Enhanced removal of antibiotic resistance genes and human bacterial pathogens during anaerobic digestion of dairy manure via addition of manure biochar.

In this study, the response of antibiotic resistance genes (ARGs), mobile gene elements (intI1), and human bacterial pathogens (HBPs) to addition of manure biochar (1-10 g/L) was studied in anaerobic digestion (AD) at 20-55 °C for treating dairy manure. Twelve ARGs comprising five tetracycline resistance genes, two sulfonamide resistance genes, two macrolide resistance genes, three β-lactam antibiotic resistance genes, and intI1 were analyzed by quantitative PCR. High-throughput sequencing data were matched against a database of putative 538 HBPs.

Comparative study on characteristics and mechanism of levofloxacin adsorption on swine manure biochar.

This study evaluated the relationship between pyrolysis temperature (300-900 ℃), characteristics of swine manure (SM)-derived biochar (BC), and its adsorption of levofloxacin (LEV). The surface structure and chemistry of SM-derived BCs were characterized using Brunauer-Emmett-Teller analysis, scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. According to the characteristic analysis, the surface area and graphitization degree of SM-derived BC increased as temperature rose.

Effects of Mechanical Refining on Anaerobic Digestion of Dairy Manure.

Mechanical refining (MR) is a cost-effective pretreatment in biochemical conversion processes that is employed to overcome biomass recalcitrance. This work studied the effects of MR on biogas and methane produced by the anaerobic digestion (AD) of dairy manure. The cumulative gas volume and yield from the AD of manure refined at 6k revolutions increased by 33.

Effects of biological pretreatments of microalgae on hydrolysis, biomethane potential and microbial community.

Parameters of temperature-phased anaerobic digestion (TPAD) were varied to study their effects on hydrolysis, biomethane potential (BMP), and microbial diversity of microalgae biodegradation. Anaerobic pretreatments at 85 °C demonstrated the release of soluble carbohydrate and protein molecules under low microbial metabolic activity. However, at 55 °C, anaerobic pretreatments showed superior performance in methane yield, nutrient release, and volatile fatty acids (VFAs) production due to dominant Clostridium.

Food insecurity among immigrants and refugees of diverse origins living in metropolitan Atlanta: the roles of acculturation and social connectedness.

Little is known about the prevalence and correlates of food insecurity among immigrants and refugees. Acculturation and social connectedness may influence food insecurity (lack of access at all times to enough food for an active, healthy life) by affecting a person's ability to access and use governmental and charitable food assistance programs, as well as other community-based or informal food-related resources. We explored associations of acculturation and social connectedness with food insecurity among diverse immigrants and refugees living in metropolitan Atlanta, a major destination for these populations in recent years.

Practice-, provider- and patient-level facilitators of and barriers to HPV vaccine promotion and uptake in Georgia: a qualitative study of healthcare providers' perspectives.

Georgia experiences higher human papillomavirus (HPV)-associated cancer burden and lower HPV vaccine uptake compared with national estimates. Using the P3 model that concomitantly assesses practice-, provider- and patient-level factors influencing health behaviors, we examined facilitators of and barriers to HPV vaccine promotion and uptake in Georgia. In 2018, we conducted six focus groups with 55 providers.

Comparing the fate of antibiotic resistance genes in two full-scale thermophilic anaerobic digestion plants treating food wastewater.

This study focus on the fate of ARGs in the full-scale AD of food wastewater (FWW). Residue was collected from two different full-scale thermophilic AD treating FWW. Ten selected ARGs, including tetracycline resistance genes (tetM, tetX, tetQ, tetH and tetG), sulfonamide resistance genes (sul1 and sul2), quinolone resistance genes (qnrD) and macrolide resistance genes (ermB and ermC), were amplified using quantitative polymerase chain reaction (qPCR).

Determining the composition of bacterial community and relative abundance of specific antibiotics resistance genes via thermophilic anaerobic digestion of sewage sludge.

In this study, the effects of different temperature transitions on the dynamics of antibiotic resistance genes (ARGs) and bacterial community were investigated during start-up of thermophilic anaerobic digestion (AD) of sewage sludge. Although two thermophilic reactors showed dissimilar removal efficiencies of ARGs in batch mode, both the removal efficiency and reduction patterns of ARGs were similar in continuous stirred tank reactor (CSTR) mode, resulting in significant reduction of the total sum of the relative abundance of ARGs. Using network analysis to explore the correlation between bacterial community and some specific ARGs revealed that composition of the bacterial community played a vital role in the fluctuations in the relative abundance of the antibiotic resistome, demonstrating that shaping the development of ARGs was facilitated by vertical gene transfer.

Thermophilic anaerobic digestion: Effect of start-up strategies on performance and microbial community.

Effects of two different start-up methods were compared during conversion from mesophilic to thermophilic anaerobic digestion of sewage sludge. During the batch operation, a transient increase in both total bacterial concentration and relative abundance of thermophilic bacteria in R1 (a one-step increase method) resulted in 34% higher volatile solids (VS) removal efficiency by R1 compared to R2 (a step-wise increase method). Meanwhile, higher total archaeal concentration and increased relative abundance of thermophilic archaea in R2 were attributed to 65% higher methane production by R2 compared to R1.

Engineered biochar from agricultural waste for removal of tetracycline in water.

For the first time the present study investigated the production, characterization and application of engineered biochar derived from alfalfa hays for removal of tetracycline (TC) in water. The NaOH activation of alfalfa-derived raw biochar (BC) made significant increase in surface area (796.50 m/g) and pore volume (0.

A novel hay-derived biochar for removal of tetracyclines in water.

The biochars derived from alfalfa (AF) and bermudagrass (BG), the abundant grass hays to cows, were prepared, characterized and used for removal of tetracycline (TC) in water. The alfalfa-derived biochar (AF-BC) has exhibited outstanding TC adsorption capacity (372 mg/g), which was about 8-fold higher than that of bermudagrass-derived biochar (BG-BC). In addition, the TC adsorption capacity of AF-BC was comparable with those of the commercial activated carbons under the same conditions.

Response of antibiotic and heavy metal resistance genes to two different temperature sequences in anaerobic digestion of waste activated sludge.

Response of antibiotic resistance genes (ARGs) and heavy metal resistance genes (HMRGs) to two different temperature sequences (i.e., mesophilic-thermophilic and thermophilic-mesophilic) were investigated.

Adsorption isotherm, kinetic modeling and mechanism of tetracycline on Pinus taeda-derived activated biochar.

The objective of this study was to evaluate the adsorption of tetracycline (TC) on the Pinus taeda-derived activated biochar (BC). After NaOH activation, the well-developed porous surface structure was observed with a significantly increase in surface area (959.9 m/g).

Effects of dairy manure-derived biochar on psychrophilic, mesophilic and thermophilic anaerobic digestions of dairy manure.

Effects of dairy manure-derived biochar (M-BC) on methane production in anaerobic digestion (AD) of dry dairy manure were investigated with three different concentrations of biochar (0, 1 and 10 g/L) and temperatures (psychrophilic, 20 °C; mesophilic, 35 °C; thermophilic, 55 °C). Compared with the AD without any biochar, the cumulative methane and yield in the AD with 10 g/L biochar were increased to 27.65% and 26.

Fate of antibiotic resistance genes and metal resistance genes during thermophilic aerobic digestion of sewage sludge.

This study examines the fate of twenty-three representative antibiotic resistance genes (ARGs) encoding tetracyclines, sulfonamides, quinolones, β-lactam antibiotics, macrolides, florfenicol and multidrug resistance during thermophilic aerobic digestion (TAD) of sewage sludge. The bacterial community, class 1 integrons (intI1) and four metal resistance genes (MRGs) were also quantified to determine the key drivers of changes in ARGs during TAD. At the end of digestion, significant decreases in the quantities of ARGs, MRGs and intI1 as well as 16S rRNA genes were observed.

Prevalence of antibiotic resistance genes from effluent of coastal aquaculture, South Korea.

The wide use of antibiotics in aquaculture for prophylactic and therapeutic purposes can potentially lead to the prevalence of antibiotic resistance genes (ARGs). This study reports for the first time the profile of ARGs from effluents of coastal aquaculture located in South Jeolla province and Jeju Island, South Korea. Using quantitative PCR (qPCR), twenty-two ARGs encoding tetracycline resistance (tetA, tetB, tetD, tetE, tetG, tetH, tetM, tetQ, tetX, tetZ, tetBP), sulfonamide resistance (sul1, sul2), quinolone resistance (qnrD, qnrS, aac(6')-Ib-cr), β-lactams resistance (bla, bla, bla), macrolide resistance (ermC), florfenicol resistance (floR) and multidrug resistance (oqxA) and a class 1 integrons-integrase gene (intI1) were quantified.

Fate of antibiotic resistance genes in mesophilic and thermophilic anaerobic digestion of chemically enhanced primary treatment (CEPT) sludge.

Anaerobic digestion (AD) of chemically enhanced primary treatment (CEPT) sludge and non-CEPT (conventional sedimentation) sludge were comparatively operated under mesophilic and thermophilic conditions. The highest methane yield (692.46±0.

Quantitative and qualitative changes in antibiotic resistance genes after passing through treatment processes in municipal wastewater treatment plants.

In this study, quantitative and qualitative changes in antibiotics resistance genes (ARGs) were investigated in two municipal wastewater treatment plants (WWTPs) treating pretreated livestock or industrial wastewater as well as municipal sewage. Total eight ARGs (tetX, tetM, tetA, sul1, sul2, ermB, qnrD, and bla) were quantified, and their relative abundance was assessed by ARGs copies/16S rRNA gene copies. The fate of ARGs was observed to be different between two WWTPs: sul, qnrD, and bla were proliferated during the treatment processes only in the WWTP1 which received pretreated livestock wastewater.

Characterization of antibiotic resistance genes in representative organic solid wastes: Food waste-recycling wastewater, manure, and sewage sludge.

In this research, the distribution of antibiotic resistance genes (ARGs) was characterized in representative organic solid waste (OSW) in Korea: food waste-recycling wastewater (FRW), manure, and sewage sludge. The amounts of total ARG (gene copies/16S rRNA gene copies) was greatest in manure followed by sewage sludge and FRW. Interestingly, there were significantly different patterns in the diversity and mechanisms of ARGs.

Effect of increased load of high-strength food wastewater in thermophilic and mesophilic anaerobic co-digestion of waste activated sludge on bacterial community structure.

In recent years, anaerobic co-digestion (AcoD) has been widely used to improve reactor performance, especially methane production. In this study, we applied two different operating temperatures (thermophilic and mesophilic) and gradually increased the load of food wastewater (FWW) to investigate the bacterial communities during the AcoD of waste activated sludge (WAS) and FWW. As the load of FWW was increased, methane production rate (MPR; L CH4/L d) and methane content (%) in both Thermophilic AcoD (TAcoD) and Mesophilic AcoD (MAcoD) increased significantly; the highest MPR and methane content in TAcoD (1.

Changes in bacterial and archaeal communities in anaerobic digesters treating different organic wastes.

The goal of this study was to characterize microbial communities in anaerobic batch digesters treating different representative organic sources (sewage sludge, food waste, septage). Among the digesters, the anaerobic digester of food waste had the highest methanogen density, producing a peak value methane yield of 813.2mLCH4/gVS.

Sequential dilute acid and alkali pretreatment of corn stover: sugar recovery efficiency and structural characterization.

The objectives of this study were to explore the feasibility of applying sequential dilute acid and alkali pretreatment into the hydrolysis of corn stover and to elucidate the effects of structural changes in the biomass on its enzymatic digestibility. H2SO4 used in the first step selectively hydrolyzed 74.6-77.