Search Results (40)

This study investigated the contribution that treated effluent from five sewage treatment plants (STPs) made to water and sediment quality in rivers within Sydney’s Warragamba Dam catchment. Warragamba Dam is the main water supply for Australia’s largest city, supplying 90% of water for >5 million people. The catchment rivers are important habitats for biodiversity. The study was prompted by an earlier investigation that discovered elevated perfluorooctane sulfonate PFOS in the liver of a platypus found in a river in the Warragamba catchment. At the site where the PFOS-contaminated platypus was collected, the river sediment had a maximum PFAS content of 8300 ng kg⁻¹. This study collected water upstream and downstream of five STPs and from STP discharges. River sediment samples were collected downstream of STPs for per- and poly-fluoroalkyl substances (PFAS). Water attributes included major ions, salinity, nitrogen, phosphorus, metals, and PFAS. Our study confirmed that STP effluent discharges contributed to river nutrient concentrations favourable to algae. The mean total nitrogen (TN) below STP outfalls was 2820 µg L⁻¹, exceeding catchment guideline (TN < 250 µg L⁻¹) by an order of magnitude. PFAS were detected in 65% of STP effluent samples and in 76.5% of river sediment samples. Full article

Background: Respiratory droplets are the main way in which the COVID-19 pandemic’s causal agent, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), spreads. Angiotensin-converting enzyme 2 (ACE2) receptors, especially in lung cells, allow the virus to enter host cells. However, ACE2 expression in intestinal cells has sparked worries about possible fecal transfer, particularly in poor-sanitation areas like India. Methods: Between July 2021 and July 2024, clinical (nasopharyngeal, saliva, and stool samples) and sewage samples were collected from outpatient departments and sewage treatment plants (STPs), respectively, from the high-population-density area under study in order to investigate SARS-CoV-2 transmission. Results: This proof-of-concept study analyzed clinical samples from n = 60 COVID-19-positive patients at a central Indian tertiary care hospital and n = 156 samples from hospital STPs. Variants of SARS-CoV-2 were found using qRT-PCR and Next-Generation Sequencing (NGS). Of the n = 37 qRT-PCR-positive patients who gave their assent, 30% had stool samples that tested positive for viral RNA. In 70% of positive NP and 65% of positive saliva samples, along with two stool samples from immunocompromised patients, the live virus was identified using Vero E6 cell lines. Although 18% of the tests reported qRT-PCR-positive results, no live virus was detected in sewage samples despite NGS validation. The detection of SARS-CoV-2 in the absence of confirmed clinical cases may indicate the silent circulation of the virus within the community, suggesting that sewage surveillance can serve as an early warning system before an outbreak occurs. Conclusions: These findings provide critical insights into the importance of continuous environmental surveillance, silent virus circulation, changes in viral epidemiology throughout the years, and strategies to mitigate coronavirus outbreaks. Full article

Sewage treatment is essential to prevent disease transmission and adverse environmental impacts. This study evaluated the performance of four Sewage Treatment Plants (STPs) in two cities in the state of Minas Gerais, Brazil. Two STPs (Santana and São José) that have Up-Flow Anaerobic Sludge Blanket (UASB) reactors as the sole biological treatment stage did not comply with the discharge standards in receiving water bodies, particularly for SetS, TSS and O&G parameters. This shows the need for improvements, such as the implementation of post-treatment. For the other plants that have UASB reactors followed by an activated sludge system (Industrial Complex STP) or an up-flow anaerobic filter (Carbonita STP) as post-treatment, only the O&G parameter was not met. With the exception of one of the STPs that lackes post-treatment (São José STP), the other three met the required minimum removals of 60% for BOD₅ and 55% for COD. The Carbonita STP promoted the highest average removals of BOD₅ and COD, at 90% and 86%, respectively. Despite the discharge of industrial wastewater into the sewage collection network of one of the cities in this study, the biodegradability of the raw sewage remained high (BOD₅/COD ratio > 0.4). The wastewater treated by the STPs that have post-treatment showed greater potential for reuse in agricultural practices. Full article

The present investigation aims to improve the efficiency of fungal mono- and mixed cultures in removing organic pollutants and metals from sewage water (SW) for further maize plant response assessments. The reduction in the organic load from the SW was harnessed using a co-culture consortium consisting of Aspergillus niger (KB5), Sordariomycetes sp. (D10), and Coniochaetaceae sp. (LB3). The testing results had evinced removal of up to 88% of the organic matter and more than 96%, 91%, 80%, and 47.6%, of removal percentages for Copper (Cu), Nickel (Ni), Cadmium (Cd), and Lead (Pb), respectively, with the developed fungal consortium [KB5 + D10 + LB3]. After treatment and lab experiments, a reuse of treated and untreated SW for plant irrigation was evaluated towards improving maize plant growth. Irrigation was conducted in pot experiments with three types of water: clean water (Control), untreated (USW), and treated SW by fungal consortia (TSW) and by station treatment plant STP (TSWP) using the randomized complete block (RCB) experimental design. Results of the pots trial revealed that the morphological parameters of SW-irrigated plants are slightly improved compared to water-irrigated plants. Data regarding assimilating area attributes indicated that the most significant enlargement of the assimilation area was observed with TSW-D (1/4) irrigation by 1051 cm², followed by TSWP-D (0) by 953.96 cm², then USW-D (1/4) by 716.54 cm², as compared to plants irrigated with clean water (506.91 cm²). On average, the assimilation areas were larger by 51.76%, 46.86%, and 29.25% in TSW, USW, and TSWP-irrigated plants, respectively. Thus, SW irrigation supports the required qualities and quantities of microelements and water for plant growth. Oxidative stress assessment showed that irrigations with treated SW caused a significant decrease in both enzymatic and non-enzymatic antioxidants, depicting that the treatment lowered the stress of sewage water. Full article

The occurrence of micropollutants, including pharmaceuticals, personal care products, pesticides, and hormones in various aquatic ecosystems is a matter of grave concern due to their possible repercussions on human and wildlife endocrine systems. The wastewater containing pharmaceuticals from various sites is usually introduced to sewage treatment plants (STPs); therefore, monitoring of pharmaceuticals in STPs is crucial. In this study, we determined the occurrence of 58 pharmaceuticals in the influent and effluent of 13 STPs based on regional and linked wastewater differences and investigated their removal rates. Furthermore, we assessed the contribution rates of some STP effluents on pharmaceutical concentration in the upstream and downstream areas of the discharge source. Different kinds of pharmaceuticals were measured in the STPs. The top five pharmaceuticals with high concentrations in the influent of each STP were similar due to the dominance of domestic sewage in the influent. The average concentration of acetaminophen, caffeine, acetylsalicylic acid, naproxen, and ibuprofen in the influent of the STPs was higher than that of other pharmaceuticals, and their removal was 94–100%. In contrast, iopamidol, cimetidine, diphenhydramine, and carbamazepine showed a high average concentration in the effluent. The monitoring results of nine streams near STPs indicated that the effluent could contribute to the increase in the types of pharmaceuticals in the receiving streams. The detected pharmaceuticals’ types were 9–29 and 17–33 in the upstream and downstream areas, respectively, of STP discharge channels. Based on flowrate data, the contribution rate of the STP effluent on the stream was −69–326%. Full article

In recent years, underground sewage treatment plants that can remarkably reduce land occupation with less environmental pollution are gradually entering the popular consciousness and are now being used widely. However, problems associated with the traditional treatment plants, such as high construction and operation cost, severe health and safety risks, and monotonous landscape design have limited their value and restricted their application and promotion. Through the literature and field investigations, the value of underground sewage treatment plants (STPs) was analyzed, their engineering and landscape design were studied, and their development direction was explored in order to supply a theoretical basis for further application and development of underground STPs. The analysis showed that as a new model of environmentally friendly sewage treatment and resource conservation, underground STPs have the apparent advantages of lower cost of land use for construction and pipeline as well as an outstanding value for the urban landscape and ecological environment. These factors can offset its relatively high construction and operating costs to a certain extent, especially when compared with above-ground STPs. The engineering design study results showed that significant differences existed between underground STPs and traditional above-ground STPs, and that the main contents of the engineering design of underground STPs consist of treatment scale and degree, influent and effluent qualities, site selection, design model, underground arrangement and structure, main treatment process, monomer structure, ventilation and deodorization, daylighting and artificial lightings, fire safety, operation and maintenance, and the linkage design between the above-ground landscape and the underground STP. Full article

Wastewater treatment plants are efficient in reducing bacterial loads but are also considered potential drivers of environmental antimicrobial resistance (AMR). In this study, we determined the effect of increased influent wastewater volume (from 40% to 66%) in the Legon sewage treatment plant (STP) on the removal of E. coli from sewage, along with changes in AMR profiles. This before and after study compared E. coli loads and AMR patterns in influent and effluent samples from a published baseline study (January–June 2018) with a follow-up study (March–May 2023). Extended-spectrum beta-lactamase (ESBL) E. coli were measured pre- and post-sewage treatment during the follow-up study. The follow-up study showed 7.4% and 24% ESBL E. coli proportions in influent and effluent, respectively. In both studies, the STP was 99% efficient in reducing E. coli loads in effluents, with no significant difference (p = 0.42) between the two periods. More E. coli resistance to antimicrobials was seen in effluents in the follow-up study versus the baseline study. The increased influent capacity did not reduce the efficiency of the STP in removing E. coli from influent wastewater but was associated with increased AMR patterns in effluent water. Further studies are required to determine whether these changes have significant effects on human health. Full article

Long-term development and pollution clean-up plans are a continuing feature of megacities such as Dhaka, Bangladesh. Bangladesh needs to deal with a legacy of past pollution and manage current pollution from a rapidly expanding economy. Surveys in the rivers around Dhaka show extremely high pollution and very low dissolved oxygen levels, with subsequent ecological impacts. Millions of people are not on public treatment of effluents and thousands of factories discharge into the rivers. The Bangladesh Government is planning to install over 12 large Sewage Treatment Plants (STPs) over the next 20 years. To assess the efficacy of these, a water quality model has been applied to the Dhaka River System. Results show that the proposed plan has beneficial effects in the short term for the most densely populated areas of Dhaka, along the Turag and Buriganga Rivers, and in the medium term in other parts of the city (Tongi Khal). However, in several reaches dissolved oxygen levels will remain low or very low due to the lack of STP capacity, remaining misconnections of untreated sewage and large effluent loads. The proposed STPs, while certainly beneficial, will need to be upgraded in the future if the predicted rates of population growth are confirmed and industrial pollution is not significantly reduced alongside. Climate change is expected to have an impact on the Dhaka River System water quality, with increased monsoon flows and lower summer flows, but these changes will not greatly affect the extremes of water quality to any great extent due to the overwhelming impact of pollutant discharges into the system. Full article

As the human population continues to escalate, its requirement for clean water is also increasing. This has resulted in an increased dependency on wastewater effluent to maintain the base flow of urban streams, especially in water-stressed regions. The present study reports the synthesis of AgNPs with green credentials using an aqueous extract of Trigonella foenum-graecum seeds. The observance of surface plasmon resonance (SPR) with UV–Vis spectrophotometry confirmed the presence of spherical/oblong particles with a mean diameter of 43.8 nm and low polydispersity index (PDI) of 0.391 measured by transmission electron microscopy (TEM) and DLS (dynamic light scattering) technique, respectively. The elemental map of AgNPs was demonstrated with energy-dispersive spectroscopy (EDS) and the constituent functional groups were identified by the FTIR spectra, which were similar to the bulk seed extract with a slight shift in the pattern. The emission spectrum of nanoparticles was recorded for the excitation wavelength of 349 using fluorescence microscopy and the crystalline structure was assessed using X-ray diffraction. The potential wastewater remedial efficacy of the synthesized AgNPs was evaluated based on the water quality parameters (pH, EC, BOD, COD) of the sewage effluent collected from a local Sewage Treatment Plant (STP). Furthermore, the photo degradative efficacy was investigated using the degradation percentage of Crystal Violet (CV) dye, which was recorded as 94.5% after 20 min. In addition, the antimicrobial activity of the NPs versus bulk seed extract was assessed against two bacterial strains, Escheria coli and Staphylococcus aureus, using the disc diffusion method. The AgNPs showed a profound modulatory effect on the water quality parameters, coupled with marked antimicrobial and photodegradative activity. Thus, the biogenically synthesized AgNPs offer a prospective potential for use in wastewater remediation strategies. Full article

The treatment and reuse of wastewater for irrigation can lead to occupational health risks for sewage treatment plant (STP) workers and farmers. Sanitation Safety Planning (SSP) is an approach which can be used to measure and mitigate these risks. This paper explores what impact a novel secondary treatment process, consisting of an integrated permeate channel (IPC) membrane combined with a constructed wetland plus, has on the occupational health risks compared with the existing activated sludge wastewater treatment process and reuse system in Kanpur, Uttar Pradesh. A mixed methodology was used, which included key informant interviews, structured observations, and E. coli analysis. This data was used to undertake semi-quantitative risk assessments following the SSP approach. The novel secondary treatment increased the number of health risks which the STP workers were exposed to, but the severity of the risks was lower. This was due to the differences in treatment processes and infrastructures. The number of health risks for the farmers decreased both in number and severity. For their children, the severity of the health impacts decreased. These changes were due to the increase in the microbiological quality of the irrigation water. This study highlights the potential of using a semi-quantitative risk assessment to assess the occupational health impacts of using novel treatment technologies. Full article

A region’s population growth inevitably results in higher water consumption. This persistent rise in water use increases the region’s wastewater production. Consequently, due to this increase in wastewater (influent), Wastewater Treatment Plants (WWTPs) are required to run effectively in order to handle the huge demand for treated/processed water (effluent). Knowing in advance the influent and effluent parameters increases the operational efficiency and enables cost-effective utilization of diverse resources at wastewater treatment plants. This paper is based on a prediction/forecasting of an influent quality parameter, namely total MLD, as well as effluent quality parameters, namely MPN, BOD, DO, COD and pH for the real-time data collected pre-, during and post-COVID-19 at the Bharwara WWTP in Lucknow, India. It is the largest UASB-based wastewater treatment facility in Uttar Pradesh and the second largest in Asia. In this paper, we propose a novel model namely, wPred comprising extensions of SARIMA with seasonal order and ANN-based ML models to estimate the influent and effluent quality parameters, respectively, and compare it with the existing machine learning models. The lowest sMAPE error for the influent parameters using wPred is 2.59%. The findings of the paper show a strong correlation (R-value), up to 0.99, between the effluent parameters actually measured and predicted. As a result, the model designed in this paper has an acceptable level of accuracy and generalizability which efficiently predicts/forecasts the performance of Bharwara WWTP. Full article

The occurrence of Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA) in a sub-catchment of the Yodo River Basin, a representative water system of a drinking water source in Japan, was investigated. The chromogenic enzyme-substrate medium method was used for the detection of S. aureus and MRSA by the presence or absence of antimicrobials in the medium for viable bacteria in a culture-based setting. The contributions of S. aureus and MRSA from wastewater to the rivers were estimated based on mass flux-based analysis, and quantitative microbial risk assessment (QMRA) was further conducted for S. aureus and MRSA in river environments. The mean abundance of S. aureus and MRSA was 31 and 29 CFU/mL in hospital effluent, 124 and 117 CFU/mL in sewage treatment plant (STP) influent, 16 and 13 CFU/mL in STP effluent, and 8 and 9 CFU/mL in river water, respectively. Contribution of the pollution load derived from the target STP effluent to river water ranged from 2% to 25%. The QMRA showed that to achieve the established health benchmarks, the drinking water treatment process would need to yield 1.7 log₁₀ and 2.9 log₁₀ inactivation in terms of infection risk and disability-adjusted life year (DALY) indexes, respectively. These findings highlight the link between medical environment and the importance of environmental risk management for antimicrobial-resistant bacteria in aquatic environments. Full article

Three years of hourly COD and NH₄⁺-N measurements for two full-scale integrated constructed wetlands (CWs) treating secondary effluents from sewage treatment plants (STPs) were used to quantify the proper sampling frequency (SF). The modified coefficient of variation (CV_m) and average variation rate (VR_a) were calculated to monitor the dynamics and annual average performance, respectively. It was found that (1) under CV_m 5%, VR_a 5%, and VR_m 5%, the sampling intervals (SI) of COD can be set as 1.19 h, 526.5 h, and 110.1 h, respectively, and the SI of NH₄⁺-N should be 4.51 h, 66.3 h, and 26.8 h, respectively; (2) under CV_m 10%, VR_a 10%, and VR_m 10%, the monitoring intervals of COD can be set as 11.92 h, 1401.7 h, and 233.5 h, respectively, and the monitoring intervals of NH₄⁺-N should be 30.73 h, 139.3 h, and 50.5 h, respectively. Therefore, to meet the need of monitoring the dynamic changes in data, hourly and 4 h SIs were recommended for COD and NH₄⁺-N evaluation, respectively, when it is necessary to consider the operation and maintenance costs at the same time, 11 h and 30 h SIs were proper for COD and NH₄⁺-N evaluation, respectively. The methods proposed in this study could provide reference to improve the management and evaluation level of full-scale CWs. Full article

Inadequately treated effluents discharged from wastewater treatment plants (WWTPs) severely affect the environment and the surrounding population. This study analyzed the presence of the Shiga toxin-producing Escherichia coli (STEC) genes, stx1, and stx2, and the E. coli gene, sfmD, in municipal WWTP A (n = 11) and B (n = 11) where the reductions were also evaluated; hospitals (n = 17), sewage treatment plants (STPs) (n = 4) and non-functional WWTPs (not-working WWTPs) (n = 5) in the Kathmandu Valley, Nepal. The sfmD gene was detected in 100% of the samples in WWTPs, hospitals, and not-working WWTPs and 50% of STP samples. The highest detection of stx1 and stx2 was shown in the WWTP influents, followed by WWTP effluents, not-working WWTP wastewater, hospital wastewater, and STP wastewater. Log₁₀ reduction values of sfmD, stx1, and stx2 in WWTP A were 1.7 log₁₀, 1.7 log₁₀, 1.4 log₁₀, whereas those in WWTP B were 0.5 log₁₀, 0.6 log₁₀, 0.5 log₁₀, respectively, suggesting the ineffective treatment of STEC in the wastewater in the Kathmandu Valley. The high concentrations of the stx genes in the wastewaters suggest the increasing presence of aggressive STEC in the Kathmandu Valley, which should be a major public health concern. Full article

Antimicrobial resistance (AMR) circulates through humans, animals, and the environments, requiring a One Health approach. Recently, urban sewage has increasingly been suggested as a hotspot for AMR even in high-income countries (HICs), where the water sanitation and hygiene infrastructure are well-developed. To understand the current status of AMR in wastewater in a HIC, we reviewed the epidemiological studies on AMR in the sewage environment in Japan from the published literature. Our review showed that a wide variety of clinically important antibiotic-resistant bacteria (ARB), antibiotic resistance genes (ARGs), and antimicrobial residues are present in human wastewater in Japan. Their concentrations are lower than in low- and middle-income countries (LMICs) and are further reduced by sewage treatment plants (STPs) before discharge. Nevertheless, the remaining ARB and ARGs could be an important source of AMR contamination in river water. Furthermore, hospital effluence may be an important reservoir of clinically important ARB. The high concentration of antimicrobial agents commonly prescribed in Japan may contribute to the selection and dissemination of AMR within wastewater. Our review shows the importance of both monitoring for AMR and antimicrobials in human wastewater and efforts to reduce their contamination load in wastewater. Full article