pathway were found in strain JH-2, suggesting new enzymes that responsible for cotinine catabolism. These findings provide meaningful insights into the biodegradation of cotinine by Gram-negative bacteria.

Bacterial cellulose-supported dual-layered nanofibrous adsorbent for thin-film micro-solid-phase extraction of antibiotics in municipal wastewaters

In this study, bacterial cellulose was coated with composite nanofibers of polyvinyl alcohol doped with beta cyclodextrin and alginate (PVA-SA-βCD), constructed using the electrospinning technique. This novel material served as an effective adsorbent for thin-film micro-solid-phase extraction (TF-μSPE) of antibiotics from water samples, followed by HPLC-UV analysis. The adsorbent was subjected to a comprehensive characterization using ATR-FTIR, FE-SEM, and BET techniques. These analyses provided valuable insights into its physicochemical structure and properties. Several key parameters that affect the performance of the TF-μSPE method were investigated including electrospinning factors (voltage, flow rate, needle tip-collector distance, and electrospinning time), desorption solvent type and volume, adsorbent dose, adsorption and desorption times, pH value, and salt percentage. Under the optimized conditions, the limits of detections and quantifications for target antibiotics were obtained in the ranges of 0.02–0.03 and 0.07–0.1 μg L⁻1, respectively. The linear range was 0.07–1000 μg L⁻1 with satisfactory determination coefficients (r2) of 0.9944–0.9984. The intra-day and inter-day precisions were obtained as 1.1–1.7 % and 2.2–3.5 %, respectively. The developed method was successfully applied to determine antibiotics in municipal wastewater samples, yielding recoveries within the range of 70–100 % (RSD%<3.7). The green features of the method were also assessed based on AGREE tool. This is the first report on the fabrication of a double-layered nanofibrous adsorbent and its application for the adsorption of antibiotics in wastewater. This robust approach combines efficiency with analytical accuracy, making it a valuable tool for antibiotic analysis in environmental samples.

Workflow to facilitate the detection of new psychoactive substances and drugs of abuse in influent urban wastewater

The complexity around the dynamic markets for new psychoactive substances (NPS) forces researchers to develop and apply innovative analytical strategies to detect and identify them in influent urban wastewater. In this work a comprehensive suspect screening workflow following liquid chromatography – high resolution mass spectrometry analysis was established utilising the open-source InSpectra data processing platform and the HighResNPS library. In total, 278 urban influent wastewater samples from 47 sites in 16 countries were collected to investigate the presence of NPS and other drugs of abuse. A total of 50 compounds were detected in samples from at least one site. Most compounds found were prescription drugs such as gabapentin (detection frequency 79%), codeine (40%) and pregabalin (15%). However, cocaine was the most found illicit drug (83%), in all countries where samples were collected apart from the Republic of Korea and China. Eight NPS were also identified with this protocol: 3-methylmethcathinone 11%), eutylone (6%), etizolam (2%), 3-chloromethcathinone (4%), mitragynine (6%), phenibut (2%), 25I-NBOH (2%) and trimethoxyamphetamine (2%). The latter three have not previously been reported in municipal wastewater samples. The workflow employed allowed the prioritisation of features to be further investigated, reducing processing time and gaining in confidence in their identification.

Spectrophotometric determination of phenol impurity in phenoxyethanol and phenol index of drinking water and municipal wastewater effluent after salting-out assisted liquid phase microextraction (SA-LPME)

In this study, a novel and convenient analytical method based on salting-out-assisted liquid phase microextraction (SA-LPME) has been developed. A spectrophotometric technique was employed to quantify the concentration of phenol in drinking water and treated wastewater, as well as the phenol impurity in 2-phenoxyethanol (PE). To accomplish this, a solution containing dissolved PE was supplemented with 4-aminoantipyrine (4-AAP) and hexacyanoferrate. Subsequently, NaCl was added to induce the formation of a two-phase system, consisting of fine droplets of PE as an extractant phase in the aqueous phase. The resulting red derivative was then extracted into the extractant phase and separated through centrifugation. Finally, the absorbance of the extracted derivative was measured at 520 nm. The Response Surface Methodology (RSM) based on the Box-Behnken Design (BBD) was employed to optimize the influential factors, namely 4-Aminoantipyrine (4-AAP), buffer (pH = 10), hexacyanoferrate, and NaCl. By utilizing the optimal conditions (buffer: 50 μL, 4-AAP (1% w/v): 80 μL, hexacyanoferrate (10% w/v): 65 μL, and NaCl: 0.7 g per 10 mL of the sample), the limit of detection was determined to be 0.7 ng mL−1 and 0.22 μg g−1 for water and PE samples, respectively. The relative standard deviation (RSD) and correlation of determination (r2) obtained fell within the range of 2.4–6.8% and 0.9983–0.9994, respectively. Moreover, an enrichment factor of 65 was achieved for a sample volume of 10 mL. The phenol concentration in two PE samples (PE-1, PE-2), provided by a pharmaceutical company (Pars Sadra Fanavar, Iran), were determined to be 0.83 ± 0.05 μg g−1 and 2.70 ± 0.14 μg g−1, respectively. Additionally, the phenol index in drinking water and treated municipal wastewater was found to be 3.60 ± 1.06 ng mL−1 and 4.60 ± 1.17 ng mL−1, respectively. These mentioned samples were spiked in order to evaluate the potential influence of the matrix. The relative recoveries from PE-1, PE-2 samples, drinking water, and treated municipal wastewater samples were measured as 104.5%, 97.5%, 101.6%, and 107.8%, respectively, indicating no matrix effect.

Isolation of Enterococcus Bacteriophages from Municipal Wastewater Samples Using an Enrichment Step.

Municipal wastewater, as an aggregate mixture of household and industrial effluents, harbors a highly diverse population of bacteria and their associated bacteriophages. Accordingly, it is a commonly used source of bacteriophages against many human-associated bacterial pathogens. Here, we describe a method for bacteriophage isolation from municipal wastewater with several optional enrichment and concentration steps.

Environmental monitoring of antimicrobial resistant bacteria in North Carolina water and wastewater using the WHO Tricycle protocol in combination with membrane filtration and compartment bag test methods for detecting and quantifying ESBL E. coli

Antimicrobial resistance (AMR) threatens human and animal health; effective response requires monitoring AMR presence in humans, animals, and the environment. The World Health Organization Tricycle Protocol (WHO TP) standardizes and streamlines global AMR monitoring around a single indicator organism, extended-spectrum-β-lactamase-producing Escherichia coli (ESBL-Ec). The WHO TP culture-based method detects and quantifies ESBL-Ec by spread-plating or membrane filtration on either MacConkey or TBX agar (supplemented with cefotaxime). These methods require laboratories and trained personnel, limiting feasibility in low-resource and field settings. We adapted the WHO TP using a simplified method, the compartment bag test (CBT), to quantify most probable numbers (MPN) of ESBL-Ec in samples. CBT methods can be used correctly in the field by typical adults after a few hours’ training. We collected and analyzed municipal wastewater, surface water, and chicken waste samples from sites in Raleigh and Chapel Hill, NC over an 8-month period. Presumptive ESBL-Ec were quantified using MF on TBX agar supplemented with cefotaxime (MF+TBX), as well as using the CBT with chromogenic E. coli medium containing cefotaxime. Presumptive ESBL-Ec bacteria were isolated from completed tests for confirmation and characterization by Kirby Bauer disk diffusion tests (antibiotic sensitivity) and EnteroPluri biochemical tests (speciation). Both methods were easy to use, but MF+TBX required additional time and effort. The proportion of E. coli that were presumptively ESBL in surface water samples was significantly greater downstream vs upstream of wastewater treatment plant (WWTP) outfalls, suggesting that treated wastewater is a source of ESBL-Ec in some surface waters. The CBT and MF+TBX tests provided similar (but not identical) quantitative results, making the former method suitable as an alternative to the more complex MF+TBX procedure in some applications. Further AMR surveillance using MF+TBX and/or CBT methods may be useful to characterize and refine their performance for AMR monitoring in NC and elsewhere.

Enhanced detection of mpox virus in wastewater using a pre-amplification approach: A pilot study informing population-level monitoring of low-titer pathogens

A recent outbreak of the mpox virus (MPXV) occurred in non-endemic regions of the world beginning in May 2022. Pathogen surveillance systems faced pressure to quickly establish response protocols, offering an opportunity to employ wastewater-based epidemiology (WBE) for population-level monitoring. The pilot study reported herein aimed to: (i) develop a reliable protocol for MPXV DNA detection in wastewater which would reduce false negative reporting, (ii) test this protocol on wastewater from various regions across the United States, and (iii) conduct a state of the science review of the current literature reporting on experimental methods for MPXV detection using WBE. Twenty-four-hour composite samples of untreated municipal wastewater were collected from the states of New Jersey, Georgia, Illinois, Texas, Arizona, and Washington beginning July 3rd, 2022 through October 16th, 2022 (n = 60). Samples underwent vacuum filtration, DNA extraction from captured solids, MPXV DNA pre-amplification, and qPCR analysis. Of the 60 samples analyzed, a total of eight (13%) tested positive for MPXV in the states of Washington, Texas, New Jersey, and Illinois. The presence of clade IIb MPXV DNA in these samples was confirmed via Sanger sequencing and integration of pre-amplification prior to qPCR decreased the rate of false negative detections by 87% as compared to qPCR analysis alone. Wastewater-derived detections of MPXV were compared to clinical datasets, with 50% of detections occurring as clinical cases were increasing/peaking and 50% occurring as clinical cases waned. Results from the literature review (n = 9 studies) revealed successful strategies for the detection of MPXV DNA in wastewater, however also emphasized a need for further method optimization and standardization. Overall, this work highlights the use of pre-amplification prior to qPCR detection as a means to capture the presence of MPXV DNA in community wastewater and offers guidance for monitoring low-titer pathogens via WBE.

Assessing the impact of a major electronic music festival on the consumption patterns of illicit and licit psychoactive substances in a Mediterranean city using wastewater analysis

The consumption patterns of five categories of psychoactive substances (PS), including “conventional” illicit drugs, new psychoactive substances (NPS), therapeutic opioids, alcohol and nicotine, were studied in the city of Split, Croatia, using wastewater-based epidemiology (WBE), with an emphasis on the impact of a large electronic music festival. The study involved the analysis of 57 urinary biomarkers of PS in raw municipal wastewater samples collected in three characteristic periods, including the festival week in the peak-tourist season (July) and reference weeks in the peak-tourist season (August) and the off-tourist season (November). Such a large number of biomarkers allowed the recognition of distinct patterns of PS use associated with the festival, but also revealed some subtle differences between summer and autumn seasons. The festival week was characterized by markedly increased use of illicit stimulants (MDMA: 30-fold increase; cocaine and amphetamine: 1.7-fold increase) and alcohol (1.7-fold increase), while consumption of other common illicit drugs (cannabis and heroin), major therapeutic opioids (morphine, codeine and tramadol) and nicotine remained rather constant. Interestingly, NPS and methamphetamine clearly contributed to the festival PS signature in wastewater, but their prevalence was rather low compared to that of common illicit drugs. Estimates of cocaine and cannabis use were largely consistent with prevalence data from national surveys, whereas differences were found for typical amphetamine-type recreational drugs, particularly MDMA, and for heroin. The WBE data suggest that the largest proportion of morphine came from heroin consumption and that the percentage of heroin users seeking treatment in Split is probably rather low. The prevalence of smoking calculated in this study (30.6 %) was consistent with national survey data for 2015 (27.5–31.5 %), while the average alcohol consumption per capita >15 years (5.2 L) was lower than sales statistics suggest (8.9 L).

Identification of SARS-CoV-2 variants in wastewater using targeted amplicon sequencing during a low COVID-19 prevalence period in Japan

Wastewater-based epidemiology is expected to be able to identify SARS-CoV-2 variants at an early stage via next-generation sequencing. In the present study, we developed a highly sensitive amplicon sequencing method targeting the spike gene of SARS-CoV-2, which allows for sequencing viral genomes from wastewater containing a low amount of virus. Primers were designed to amplify a relatively long region (599 bp) around the receptor-binding domain in the SARS-CoV-2 spike gene, which could distinguish initial major variants of concern. To validate the methodology, we retrospectively analyzed wastewater samples collected from a septic tank installed in a COVID-19 quarantine facility between October and December 2020. The relative abundance of D614G mutant in SARS-CoV-2 genomes in the facility wastewater increased from 47.5 % to 83.1 % during the study period. The N501Y mutant, which is the characteristic mutation of the Alpha-like strain, was detected from wastewater collected on December 24, 2020, which agreed with the fact that a patient infected with the Alpha-like strain was quarantined in the facility on this date. We then analyzed archived municipal wastewater samples collected between November 2020 and January 2021 that contained low SARS-CoV-2 concentrations ranging from 0.23 to 0.43 copies/qPCR reaction (corresponding to 3.30 to 4.15 log10 copies/L). The targeted amplicon sequencing revealed that the Alpha-like variant with D614G and N501Y mutations was present in municipal wastewater collected on December 4, 2020 and later, suggesting that the variant had already spread in the community before its first clinical confirmation in Japan on December 25, 2020. These results demonstrate that targeted amplicon sequencing of wastewater samples is a powerful surveillance tool applicable to low COVID-19 prevalence periods and may contribute to the early detection of emerging variants.

Monitoring Alcohol Consumption in Slovak Cities during the COVID-19 Lockdown by Wastewater-Based Epidemiology.

The consumption of alcohol in a population is usually monitored through individual questionnaires, forensics, and toxicological data. However, consumption estimates have some biases, mainly due to the accumulation of alcohol stocks. This study's objective was to assess alcohol consumption in Slovakia during the COVID-19 pandemic-related lockdown using wastewater-based epidemiology (WBE). Samples of municipal wastewater were collected from three Slovak cities during the lockdown and during a successive period with lifted restrictions in 2020. The study included about 14% of the Slovak population. The urinary alcohol biomarker, ethyl sulfate (EtS), was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). EtS concentrations were used to estimate the per capita alcohol consumption in each city. The average alcohol consumption in the selected cities in 2020 ranged between 2.1 and 327 L/day/1000 inhabitants and increased during days with weaker restrictions. WBE can provide timely information on alcohol consumption at the community level, complementing epidemiology-based monitoring techniques (e.g., population surveys and sales statistics).

Biological Properties of 12 Newly Isolated Acinetobacter baumannii-Specific Bacteriophages.

Infections with the opportunistic Gram-negative bacterium Acinetobacter baumannii pose a serious threat today, which is aggravated by the growing problem of multi-drug resistance among bacteria, caused by the overuse of antibiotics. Treatment of infections caused by antibiotic-resistant A. baumannii strains with the use of phage therapy is not only a promising alternative, but sometimes the only option. Therefore, phages specific for clinical multi-drug resistant A. baumannii were searched for in environmental, municipal, and hospital wastewater samples collected from different locations in Poland. The conducted research allowed us to determine the biological properties and morphology of the tested phages. As a result of our research, 12 phages specific for A. baumannii, 11 of which turned out to be temperate and only one lytic, were isolated. Their lytic spectra ranged from 11 to 75%. The plaques formed by most phages were small and transparent, while one of them formed relatively large plaques with a clearly marked 'halo' effect. Based on Transmission Electron Microscopy (TEM), most of our phages have been classified as siphoviruses (only one phage was classified as a podovirus). All phages have icosahedral capsid symmetry, and 11 of them have a long tail. Optimal multiplicity of infections (MOIs) and the adsorption rate were also determined. MOI values varied depending on the phage-from 0.001 to 10. Based on similarities to known bacteriophages, our A. baumannii-specific phages have been proposed to belong to the Beijerinckvirinae and Junivirinae subfamilies. This study provides an additional tool in the fight against this important pathogen and may boost the interest in phage therapy as an alternative and supplement to the current antibiotics.

Electrochemical Dechlorination of Municipal Wastewater Effluent.

The use of sodium bisulfite as an electron donor to quench chloramine disinfectant residuals in municipal wastewater effluents prior to discharge incurs the cost of purchasing and transporting bisulfite to the utility and increases the loading of salts to the receiving water. In this study, degradation of chloramine residuals within authentic municipal wastewater effluents was achieved within a 30 min timescale using a reductive electrochemical reactor, which supplied electrons via a stainless-steel cathode under galvanostatic conditions without an ion exchange membrane separating the cathode and anode. Application of a 0.26 mA/cm2 cathodic current density reduced chloramines to ammonia and avoided oxidation at the IrO2-coated titanium anode of chloride to chlorine or chlorate and of ammonia to nitrite or nitrate. Net chloramine production was observed at a higher current density (2 mA/cm2). Chloramine degradation rates and Coulombic efficiencies were highest and electrical energy per order (EEO) values were lowest for the 304-grade stainless-steel cathode, which contains the highest nickel content, and for a stainless-steel cathode with a high surface area. Differences in ionic strength and pH were less important. For chloraminated municipal wastewater samples, the highest Coulombic efficiency was 4.1% and the lowest EEO value was 0.08 kWh/m3. An initial comparison indicated that the electricity cost associated with this EEO value would be comparable to the cost of sodium bisulfite for areas with low electricity costs.

Inkjet-printed flexible graphene paper electrode for the electrochemical determination of mercury.

Here, we report an inkjet-printed graphene paper electrode (IP-GPE) for the electrochemical analysis of mercuric ions (Hg(ii)) in industrial wastewater samples. Graphene (Gr) fabricated on a paper substrate was prepared by a facile solution-phase exfoliation method in which ethyl cellulose (EC) behaves as a stabilizing agent. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to determine the shape and multiple layers of Gr. The crystalline structure and ordered lattice carbon of Gr were confirmed by X-ray diffraction (XRD) and Raman spectroscopy. The nano-ink of Gr-EC was fabricated on the paper substance via an inkjet printer (HP-1112) and IP-GPE was exploited as a working electrode in linear sweep voltammetry (LSV) and cyclic voltammetry (CV) for the electrochemical detection of Hg(ii). The electrochemical detection is found to be diffusion-controlled illustrated by obtaining a correlation coefficient of 0.95 in CV. The present method exhibits a better linear range of 2-100 μM with a limit of detection (LOD) of 0.862 μM for the determination of Hg(ii). The application of IP-GPE in electrochemical analysis shows a user-friendly, facile, and economical method for the quantitative determination of Hg(ii) in municipal wastewater samples.

Biological Nitrogen Transformation Efficiency in Removing Nitrogen and Improving Water Quality from Zakho Municipal Wastewater in Kurdistan Region/Iraq

Samples of municipal waste water was taken and subjected to biological nitrogen transformation (BNT) of ammonification nitrification, and denitrification processes in order to remove the excesses level of harmful nitrogen forms and to improve physio-chemical properties of wastewater. Results revealed that the BNT is efficient in removing all forms of Nitrogen from waste water, especially in end of denitrification process, nitrite reduced about 96% and nitrate reduced to 75%. nitrification process can convert about 17 % to nitrate in one-month period while in the end of denitrifying process this range was elevated to 40 %. Total Kjeldahl nitrogen reduced by ammonification about 17%, and nitrifying bacteria are able to convert about 74% of total Kjeldahl nitrogen to nitrate. the denitrifying bacteria are able to convert this nitrate to gaseous form of nitrogen and to remove 92% of total Kjeldahl nitrogen. Different BNT process were able to reduce 24%, 64%, and 81% of organic nitrogen by ammonification, nitrification, and denitrification respectively. The COD/ N is 1 and the nitrogen removal efficiency is high. BNT is efficient in reducing TS, TSS, and TDS in the water was brought to the excellent ranges for drinking water between 50-150 mg/l. Regarding hardness, hard wastewater higher than 350 mg/l removed significantly by all BNT to bring it to soft water 180 mg/l in the end of experiment. Alkalinity was elevated by the BNT as CO3 react with H coming from nitrification to form more HCO3 ions in the water. EC values during whole experiment were changed about 10 units to return to its natural values around 160 ds.m-1 as the soluble salts cannot be removed by BNT. Turbidity of waste water was significantly removed by BNT process as microbes decompose the majority of total suspended and dissolved solid that create the turbidly.

Wastewater monitoring in tourist cities as potential sentinel sites for near real-time dynamics of imported SARS-CoV-2 variants

Wastewater-based epidemiology (WBE) complements the clinical surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants' distribution in populations. Many developed nations have established national and regional WBE systems; however, governance and budget constraints could be obstacles for low- and middle-income countries. An urgent need thus exists to identify hotspots to serve as sentinel sites for WBE. We hypothesized that representative wastewater treatment plants (WWTPs) in two international gateway cities, Bangkok and Phuket, Thailand, could be sentineled for SARS-CoV-2 and its variants to reflect the clinical distribution patterns at city level and serve as early indicators of new variants entering the country. Municipal wastewater samples (n = 132) were collected from eight representative municipal WWTPs in Bangkok and Phuket during 19 sampling events from October 2021 to March 2022, which were tested by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) using the US CDC N1 and N2 multiplex and variant (Alpha, Delta, and Omicron BA.1 and BA.2) singleplex assays. The variant detection ratios from Bangkok and Phuket followed similar trends to the national clinical testing data, and each variant's viral loads agreed with the daily new cases (3-d moving average). Omicron BA.1 was detected in Phuket wastewater prior to Bangkok, possibly due to Phuket's WWTPs serving tourist communities. We found that the Omicron BA.1 and BA.2 viral loads predominantly drove the SARS-CoV-2 resurgence. We also noted a shifting pattern in the Bangkok WBE from a 22-d early warning in early 2021 to a near real-time pattern in late 2021. The potential application of tourist hotspots for WBE to indicate the arrival of new variants and re-emerging or unprecedented infectious agents could support tourism-dependent economies by complementing the reduced clinical regulations while maintaining public health protection via wastewater surveillance.