• Fungi enable the constant UASB operation even at OLR of 25.0 kg/(m3×d).• The COD removal of 85.9% and methane production of 5.6 m3/(m3×d) are achieved.• Fungi inhibit VFAs accumulation and favor EPS generation and sludge granulation.• Fungi enrich methanogenic archaea and promote methanogenic pathways. Anaerobic digestion is widely applied in organic wastewater treatment coupled with bioenergy production, and how to stabilize its work at the high organic loading rate (OLR) remains a challenge. Herein, we proposed a new strategy to address this issue via involving the synergetic role of the Aspergillus sydowii 8L-9-F02 immobilized beads (AEBs). A long-term (210-day) continuous-mode operation indicated that the upflow anaerobic sludge bed (UASB) reactor (R1, with AEBs added) could achieve the OLR as high as 25.0 kg/(m3×d), whereas the control reactor (R0, with AEBs free) could only tolerate the maximum OLR of 13.3 kg/(m3×d). Remarkably, much higher COD removal (85.9% vs 23.9%) and methane production (5.4 m3/(m3×d) vs 2.2 m3/(m3×d)) were achieved in R1 than R0 at the OLR of 25.0 kg/(m3×d). Such favorable effect results from the facts that fungi inhibit VFAs accumulation, favor the pH stabilization, promote the generation of more extracellular polymeric substance, and enhance the sludge granulation and settleability. Moreover, fungi may enhance the secretion of acetyl-coenzyme A, a key compound in converting organic matters to CO2. In addition, fungi are favorable to enrich methanogenic archaea even at high OLR, improving the activity of acetate kinase and coenzyme F420 for more efficient methanogenic pathway. This work may shed new light on how to achieve higher OLR and methane production in anaerobic digestion of wastewater. 相似文献
An updated systematic review was conducted to assessing on the association between indoor air pollution caused by household energy consumption and childhood pneumonia in low- and middle-income countries. We performed a meta-analysis from the electronic databases of PubMed, Cochrane library, Web of Science, EMBASE. Studies were selected when they reported childhood pneumonia or ALRI in relation to indoor air pollution resulted from solid fuel. Studies must provide results on exposure prevalence of children aged below 5 years from Asia or Africa. We devoted ourselves to identifying randomized controlled experiments and observational epidemiological researches, which revealed the relation between household usage of solid fuel and childhood pneumonia. Among 1954 articles, 276 were reviewed thoroughly and 16 conduced to such a meta-analysis. It was found that there is a significant relationship between the solid fuel combustion and increasing risk of childhood pneumonia (OR?=?1.66, 95%CI 1.36–2.02). The summary odds ratios from biomass use and mixed fuel use were, respectively, 1.86 (95%CI 1.15–3.02) and 1.58 (95%CI 1.38–1.81), with substantial between study heterogeneity (I2?=?87.2% and 29.2%, respectively). According to the subgroup analysis along with the meta-regression analysis, the risk of using solid fuel in Asian regions is higher than that in African regions. Studies based on non-hospital participates (I2?=?49.5%) may also a source of heterogeneity. We found that indoor air pollution generated by the usage of solid fuel might be a significant risk factor for pneumonia in children and suggested improving the indoor air quality by promoting cleaner fuel will be important in undeveloped countries.
Environmental Science and Pollution Research - The geographical distribution of plant resources is of great significance for studying the origin, distribution, and evolution of species. Climate and... 相似文献
• The Large scale Urban Consumption of energY model was updated and coupled with WRF.• Anthropogenic heat emissions altered the precipitation and its spatial distribution.• A reasonable AHE scheme could improve the performance of simulated PM2.5.• AHE aggravated the O3 pollution in urban areas. Anthropogenic heat emissions (AHE) play an important role in modulating the atmospheric thermodynamic and kinetic properties within the urban planetary boundary layer, particularly in densely populated megacities like Beijing. In this study, we estimate the AHE by using a Large-scale Urban Consumption of energY (LUCY) model and further couple LUCY with a high-resolution regional chemical transport model to evaluate the impact of AHE on atmospheric environment in Beijing. In areas with high AHE, the 2-m temperature (T2) increased to varying degrees and showed distinct diurnal and seasonal variations with maxima in night and winter. The increase in 10-m wind speed (WS10) and planetary boundary layer height (PBLH) exhibited slight diurnal variations but showed significant seasonal variations. Further, the systematic continuous precipitation increased by 2.1 mm due to the increase in PBLH and water vapor in upper air. In contrast, the precipitation in local thermal convective showers increased little because of the limited water vapor. Meanwhile, the PM2.5 reduced in areas with high AHE because of the increase in WS10 and PBLH and continued to reduce as the pollution levels increased. In contrast, in areas where prevailing wind direction was opposite to that of thermal circulation caused by AHE, the WS10 reduced, leading to increased PM2.5. The changes of PM2.5 illustrated that a reasonable AHE scheme might be an effective means to improve the performance of PM2.5 simulation. Besides, high AHE aggravated the O3 pollution in urban areas due to the reduction in NOx. 相似文献
Effects of ionic strength, pH, organic content, cell concentration, and growth phase on the removal of MA cells using chitosan-modified sepiolite were studied in the laboratory. The MA removal efficiency increased with the increase of salinity for normal clay flocculation. In contrast, for chitosan-modified clays/soils, MA removal efficiency increased with the decrease of salinity. The removal efficiency of chitosan-modified sepiolite was not significantly affected by pH (6-9), but dropped dramatically beyond pH 10. Humic acid had a small negative effect on the removal of MA cells. Cells were removed more effectively by clays around the early senescence growth phase than other growth stages. The removal efficiency increased as the cell concentration increased. In a field enclosure of Taihu Lake, a loading of 0.025 g/L chitosan-modified local soils removed 99% algal cells and no increase of chlorophyll-a was observed during the following one month's monitoring process. 相似文献
Both the advanced oxidation process (AOP) using a combination of hydrogen peroxide addition and microwave heating (H2O2/microwave), and the microwave heating process were used for solubilization of phosphorus from liquid dairy manure. About 80% of total phosphate was released into the solution at a microwave heating time of 5 min at 170 degrees C. With an addition of H2O2, more than 81% of total phosphate could be released over a reaction period of 49 h at ambient temperature. The AOP process could achieve up to 85% of total phosphate release at 120 degrees C. The results indicated that both the microwave, and the AOP processes could effectively release phosphate from liquid dairy manure. These processes could serve as pretreatments for phosphorus recovery from animal wastes, and could be combined with the struvite crystallization process to provide a new approach in treating animal wastes. 相似文献
Sorption characteristics of phenanthrene (PHE) were studied on eight soils with organic carbon contents spanning over an order of magnitude using phase distribution relationships (PDRs) at 1 h, 48 h, and 720 h contact times. A new algebraic method was employed to describe the sorption characteristics at different time intervals (between 1 h and 48 h, and 1 h and 720 h). It was found that nonlinearity increased with increasing contact time and sorption that occurred in the subsequent time interval following the initial 1 h exhibited stronger isotherm nonlinearity. Sorption coefficients were positively correlated with the organic carbon contents of the soils. Detailed sorption dynamics were also examined on these soils. A two-compartment, first-order model was used to describe the sorption dynamics. The rate constants of the two compartments differed 18-170 times, suggesting the dissimilar sorption behaviors of the mathematically separated compartments. These two compartments were labeled fast and slow sorption compartment according to the rate constants. Calculation showed that the fast compartment accounted for over 80% of the overall sorption at the initial 1 h, while the slow compartment predominated the total sorption in the following 47 h. By combining the discussion of PDRs and sorption dynamics, the contributions of the two compartments to linear and nonlinear sorption were differentiated. The slow sorption compartment made a major contribution to nonlinear sorption and possibly to sequestration of organic pollutants by these soils. 相似文献