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1.
Hig. Aliment. (Online) ; 38(298): e1146, jan.-jun. 2024. tab
Article in Portuguese | LILACS, VETINDEX | ID: biblio-1531450

ABSTRACT

Os Centros de Tradições Gaúchas (CTG) são entidades de divulgação e perpetuação da cultura do Rio Grande do Sul. A produção de refeições nessas entidades ocorre nos ensaios dos grupos de danças tradicionais e nos eventos oferecidos à comunidade, como jantares. Sabendo do impacto das doenças transmitidas por alimentos (DTA) na saúde humana, o objetivo deste trabalho é identificar a adequação dos CTG às boas práticas para manipulação de alimentos (BPM), explorar quem são os responsáveis pelas atividades de manipulação de alimentos e identificar a frequência e o número da produção de refeições servidas nessas instituições. A Portaria SES-RS nº 78/2009 e um questionário de coleta de dados dos grupos de dança e da produção de refeições foram aplicados em 5 CTG do Rio Grande do Sul. Outros 17 CTG do estado responderam a um segundo questionário, semelhante ao primeiro, com adição de perguntas sobre controle sanitário. Obteve-se uma média de adequação às BPM de 38% entre os CTG. Verificou-se que são servidas, em média, 4 refeições por semana entre os ensaios das invernadas artísticas próximos a competições. Em 36% dos CTG, ocorrem de 2 a 3 eventos por trimestre com produção de refeições. Em 45% dos CTG, são servidas de 100 a 200 pessoas nos eventos. Em relação aos trabalhos na cozinha, apenas 23,5% dos CTG têm como responsáveis dessas atividades pessoas devidamente capacitadas. Sendo os CTG instituições sem fins lucrativos, a criação de programas para a garantia do alimento seguro nesses espaços se faz necessária.


Centros de Tradições Gaúchas (CTG) are entities for the dissemination and perpetuation of Rio Grande do Sul culture. The production of meals in these entities takes place in the rehearsals of traditional dance groups and in events offered to the community, such as dinners. Knowing the impact of the foodborne diseases in human health, the objective of this work is to identify the adequacy of CTG to good food handling practices, to explore who are responsibles for food handling activities and identify the frequency and number of meals served in these institutions. The Portaria SES-RS No. 78/2009 and a questionnaire for data collection from dance groups and meals production were applied in 5 CTG in Rio Grande do Sul. Another 17 CTG in the state answered a second questionnaire, similar to the first, with the addition of questions about sanitary control. The average compliance with good practices was 38% among the CTG. It was found that, on average, 4 meals are served per week between rehearsals of the dance groups close to competitions. In 36% of the CTG, 2 to 3 events are held per quarter with production of meals. In 45% of the CTG, the number of people served at the events varies from 100 to 200. Regarding the work in the kitchen, only 23.5% of the CTG have duly trained people for these activities. Given that CTG are non-profit institutions, the creation of programs to ensure food safety in these spaces is necessary.


Subject(s)
Food Hygiene , Food Handling , Foodborne Diseases , Communitarian Organization , Good Distribution Practices
2.
BMC Public Health ; 24(1): 888, 2024 Mar 25.
Article in English | MEDLINE | ID: mdl-38523308

ABSTRACT

BACKGROUND: Food safety is integral to food security and is increasingly becoming a significant concern in the urban areas of Africa, which are rapidly growing in population. In the case of Ghana, many urban households depend on traditional open-air markets for most of their food needs. However, these urban food markets also depend on domestic food supply chains, which are prone to risks, including poor hygiene and sanitation and weather seasonality. Food safety compliance has associated costs which increase the unit cost of food products. Thus, higher food price is a risk factor to food availability and accessibility-fundamental pillars of food security. METHOD: We use food microbial data and food retail data from food market surveys in major cities in Ghana to assess the safety of selected fresh food commodities and how retailers handle the food products they sell. Additionally, based on a two-wave balanced panel household data, we used fixed effects Poisson and Correlated Random Effects (CRE) Probit models to estimate the effect of weather seasonality on the incidence of diarrhoea and urban household dietary diversity score (HDDS). A final sample of 609 households and 565 market respondents participated in the study. RESULTS: Our findings show that selected food samples tested positive for Staphylococcus aureus and E.coli and had aflatoxin B1 levels above 5.0 ppb. Additionally, the household incidence of diarrhoea/vomiting, a proxy for food safety status, is higher in the dry season. In the dry season, the household incidence of diarrhoea/vomiting increases on average by a probability of 38% points compared to the rainy season. Regarding HDDS, the average HDDS is 7.3; however, we did not find the effect of seasonality on HDDS to be significant. CONCLUSIONS: Although urban food availability and household dietary diversity are not challenges for many urban households, food safety is a challenge in the major food markets in Ghanaian cities and is associated with weather seasonality. Foods available in traditional open-air markets are not always safe for consumption, undermining households' food security. Weak enforcement of food safety regulations contributes to the food safety challenges in Ghanaian urban food markets.

3.
Environ Geochem Health ; 46(3): 81, 2024 Feb 17.
Article in English | MEDLINE | ID: mdl-38367190

ABSTRACT

This study presents an environmentally sustainable method for minimizing sludge production in the textile effluent sector through the combined application of electrokinetic (EK) and electrooxidation (EO) processes. AAS and XRF analyses reveal that utilizing acidic electrolytes in the EK method successfully eliminates heavy metals (Cu, Mn, Zn, and Cr) from sludge, demonstrating superior efficiency compared to alkaline conditions. In addition, the total removal efficiency of COD contents was calculated following the order of EK-3 (60%), EK-1 (51%) and EK-2 (34%). Notably, EK-3, leveraging pH gradient fluctuations induced by anolyte in the catholyte reservoir, outperforms other EK systems in removing COD from sludge. The EK process is complemented by the EO process, leading to further degradation of dye and other organic components through the electrochemical generation of hypochlorite (940 ppm). At an alkaline pH of 10.0, the color and COD removal were effectively achieved at 98 and 70% in EO treatment, compared to other mediums. In addition, GC-MS identified N-derivative residues at the end of the EO. This study demonstrates an integrated approach that effectively eliminates heavy metals and COD from textile sludge, combining EK with EO techniques.


Subject(s)
Metals, Heavy , Sewage , Sewage/chemistry , Metals, Heavy/analysis , Textiles
4.
Sci Total Environ ; 921: 171134, 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38401720

ABSTRACT

Sewage treatment plants (STPs) are primary sources of antibiotics in aquatic environments. However, limited research has been conducted on antibiotic attenuation in STPs and their downstream waters in low-urbanized areas. This study analyzed 15 antibiotics in the STP sewage and river water in the Zijiang River basin to quantify antibiotic transport and attenuation in the STPs and downstream. The results showed that 14 target antibiotics, except leucomycin, were detected in the STP sewage, dominated by amoxicillin (AMOX), ofloxacin, and roxithromycin. The total antibiotic concentration in the influent and effluent ranged from 158 to 1025 ng/L and 99.9 to 411 ng/L, respectively. The removal efficiency of total antibiotics ranged from 54.7 % to 75.7 % and was significantly correlated with total antibiotic concentration in the influent. The antibiotic emission from STPs into rivers was 78 kg/yr and 4.6 g/km2yr in the Zijiang River basin. The total antibiotic concentration downstream of the STP downstream was 23.6 to 213 ng/L and was significantly negatively correlated with the transport distance away from the STP outlets. Antibiotics may pose a high ecological risk to algae and low ecological risk to fish in the basin. The risk of AMOX and ciprofloxacin resistance for organisms in the basin was estimated to be moderate. This study established antibiotic removal and attenuation models in STPs and their downstream regions in a low-urbanized basin, which is important for simulating antibiotic transport in STPs and rivers worldwide.


Subject(s)
Anti-Bacterial Agents , Water Pollutants, Chemical , Animals , Anti-Bacterial Agents/analysis , Sewage/analysis , Water , Environmental Monitoring , Amoxicillin , China , Water Pollutants, Chemical/analysis
5.
Sci Total Environ ; 921: 171175, 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38402967

ABSTRACT

Anaerobic digestion (AD) of sewage sludge reduces organic solids and produces methane, but the complex nature of sludge, especially the difficulty in solubilization, limits AD efficiency. Pretreatments, by destroying sludge structure and promoting disintegration and hydrolysis, are valuable strategies to enhance AD performance. There is a plethora of reviews on sludge pretreatments, however, quantitative comparisons from multiple perspectives across different pretreatments remain scarce. This review categorized various pretreatments into three groups: Physical (ultrasonic, microwave, thermal hydrolysis, electric decomposition, and high pressure homogenization), chemical (acid, alkali, Fenton, calcium peroxide, and ozone), and biological (microaeration, exogenous bacteria, and exogenous hydrolase) pretreatments. The optimal conditions of various pretreatments and their impacts on enhancing AD efficiency were summarized; the effects of different pretreatments on microbial community in the AD system were comprehensively compared. The quantitative comparison based on dissolution degree of COD (DDCOD) indicted that the sludge solubilization performance is in the order of physical, chemical, and biological pretreatments, although with each below 40 % DDCOD. Biological pretreatment, particularly microaeration and exogenous bacteria, excel in AD enhancement. Pretreatments alter microbial ecology, favoring Firmicutes and Methanosaeta (acetotrophic methanogens) over Proteobacteria and Methanobacterium (hydrogenotrophic methanogens). Most pretreatments have unfavorable energy and economic outcomes, with electric decomposition and microaeration being exceptions. On the basis of the overview of the above pretreatments, a full energy and economy assessment for sewage sludge treatment was suggested. Finally, challenges associated with sludge pretreatments and AD were analyzed, and future research directions were proposed. This review may broaden comprehension of sludge pretreatments and AD, and provide an objective basis for the selection of sludge pretreatment technologies.


Subject(s)
Sewage , Ultrasonics , Anaerobiosis , Sewage/microbiology , Methane/chemistry , Hydrolysis , Waste Disposal, Fluid , Bioreactors
6.
Environ Pollut ; 345: 123534, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38342432

ABSTRACT

The Fe-based catalysts typically undergo severe problems such as deactivation and Fe sludge emission during the peroxymonosulfate (PMS) activation, which commonly leads to poor operation and secondary pollution. Herein, an S-doped Fe-based catalyst with a core-shell structure (Fe@CT, T = 1000°C) was synthesized, which can solve the above issues via the dynamic surface evolution during the reaction process. Specifically, the Fe0 on the surface of Fe@C1000 could be consumed rapidly, leaving numerous pores; the Fe3C from the core would subsequently migrate to the surface of Fe@C1000, replenishing the consumed active Fe species. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses demonstrated that the reaction surface reconstructed during the PMS activation, which involved the FeIII in-situ reduction by S species as well as the depletion/replenishment of effective Fe species. The reconstructed Fe@C1000 achieved near-zero Fe sludge emission (from 0.59 to 0.08-0.23 mg L-1) during 5 cycles and enabled the dynamic evolution of dominant reactive oxygen species (ROS) from SO4·- to FeIVO, sustainably improving the oxidation capacity (80.0-92.5% in following four cycles) to ciprofloxacin (CIP) and reducing the toxicity of its intermediates. Additionally, the reconstructed Fe@C1000/PMS system exhibited robust resistance to complex water matrix. This study provides a theoretical guideline for exploring surface reconstruction on catalytic activity and broadens the application of Fe-based catalysts in the contaminants elimination.


Subject(s)
Iron , Sewage , Iron/toxicity , Iron/chemistry , Ciprofloxacin/toxicity , Peroxides/chemistry , Catalysis
7.
Heliyon ; 10(4): e25614, 2024 Feb 29.
Article in English | MEDLINE | ID: mdl-38375279

ABSTRACT

Food safety is a major public health issue particularly in developing countries. Ready-to-eat street-vended foods contribute significantly to dietary intake in urban and peri-urban areas, but with elevated public health risk. In this study, hygiene and food safety practices as well as the microbial contamination in Uganda's edible grasshopper value chain were evaluated."A total of 29 grasshopper-processing households participated, and grasshopper samples collected. Indicator pathogens were analyzed using standard microbiological methods. In Kampala 50% and in Masaka 12% households had earth floors. All households in Kampala were one or two-roomed dwellings with no separate room as a kitchen, and shared a toilet. In contrast, 59% of households in Masaka had three or more rooms, 35% had a separate room for a kitchen and 47% did not share a toilet. 83% households in Kampala and 56% in Masaka obtained drinking water from public taps. Handwashing was inadequate and none of the actors was observed to wash their hands after taking a break or handling waste. For vendors, wearing protective clothing was not common, with only 28.5% in Kampala and 30.8% in Masaka wearing an apron. Containers for vending grasshoppers were largely uncovered and the utensils for measuring the grasshoppers were left mainly uncovered. Indicator organisms, Escherichia coli and Salmonella typhimurium, were detected. E. coli was the most common contaminant, but with lower levels in Masaka compared to Kampala. S. typhimurium was mainly a burden in Kampala. Our findings demonstrate that there are enormous contributors to poor hygiene and sanitation along the edible grasshopper value chain. The existence of pathogenic bacteria such as E. coli in ready-to-eat foods imply that their consumption poses a health risk.

8.
Environ Pollut ; 346: 123591, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38367696

ABSTRACT

This study developed an efficient and stable landfill leachate treatment process, which was based on the combination of biochar catalytic ozonation and activated sludge technology for intensive treatment of landfill leachate, aiming to achieve the standard discharge of leachate. The focus is to investigate the effect of manganese loading on the physicochemical properties of biochar and the mechanism of its catalytic ozonation. It was found that more surface functional groups (CO, Mn-O, etc.) and defects (ID/IG = 1.27) were exposed via the change of original carbon structure by loading Mn, which is conducive to the generation of lattice oxygen. Meanwhile, generating different valence states of Mn metal can improve the redox properties and electron migration rate, and encourage the production of reactive oxygen species (ROS) during the reaction process and enhance the catalytic efficiency. The synergistic action of microorganisms, especially denitrifying bacteria, was found to play a key role in the degradation of nitrogenous pollutants during the activated sludge process. The concentration of NH+4-N was reduced from the initial 1087.03 ± 9.56 mg/L to 9.05 ± 1.91 mg/L, while COD was reduced from 2290 ± 14.14 mg/L to 86.5 ± 2.12 mg/L, with corresponding removal rates of 99.17% and 99.20%, respectively. This method offers high efficiency and stability, achieving discharge standards for leachate (GB16889-2008). The synergy between Mn-loaded biochar and microorganisms in the activated sludge is key to effective treatment. This study offers a new approach to solving the challenge of waste leachate treatment.


Subject(s)
Charcoal , Ozone , Water Pollutants, Chemical , Ozone/chemistry , Manganese , Water Pollutants, Chemical/chemistry , Sewage
9.
Int J Food Microbiol ; 414: 110615, 2024 Apr 02.
Article in English | MEDLINE | ID: mdl-38325260

ABSTRACT

Burkholderia gladiolus (B. gladiolus) is foodborne pathogenic bacteria producing bongkrekic acid (BA), which causes food poisoning and has a mortality rate of up to 40 % or more. However, no drugs have been reported in the literature for the prevention and treatment of this infection. In this study, a phage was identified to control B. gladiolus. The novel phage vB_BglM_WTB (WTB), which lyse B. gladiolus with high efficiency, was isolated from sewage of Huaihe Road Throttle Well Sewage Treatment Plant in Hefei. Transmission electron microscopy showed that WTB had an icosahedral head (69 ± 2 nm) and a long retractable tail (108 ± 2 nm). Its optimal temperature and pH ranges to control B. gladiolus were 25 °C -65 °C and 3-11 respectively. The phage WTB was identified as a linear double-stranded DNA phage of 68, 541 bp with 60.04 % G + C content, with a long latent period of 60 min. Phylogenetic analysis and comparative genetic analysis indicated that phage WTB has low identity (<50 %) with other phages, with the highest similarity to Burkholderia phage Maja (25.7 %), which showed that it does not belong to any previous genera recognized by the International Committee on Taxonomy of Viruses (ICTV) and was a candidate for a new genus within the Caudoviricetes. We have submitted a new proposal to ICTV to create a new genus, Bglawtbvirus. No transfer RNA (tRNA), virulence associated and antibiotic resistance genes were detected in phage WTB. Experimental results indicated that WTB at 4 °C and 25 °C had excellent inhibition activity against B. gladiolus in the black fungus, with an inhibition efficiency of over 99 %. The amount of B. gladiolus in the black fungus was reduced to a minimum of 89 CFU/mL when treated by WTB at 25 °C for 2 h. The inhibition rate remained at 99.97 % even after 12 h. The findings showed that the phage WTB could be applied as a food-cleaning agent for enhancing food safety and contributed to our understanding of phage biology and diversity.


Subject(s)
Bacteriophages , Burkholderia , Bacteriophages/genetics , Burkholderia/genetics , Sewage , Phylogeny , Genome, Viral , DNA, Viral/genetics , Fungi/genetics
10.
Environ Sci Pollut Res Int ; 31(10): 15126-15152, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38289557

ABSTRACT

Water treatment sludge (WTS) is produced daily and disposed of as hazardous material. It would be advisable to use locally available waste products as supplementary cementitious materials that ensure to be disposed of without harming the environment. As a novelty, this research investigated the potential of using recycled WTS with fly ash (FA) and ground-granulated blast furnace slag (BFS) as ternary blended binders. Thus, it can provide an economical solution and alleviate the adverse environmental effects of excessive production of wastes and cement production. Within this scope, the mortars with 0-30 wt% replacement of cement with modified WTS (MWTS) were produced as binary blend, and also, they were combined with FA/BFS as ternary blended binders. Therefore, optimum utilization of waste products into the mortar in terms of rheological, mechanical, durability, microstructural properties, and environmental-economical aspects was examined. Adding 10% recycled WTS as binary caused higher strengths with lower porosity measured by the mercury intrusion porosimeter test and denser microstructure, as revealed by XRD patterns and SEM results. However, the drawbacks of using recycled WTS, in terms of rheological parameters and environmental-economical aspects, were suppressed by adding FA/BFS with comparable strength values. Specifically, cost, CO2 footprint, and embodied energy were reduced by combining 10% MWTS with FA by 8.87%, 37.88%, and 33.07%, respectively, while 90-day compressive and flexural strength were 5.1% and 5.32% lower. This study developed a feasible solution to use recycled MWTS by obtaining more eco-friendly and cost-effective cement-based materials.


Subject(s)
Drug-Related Side Effects and Adverse Reactions , Sewage , Humans , Coal Ash , Waste Products , Hazardous Substances , Climate
11.
Environ Sci Technol ; 58(5): 2528-2541, 2024 Feb 06.
Article in English | MEDLINE | ID: mdl-38266239

ABSTRACT

Resource recovery from wet organic wastes can support circular economies by creating financial incentives to produce renewable energy and return nutrients to agriculture. In this study, we characterize the potential for hydrothermal liquefaction (HTL)-based resource recovery systems to advance the economic and environmental sustainability of wastewater sludge, FOG (fats, oils, and grease), food waste, green waste, and animal manure management through the production of liquid biofuels (naphtha, diesel), fertilizers (struvite, ammonium sulfate), and power (heat, electricity). From the waste management perspective, median costs range from -193 $·tonne-1 (FOG) to 251 $·tonne-1 (green waste), and median carbon intensities range from 367 kg CO2 eq·tonne-1 (wastewater sludge) to 769 kg CO2 eq·tonne-1 (green waste). From the fuel production perspective, the minimum selling price of renewable diesel blendstocks are within the commercial diesel price range (2.37 to 5.81 $·gal-1) and have a lower carbon intensity than petroleum diesel (101 kg CO2 eq·MMBTU-1). Finally, through uncertainty analysis and Monte Carlo filtering, we set specific targets (i.e., achieve wastewater sludge-to-biocrude yield >0.440) for the future development of hydrothermal waste management system components. Overall, our work demonstrates the potential of HTL-based resource recovery systems to reduce the costs and carbon intensity of resource-rich organic wastes.


Subject(s)
Refuse Disposal , Wastewater , Animals , Sewage , Carbon Dioxide/analysis , Food , Biofuels/analysis , Carbon
12.
Bioresour Technol ; 394: 130262, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38184090

ABSTRACT

Long-term high efficiency and stable partial nitrification (PN) performance was achieved using gel-immobilized partial nitrifying bacteria. The PN characteristics of the filler under high and low ammonia nitrogen concentrations and low temperature were comprehensively studied and the rapid reactivation was achieved after reactor breakdown or long stagnation period. The results showed that the maximum ammonia oxidation rate was 66.8 mg•(L•h)-1 and the nitrite accumulation rate was above 95 % for the filler. Efficient and stable PN performance depends on the high abundance of ammonia-oxidizing bacteria (AOB) inside the filler and dynamically microbial community. In addition, the oxygen-limited zone and competition between the microorganisms inside the filler effectively inhibited the growth of nitrite oxidizing bacteria, and the sludge outside the filler assisted in this process, which supported the dominant position of AOB in fillers. This study provides a reliable technology for the practical application of the PN nitrogen removal process.


Subject(s)
Ammonia , Nitrites , Nitrites/metabolism , Ammonia/metabolism , Bioreactors/microbiology , Sewage/microbiology , Nitrification , Bacteria/metabolism , Nitrogen/metabolism , Oxidation-Reduction
13.
J Hazard Mater ; 465: 133083, 2024 03 05.
Article in English | MEDLINE | ID: mdl-38181593

ABSTRACT

In this study, an organic loading (OL) of 300 mg/(L d) was set as the relative normal condition (OL-300), while 150 mg/(L d) was chosen as the condition reflecting excessively low organic loading (OL-150) to thoroughly assess the associated risks in the effluent of the biological wastewater treatment process. Compared with OL-300, OL-150 did not lead to a significant decrease in dissolved organic carbon (DOC) concentration, but it did improve dissolved organic nitrogen (DON) levels by ∼63 %. Interestingly, the dissolved organic matter (DOM) exhibited higher susceptibility to transformation into chlorinated disinfection by-products (Cl-DBPs) in OL-150, resulting in an increase in the compound number of Cl-DBPs by ∼16 %. Additionally, OL-150 induced nutrient stress, which promoted engendered human bacterial pathogens (HBPs) survival by ∼32 % and led to ∼51 % increase in the antibiotic resistance genes (ARGs) abundance through horizontal gene transfer (HGT). These findings highlight the importance of carefully considering the potential risks associated with low organic loading strategies in wastewater treatment processes.


Subject(s)
Wastewater , Water Purification , Humans , Sewage/microbiology , Disinfection/methods , Nitrogen , Water Purification/methods
14.
J Hazard Mater ; 465: 133435, 2024 Mar 05.
Article in English | MEDLINE | ID: mdl-38224639

ABSTRACT

Nylon-6,6 microplastics (NMPs) in aquatic systems have emerged as potential contaminants to the global environment and have garnered immense consideration over the years. Unfortunately, there is currently no efficient method available to eliminate NMPs from sewage. This study aims to address this issue by isolating Brucella intermedia ZL-06, a bacterium capable of producing a bacterial polysaccharide-based flocculant (PBF). The PBF generated from this bacterium shows promising efficacy in effectively flocculating NMPs. Subsequently, the precipitated flocs (NMPs + PBF) were utilized as sustainable feedstock for synthesizing PBF. The study yielded 6.91 g/L PBF under optimum conditions. Genome sequencing analysis was conducted to study the mechanisms of PBF synthesis and nylon-6,6 degradation. The PBF exhibited impressive flocculating capacity of 90.1 mg/g of PBF when applied to 0.01 mm NMPs, aided by the presence of Ca2+. FTIR and XPS analysis showed the presence of hydroxyl, carboxyl, and amine groups in PBF. The flocculation performance of PBF conformed to Langmuir isotherm and pseudo-first-order adsorption kinetics model. These findings present a promising approach for reducing the production costs of PBF by utilizing NMPs as sustainable nutrient sources.


Subject(s)
Brucella , Caprolactam/analogs & derivatives , Microplastics , Polymers , Plastics , Sewage/microbiology , Flocculation
15.
J Hazard Mater ; 466: 133552, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38246061

ABSTRACT

Increasing occurrence of heavy metals (HMs) in sewage sludge threatens its widespread land utilization in China due to its potential impact on nutrient cycling in soil, requiring a better understanding of HM-induced impacts on nitrification. Herein, lab-scale experiments were conducted over 185-day, evaluating the effect of sludge-derived chromium (Cr3+), nickel (Ni2+), and lead (Pb2+) on soil nitrification at different concentrations. Quantitative polymerase chain reaction and linear regression results revealed an inhibitory sequence of gene abundance by HMs' labile fraction: ammonia-oxidizing bacteria (AOB)-ammonia monooxygenase (amoA)> nitrite oxidoreductase subunit alpha (nxrA)> nitrite oxidoreductase subunit beta (nxrB). The toxicity of HMs' incremental labile fraction decreased in the order of Ni2+>Cr3+>Pb2+, with respective threshold values of 5.01, 24.03 and 38.42 mg·kg-1. Furthermore, extending incubation time reduced HMs inhibition on ammonia oxidation, mainly related to their fraction bound to carbonate minerals. Random Forest analysis, variation partitioning analysis, and Mantel test indicated that soil physicochemical properties primarily affected nitrification genes, especially in the test of Cr3+ on AOB-amoA, nxrA, nxrB, Ni2+ for complete ammonia-oxidizing bacteria-amoA, and Pb2+ for nxrA and nxrB. These findings underline the importance of labile HMs fractions and soil physicochemical properties to nitrification, guiding the establishment of HM control standards for sludge utilization.


Subject(s)
Bacteria , Metals, Heavy , Bacteria/metabolism , Archaea/metabolism , Nitrification , Soil/chemistry , Sewage/chemistry , Chromium/toxicity , Chromium/metabolism , Nickel , Lead/metabolism , Nitrites/metabolism , Ammonia/metabolism , Oxidation-Reduction , Oxidoreductases/metabolism , Metals, Heavy/toxicity , Metals, Heavy/metabolism , Soil Microbiology
16.
Water Res ; 251: 121168, 2024 Mar 01.
Article in English | MEDLINE | ID: mdl-38266439

ABSTRACT

Carbon sources are critical factors influencing bacterial bioaugmentation, however, the underlying mechanisms, particularly the metabolic characteristics of bioaugmented bacteria remain poorly understood. The bioaugmented bacterium Rhodococcus sp. BH4 secretes the quorum quenching (QQ) enzyme QsdA to disrupt the quorum sensing (QS) in the activated sludge (AS) process, reducing AS yield in-situ. This study investigated the carbon metabolic characteristics of BH4 and explored the effects on bioaugmentation with different influent carbon sources. Because of the absence of glucose-specific phosphoenol phosphotransferase system (PTS), BH4 prefers sodium acetate to glucose. However, the lactones produced during extracellular glucose metabolism enhance BH4 qsdA expression. Moreover, BH4 possess carbon catabolite repression (CCR), acetate inhibits glucose utilization. BH4 microbeads were added to reactors with different carbon sources (R1: sodium acetate; R2: glucose; R3: a mixture of sodium acetate and glucose) for in-situ AS yield reduction. During operation, AS reduction efficiency decreased in the following order: R1 > R3 > R2. R2 and R3 microbeads exhibited similar QQ activity to R1, with less BH4 biomass at 5 d. 13C labeling and Michaelis-Menten equation showed that, due to differences in the competitiveness of carbon sources, R1 BH4 obtained the most carbon, whereas R2 BH4 obtained the least carbon. Moreover, acetate inhibited glucose utilization of R3 BH4. Transcriptome analysis showed that R1 BH4 qsdA expression was the lowest, R2 BH4 was the most serious form of programmed cell death, and the R3 BH4 PTS pathway was inhibited. At 10 d, R1 BH4 biomass and microbead QQ activity were higher than that in R3, and the R2 BH4 lost viability and QQ activity. This study provides new insights into bioaugmentation from the perspectives of carbon source competitiveness, carbon metabolism pathways, and CCR.


Subject(s)
Quorum Sensing , Rhodococcus , Quorum Sensing/physiology , Carbon , Sodium Acetate , Sewage/microbiology , Glucose , Bioreactors/microbiology
17.
Environ Pollut ; 344: 123326, 2024 Mar 01.
Article in English | MEDLINE | ID: mdl-38195026

ABSTRACT

Suitable operating parameters are one of the key factors to efficient and stable biological wastewater treatment of N, N-dimethylformamide (DMF) wastewater. In this study, an improved AnSBR-ASBR reactor (anaerobic sequencing batch reactor, AnSBR, and aerobic SBR, ASBR, run in series) was used to investigated the effects of operating conditions such as hydraulic residence time (HRT), AnSBR stirring speed and ASBR dissolved oxygen (DO) for DMF wastewater treatment. When HRT decreased from 24 h to 12 h, the average removal rates of COD by the AnSBR were 34.59% and 39.54%, respectively. Meanwhile, the removal rate of NH4+-N by ASBR decreased from 88.38% to 62.81%. The DMF removal rate reached the best at 18 h and the expression of dehydrogenase was the highest in the AnSBR. The abundance of Megasphaera, the dominant sugar-degrading bacteria in the AnSBR, continued to decline due to the decrease of HRT. The relative abundance of Methanobacterium gradually increased to 80.2% with the decrease of HRT and that hydrotrophic methanogenesis dominated the methanogenic process. The HRT decrease promoted butyrate and pyruvate metabolism in anaerobic sludge, but the proportion of glycolysis and methane metabolism decreased. The AnSBR-ASBR reactor had the best operation performance when HRT was 18 h, AnSBR speed was 220 r/min, and ASBR DO content was 3-4 mg/L. This study provided an effective reference for the reasonable selection of operating parameters in the treatment of DMF-containing wastewater by the AnSBR-ASBR.


Subject(s)
Microbiota , Wastewater , Dimethylformamide/metabolism , Waste Disposal, Fluid , Bioreactors/microbiology , Sewage/microbiology , Anaerobiosis
18.
ACS Appl Bio Mater ; 7(2): 990-998, 2024 Feb 19.
Article in English | MEDLINE | ID: mdl-38226433

ABSTRACT

Catheter-associated urinary tract infections (CAUTI) are among the most common bacterial infections associated with prolonged hospitalization and increased healthcare expenditures. Despite recent advances in the prevention and treatment of these infections, there are still many challenges remaining, among them the creation of a durable catheter coating, which prevents bacterial biofilm formation. The current work reports on a method of protecting medical tubing endowed with antibiofilm properties. Silicone catheters coated sonochemically with ZnO nanoparticles (NPs) demonstrated excellent antibiofilm effects. Toward approval by the European Medicines Agency, it was realized that the ZnO coating would not withstand the regulatory requirements of avoiding dissolution for 14 days in artificial urine examination. Namely, after exposure to urine for 14 days, the coating amount was reduced by 90%. Additional coatings with either carbon or silica maintained antibiofilm activity against Staphylococcus aureus while resisting dissolution in artificial urine for 14 days (C- or SiO2-protected catheters exhibited only 29% reduction). HR-SEM images of the protected catheters indicate the presence of the ZnO coating as well as the protective layer. Antibiofilm activity of all catheters was evaluated both before and after exposure to artificial urine. It was shown that before artificial urine exposure, all coated catheters showed high antibiofilm properties compared to the uncoated control. Exposure of ZnO-coated catheters, without the protective layer, to artificial urine had a significant effect exhibited by the decrease in antibiofilm activity by almost 2 orders of magnitude, compared to unexposed catheters. Toxicity studies performed using a reconstructed human epidermis demonstrated the safety of the improved coating. Exposure of the epidermis to ZnO catheter extracts in artificial urine affects tissue viability compared with control samples, which was not observed in the case of ZnO NPs coating with SiO2 or C. We suggest that silica and carbon coatings confer some protection against zinc ions release, improving ZnO coating safety.


Subject(s)
Bathroom Equipment , Zinc Oxide , Humans , Zinc Oxide/pharmacology , Silicon Dioxide/pharmacology , Biofilms , Anti-Bacterial Agents/pharmacology , Catheters , Carbon
19.
J Environ Manage ; 352: 119964, 2024 Feb 14.
Article in English | MEDLINE | ID: mdl-38228044

ABSTRACT

The application of sewage sludge to agricultural land is facing increasing restrictions due to concerns about various micropollutants, including polycyclic aromatic hydrocarbons (PAHs), dioxins and furans (PCDD/Fs), polychlorinated biphenyls (PCBs), per- and poly-fluoroalkyl substances (PFAS), and heavy metals (HMs). As an alternative approach to manage this residue, the use of pyrolysis, a process that transforms sludge into biochar, a carbon-rich solid material, is being explored. Despite the potential benefits of pyrolysis, there is limited data on its effectiveness in removing micropollutants and the potential presence of harmful elements in the resulting biochar. This study aims to evaluate the impact of the temperature and the use of a carrier gas (N2) during a two-stage pyrolysis and cooling on micropollutant removal. Pilot-scale tests showed that a higher temperature (650 °C) and the use of a carrier gas (0.4 L/min N2) during the pyrolysis and the cooling process led to a reduction of PAHs, PCDD/Fs, PCBs and PFAS below their detection limits. As such, the generated biochar aligns with the guidelines set by the International Biochar Initiative (IBI) and the European Biochar Certificate (EBC) for all micropollutants, except for zinc and copper. Additional investigation is required to determine whether the micropollutants undergo destruction or transition into other pyrolysis end-products, such as the gas or liquid phase.


Subject(s)
Fluorocarbons , Polychlorinated Biphenyls , Polychlorinated Dibenzodioxins , Sewage/chemistry , Temperature , Dibenzofurans , Pyrolysis , Charcoal/chemistry
20.
J Environ Manage ; 352: 120052, 2024 Feb 14.
Article in English | MEDLINE | ID: mdl-38244409

ABSTRACT

The pulp-paper industry is one of the main industrial sectors that produce massive amounts of residual sludge, constituting an enormous environmental burden for the industries. Traditional sludge management practices, such as landfilling and incineration, are restricted due to mounting environmental pressures, complex regulatory frameworks, land availability, high costs, and public opinion. Valorization of pulp-paper industry sludge (PPS) to produce high-value products is a promising substitute for traditional sludge management practices, promoting their reuse and recycling. Valorization of PPIS for biorefinery beneficiation includes biomethane, biohydrogen, bioethanol, biobutanol, and biodiesel production for renewable energy generation. Additionally, the various thermo-chemical technologies can be utilized to synthesize bio-oil, hydrochar, biochar, adsorbent, and activated carbon, signifying potential for value-added generation. Moreover, PPIS can be recycled as a byproduct by incorporating it into nanocomposites, cardboard, and construction materials development. This paper aims to deliver a comprehensive overview of PPIS management approaches and thermo-chemical technologies utilized for the development of platform chemicals in industry. Substitute uses of PPIS, such as making building materials, developing supercapacitors, and making cardboard, are also discussed. In addition, this article deeply discusses recent developments in biotechnologies for valorizing PPIS to yield an array of valuable products, such as biofuels, lactic acids, cellulose, nanocellulose, and so on. This review serves as a roadmap for future research endeavors in the effective handling of PPIS.


Subject(s)
Sewage , Waste Management , Industrial Waste , Proton Pump Inhibitors , Biofuels
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