Sludge Samples Research Articles

Novel thermodynamic mechanisms of co-conditioning with polymeric aluminum chloride and polyacrylamide for improved sludge dewatering: A paradigm shift in the field

This study investigated the combined effects of polymeric aluminum chloride (PAC) and polyacrylamide (PAM) on sludge dewatering, aiming to unveil underlying mechanisms. Co-conditioning with 15 mg g−1 PAC and 1 mg g−1 PAM achieved optimal dewatering, reducing specific filtration resistance (SFR) of co-conditioned sludge to 4.38 × 1012 m−1kg−1, a mere 48.1% of raw sludge's SFR. Compared with the CST of raw sludge (36.45 s), sludge sample can be significantly reduced to 17.7 s. Characterization tests showed enhanced neutralization and agglomeration in co-conditioned sludge. Theoretical calculations revealed elimination of interaction energy barriers between sludge particles post co-conditioning, converting sludge surface from hydrophilic (3.03 mJ m−2) to hydrophobic (−46.20 mJ m−2), facilitating spontaneous agglomeration. Findings explain improved dewatering performance. Based on Flory-Huggins lattice theory, connection between polymer structure and SFR was established. Raw sludge formation triggered significant change in chemical potential, increasing bound water retention capacity and SFR. In contrast, co-conditioned sludge exhibited thinnest gel layer, reducing SFR and significantly improving dewatering. These findings represent a paradigm shift, shedding new light on fundamental thermodynamic mechanisms of sludge dewatering with different chemical conditioning.

THE INFLUENCE OF TEMPERATURE CONDITIONS ON THE YIELD OF BIOGAS AND METHANE, WHICH IS OBTAINED FROM AQUACULTURE WASTE

The research looks into the potential of generating biogas from waste generated by aquaculture. The EDF-5.4_2 bioreactor, produced by "Biotehniskais centrs" (Latvia), was utilized for the experimental study. Samples of sludge from a fish farm located in Nagļu parish, Rēzekne district were collected and analysed for their moisture and organic matter content before being mixed with crushed reeds to increase the organic matter available for fermentation and biogas extraction.In this study, biogas was produced by mixing different ratios of sludge and reed residue. The yield of biogas varied based on the temperature, with the best results being achieved at 40°C. During the experiment, 2.75 L of biogas containing 37.3% methane was produced from the mixture of 1,200 g of fish farming sludge and 100 g of crushed reeds. Although the highest methane content of 40.16% was recorded at 43°C, the total amount of biogas produced was lower by 15% at this temperature.The least favourable results were recorded at 37°C, in terms of both the amount of biogas produced and the methane content. The experimental studies demonstrate that residues from aquaculture can be used for biogas production.

Isolation, identification, and screening of biosurfactant-producing and hydrocarbon-degrading bacteria from oil and gas industrial waste

Qatar is one of the biggest oil and gas producers in the world, coupled with it is challenging environmental conditions (high average temperature: >40 °C, low annual rainfall: 46.71 mm, and high annual evaporation rate: 2200 mm) harbors diverse microbial communities that are novel and robust, with the potential to biodegrade hydrocarbons. In this study, we collected hydrocarbon contaminated sludge, wastewater and soil samples from oil and gas industries in Qatar. Twenty-six bacterial strains were isolated in the laboratory from these samples using high saline conditions and crude oil as the sole carbon source. A total of 15 different bacterial genera were identified in our study that have not been widely reported in the literature or studied for their usage in the biodegradation of hydrocarbons. Interestingly, some of the bacteria that were identified belonged to the same genus however, demonstrated variable growth rates and biosurfactant production. This indicates the possibility of niche specialization and specific evolution to acquire competitive traits for better survival. The most potent strain EXS14, identified as Marinobacter sp., showed the highest growth rate in the oil-containing medium as well as the highest biosurfactant production. When this strain was further tested for biodegradation of hydrocarbons, the results showed that it was able to degrade 90 to 100% of low and medium molecular weight hydrocarbons and 60 to 80% of high molecular weight (C35 to C50) hydrocarbons. This study offers many promising leads for future studies of microbial species and their application for the treatment of hydrocarbon contaminated wastewater and soil in the region and in other areas with similar environmental conditions.

Large-scale comparative analysis reveals different bacterial community structures in full- and lab-scale wastewater treatment bioreactors

The activated sludge process is widely used for biological wastewater treatment due to its low cost and high efficiency. Although numerous lab-scale bioreactor experiments have been conducted to investigate the microorganism performance and mechanisms in activated sludge, understanding the bacterial community differences between full- and lab-scale bioreactors has remained elusive. In this study, we investigated the bacterial communities in 966 activated sludge samples obtained from various bioreactors, including both full- and lab-scale ones, from 95 previous studies. Our findings reveal significant differences in the bacterial communities between full- and lab-scale bioreactors, with thousands of bacterial genera exclusive to each scale. We also identified 12 genera that are frequently abundant in full-scale bioreactors but rarely observed in lab-scale reactors. By using a machine-learning method, organic matter and temperature were determined as the primary factors affecting microbial communities in full- and lab-scale bioreactors. Additionally, transient bacterial species from other environments may also contribute to the observed bacterial community differences. Furthermore, the bacterial community differences between full- and lab-scale bioreactors were verified by comparing the results of lab-scale bioreactor experiments to full-scale bioreactor sampling. Overall, this study sheds light on the bacteria overlooked in lab-scale studies and deepens our understanding of the differences in bacterial communities between full- and lab-scale bioreactors.

Effects of several factors in accelerated carbonation on neutralization and carbon dioxide capture of alkaline sludges treated with paper sludge ash-based stabilizer

Recently, a technology was developed in Japan to accelerate the carbonation of alkaline construction sludge and reduce its alkalinity. Alkaline construction sludge is treated in advance using a paper sludge ash-based stabilizer (PSAS) so that it becomes granular and well aerated. Subsequently, CO2 gas is injected from the bottom to the top of the treated sludge layer in the underground pit. This technology can reduce the pH of alkaline sludge within short periods; however, the completion period of pH neutralization has often been predicted empirically. This may be due to the combined effects of density, water content, particle size, PSAS amount in the sludge, and CO2 concentration in the accelerated carbonation on the pH neutralization process. However, there have been few studies on how these factors affect the pH neutralization and CO2 capture of PSAS-treated alkaline sludges subjected to accelerated carbonation. Therefore, in this study, the effects of several accelerated carbonation factors on neutralization and CO2 capture from alkaline sludge were experimentally investigated. PSAS-treated alkaline sludges with different densities, water contents, particle sizes, and amounts of PSAS were cured in incubators with controlled CO2 concentrations. Based on the pH measurements, the pH neutralization completion period (tN) was evaluated for each alkaline sludge sample. The test results revealed that tN increased with increasing dry density and particle size and decreasing CO2 concentration. The results also suggest that tN increases with increasing amounts of PSAS. However, the water content had a more significant effect on tN than the PSAS amount. There may be an optimum water content for pH neutralization if conditions other than the water content are the same. From the results of the carbonate content evaluation, the amounts of CO2 captured in each specimen (mCO2) and mCO2 at tN were determined for each alkaline sludge sample. The results revealed that the density, water content, particle size of the alkaline sludge, and CO2 concentration in the incubators did not significantly affect the amount of CO2 captured by the sludge (mCO2) upon the completion of pH neutralization. However, the amount of PSAS significantly affects the captured CO2 content. A higher amount of PSAS caused mCO2 to increase at tN.

Mass flow of per- and polyfluoroalkyl substances (PFAS) in a Swedish municipal wastewater network and wastewater treatment plant

Perand polyfluoroalkyl substances (PFAS) are ubiquitously distributed in wastewater, due to their numerous uses in industry and consumer products, but little is known of PFAS mass flows in municipal wastewater network systems and within wastewater treatment plants (WWTPs). This study assessed mass flows of 26 PFAS in a wastewater network and WWTP, to provide new insights into their sources, transport, and fate in different treatment steps. Wastewater and sludge samples were collected from pumping stations and the main WWTP in Uppsala, Sweden. PFAS composition profiles and mass flows were used to identify sources within the sewage network. Wastewater from one pumping station showed elevated concentrations of C3–C8 PFCA, likely caused by an industrial source, and two stations had elevated concentrations of 6:2 FTSA, probably originating from a nearby firefighter training facility. Within the WWTP, short-chain PFAS dominated in wastewater, whereas long-chain PFAS dominated in sludge. The ratio of perfluoroalkyl sulfonates (PFSA) and ethylperfluorooctanesulfonamidoacetic acid (EtFOSAA) to ∑26PFAS decreased during the WWTP process, likely due to sorption to sludge, but also transformation (EtFOSAA). Overall, PFAS were not efficiently removed in the WWTP, with mean removal efficiency of 10 ± 68% for individual PFAS, resulting in discharge of 7000 mg d−1 ∑26PFAS into the recipient. This shows that conventional WWTPs are inefficient in removing PFAS from wastewater and sludge, so advanced treatment techniques are needed.

Cross-media migration behavior of antibiotic resistance genes (ARGs) from municipal wastewater treatment systems (MWTSs): Fugitive characteristics, sharing mechanisms, and aerosolization behavior

The municipal wastewater treatment systems (MWTSs) are the leading enrichment site of antibiotic resistance genes (ARGs), the occurrence of which in sewage and sludge significantly influences the ARGs burden of aerosols. However, the migration behavior and impact factors of ARGs in gas–liquid–solid phase are still unclear. This study collected gas (aerosol), liquid (sewage), and solid (sludge) samples from three MWTSs to explore the cross-media transport behavior of ARGs. The results showed that the main ARGs detected in the solid–gas-liquid phase were consistent, constituting the central antibiotic resistance system of MWTSs. Multidrug resistance genes dominated cross-media transmission (average relative abundance is 42.01 %). Aminocoumarin, fluoroquinolone, and aminoglycoside resistance genes (aerosolization index of 1.260, 1.329, and 1.609, respectively) were prone to migrating from the liquid to gas phase, resulting in long-distance transmission. Environmental factors (mainly temperature and wind speed), water quality index (mainly COD), and heavy metals may be the key factors affecting the trans-media migration of ARGs between the liquid, gas, and solid phase. Based on partial least squares path modeling (PLS-PM), the migration of ARGs in gas phase is primarily influenced by ARGs' aerosolization potential in liquid and solid phase, while heavy metals indirectly influences almost all categories of ARGs. Impact factors aggravated the migration of ARGs in MWTSs through co-selection pressure. This study clarified the key pathways and impact factors that form the cross-media migration behavior of ARGs, which can more specifically control ARGs pollution from different media.

Exploration of an efficient method for removing antibiotics from water and digested sewage sludge using Fe(VI): Kinetics and P phytoavailability and compostability in treated sludge

Potassium ferrate (K2FeO4) containing hexavalent iron [Fe(VI)] is an environmentally friendly oxidant, which possesses strong oxidizing power to treat wastewater and sludge. Therefore, the present study investigated degradation of selected antibiotics, namely levofloxacin (LEV), ciprofloxacin (CIP), oxytetracycline (OTC), and azithromycin (AZI), in water and anaerobically digested sewage sludge samples using Fe(VI).The effects of different Fe(VI) concentrations and initial pH values on antibiotic removal efficiency were evaluated. Under the studied conditions, LEV and CIP were almost completely removed from water samples, following second-order kinetics. In addition, over 60% of the four selected antibiotics were removed from sludge samples using 1 g L−1 Fe(VI).Furthermore, P phytoavailability and compostability of Fe(VI)-treated sludge were evaluated using different extraction reagents and a small composting unit. The extraction efficiency of phytoavailable P using 2% citric acid and neutral ammonium citrate was approximately 40% and 70%, respectively. The mixture of Fe(VI)-treated sludge and rice husk was self-heated in a closed composting reactor through the biodegradation of organic matter derived from the treated sludge.Therefore, Fe(VI)-treated sludge may be used as an organic material containing phytoavailable P for compost.

Sensitive method for simultaneous determination of TBBPA and its ten derivatives

Tetrabromobisphenol A (TBBPA) and its derivatives are regarded as new contaminants, raising much attention on their environmental occurrence and fates. However, the sensitive detection of TBBPA and its main derivatives is still a great challenge. This study investigated a sensitive method for simultaneous detection of TBBPA and its ten derivatives using high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (HPLC-MS/MS) with atmospheric pressure chemical ionization (APCI) source. The method exhibited much better performance than previously reported methods. Furthermore, it was successfully applied in determining complicated environmental samples, including sewage sludge, river water and vegetable samples with concentration range from undetected (n.d.) to 25.8 ng g−1 dry weight (dw). For sewage sludge, river water and vegetable samples, the spiking recoveries of TBBPA and its derivatives ranged from 69.6 ± 7.0% to 86.1 ± 12.9%, 69.5 ± 13.9% to 87.5 ± 6.6%, and 68.2 ± 5.6% to 80.2 ± 8.3%, respectively; the accuracy ranged from 94.9 ± 4.6% to 113 ± 5%, 91.9 ± 10.9% to 112 ± 7%, and 92.1 ± 5.1% to 106 ± 6%, and the method quantitative limits ranged from 0.00801 to 0.224 ng g−1 dw, 0.0104–0.253 ng L−1, and 0.00524–0.152 ng g−1 dw, respectively. Moreover, the present manuscript describes for the first time the simultaneous detection of TBBPA and ten derivatives from various environmental samples, providing fundamental work for further research on their environmental occurrences, behaviors and fates.

Thermal Hydrolysis Pretreatment Effects on Endocrine Disrupting Compounds and Microbial Communities in Wastewater Sludge from Anaerobic Digestion

Concerns regarding endocrine disrupting compounds (EDCs) in wastewater treatment plant effluents have led to the need to better understand their fate during various treatment processes. The thermal hydrolysis process (THP) is a growing technology; this article aims to better understand the impacts of THP on EDCs. Serum bottles were used to understand how the THP of anaerobically digested wastewater influences concentrations of phthalic acid esters (PAEs) and antimicrobials. The succession of DNA-based microbial community was followed to assess conditions of contaminant biotransformation. Sludge samples were collected at different locations, placed in 250 mL serum bottles, and inoculated with samples collected from the anaerobic digestion solid recycle line to compare the influence of the THP pretreatment. Bottles were covered, kept at 37°C, and agitated for 22 days, with periodic destructive sampling for the chemical analysis of antimicrobials, PAEs, and transformation products, as well as the microbial community structure. Results demonstrated an increase in the concentrations of triclosan (TCS), triclocarban (TCC), and their transformation products with and without THP pretreatment. 2,4-Dichlorophenol increased at a significantly higher rate in pretreated sludge, while the TCC concentrations increased significantly faster in untreated sludge. Pretreatment did not significantly influence the formation rates of TCS and methyl triclosan. Pretreatment impacts on phthalate concentrations varied. Di(2-ethylhexyl) phthalate decreased and diisononyl phthalate concentrations were unchanged. Benzyl butyl phthalate increased in sludge that had undergone pretreatment and decreased in sludge without. PAE metabolites generally increased during the course of the experiments. Results demonstrate the potential for complex transformation processes and indicate the ability of THP to influence concentrations of certain compounds of concern. Analysis of the microbial community structure did not demonstrate any statistically significant difference between sludge with pretreatment and sludge without over the course of the experiment. These results indicate that changes in chemical concentrations could be due to other physicochemical mechanisms not examined.

ВИВЧЕННЯ СКЛАДУ ТА ВЛАСТИВОСТЕЙ НАФТОШЛАМІВ, УТВОРЕНИХ ВНАСЛІДОК ПЕРЕРОБКИ НАФТИ

The paper describes the results of studying the composition and properties of oil sludge obtained during oil processing at an oil refinery. Samples of fresh oil sludge and oil sludge of long-term storage, taken at different depths of the storage pond, were studied. The main properties and group hydrocarbon composition of the organic part of oil sludges were studied.

Perfluoroalkyl substances in Romanian wastewater treatment plants: Transfer to surface waters, environmental and human risk assessment

The current study aimed to determine the concentration levels of nine perfluoroalkyl substances (PFAS) in the five most significant Romanian wastewater treatment plants (WWTPs) and their transfer to natural receivers. The analytes were concentrated using a solid-phase extraction/ultrasonic-assisted extraction procedures and then selectively quantified by liquid chromatography–tandem mass spectrometry (LC–MS/MS) using electrospray ionization. In most of the wastewater samples investigated, the dominant compounds were perfluoropentanoic acid (PFPeA), perfluorooctanoic acid (PFOA), and perfluorooctansulfonate acid (PFOS), with the maximum concentration range between 105 and 316 ng/L in influents, 14.8–31.3 ng/L in effluents and removal efficiencies higher than 80 % for all selected PFAS compounds. In sewage sludge samples, PFOA and PFOS were the majority substances, with values up to 35.8 ng/g dw for PFOA and 27.8 ng/g dw for PFOS. PFOA and PFOS achieved the maximum levels by estimating mass loading and emission levels. As a result, 237 mg/day/1000 people of PFOA and 95.5 mg/day/1000 people of PFOS are entering daily in the WWTPs, while up to 31 mg/day/1000 people of PFOA and up to 13.6 mg/day/1000 people of PFOS are discharged daily into the natural emissaries. Human risk assessment shows that PFOA and PFOS are low to high risk for all age and gender categories. Children are the most exposed to PFOA and PFOS contamination in drinking water. Environmental risk assessment reveals that PFOA exhibits a low risk for some insect species, PFOS - a low risk for freshwater shrimps and a medium risk for midges, while perfluoroundecanoic acid (PFNuDA) could have a low to medium risk for midges. No assessment studies regarding the environmental and human risk of PFAS have been performed in Romania.

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. The RNA of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been extracted from the collected wastewater influent and primary sewage sludge samples. The outcomes were contrasted with the COVID-19 cases in the WWTPs served area. Additionally, whole transcriptome sequencing was used to compare the microbial community alterations before and after the COVID-19 outbreak and SARS-CoV-2 variations. The results demonstrated that the changes in SARS-CoV-2 RNA concentrations in the influent and sludge matched the trends of reported COVID-19 cases, especially sludge showed high-resolution data, which is well-matched when fewer COVID-19 cases (0−250) are reported. Interestingly, one month before the clinical report, we found that the SARS-CoV-2 Beta variant (South Africa, B.1.351) in the wastewater. In addition, the Aeromonas bacterial species was dominated (21.2%) among other bacterial species in wastewater after the COVID-19 outbreak, suggesting a potential indirect microbial indicator of the COVID-19 outbreak.

Basic micro-pollutants in sludge from municipal wastewater treatment plants in the Northwest Spain: Occurrence and risk assessment of sludge disposal

Sludge is one of the most problematic residues generated during wastewater treatment. Herein, we validate a single-step, sensitive procedure for the determination of a selection of 46 basic micro-pollutants, either used as pharmaceuticals or pesticides, in sludge from municipal sewage treatment plants (STPs), using liquid chromatography tandem mass spectrometry as determination technique. The proposed method permitted to achieve accurate recoveries (values from 70% to 120%, for samples spiked at different concentration levels) using solvent-based calibration standards. This feature, combined with limits of quantification lower than 5 ng g−1 (dry weight), allowed the rapid and sensitive quantification of target compounds in freeze-dried sludge samples. Out of 46 investigated pollutants, 33 species showed detection frequencies above 85% in a group of 48 sludge samples, obtained from 45 STPs located in the Northwest of Spain. The assessment of eco-toxicological risks associated to sludge disposal as fertilizer in agriculture and/or forestry, considering average concentrations found in sludge samples, highlighted eight pollutants (sertraline, venlafaxine, N-desethyl amiodarone, amiodarone, norsertraline, trazodone, amitriptyline and ketoconazole) representing an environmental hazard based on ratios between predicted soil levels and non-effect concentrations estimated using the equilibrium partition method.

Extracellular Synthesis of Fe-NPs by Bacteria/Biosurfactant, Kinetic Parameter and Reduction of Cr (VI) from Pollutant Samples

Hexavalent Cr is most toxic metal and hazardous compound worldwide. It is also considered to be cellular oxidizing pollutant causing damage, mutagenic and hematopoietic effects to living systems. Present work is focused on synthesis of zero valent iron nano particles (Fe-NPs) using Bacillus subtilis SHB 13, Achromobacter xylosoxidans SHB 204 and Surfactin and their application for Cr (VI) detoxification (100 ppm) in synthetic solutions and polluted sludge, sewage and soil samples about 90-100% reduction observed with above particles. Qualitative analysis, structural characterization of Fe-NPs, adsorption, and recovery of Cr (VI) were carried out using XRD, SEM and TEM. This work explains adsorption isotherm of Cr with iron nano particles (Fe- NPs), was best fitted with Langmuir model and it followed first order rate kinetic reaction. Microcosm studies were carried out using Fe-NPs in sludge, sewage and tannery samples and Cr (VI) was completely (100 %) removed within 72 h. In another microcosm experiment, bacteria were able to reduce (60-70 %) Cr (VI) from soils with and without moisture and glucose. In green house experiments both the bacteria were able to reduce Cr (VI) (65-90%) effectively from both polluted and non-polluted soil and there was increase in root length and shoot length of plant L. esculentum was observed and maximum plant biomass was observed with plants inoculated with SHB 204 and SHB 13.

Determining the potential human health risks posed by heavy metals present in municipal sewage sludge from a wastewater treatment plant

The study looked to establish the elemental composition of heavy metals such as Zn, Mn, Cu, Cr, Ni, Pb, As, and Co, present in sewage sludge and assessed their health risks. Samples were taken from the Gammams Wastewater Treatment Plant in Windhoek, Namibia and used for the analysis. Two samples of sludge were collected twice in the same week. The samples of sewage sludge were subjected to the hot-plate acid digestion method prior to the determination of the heavy metals using an Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The evaluation of the health risks was performed according to the U.S Environmental Protection Agency (USEPA) and South African Guidelines. Their elemental contents ranged from 65.75 - 82.17 mg/kg for Zn, 29.31 - 56.98 mg/kg for Mn, 21.46 - 49.20 mg/kg for Cu, 19.44 - 29.20 mg/kg for Cr, 2.88 - 3.82 mg/kg for Ni, 1.84 - 4.22 mg/kg for Pb, 0.83 - 1.74 mg/kg for As and 0.26 - 0.98 mg/kg for Co. Each of the levels for the heavy metals were found to be below the standard permissible limits of the two regulations and therefore are considered safe for land-based applications (agriculture) and were also associated with low health risks. The risk assessment is considered for the estimation of potential human health risks which also evaluates the likelihood of adverse health risks. Furthermore, the study revealed that children are more susceptible to carcinogenic and non-carcinogenic health risks in comparison to adults via the ingestion pathway.

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.

Unlocking environmental contamination of animal tuberculosis hotspots with viable mycobacteria at the intersection of flow cytometry, PCR, and ecological modelling

Mycobacterium bovis, a member of the Mycobacterium tuberculosis complex (MTBC), circulates in multi-host mammal communities. While interactions between different host species are mainly indirect, current knowledge postulates interspecific transmission is favored by animal contact with natural substrates contaminated with droplets and fluids from infected animals. However, methodological constraints have severely hampered monitoring of MTBC outside its hosts and the subsequent validation of this hypothesis.In this work, we aimed to evaluate the extent to which environmental contamination with M. bovis occurs in an endemic animal TB setting, taking advantage of a new real-time monitoring tool we recently developed to quantify the proportion of viable and dormant MTBC cell fractions in environmental matrices. Sixty-five natural substrates were collected nearby the International Tagus Natural Park region, in the epidemiological TB risk area in Portugal. These included sediments, sludge, water, and food deployed at unfenced feeding stations. The tripartite workflow included detection, quantification, and sorting of different M. bovis cell populations: total, viable, and dormant. Real-time PCR targeting IS6110 to detect MTBC DNA was performed in parallel. The majority of samples (54 %) contained metabolically active or dormant MTBC cells. Sludge samples had a higher burden of total MTBC cells and a high concentration of viable cells (2.3 × 104 cells/g). Ecological modelling informed by climate, land use, livestock and human disturbance data suggested eucalyptus forest and pasture cover as potential major factors affecting the occurrence of viable MTBC cells in natural matrices.Our study demonstrates, for the first time, the widespread environmental contamination of animal TB hotspots with viable MTBC bacteria and with dormant MTBC cells that are able to recover metabolic activity. Further, we show that viable MTBC cell load in natural substrates is superior to the estimated minimum infective dose, providing real-time insights into the potential magnitude of environmental contamination for indirect TB transmission.

Nationwide occurrence and distribution of liquid crystal monomers in municipal sewage sludge of China

Environmental pollution and the fate of liquid crystal monomers (LCMs) in different matrices have received increasing attention owing to their potential persistence and toxicity. Sewage sludge, a representative environmental matrix, may be an important sink for LCMs. However, the contamination status of LCMs in sewage sludge remains unknown, especially on a large scale. In this study, a robust method was developed using GC–MS/MS analysis to determine 65 LCMs in sewage sludge. The occurrence of 65 LCMs in municipal sewage sludge in China was investigated for the first time. Among the 65 target LCMs, 48 were detectable, including 14 biphenyls/bicyclohexyls and their analogs (BAs) and 34 fluorobiphenyls and their analogs (FBAs). Six LCMs were detected at a rate >50 %. These results demonstrate the ubiquity of this class of synthetic chemicals in China. The total concentrations of LCMs in sludge ranged from 17.2 to 225 ng/g, with a median concentration of 46.4 ng/g. BAs were the major components of LCMs contamination in the sludge, with total BAs concentrations accounting for approximately 75 % of the total LCMs concentrations. A comparative analysis of sludge samples from different regions revealed significant regional distribution differences in LCMs: the concentrations of LCMs in sludge from East and Central China were significantly higher than those from West China (p < 0.05). Correlation and principal component analyses of the concentrations of LCMs revealed that LCMs in sludge share similar contamination sources and environmental behaviors. E-waste dismantling, domestic releases, and industrial releases may be sources of LCMs in sludge. Furthermore, the results of the degradation prediction implied that the plausible transformation products exhibited the same or even stronger persistence as the parent LCMs. Our study will be beneficial for LCMs regulation and offer suggestions for its development and safe application.

ANALISIS DENSITAS LUMPUR STARCH DAN DRISPAC TERHADAP PROSES PENGANGKATAN CUTTING DENGAN MENGGUNAKAN METODE CUTTING TRANSPORT RATIO

The use of the right drilling mud in a drilling well has a good ability to clean the hole so that the process of removing the cutting to the surface can run optimally.. Aim: In this research, we will analyze the physical properties of density mud using starch and Drispac mud samples which are natural. The two mud samples are used to find out whether the two mud samples can carry cuttings optimally. Cutting Transport Ratio is one of the cutting removal methods used in the cutting lifting process using the average speed and slip speed of the mud. The cutting removal process can be said to be successful if it has a percentage of &gt; 50%. Methodology and Results: The starch and Drispac sludge samples will be tested using several temperatures, namely 150°F, 200°F and 250°F. Both samples will be tested for their physical properties, namely the density value. The selected density value is one of the parameters needed in the slip speed calculation process in the cutting lifting process. The density value obtained in the starch mud sample was 8.7-9.1 ppg while in the Drispac sample it was 8.65 - 9 ppg. These results are the initial results obtained, but because the results on the 200°F and 250°F samples are not in accordance with the specifications, an additional barite is needed for each of these samples. Both starch and drispac sludge added 60 grams of barite at a sample temperature of 200°F and 120 grams at a sample temperature of 250°F. The results of the density values ​​obtained when barite was added were 10-10.7 ppg for starch mud samples and 9.9-10.65 ppg for Drispac mud samples. The results of the density test will be carried out by testing the removal of cuttings using the Cutting Transport Ratio. The results obtained for the two samples, for starch sludge, obtained a value of 98.31-99.19% while for drispac mud 98.61-99.18%.m. Conclusions: The increase in temperature causes the value of the filtration loss to decrease because the water content in the filtrate also evaporates, causing the filtration loss to decrease. The mudcake value in this experiment was also influenced by the results of the filtration loss value. The higher the filtration loss value, the thicker the value of the mudcake is due to the large number of precipitated particles.