Comparative assessment of sewer sampling methods for infectious disease surveillance: Insights from transport modeling and simulations of SARS-CoV-2 emissions.

Emerging infectious diseases like COVID-19 present significant public health challenges, necessitating effective surveillance methods. Wastewater-based epidemiology (WBE), detecting viral pathogens in wastewater, has emerged as a proactive tool for monitoring infections. This study evaluated various wastewter sampling methods through SARS-CoV-2 transport simulations in an urban sewer network in Sejong City, South Korea, to identify cost-effective strategies for accurate infection monitoring.

Optimizing nano-sized oxygen bubble application for prolonged aerobic degradation of BTEX in contaminated groundwater.

This study investigates the use of nano-sized oxygen bubbles (NOBs) to enhance BTEX (benzene, toluene, ethylbenzene, xylene) biodegradation in groundwater. Optimized NOBs, averaging 155 nm and at a concentration of 6.59 × 10⁸ bubbles/mL, were found to provide sustained oxygen release with a half-life of approximately 50 days.

Chronic Exposure of Adult Zebrafish to Polyethylene and Polyester-based Microplastics: Metabolomic and Gut Microbiome Alterations Reflecting Dysbiosis and Resilience.

The study explored the ecotoxicological effects of chronic exposure to microplastic (MP) on adult zebrafish, focusing on environmentally relevant concentrations of polyethylene (PE) beads and polyester (PES). High-throughput untargeted metabolomics via UPLC-QToF-MS and 16S metagenomics for gut microbiota analysis were used to assess ecotoxicity in zebrafish exposed to varying concentrations of PE and PES. The VIP (Variable Importance in Projection) scores indicated PE exposure primarily impacted phospholipids, ceramides, and nucleotide-related compounds, while PES exposure led to alterations in lipid-related compounds, chitin, and amino acid derivatives.

Monitoring viruses and beta-lactam resistance genes through wastewater surveillance during a COVID-19 surge in Suwon, South Korea.

The present study reports data on a long-term campaign for monitoring SARS-CoV-2, norovirus, hepatitis A virus, and beta-lactam resistance genes in wastewater samples from a wastewater treatment plant during COVID-19 surge in Suwon, South Korea. Real-time digital PCR (RT-dPCR) assays indicated 100 % occurrence of all but hepatitis A virus and bla gene in influent wastewater samples. CDC-N1 assay detected SARS-CoV-2 in all influent samples with an average log-transformed concentration of 5.

Enhanced bioremediation of acid mine-influenced groundwater with micro-sized emulsified corn oil droplets (MOD) and sulfate-reducing bacteria (Desulfovibrio vulgaris) in a microcosm assay.

High concentrations of metals and sulfates in acid mine drainage (AMD) are the cause of the severe environmental hazard that mining operations pose to the surrounding ecosystem. Little study has been conducted on the cost-effective biological process for treating high AMD. The current research investigated the potential of the proposed carbon source and sulfate reduction bacteria (SRB) culture in achieving the bioremediation of sulfate and heavy metals.

Establishment of wastewater-based SARS-CoV-2 monitoring system over two years: Case studies in South Korea.

With the global COVID-19 pandemic, wastewater surveillance has received a considerable attention as a method for the early identification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater treatment plant (WWTP) and sewer systems. For the first time in Korea, this study utilized the wastewater surveillance technique to monitor the COVID-19 outbreak. Sampling efforts were carried out at the WWTPs in the capital city of Korea, Seoul, and Daegu the place where the first severe outbreak was reported.

Identifying the acute toxicity of contaminated sediments using machine learning models.

Ecological risk assessment of contaminated sediment has become a fundamental component of water quality management programs, supporting decision-making for management actions or prompting additional investigations. In this study, we proposed a machine learning (ML)-based approach to assess the ecological risk of contaminated sediment as an alternative to existing index-based methods and costly toxicity testing. The performance of three widely used index-based methods (the pollution load index, potential ecological risk index, and mean probable effect concentration) and three ML algorithms (random forest, support vector machine, and extreme gradient boosting [XGB]) were compared in their prediction of sediment toxicity using 327 nationwide data sets from Korea consisting of 14 sediment quality parameters and sediment toxicity testing data.

Optimal allocation and operation of sewer monitoring sites for wastewater-based disease surveillance: A methodological proposal.

Wastewater-based epidemiology (WBE) is drawing increasing attention as a promising tool for an early warning of emerging infectious diseases such as COVID-19. This study demonstrated the utility of a spatial bisection method (SBM) and a global optimization algorithm (i.e.

Seasonal trends of mercury bioaccumulation and assessment of toxic effects in Asian clams and microbial community from field study of estuarine sediment.

This study investigated seasonal trends in bioaccumulation potential and toxic effects of mercury (Hg) in Asian clams (Corbicula fluminea) and microbial community. For this, a clam-exposure experiment was performed during summer, fall, and winter seasons in four different sites (HS1: control/clean site; HS2, HS3, and HS4: contaminated sites) of Hyeongsan River estuary, South Korea. Total mercury (THg) and methylmercury (MeHg) in whole sediments were highest at HS4 site during fall, sustained similar levels during winter, but decreased during summer.

Toxicity impact of hydrogen peroxide on the fate of zebrafish and antibiotic resistant bacteria.

Hydrogen peroxide (HO) is applied in various environments. It could be present at concentrations ranging from nanomolar to micromolar in a water system. It is produced through pollutants and natural activities.

Reduction in mercury bioavailability to Asian clams (Corbicula fluminea) and changes in bacterial communities in sediments with activated carbon amendment.

Activated carbon (AC) amendment is considered as one of the alternatives for managing and remediating mercury (Hg) contaminated sediments because of its high sorptive capacity and potential to immobilize the contaminant. For this study, the underlying mechanisms that control the reduction of Hg bioavailability in AC-amended estuarine sediments were investigated in box microcosm set-ups with 28-day Asian clam bioassay experiments. The application of diffusive gradients in thin film technique (DGT) revealed that the total mercury and methylmercury levels in sediment pore water decreased by 60%-75% in 1%-3% AC-amended sediments.

Long-term seasonal and temporal changes of hydrogen peroxide from cyanobacterial blooms in fresh waters.

In water, hydrogen peroxide (HO) is produced through abiotic and biotic reactions with organic matter, including algal cells. The production of HO is influenced by harmful algal cell communities and toxicity. However, only a few studies have been conducted on HO concentrations in natural water.

A high-rate and stable nitrogen removal from reject water in a full-scale two-stage AMX system.

This paper reports long-term performance of a two-stage AMX system with a capacity of 70 m/d treating actual reject water. An air-lift granulation reactor performed partial nitritation (PN-AGR) at an average nitrogen loading rate (NLR) of 3.1 kgN/m-d, producing an average effluent NO-N/NH-N ratio of 1.

Effects of powdered activated carbon and calcium on trihalomethane toxicity of zebrafish embryos and larvae in hybrid membrane bioreactors.

This study investigated the effect of powdered activated carbon and calcium on trihalomethane toxicity in zebrafish embryos and larvae in hybrid membrane bioreactors. Two hybrid membrane bioreactors were configured with the addition of powdered activated carbon or calcium to reduce the trihalomethane formation potential. Trihalomethane formation decreased by approximately 37.

Algal softening followed by ozonation: The fate of persistent micropollutants and natural organic matter in groundwater.

A proof-of-concept study evaluates the performance of a novel strategy using photosynthetic microorganisms to soften groundwater instead of using caustic chemicals. The microalga Scenedesmus quadricauda was used to increase the pH of the groundwater via natural photosynthesis. This work applied softening as a pretreatment to ozonation of hard groundwater and mainly focused on investigating the multiple effects of algal softening on the degradation of persistent micropollutants upon subsequent ozonation.

A proof of concept study for wastewater reuse using bioelectrochemical processes combined with complementary post-treatment technologies.

This article describes a proof-of-concept study designed for the reuse of wastewater using microbial electrochemical cells (MECs) combined with complementary post-treatment technologies. This study mainly focused on how the integrated approach works effectively for wastewater reuse. In this study, microalgae and ultraviolet C (UVC) light were used for advanced wastewater treatment to achieve site-specific treatment goals such as agricultural reuse and aquifer recharge.

Evaluation of organic migration and biomass formation on polymeric components in a point-of-use water dispenser.

To minimize the aesthetic and hygienic concerns regarding tap water (e.g., odor, taste, suspended solids, and microorganisms), point-of-use (POU) water dispensers and filters are used in households worldwide.

Metabolite tracking to elucidate the effects of environmental pollutants.

The purpose of this study was to determine whether behavioral tests and metabolic profiling of organisms can be promising alternatives for assessing the health of aquatic systems. Water samples from four potential pollution sources in South Korea were collected for toxicity evaluation. First, conventional acute toxicity test in Daphnia magna and behavioral test in zebrafish was conducted to assess water quality.

Treatment of reverse osmosis concentrate using an algal-based MBR combined with ozone pretreatment.

Algal treatment was combined with ozone pretreatment for treatment of synthetic reverse osmosis concentrate (ROC) prior to microfiltration. The research mainly focused on minimizing the fouling of polyvinylidene-fluoride membranes and maximizing the restoration of membrane permeability. The algal treatment alone was only moderately effective for the mitigation of fouling in microfiltration, while a markedly improved performance was achieved when the algal treatment followed ozonation.

Effects of nanoscale zero valent iron (nZVI) concentration on the biochemical conversion of gaseous carbon dioxide (CO) into methane (CH).

This study presents the effects of nanoscale zero valent iron (nZVI) concentration on the biomethanation of gaseous CO. During anaerobic batch experiment with 9 times injection of CO, the CO concentration in the headspace rapidly decreased by dissolution. Then, when nZVI was added at 6.

The difference of morphological characteristics and population structure in PAO and DPAOgranular sludges.

We examined how long-term operation of anaerobic-oxic and anaerobic-anoxic sequencing batch reactors (SBRs) affects the enhanced biological phosphorus removal (EBPR) performance and sludge characteristics. The microbial characteristics of phosphorus accumulating organism (PAO) and denitrifying PAO (DPAO) sludge were also analyzed through a quantitative analysis of microbial community structure. Compared with the initial stage of operation characterized by unstable EBPR, both PAO and DPAO SBR produced a stable EBPR performance after about 100-day operation.

Seasonal Changes in Antibiotic Resistance Genes in Rivers and Reservoirs in South Korea.

The fate of antibiotic resistance genes (ARGs) in aquatic environments, especially in rivers and reservoirs, is receiving growing attention in South Korea because reservoirs are an important source of drinking water in this country. Seasonal changes in the abundance of 11 ARGs and a mobile genetic element () in two reservoirs in South Korea, located near drinking water treatment plants in Cheonan and Cheongju cities, were monitored for 6 mo. In these drinking water sources, total ARG concentrations reached 2.

Quantitative and qualitative changes in antibiotic resistance genes after passing through treatment processes in municipal wastewater treatment plants.

In this study, quantitative and qualitative changes in antibiotics resistance genes (ARGs) were investigated in two municipal wastewater treatment plants (WWTPs) treating pretreated livestock or industrial wastewater as well as municipal sewage. Total eight ARGs (tetX, tetM, tetA, sul1, sul2, ermB, qnrD, and bla) were quantified, and their relative abundance was assessed by ARGs copies/16S rRNA gene copies. The fate of ARGs was observed to be different between two WWTPs: sul, qnrD, and bla were proliferated during the treatment processes only in the WWTP1 which received pretreated livestock wastewater.

Sub-lethal pharmaceutical hazard tracking in adult zebrafish using untargeted LC-MS environmental metabolomics.

Antibiotics in the aquatic environment are dispersed through anthropogenic activities at low concentrations. Despite their sub lethal concentration, these biologically active compounds may still have adverse effects to non-target species. This study examined the response of adult zebrafish to 0.

Fate of tetracycline resistance in synthetic livestock carcass leachate for two years.

To simulate the fate of antibiotic resistance in leachate from anaerobic carcass landfill site, anaerobic reactors were set-up and their antibiotic resistance activities were monitored for 2 years. Initially, Escherichia coli DH5α with tetracycline resistance pB10 plasmid was inoculated in nutrient rich anaerobic reactors. The fate of tetracycline resistant bacteria (TRB) was tracked by analysis using culture-based method, EC (half maximal effective concentration), and quantitative polymerase chain reaction (qPCR).