Aeration Tank Research Articles

Bioaerosol emission and exposure risk from a wastewater treatment plant in winter and spring

The potential health risks posed by bioaerosols containing pathogens originating from wastewater treatment plants (WWTPs) have gaining intensive attention. This study designated sampling locations within a WWTP situated in Xi'an, a major city in northwest China. The airborne bacterial concentration, taxonomic composition, and the associated health risks were analyzed in the aeration tanks with bottom microporous aeration system. The Anaerobic-Anoxic-Oxic (AAO) tank emitted significantly higher culturable bacteria (1.58×104 CFU m−3 in spring, 6.69×103 CFU m−3 in winter) compared to Double-ditch (DE) oxidation ditch and aerated grit chamber (AGC) chamber, aligning with 16S rDNA quantification results. The bacterial concentrations are higher in spring than that in winter, with the AAO tank posing the highest exposure risk during the spring season. The dominant genera in the air samples include Cutibacterium, Lawsonella, Acinetobacter, Pseudomonas, and Aeromonas. Among the identified genus, 139 bacterial genera were identified as potential human pathogens like Neisseria, Moraxella, Haemophilus, Escherichia-Shigella and Streptococcus. These pathogens further elevate exposure risks from WWTP bioaerosols. This study provides relevant information on the seasonal health risk variations tied to bioaerosol emissions from diverse aeration tanks with bottom microporous aeration system in the mega city of northwest China, emphasizing the imperative to enhance the management and control measures for bioaerosols originating from the AAO tank.

Antibiotic resistance and resistome risks of inhalable bioaerosols at aeration tank of a full-scale wastewater treatment plant

Antibiotic resistome could be aerosolized under wastewater aeration processes, however, their seasonal variation, mobility, hosts, aerosolization behavior, and risk, are largely unknown. Herein, the antibiotic resistant pollution associated with fine particulate matter (PM2.5) from the actual aeration tank (AerT), was analyzed using metagenomic assembly. The antibiotic resistance of AerT-PM2.5 was characterized by significant seasonality. Antibiotic resistance genes (ARGs) in AerT-PM2.5, exhibited higher enrichment and mobility and were harbored more by pathogens than those in upwind-PM2.5, regardless of sampling season. Mobile ARGs were mainly flanked by transposase. Totally, 18 pathogenic antibiotic-resistant bacteria (PARB) carried more than one ARG, including 9 PARB with multiple ARG types. Although wastewater exerted a dominant source contribution for the airborne ARGs (47.31–55.56 %) and PARB (46.18–64.32 %), aeration endowed differential aerosolization capacity for various ARGs and PARB from wastewater. Airborne antibiotic resistome was mainly determined by bacterial community and indirectly influenced by meteorological conditions (i.e., relative humidity). Higher PM2.5-borne resistome risk was observed in AerT than upwind, and the most serious resistome risk of AerT-PM2.5 was found in winter. This study emphasizes the importance of wastewater aeration processes in emission of airborne antibiotic resistome and offers referenced information for mitigating air pollution in wastewater treatment plants.

Effects of Pulse Electromagnetic Field on Wastewater in Treatment Plants

The influence of a pulsed electromagnetic field (PEMF) with a pulse repetition rate of 16 Hz and a magnetic induction of no more than 500 nT on the solubility of oxygen in water and on wastewater treatment in two operating treatment plants was studied. It has been shown that treating wastewater with these pulses increases the maximum solubility of oxygen in water approximately by 30%, from 5.1 mg/dm3 to 6.8 mg/dm3 and accelerates all wastewater treatment processes by 10–20% and thereby creates a productivity reserve of the wastewater treatment plants. It was concluded that when operating blowers controlled by oxygen sensors, which turn on at an oxygen concentration of about 2 mg/dm3 and turn off at 4 mg/dm3, water PEMF treatment in the aeration tank leads to a reduction in the operating time of the blowers and, accordingly, energy savings by 15–28 %.

Performance of Dairy Factory Wastewater Treatment Plant (Case Study of Pasuruan Dairy Factory East Java)

The 'ILP' company produces bottled milk with chocolate, melon, strawberry, and vanilla flavors in colorless HDPE (High-Density Polyethylene) plastic bottles and aluminum foil covers. The 'ILP' dairy industry wastewater treatment process stages include bar screen, grease trap, equalization tank, flocculation-coagulation, primary clarifier, aeration tank/activated sludge, and secondary clarifier. The research aims to determine the performance of the dairy factory's WWTP (Wastewater Treatment Plant) in terms of TSS (Total Suspended Solids) and COD (Chemical Oxygen Demand) parameters. This field-scale research was carried out for approximately 5 weeks (35 days) at the wastewater treatment plant of the ILP company. Wastewater sampling is carried out at the inlet point, equalization tank, primary sedimentation, aeration tank, and outlet point of WWTP. Wastewater examination conducted in the company's internal laboratory, including temperature, pH, total suspended solids (TSS), and chemical oxygen demand (COD). The dairy factory WWTP (wastewater treatment plant) can generate TSS (total suspended solids) effluent of 22 mg/L and COD (chemical oxygen demand) of 26.8 mg/L to meet the applicable wastewater quality standards. The treatment efficiency of the dairy industry WWTP for TSS is 94.7% and COD is 98.1%.

Enhancing energy and nitrogen removal efficiency through automatic split injection and innovative aeration device: A study of low C/N ratio environments

A new aeration device based on Bernoulli's principle, Jetventrumixer (JVM), was introduced into an aeration tank in denitrification process, which involved an automatic split injection system (ASIS) into two denitrification tanks every 10 minutes. Real-time monitoring of influent water allowed the calculation of the C/N ratio, enhancing the utilization efficiency of internal carbon sources while reducing the need for external carbon. The comparison of the JVM with the conventional air diffuser for 100 days operation showed that the removal efficiency for NH4+-N in both systems was approximately 98 %, but the nitrification efficiencies were 84 % and 80 %, respectively. This indicates that the JVM achieves an high enough removal efficiency and nitrification efficiency compared with conventional air diffuser system with dramatic reduction in energy consumption by 52.1 %. When the influent wastewater was split and injected into duplicate denitrification tanks at ratios of 3:7, 5:5, and 7:3, the total nitrogen (TN) removal efficiencies were 77 %, 73 %, and 72 %, respectively. In contrast, with the implementation of the ASIS, the TN removal efficiency increased up to 82 %. The increase in TN removal indicates that real-time monitoring could stably track changes chemical composition in wastewater influent over 24 h and introducing ASIS facilitate the efficient utilization of internal carbon sources, thereby enhancing denitrification efficiency and improving TN removal efficiency. Finally, the greenhouse gas (GHG) emissions from the JVM and air diffuser were 9.39401 and 19.60488 tCO2eq year-1, respectively, representing a 52% reduction. Therefore, JVM and ASIS successfully reduced energy consumption and enhanced both nitrification and denitrification efficiencies.

Performance Evaluation of Advanced Wastewater Treatment Technologies in Herbal Processing and Extraction Industry

"Due to enormous quantities with hazards and complexity in nature is a big challenge for effective treatment of wastewater from pharmaceutical processes including herbal extraction through conventional methods of distillation. The situation is further aggravated in countries facing high rising population, urbanization, and industrialization resulting in the generation of industrial wastes. The study has been carried out in the herbal extraction industry by conducting stage-wise sampling of ETP based on the conventional method and further coupled with ozonation as an advanced treatment to comply with regulatory standards. Additionally, the same process was studied that implementing the best available technology (BAT) by providing ETP with advanced technology modules such as MBR (membrane bioreactor) + RO + O3 has not only resulted in compliance with standards but also reuse of treated wastewater into the process and utilities has been proved to be techno-economically a viable and sustainable option. Modifying existing aeration tanks and advanced oxidation through ozone injection post-biological treatment has resulted in COD and BOD reduction of 96.42% and 99.0% respectively. Whereas in the case of MBR + RO + O3, the values of pH, BOD, COD, TSS, and sulfide have been observed as 8.32, 2.0 mg.L-1, 14.0 mg.L-1, 1.0 mg.L-1 and 0.0 mg.L-1 respectively and 98% recovery of treated effluent, thus saving 44 KL.day-1 of freshwater resulting into significant financial benefits of Rupees 12.59 acs annually, which otherwise was outsourced through tankers."

Anaerobic fermentation for hydrogen production and tetracycline degradation: Biodegradation mechanism and microbial community succession

The misuse and continues discharge of antibiotics can cause serious pollution, which is urgent to take steps to remit the environment pollution. In this study, anaerobic bacteria isolated from the aeration tank of a local sewage treatment plant were employed to investigate hydrogen production and tetracycline (TC) degradation during anaerobic fermentation. Results indicate that low concentrations of TC enhanced hydrogen production, increasing from 366 mL to a maximum of 480 mL. This increase is attributed to stimulated hydrolysis and acidogenesis, coupled with significant inhibition of homoacetogenesis. Furthermore, the removal of TC, facilitated by adsorption and biodegradation, exceeded 90 %. During the fermentation process, twenty-one by-products were identified, leading to the proposal of four potential degradation pathways. Analysis of the microbial community revealed shifts in diversity and a decrease in the abundance of hydrogen-producing bacteria, whereas bacteria harboring tetracycline resistance genes became more prevalent. This study provides a possibility to treat tetracycline-contaminated wastewater and to produce clean energy simultaneously by anaerobic fermentation.

Pengukuran Kinerja Mesin Sewage Treatment Plant (STP) menggunakan Metode Overall Equipment Efeectiveness

One of the important things in supporting the operational management of the building which is part of the building's mechanical and electrical aspects is the building's domestic liquid waste management system. The availability of liquid waste production cannot be separated from the performance of the Sewage Treatment Plan (STP) machine as a work tool that produces domestic liquid waste production in HDI Hive Menteng Building. STP machine maintenance is one of the important factors in ensuring the quality of liquid waste production in accordance with the Environmental Service (DLH) quality standards. The machine maintenance system can be used as a benchmark for measuring the effectiveness of STP machines. Machine performance with a high rhythm without stopping 24 hours which continues to increase and is comparable to the tenant accoupancy level, of course requires anticipatory action for machine breakdown problems. Overall Equipment Effectiveness (OEE) is a method used to measure and maximize machine effectiveness based on three categories, namely Availability rate, Performance rate, Quality rate. From the results of calculating the OEE value for the STP machine at PT. Gaia Care International) of 82.96%, in general the OEE value is still below the JIPM standard value, namely greater than 85%. For this reason, in this research, an analysis was carried out using a fishbone diagram, which is used to determine the causes and effects of not achieving the effectiveness of the STP machine. Based on the results of the Fish Bone Diagram analysis with several factors including; Machines, methods, people and materials can be concluded as factors that cause a decrease in the OEE value of STP machines, namely rework losses which are quite high so that they affect the Quality OEE value in STP machine measurements. The proposal given to increase the effectiveness of the STP Machine for controlling Rework Losses is to improve the general cleaning routine and increase the Backwash Pump Capacity in the aeration tank and Inlet.

Metatranscriptomic Analysis Reveals Synergistic Activities of Comammox and Anammox Bacteria in Full-Scale Attached Growth Nitrogen Removal System.

Leveraging comammox Nitrospira and anammox bacteria for shortcut nitrogen removal can drastically lower the carbon footprint of wastewater treatment facilities by decreasing aeration energy, carbon, alkalinity, and tank volume requirements while also potentially reducing nitrous oxide emissions. However, their co-occurrence as dominant nitrifying bacteria is rarely reported in full-scale wastewater treatment. As a result, there is a poor understanding of how operational parameters, in particular, dissolved oxygen, impact their activity and synergistic behavior. Here, we report the impact of dissolved oxygen concentration (DO = 2, 4, 6 mg/L) on the microbial community's transcriptomic expression in a full-scale integrated fixed film activated sludge (IFAS) municipal wastewater treatment facility where nitrogen removal is predominantly performed by comammox Nitrospira and anammox bacterial populations. 16S rRNA transcript compositions revealed anammox bacteria and Nitrospira were significantly more active in IFAS biofilms compared to suspended sludge biomass. In IFAS biofilms, anammox bacteria significantly increased hzo expression at lower dissolved oxygen concentrations and this increase was highly correlated with the amoA expression levels of comammox bacteria. Interestingly, the genes involved in nitrite oxidation by comammox bacteria were significantly more upregulated, relative to the genes involved in ammonia oxidation with decreasing dissolved oxygen concentrations. Ultimately, our findings suggest that comammox Nitrospira supplies anammox bacteria with nitrite via ammonia oxidation and that this synergistic behavior is dependent on dissolved oxygen concentrations.

Bioaerosols emission from source facilities in a wastewater treatment plant: Critical exposure time and sensitivity analysis

Overexposure of sewage workers to bioaerosol released from wastewater treatment plants (WWTPs) can cause serious infections, but practical method for controlling their health risk is lacking. In this study, reverse quantitative microbial risk assessment was used to estimate the daily critical exposure time (CET) of sewage workers exposing to Staphylococcus aureus bioaerosol emitted by three emission sources facilities in a WWTP based on either U.S. EPA or WHO benchmark, and sensitivity analysis was conducted to analyze the influence of various parameters on the outcomes of CET. The results showed that the CET of females was always 1.12–1.29 times that of males. In addition, the CET after wearing face masks was 28.28–52.37 times as long as before. The working time can be determined based on the CET results of male workers wearing face masks exposed to the inverted-umbrella aeration tank (14.73–550.98 min for U.S. EPA benchmark and 55.07–1972.24 min for WHO benchmark). In each scenario, the variable parameter exposure concentration (ec) always showed the most influence on the CET results. After wearing the face masks, the removal fraction by employing face masks also had a significant effect on the results, only second to ec. Therefore, the wearing of face mask is the most convenient and effective measure to prolong the CET. Furthermore, practical methods to reducing bioaerosol concentration in WWTPs exposure are also necessary to extend CET and safeguard worker health. This study enriches the application range of reverse quantitative microbial risk assessment framework and provides theoretical support for stakeholders to establish reasonable working time threshold guidelines, and practical method and novel perspective to protect the on-site health risks of sewage workers exposing to various facilities.

Study of Eco-Enzyme Application in Reducing Nitrite Concentration and Ph Value in Water Sample

The number of high fruit loss must be resolved immediately. East Java produces the highest number of banana and orange. To prevent the fruit loss, as mitigation, the fruit loss can be used to make eco-enzymes as biodegradable agents which was made from nature to treat contaminated water from nitrite contamination and high pH value. Contaminations such as nitrite in water pose significant risks, particularly to organisms. Nitrite contamination can adversely affect humans by reacting with hemoglobin, leading to the formation of methemoglobin, which hampers the blood's ability to bind with oxygen and transport it to body tissues. Eco-enzymes serve as biocatalysts to accelerate the nitrification process, converting ammonia into nitrate with nitrite as an intermediate product. This study was conducted on a laboratory scale, using water samples comprised of distilled water and nitrite standard solution. Two types of eco-enzymes, derived from banana and orange waste, were applied at a 5% concentration to reduce nitrite levels and pH values in the water samples. The results indicated that the orange eco-enzyme reduced nitrite concentrations by 73.2% and pH values by 38.42%, while the banana eco-enzyme achieved a reduction of 93.89% in nitrite concentrations and 23.15% in pH values. As an application of this study, the 5% eco-enzyme solution holds promise for use in biological treatment within wastewater treatment plants, particularly in aeration tanks, to enhance the nitrification process, thereby aiding in the reduction of nitrite concentrations and pH values in wastewater.

Identification of microbial groups in the aeration tanks of secondary wastewater treatment stage

Microbes are prevalent in wastewater, degrading organic matter that impact the environment. In recent years, wastewater treatment plants have been used to process treated water for domestic purposes, sustaining groundwater resources for the future. The current study assessed the present microbial species in the aeration tanks for the secondary wastewater treatment stage in the Sulaibiya Wastewater Treatment and Reclamation Plant, Kuwait. Biweekly wastewater samples were collected for a period of three months from October 2022 to December 2022 from the aeration tanks. The collected wastewater samples were analyzed for microbiological parameters including total coliform, fecal coliform, Salmonella, and E. coli. Further, the microbial species were identified using the Biolog Omnilog Instrument. The results indicated that a total of 45 bacterial species isolates were identified with the most dominant genus being Bacillus with twenty-one isolates. Though Bacillus is common in aeration tanks, the presence of Bacillus thuringiens/cereus is rare and their existence could be due to the change in climatic conditions such as rainfall, dust and wind. Therefore, the study recommends that all microbial groups should be identified at all treatment stages including, primary, secondary, tertiary, and advanced treatment stages to ensure the complete removal of microbes.

Biogas production performance using soybean residue and hydrothermal pretreated food waste hydrolysate in a continuously anaerobic two-stage pilot plant

In this study, a continuously anaerobic two-stage pilot plant was established for bioenergy production, comprising 5 major pieces of equipment: a mixing tank, 1st anaerobic digester (AD), 2nd AD, sediment tank, aeration tank, and final sediment tank, all operating at ambient conditions. The operation of the continuously anaerobic two-stage pilot plant was automatically controlled by a programmable logic controller (PLC) using a designed control logic concept to set the hydraulic retention time (HRT) and inlet substrate concentration. The organic loading rate, pretreatment of hydrolysis pressure, and microbial community analysis were investigated for their effects on biogas production performance using different substrates: soybean residue (SR) and food waste hydrolysate (FWH), respectively. It was found that the peaks of biogas production rate on daily volumetric feeding were 1.20 m³·m⁻³·d⁻1, and the biogas yield on VS added was 760 dm³·kg⁻1 from food waste hydrolysate with a pretreatment hydrolysis pressure of 10 kg cm⁻2, at an OLR in COD concentration of 3.56 kg m⁻³·d⁻1, and an HRT of 11 days, respectively. The Methanobrevibacter genus was found to be abundant in the 1st AD, approximately 6.7 times more abundant than in the 2nd AD. The continuous anaerobic two-stage pilot plant was properly examined for its application in treating food waste and soybean residue with the goal of obtaining renewable bioenergy.

Filling the Knowledge Gap Regarding Microbial Occupational Exposure Assessment in Waste Water Treatment Plants: A Scoping Review.

Wastewater treatment plants (WWTPs) are crucial in the scope of European Commission circular economy implementation. However, bioaerosol production may be a hazard for occupational and public health. A scoping review regarding microbial contamination exposure assessment in WWTPs was performed. This study was performed through PRISMA methodology in PubMed, Scopus and Web of Science. 28 papers were selected for data extraction. The WWTPs' most common sampled sites are the aeration tank (42.86%), sludge dewatering basin (21.43%) and grit chamber. Air sampling is the preferred sampling technique and culture-based methods were the most frequently employed assays. Staphylococcus sp. (21.43%), Bacillus sp. (7.14%), Clostridium sp. (3.57%), Escherichia sp. (7.14%) and Legionella sp. (3.57%) were the most isolated bacteria and Aspergillus sp. (17.86%), Cladosporium sp. (10.71%) and Alternaria sp. (10.71%) dominated the fungal presence. This study allowed the identification of the following needs: (a) common protocol from the field (sampling campaign) to the lab (assays to employ); (b) standardized contextual information to be retrieved allowing a proper risk control and management; (c) the selection of the most suitable microbial targets to serve as indicators of harmful microbial exposure. Filling these gaps with further studies will help to provide robust science to policy makers and stakeholders.

Water-Energy Nexus Flow Analysis of a Wastewater Treatment Plant in Thailand

Abstract The Wastewater Treatment Plant in Thailand plays a vital role in treating raw domestic wastewater. As the demand for treating wastewater grows, the energy requirements associated with treatment processes become essential. This study aims to identify energy-intensive areas in wastewater treatment plants and provide inventory data for the indirect environmental impact. It also determines the suitable opportunities to recover energy from wastewater treatment plants. The water-energy nexus was examined through Material Flow Analysis (MFA) using Substance Flow Analysis (STAN) Software. The wastewater treatment plant is extended to produce water for reuse. System allocation is adopted to separate the treated wastewater and reuse water products. In Thailand, the aeration tank unit is the most energy-intensive. This condition can be explained by operating the aeration tank, which accounts for 33.87% of the total energy demand. The research found that around 0.155 kWh/m3 is needed for treating raw domestic wastewater to meet the effluent standard. The extended treatment for converting the raw wastewater into reuse water requires 0.3286 kWh/m3. Reuse water is beneficial for providing sustainable water resources but requires a 112% energy increase. The plant relies on Thailand’s EGAT Energy Mix (58.09% Natural Gas, 29.01% Lignite, 10.21% Hydropower, 2.52% Diesel, 0.16% Fuel Oil, 0.002% Geothermal Energy and 0.008% remain unidentified). Rather than fully relying on Thailand EGAT, the research suggests renewable energy installations and nutrient recovery options. Solar panels and micro-hydro power generation are promising ideas to install. Moreover, recovering the nutrients from wastewater can address environmental problems and offer valuable resources simultaneously. The findings of this Study provide profound benefits for developing sustainability in wastewater treatment plants.

Characterization and removal of microplastics in the Guheshwori Wastewater Treatment Plant, Nepal

Contamination of river water systems by microplastic particles (MPPs) is one of the emerging global environmental concerns with potentially widespread ecological, socioeconomic, and health implications. A wastewater treatment plant (WWTP) processes and treats wastewater to remove pollutants and release safe water into the environment. There has been limited research on the characterization of microplastics and their removal in WWTP in South Asia. In this work, we report on the characterization of microplastics in wastewater and sludge samples (n = 300) from Guheshwori WWTP located on the bank of the Bagmati River in Kathmandu city, Nepal representing inlet, secondary aeration tank (SAT), outlet, and sludge from November 2021 to November 2022. On average, we detected 31.2 ± 17.3 MPPs/L, 11.2 ± 9.4 MPPs/L, 8.5 ± 5.6 MPPs/L, and 6.6 ± 4.8 MPPs/g in the samples collected from inlet, SAT, outlet, and sludge, respectively. Commonly found MPPs were in the form of fiber, fragments, foam, and pellets. Largely, MPPs were red, yellow, white, blue, and black. Among the 44 μm – 150 μm, 150 μm – 500 μm and 500 μm – 5 mm categories of size fractions, the most dominant fractions were 500 μm – 150 μm in inlet, SAT, and sludge, and 150 μm – 44 μm in the outlet sampling unit. The Guheshwori WWTP was able to remove 72.5 % of MPPs on average, that mostly occurred in the inlet. The effluent released into the river and the sludge still contained a significant number of MPPs.

Bioaerosol Sampling Devices and Pretreatment for Bacterial Characterization: Theoretical Differences and a Field Experience in a Wastewater Treatment Plant.

Studies on bioaerosol bacterial biodiversity have relevance in both ecological and health contexts, and molecular methods, such as 16S rRNA gene-based barcoded sequencing, provide efficient tools for the analysis of airborne bacterial communities. Standardized methods for sampling and analysis of bioaerosol DNA are lacking, thus hampering the comparison of results from studies implementing different devices and procedures. Three samplers that use gelatin filtration, swirling aerosol collection, and condensation growth tubes for collecting bioaerosol at an aeration tank of a wastewater treatment plant in Trieste (Italy) were used to determine the bacterial biodiversity. Wastewater samples were collected directly from the untreated sewage to obtain a true representation of the microbiological community present in the plant. Different samplers and collection media provide an indication of the different grades of biodiversity, with condensation growth tubes and DNA/RNA shieldTM capturing the richer bacterial genera. Overall, in terms of relative abundance, the air samples have a lower number of bacterial genera (64 OTUs) than the wastewater ones (75 OTUs). Using the metabarcoding approach to aerosol samples, we provide the first preliminary step toward the understanding of a significant diversity between different air sampling systems, enabling the scientific community to orient research towards the most informative sampling strategy.

Comparison of the density and composition of bacteria and fungi in the air of anoxic and aeration tanks in the wastewater treatment plant

The bioaerosols from the wastewater treatment plant can be propagated into the air, affecting the health of residents, animals, and plants around the area. This study was conducted to evaluate the density and composition of bioaerosols (bacteria and fungi) in anoxic and aeration tanks of a domestic wastewater treatment plant. Bioaerosol samples were taken by the active method with SKC Biostage. The agar dishes were placed at a height of 1.5 m above the ground. After sample collection, the dishes were incubated at 37 ±1 °C for 24h-48h for bacteria and at 25 ±1 °C for 72h-120h for fungi. Then, these microorganisms were identified by 16S rRNA (16S Metabarcoding) method for bacteria and taxonomy method for fungi. The results showed that the density of bacteria and mold in the anoxic tank ranged from 233.2 ±7.8 to 339.2 ±13.9 CFU/m3 and 91.8 ±3.2 to 197.9 ±10.1 CFU/m3, respectively. Meanwhile, bacterial and mold densities of aeration tank ranged from 275.6 ±10.4 to 424.0 ±17.3 CFU/m3 and 176.7 ±5.8 to 254.4 ±12.1 CFU/m3, respectively. The density of bacteria and mold in the aeration tank is higher than in the anoxic tank. On the other hand, the 16S Metabarcoding analysis for the microbial diversity detects more than 100 species in two tanks, the predominant bacterial species are: Bacillus megaterium (B. megaterium), Bacillus cereus (B. cereus), Staphylococcus sciuri (S. sciuri) and two common fungi Aspergillus tamarii (A. tamarii), and Penicillium rubers (P. rubers). This preliminary survey in Viet Nam reveals the existence and diversity of bioaerosols in the air from the biological treatment tanks of the wastewater treatment plant.

Description and Genomic Characteristics of Diaphorobacter limosussp. nov., Isolated from a Sewage-Treatment Plant.

A Gram-stain-negative, rod-shaped, non-motile, catalase-positive, denitrifying bacterium, designated strain Y-1T, was isolated from an aeration tank of a sewage treatment plant in China and characterized using polyphasic taxonomic approaches. Strain Y-1T could grow at 10-37°C (optimum 25°C), at pH 5.0-10.0 (optimum 7.0) and in the presence of 0-3.0% (w/v) NaCl (optimum 0.5%). The phylogenetic tree based on the 16S rRNA gene sequences revealed that strain Y-1T was a member of genus Diaphorobacter, and showed the highest sequence similarities with Diaphorobacter oryzae RF3T (97.50%), Diaphorobacter nitroreducens NA10BT (97.38%) and Diaphorobacter aerolatus 8604S-37T (96.56%). In terms of carbon source utilization and enzyme activities, strain Y-1T was significantly different from its similar strains. The major respiratory quinone was Q-8, and the main polar lipid was phosphatidylethanolamine. Comparative genomic analysis of strain Y-1T and other Diaphorobacter species was conducted to explore the mechanisms underlying the differences among these strains. Strain Y-1T encoded 3957 genes, consisting of 3813 protein-coding genes and 144 RNA coding genes, and encoded 652 enzymes with 31 unique enzymes compared with other related species. The DNA G + C content was 69.95mol%. Strain Y-1T exhibited 41.71%DNA-DNA relatedness and 95% ANIb with the most related type strains.On the basis of the evidence presented from polyphasic analysis, strain Y-1T was suggested as a novel species within the genus Diaphorobacter, for which the name Diaphorobacter limosus sp. nov. is proposed, with the type strain Y-1T (= KCTC 92852T = CCTCCAB2023032T).

A simplified open flux chamber method for the measurement of greenhouse gas emissions from activated sludge reactors

ABSTRACT Measuring greenhouse gas emissions from wastewater treatment plants is of utmost importance in the context of climate change. However, due to their variability and complexity, it is a particularly challenging task in aerated reactors. The current methods involve capturing gas emissions from the water surface, measuring gas flow rates, and determining the concentration of the emitted gas at that location. Our study proposes a new, more efficient method that eliminates the need for gas flow rate measurements and additional equipment. The proposed technique uses a gas analyzer and a specially designed floating chamber to measure the transient trend of gas concentration within the chamber from the moment it is deployed to when it reaches a new steady state. Our research shows that this method accurately determines methane and carbon dioxide emissions from aerated reactors and potentially other gases emitted in wastewater treatment plants. It is cost effective, versatile, and simplifies the measurement process. This method facilitates the assessment of greenhouse gas emissions in wastewater treatment plants. Our findings are backed by comprehensive testing in the aeration tanks of a full-scale activated sludge plant, across diverse conditions, including fine- and coarse-bubble aeration.