Domestic Wastewater Treatment Plant Research Articles

Genomic profiling and characteristics of a C1 degrading heterotrophic fresh-water bacterium Paracoccus sp. strain DMF.

Paracoccus species are metabolically versatile gram-negative, aerobic facultative methylotrophic bacteria showing enormous promise for environmental and bioremediation studies. Here we report, the complete genome analysis of Paracoccus sp. strain DMF (P. DMF) that was isolated from a domestic wastewater treatment plant in Kanpur, India (26.4287°N, 80.3891°E) based on its ability to degrade a recalcitrant organic solvent N, N-dimethylformamide (DMF). The results reveal a genome size of 4,202,269 base pairs (bp) with a G + C content of 67.9%. The assembled genome comprises 4141 coding sequences (CDS), 46 RNA sequences, and 2 CRISPRs. Interestingly, catabolic operons related to the conventional marine-based methylated amines (MAs) degradation pathway were functionally annotated within the genome of an obligated aerobic heterotroph that is P. DMF. The genomic data-based characterization presented here for the novel heterotroph P. DMF aims to improve the understanding of the phenotypic gene products, enzymes, and pathways involved with greater emphasis on facultative methylotrophic motility-based latent pathogenicity.

Ozone micron bubble pretreatment for antibiotic resistance genes reduction in hospital wastewater treatment

Ozone micron bubble (OMB) treatment offers a promising approach to effectively eliminate Antibiotic Resistance Genes (ARGs) from infectious medical wastewater and mitigate the threat of drug resistance transmission. This study evaluated the effectiveness of OMB treatment for reducing ARGs from infectious medical wastewater in laboratory and on-site pilot treatment setups. In part, the presence of antibiotic residues in a hospital wastewater treatment plant (WWTP) and the impact of hospital wastewater on the distribution of ARGs in a wastewater collection system were also investigated. The results of wastewater collection system survey revealed a high prevalence of ARGs in the system, particularly mcr-1, largely originating from medical wastewater discharges. Furthermore, analysis of antibiotic residues in the hospital wastewater treatment system showed significant accumulation, particularly of quinolone antibiotics, in the biomass of the biological oxidation tank, suggesting a potential risk of ARG proliferation within the system. Comparison of wastewater samples from domestic and hospital WWTPs revealed a relatively higher abundance of ARGs in the latter, with differences ranging from 2.2 to sixfold between corresponding locations in the treatment plants. Notably, the biological oxidation unit of both WWTPs exhibited a greater proportion of ARGs among all sampled points, indicating the potential proliferation of ARGs within the biomass of the treatment units. ARG degradation experiments showed that OMB treatment resulted in a significantly lower CT value (9.3 mg O3 L−1 min) compared to ozone coarse bubble treatment (102 mg O3 L−1 min) under identical test conditions. Moreover, the use of OMB on site significantly reduced the accumulation of ARGs in hospital wastewater, underscoring its potential as an effective solution for mitigating ARG spread.

Dynamic-chance-constrained-based Fuzzy Programming Approach for Optimizing Wastewater Facultative Ponds for Multi-period Case

In this article, a novel optimization model that was specifically designed as a dynamic-chance-constrained fuzzy uncertain programming framework is introduced. This model serves the purpose of optimizing the efficiency of facultative ponds utilized in domestic wastewater treatment. The primary focus of this study was maximizing the amount of the wastewater treated in the facility subject to quality requirements via the assessment of wastewater quality through the measurement of Biological Oxygen Demand (BOD). The model's development was grounded in a real-world scenario, where decision-makers encountered uncertainties in various parameters, such as the rate of BOD degradation and the incoming wastewater load, both characterized by fuzzy membership functions. In light of this uncertainty, the decision-maker aimed to maximize the wastewater treatment capacity while maintaining a suitable safety margin for both objective and constraint functions, employing policies founded on probability and chance. A case study was carried out at the Bantul domestic wastewater treatment plant, situated in Yogyakarta, Indonesia. The study successfully identified optimal decisions regarding wastewater flow rates and processing times. As a result, it can be concluded that the proposed model effectively resolved the problem at hand, making it a valuable tool for decision-makers in similar contexts.

Carbon footprint of a conventional wastewater treatment plant: An analysis of water-energy nexus from life cycle perspective for emission reduction

Reducing greenhouse gas (GHG) emissions is of far-reaching implications for the sustainable development of a conventional domestic wastewater treatment plant (WWTP). GHG emissions of the WWTP in different working loads were monitored to quantify the influence of critical processes on GHG emissions and shed light on the relations between direct and indirect GHG emissions with the water-energy nexus. The life cycle carbon footprint of the WWTP was assessed to find the most critical impact factor. A conceptual model of direct and indirect GHG emissions was established based on the water-energy nexus and life cycle assessment (LCA). Results showed that direct GHG emissions were highest in medium working load in May. While high indirect GHG emissions were in February, with the highest working load. Methane (CH4) emission rates, from 44.39 ± 42.49 to 4.94 ± 2.29 kg CO2e·d−1, decreased along the treatment processes due to oxidation. Dissolved CH4 in wastewater mainly came from the influent that was 0.08 ± 0.04 kg CH4·d−1. The increase of nitrous oxide (N2O) emissions and dissolved N2O occurred in the secondary treatment stage and was affected by the C/N ratio. The operation and maintenance phase had the most significant carbon footprint due to 86.4% of indirect GHG emissions from electricity usage through LCA. Electricity usage and glucose dosing were significantly correlated with N2O emissions but had no contribution to CH4 emissions. The conceptual model qualitatively demonstrated that direct and indirect GHG emissions reduced as electricity usage decreased based on the water-energy nexus. This study provided new insight into the analysis of GHG emissions from WWTPs.

Comprehensive analysis of greenhouse gas emissions and emission factors in a Korean domestic wastewater treatment plant: Insights into mechanisms and pathways for climate change mitigation

This study aimed to estimate greenhouse gas (GHG) emissions from the Daejeon wastewater treatment plant (WWTP) in South Korea and identify strategies for reducing its carbon footprint. Both the worksheet-based Carbon Footprint Calculation Tool and the Massflow3 simulator were used to calculate the total GHG emissions from the “D” WWTP and identify the main sources of emissions. The results revealed that electricity consumption contributed to 45 − 48 % of emissions, while direct emissions from N2O accounted for 35–38 % of the total emissions. Furthermore, it was discovered that the WWTP's GHG emissions were 33–57 % higher compared to European sewage treatment plants that had established GHG reduction programs. To decrease the plant's carbon footprint, recommendations include optimizing nitrogen removal rates while minimizing incomplete nitrification and controlling the air flow rate in the aeration tank. Additionally, there is an emphasize on the importance of establishing a strategy to reduce indirect GHG emissions resulting from power consumption. These findings have important implications for the policy and management of WWTPs, highlighting the potential environmental and economic benefits of GHG emissions reduction.

Microplastics in the Syr Darya River Tributaries, Uzbekistan

The objective of the study was a pre-screening of the microplastic (MP) content in surface water and benthic sediments of Kara Darya and Chirchiq rivers, the first-order tributaries of the Syr Darya River (Uzbekistan). For the first time, surface water and benthic sediment samples were taken from this region, and quantitative screening of MPs 0.15–5.00 mm in size was performed. A combined visual and μRaman-based methodology was used to quantify and characterize artificial polymer microparticles from the surface water and bottom sediments of two rivers. The average abundance of MPs in the Kara Darya River and Chirchiq River waters was found to be 4.28 ± 0.09 and 0.95 ± 0.36 items per m3, and that in benthic sediments attained 244 ± 28.9 and 333 ± 11.5 items per kg of dry soil, respectively. MP concentration in surface water and benthic sediments of the Kara Darya River significantly exceeded (p-value < 0.01) that in the Chirchiq River. Microfibers were most abundant; the proportion of MP fibers in the water of the Kara Darya and Chirchiq rivers amounted to 89 and 95%, respectively, and that in benthic sediments of the rivers was 86 and 84%, respectively. The dominance of microfibers may indicate the route of entry to the rivers through domestic wastewater treatment plant discharges. The polymer microparticles in the surface water and benthic sediments of the Kara Darya and Chirchiq rivers were mainly represented by polyethylenterephtalate (PET), which accounted for half of all MPs detected in the Kara Darya River. Microparticles of textile origin were particularly abundant in the Kara Darya River, where viscose and nylon fibers were also found, which suggests the leading role of synthetic textiles in the pollution. The reported data are the first experimental evidence of MP pollution of the Syr Darya tributaries, but the distribution and circulation of MPs in surface water in Central Asia requires further comprehensive studies.

Helicobacter pylori virulence genotypes in Bogotá River and wastewater treatment plants in Colombia.

Helicobacter pylori is a bacterium that infects 70%-80% of the population in Colombia, causing chronic gastritis in all those infected and gastric cancer in 1%-2% of those infected. In Colombia, some studies have identified the presence of vacA and cagA genes in environmental samples such as treated, surface, and wastewater, but they have not been evaluated in the Bogotá River. For this, the aim of this study was to identify the virulence genotypes of H. pylori present in samples from the Bogotá River and domestic wastewater treatment plants (WWTPs). A total of 75 water samples (51 from the Bogotá River and 24 from wastewater treatment plants) were collected. The presence of H. pylori DNA and its virulence genotypes was determined by polymerase chain reaction (PCR). The presence of H. pylori DNA was demonstrated in 44% (33/75) of the samples, obtaining 63.6% (21/33) from the Bogotá River and 36.4% (12/33) from the WWTPs. The most prevalent H. pylori genotype was cagA (-) and vacAm1/s1/i1 being the most virulent of the vacA gene. This is the first study in Colombia that determines the cagA and vacA genotypes in surface water and WWTPs, indicating the circulation of virulent genotypes in the population. The presence of this pathogen in the waters can be represent a risk to the health of the surrounding population since these waters are reused by the communities for different purposes.

Assessment of the Role of Photovoltaic Systems in Reducing the Carbon Footprint of Wastewater Treatment Plants

<p>Wastewater treatment plants (WWTPs) consume large amounts of energy and thus cause an increase in carbon footprint. For this reason, it has become important not only to meet the discharge criteria in treatment plants, but also to reduce the carbon footprint resulting from treatment processes and energy use. In this study, the effect of supplying the energy required by a real domestic biological wastewater treatment plant from a photovoltaic (PV) system on the reduction of its carbon footprint was investigated. For this purpose, the annual energy consumption profile of the plant was prepared, and direct emissions from treatment processes and indirect emissions from electricity consumption were calculated for 2020 and 2021. Indirect emissions contribute 54% and 69% to the total carbon footprint of the plant for 2020 and 2021, respectively, while direct emissions contribute 46% and 31%. With the partial transition of the plant to a PV system in 2021, annual electricity consumption decreased by 401,000 kWh/year and the carbon footprint decreased by 21% to 819 tCO2e. In this way, the plant also achieved 40% economic savings. If the plant meets all the energy it needs from the PV system, it will reduce its carbon footprint by 45%.</p>

Vertical Flow Constructed Wetland Design for Domestic Wastewater Treatment for Communal Scale in DKI Jakarta Environmental Service Dormitory

To better manage Jakarta's domestic wastewater, the DKI Jakarta Provincial Government commissioned the construction of Domestic Wastewater Treatment Plants (WWTP) in multiple locations across the city. After the results of the measurements have been determined, engineering work needs to order to address the numerous parameters more than excesses of the quality in addition, there. This study intends to develop a vertical flow CW design as an additional treatment for the DKI Jakarta Environmental Service Dormitory Communal Domestic WWTP as a recommendation for improvement so that the quality of treated water can meet domestic wastewater quality standards. This study aims to ensure that the quality of treated water can meet domestic wastewater quality standards. This redesign makes use of a variety of data sources, including primary data as well as secondary data. The necessary information is the quantity of constable water consumption and the quality of the domestic wastewater produced within the environment of the DKI Jakarta DLH Dormitory. Through a network of pipelines, wastewater from activities such as bathing and using the latrines is transported directly to the WWTP. During this time, water from activities such as washing and runoff caused by rain will enter various drainage channels to the receiving water body, the Ciliwung River. The length of the CW at WWTP 1 is 6.718 meters, and its width is 3.35 meters. Following more in-depth processing of the available data, it was discovered that the existing outlet wastewater had a low C/N ratio. When creating wetlands in the field using artificial CW, the discharge that flows into the wetland and the release that flows out of the wetland is not the same. The amount can either be decreased or increased according to the current circumstances. This needs to be considered for the presence of water in the swamp system to be managed. After being processed with VFCW, it was discovered that the total BOD value of the effluent produced was less than 30 mg/L. This suggests that the processing of VFCW can conform to the requirements of PermenLHK No. 68/2016, which is concerned with the Quality Standards for Domestic Wastewater. The ammonium-nitrogen value by comparing the molar mass value to NH3. As a result, WWTP locations 1, 2, and 3 have all achieved the required quality. The NH4 value, on the other hand, has not been able to meet the quality standard of PermenLHK No. 68/2016 concerning Domestic Wastewater Quality Standards. This is because the ammonia concentration from Domestic Communal WWTP 4 is so high. As a solution to this problem, WWTP 4 will be upgraded from four plants per square meter (ppm) to five plants per sq m (ppm), hoping to improve the rate at which plants absorb nutrients. The removal of ammonia using VFCW can range anywhere from 34 - 95 percent. Keywords: Domestic Wastewater, Planning, Constructed Wetland, WWTP

Comparative Analysis of Greenhouse Gas Emissions from Domestic Wastewater Treatment Processes by Modeling: Existing Estimation Methods vs Modeling

This study examined the existing methodologies and the applicability of process modeling concerning the estimation of nitrous oxide (N<sub>2</sub>O) emissions from wastewater treatment processes. The method of extimating N<sub>2</sub>O emissions from wastewater occurring during biological nitrification and denitrification processes can be divided into those before and after legal nitrogen effluent quality enhancement for domestic wastewater treatment plant. Initial IPCC guidelines such as IPCC 1996 GL, GPG 2000, and IPCC 2006 GL, provided methods for estimating N<sub>2</sub>O emissions throughout domestic wastewater, while the revised version, IPCC 2019 RF, proposed methods for estimating each N<sub>2</sub>O emission by distinguishing wastewater treatment and effluent after the advancement of wastewater treatment plants. The National Greenhouse Gas Inventory Report (NIR) in Korea adopted the methodology of GPG 2000, and the Emissions Trading System (ETS) applies the estimation method of IPCC 2006 GL in the wastewater treatment plants. This study utilized process modeling to consider the process characteristics and operating conditions of wastewater treatment plants. IPCC, NIR, and ETS estimate N<sub>2</sub>O emissions based on nitrogen behavior activity data and emissions factors. On the other hand, process modeling estimates N<sub>2</sub>O emissions in each unit process of the wastewater treatment plant using a 4-step AOB nitrification/4-step denitrification model and a liquid/gas transfer model. The estimation results of N<sub>2</sub>O emissions from modeling method were compared with the estimation results of IPCC, NIR, and ETS to analyze the suitability of the estimation method. Through this, it was evaluated how appropriate process modeling is for estimating N<sub>2</sub>O emissions in domestic wastewater treatment plants.

Van İli Evsel Atıksu Arıtma Tesislerindeki Atıksu Karakteristiğinin ve Çıkış Suyu Kalitesinin Değerlendirilmesi: Edremit ve Gevaş Örneği

Bu çalışmada, Van ilinde bulunan Edremit ve Gevaş Atıksu Arıtma Tesisleri atıksu karakteristiğinin mevsimsel olarak değişimi incelenmiştir. Bu amaçla atıksu karakterizasyonunu incelemek için arıtma tesislerinin giriş ve çıkışlarından 2021 yılı ocak ve temmuz aylarında numuneler alınmıştır ve bu numunelerde pH, alkalinite, sülfat, askıda katı madde, toplam katı madde, toplam uçucu katı madde, çözünmüş oksijen, biyokimyasal oksijen ihtiyacı, kimyasal oksijen ihtiyacı, iletkenlik, sıcaklık, toplam azot, toplam fosfor ve yağ-gres gibi parametreler ölçülmüştür. Gevaş atıksu arıtma tesisinin kimyasal oksijen ihtiyacı için ortalama giderim verimi %83, Edremit atıksu arıtma tesisi için ise yaklaşık %80, Gevaş atıksu arıtma tesisinin biyokimyasal oksijen ihtiyacı için ortalama giderim verimi %92, Edremit atıksu arıtma tesisi için ise yaklaşık %86 olarak bulunmuştur. Askıda katı madde giderim verimi Gevaş atıksu arıtma tesisi için yağışlı ve kurak dönem için sırasıyla; %88, %98 iken Edremit atıksu arıtma tesisi için ise %90 ve %84 olmuştur. Her iki arıtma tesisinde arıtma işleminden sonra deşarj edilen atıksuyun birçok parametre için Su Kirliliği Kontrol Yönetmeliği’ne uygun olduğu söylenebilir. Bu çalışmada elde edilen sonuçların, diğer atıksu arıtma tesisleri için yol gösterici olacağı kanısındayız ve ayrıca standartlara uymayan parametrelere dikkat edilmesinin zaruri bir durum olduğu raporlanmıştır.

Energy Recovery from Biogas in Domestic Waste Water Treatment Plant in the Last 5 Decades: A Bibliometric Analysis

Energy Recovery from Biogas in Domestic Waste Water Treatment Plant in the Last 5 Decades: A Bibliometric Analysis

ANALISIS MULTI KRITERIA DALAM PEMILIHAN UNIT BIOLOGIS DI IPAL TUNGGAKJATI, KARAWANG

This study aims to design a domestic wastewater treatment plant for the West Karawang and East Karawang Sub-districts in Karawang Regency, where each sub-district has an area of 13.368 Ha and 2.977 Ha. In 2041, the Tunggakjati WWTP will have a capacity of 48,000 m3/day to serve a population of 404,568 people. The WWTP performance is designed so that the effluent complies with the Regulation of the Minister of Environment and Forestry No. 68 of 2016 concerning Domestic Wastewater Quality Standards for its BOD, COD, and TSS parameter. The biological treatment design consists of three (3) alternatives namely Oxidation Ditch, Complete Mixed Activated Sludge, and Aerated Lagoon, selected based on multi criteria with three (3) aspects, namely economic, environmental and technical aspects consisting of technological considerations, land availability and human resources to operate the technology. The selected biological treatment unit alternative is Aerated Lagoon, because it has high efficiency, human resources for operating the technology are already available, and ease of development. Based on multi criteria analysis all the alternative has high eligibility level to be chosen as technology for domestic waste water treatment. Alternative III, the Aerated Lagoon is the best alternative with the highest score of 60 compared to other alternatives, alternative I is 52.5 and alternative II is 57.5. That concludes the processing units on processing units at the Tunggakjati WWTP consist of collection wells, bar screens, grit chambers, equalization tanks, aerated lagoons, maturation ponds, and sludge drying beds.

Life Cycle Assessment of a Domestic Wastewater Treatment Plant Simulated with Alternative Operational Designs

Life cycle assessment (LCA) is a powerful tool to evaluate the environmental impacts of domestic wastewater treatment plant (WWTP) operations. It involves a thorough evaluation of the main characteristics or components of the environment, human health, and resources. However, the literature to date is still lacking analysis on the widely varied designs and operational conditions of full-scale WWTPs. The aim here was to integrate analyses such as LCA, greenhouse gas (GHG) emissions, and energy consumption, when considering the environmental impacts of a full-scale WWTP, which can provide practical outputs to aid decision-making on optimum designs and operational conditions. The Russtmiya domestic WWTP, located in Iraq, was considered as the case study. Three operational alternatives were proposed as solutions to improve the WWTP’s performance, as follows: (1) conventional activated sludge with sand filter (CAS), (2) conventional activated sludge with sand filter and nitrogen removal (CAS-N), and (3) membrane bioreactor (MBR). The operation of such alternatives was investigated through modeling and simulation using GPS-X 8.0.1 software. The energy consumption of each alternative was estimated via GPS-X, while the GHG emissions were estimated using three different methods according to the intergovernmental panel on climate change (IPCC), the United States Environmental Protection Agency (USEPA), and GPS-X software. The OpenLCA software (1.10.3) was used to measure all impact categories at both the midpoint and endpoint levels using various methods. As a conclusion, comparing the three proposed alternatives indicated that: (1) the MBR alternative provided the lowest energy consumption and moderate GHG emissions, and (2) the CAS alternative provided the best environmental performance, particularly in aspects such as ozone depletion, global warming, and climate change, where the lowest GHGs emission values had the major contribution.

Health risk assessment of metal(loid)s for land application of domestic sewage sludge in city of Bursa, Türkiye.

This study aims to determine the potential health risks (Carcinogenic and non-carcinogenic) of metal(loid)s in sewage sludge samples for agricultural purposes. For this purpose, sewage sludge was collected annually from a domestic wastewater treatment plant, and metal(loid)s were determined by ICP-MS. Metal(loid)s concentration in sludge samples was within the legal standards. No statically significant seasonal variation of metal(loid)s were observed. The total cancer risk and the hazard index (HI) of metal(loid)s through ingestion, dermal, and inhalation exposure from sewage sludge samples were estimated. The main risk contributor to metal(loid)s were Pb, Zn, and Ni. The average HI values were 0.75 (child) and 0.09 (adult). The total carcinogenic risk (TCR) for child and adult was found to be 3.43 × 10-5 and 2.31 × 10-5, respectively. EPA risk assessment model and Monte Carlo Simulation were used to estimate probability and sensitivity distributions for carcinogenic and non-carcinogenic risks. Sensitivity analysis showed that metal(loid)s concentration, exposure duration, exposure frequency, and body weight significantly affect total health risk. The sewage sludge can be applied safely in agriculture due to no important carcinogenic and non-carcinogenic risk for child and adult.

RECYCLING DOMESTIC SEWAGE SLUDGE TO AGRICULTURAL AND FARMING AREAS IN LINE WITH SUSTAINABLE DEVELOPMENT GOALS (SDG)

Corresponding to the rapid increase in population, the increase in the number of domestic wastewater treatment plants, as well as the increase in domestic sludge levels above acceptable levels, pave the way to utilize sewage sludge in a variety of different applications and usage areas. Using sewage sludge in agriculture, landscape plant cultivation, and other agricultural areas has a number of advantages, including the ability to make rational use of waste without damaging the environment as well as delivering fertilizer benefits to the plant due to the high organic matter content of the wastewater sludge. Aside from these advantages, the most serious drawbacks of waste sewage are pathogenic bacteria, heavy metal contamination, and the presence of potentially hazardous compounds. The use of existing waste in the soil in appropriate proportions and in methods that are compatible with ecological life, on the other hand, will contribute to the fertilization of agricultural areas, providing an alternative to the fertilizer industry. The Sustainable Development Goals (SDGs), also known as the Global Goals, are a global call to action to end poverty, safeguard the environment, and guarantee that everyone lives in peace and prosperity. It is expected that this research will help to promote awareness about the reuse of waste within the context of a sustainable environment, as well as shed light on the application of sewage sludge to agricultural fields in accordance with the Sustainable Development Goals. Furthermore, the support for sewage sludge recycling in agricultural regions for long-term development goals is shown.

Seasonal monitoring of microbial activity using conventional approaches in a full-scale urban biological wastewater treatment plant.

Activated sludge processes contain various groups of microorganisms with different metabolic properties, which are responsible for contaminants removal. Therefore, it is important to elucidate the general structure and functional properties of biomass in activated sludge processes. For this purpose, a full-scale domestic biological wastewater treatment plant in Tunceli (Turkey), Tunceli WWTP (wastewater treatment plant), was monitored to observe seasonal variations in process performance and biomass properties for a year. It was observed that nitrifying bacteria developed abundantly in the rainy and cool spring season as they were suppressed in summer because their large losses took place due to an environment containing high alkalinity values. In September, aerobic heterotrophic, nitrify, denitrify, and anaerobic activities increased. It can be said that the biomass contained young and mature microorganism in this environment in which the sludge volume index (SVI) value increased to 196mL/g. As a result of the improvement in the structural and functional properties of biomass, the nitrogen removal efficiency reached 99%. Throughout the whole study, the structural improvement observed in biomass was reflected in its removal activity. The amount of biomass and removal activity decreased with the abundance of organic matter in the influent at the period in which biomass was closer to being categorized in the aged sludge class. The results showed that as the lowest mixed liquid suspended solids (MLSS) and mixed liquid volatile suspended solids (MLVSS) values of the year were 530 and 400mg/L, respectively, in November 2017, MLSS and MLVSS values reached the highest amount (1700 and 1400mg/L, respectively) in December 2017 when aerobic heterotrophic activity accelerated with a decrease in organic matter level.

Evidence of Bacterial Community Coalescence between Freshwater and Discharged tpm-Harboring Bacterial Taxa from Hospital and Domestic Wastewater Treatment Plants among Epilithic Biofilms.

The ability of WWTP outflow bacteria at colonizing rock surfaces and contributing to the formation of river epilithic biofilms was investigated. Bacterial community structures of biofilms (b-) developing on rocks exposed to treated wastewaters (TWW) of a hospital (HTWW) and a domestic (DTWW) clarifier, and to surface waters of the stream located at 10 m, 500 m, and 8 km from the WWTP outlet, were compared. Biofilm bacterial contents were analyzed by cultural approaches and a tpm-based DNA metabarcoding analytical scheme. Co-occurrence distribution pattern analyses between bacterial datasets and eighteen monitored pharmaceuticals were performed. Higher concentrations of iohexol, ranitidine, levofloxacin, and roxithromycin were observed in the b-HTWW while atenolol, diclofenac, propranolol, and trimethoprim were higher in the b-DTWW. MPN growth assays showed recurrent occurrences of Pseudomonas aeruginosa and Aeromonas caviae among these biofilms. An enrichment of multi-resistant P. aeruginosa cells was observed in the hospital sewer line. P. aeruginosa MPN values were negatively correlated to roxithromycin concentrations. The tpm DNA metabarcoding analyses confirmed these trends and allowed an additional tracking of more than 90 species from 24 genera. Among the recorded 3082 tpm ASV (amplicon sequence variants), 41% were allocated to the Pseudomonas. Significant differences through ANOSIM and DESeq2 statistical tests were observed between ASV recovered from b-HTWW, b-DTWW, and epilithic river biofilms. More than 500 ASV were found restricted to a single sewer line such as those allocated to Aeromonas popoffii and Stenotrophomonas humi being strictly found in the b-HTWW file. Several significant correlations between tpm ASV counts per species and pharmaceutical concentrations in biofilms were recorded such as those of Lamprocystis purpurea being positively correlated with trimethoprim concentrations. A tpm source tracking analysis showed the b-DTWW and b-HTWW tpm ASV to have contributed, respectively, at up to 35% and 2.5% of the epilithic river biofilm tpm-taxa recovered downstream from the WWTP outlet. Higher contributions of TWW taxa among epilithic biofilms were recorded closer to the WWTP outlet. These analyses demonstrated a coalescence of WWTP sewer communities with river freshwater taxa among epilithic biofilms developing downstream of a WWTP outlet.

Mitigation of Antimicrobial Resistance during Wastewater Treatment by Membrane Technologies

The threat of antimicrobial resistance (AMR) to human health is predicted to become a significant infectious disease. Domestic sewage and wastewater treatment plants (WWTPs) are critical hotspots for controlling the spread of antibiotic resistant bacteria (ARB) and antimicrobial resistance genes (ARGs) in the environment. A wastewater treatment system is not necessarily designed to mitigate AMR problems in wastewater. Furthermore, the presence of ARB and ARGs for a long time in WWTPs is reported as a reservoir of intracellular and extracellular ARG through horizontal gene transfer. Based on the studies, the additional membrane filtration with either microfiltration (MF) or ultrafiltration (UF) can reduce ARB and ARGs effectively through the separation mechanism. However, there are still inconclusive results when comparing ARG removal efficiencies between MBR and conventional processes. Further studies are required to clarify the effect of water qualities and membrane fouling conditions on ARG removal.

The combined effect of three floating macrophytes in domestic wastewater treatment

We conducted this study to assess the efficiency of the combination of three floating macrophytes (Eichhornia crassipes (water hyacinth), Pistia stratiotes L. (water lettuce), and Lemna minor L. (duckweed)) for the treatment of domestic wastewater. The experiments were performed on a pilot scale consisting of four basins aligned in series: one anaerobic pond, two facultative ponds (containing water hyacinth and water lettuce respectively), and one maturation pond (containing duckweed). The study showed that combining the different macrophytes studied led to significantly reduced pollution in domestic wastewater. Based on inlet pollution loads, water hyacinth pond better eliminate carbon pollution. The water lettuce pond was good at removing nitrogen pollution, and the duckweed pond better-eliminated phosphorus. The overall yield for TSS, COD, BOD5, TKN, and PO43− was 92%, 98%, 98%, 87%, and 80% respectively. Based on the results, combining different floating macrophytes in a domestic wastewater treatment plant could improve its overall treatment performance.