Ammonia emission during composting results in anthropogenic odor nuisance and reduces the agronomic value of the compost due to the loss of nitrogen. Adjusting the operating parameters during composting is an emerging in situ odor control technique that is cheap and highly efficient. The effects of in situ NH3 emission control were investigated in this study by simultaneously adjusting key operating parameters (such as C/N ratio, aeration rate, and moisture content) during the composting processes (C1–C9). Results showed that the average NH3 emission concentrations for different treatments were in the order of C1 > C4 > C2 > C5 > C3 > C6 > C7 > C8 > C9. The total content of NH3 emission (21.02 g/kg) in C9 (C/N ratio = 35, aeration rate = 15 L/min, and moisture content = 60%) was much lower than that (65.95 g/kg) in C1 (C/N ratio = 15, aeration rate = 5 L/min, and moisture content = 60%). The nitrogen loss ratio was 27.36% for C1, while 16.15% for C9. The microbial diversity and abundance in C9 and C1 were compared using high-throughput sequencing. The relationship between NH3 emission, operating parameters, and the related functional microbial communities was also investigated. Results revealed that Nitrosospira, Nitrosomonas, Nitrobacter, Pseudomonas, Methanosaeta, Rhodobacter, Paracoccus, and Sphingobacterium were negatively related to NH3 emission. According to the above results, the optimal values for different operating parameters for the in situ NH3 control during kitchen waste composting were, respectively, moisture content of 70%, C/N ratio of 35, and aeration rate of 15 L/min, with the order of effectiveness from high to low being aeration rate > C/N > moisture. This information could be used as a valuable reference for the in situ NH3 emission control during kitchen waste composting.
Understanding the emission sources of volatile organic compounds (VOCs) is critical for air pollution mitigation. Continuous measurements of atmospheric VOCs were conducted from January to February in Hangzhou in 2021. The average measured concentration of total VOCs (TVOCs) was 38.2 ± 20.9 ppb, > 42% lower than that reported by previous studies at the urban center in Hangzhou. The VOC concentrations and proportions were similar between weekdays and weekends. During the long holidays of the Spring Festival in China, the concentrations of TVOCs were ∼50% lower than those during the regular days, but their profiles showed no significant difference (p > 0.05). Further, we deduced that aromatics and alkenes were the most crucial chemicals promoting the formation of O3 and secondary organic aerosol (SOA) in Hangzhou. According to interspecies correlations, combustion processes and solvent use were inferred as major VOC emission sources. This study provides implications for air quality improvements before and during the upcoming Asian Games that will be hosted in Hangzhou in 2022. 相似文献
The Zijin heap bioleaching plant started operation by the end of 2005; due to the proximity of the Ting River, concerns rose about the migration of acidophiles outside of the heap. In this study, 53 soil samples and 51 liquid samples were collected, and the biogeographical distribution of acidophiles was investigated using clone libraries and real-time polymerase chain reaction (PCR), the physicochemical characteristics were analysed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP). The results indicated the bioleaching system had some influence on the surrounding environment. Both microbial community and physiochemical index emerged correlation with distance of sampling sites from bioleaching system, mainly limited in the zone 30?m outside bioleaching system. Correlation analysis indicated the migration of different acidophiles was influenced by different factors. Leptospirillum had higher migration capability than the other acidophiles, and such migration capability was one of the important influence factors for its distribution. Environment factors and survival ability were the key influence factors for Acidithiobacillus, Sulfobacillus and Ferroplasma to survive in the surrounding environment. 相似文献
To explore the effect of traffic emissions on air quality within street canyon, the wind flow and pollutant dispersion distribution in urban street canyons of different H/W, building gap and wind direction are studied and discussed by 3D computational fluid dynamics simulations. The largest PM2.5 concentrations are 46.4, 37.5, 28.4 µg/m3 when x = ? 88, ? 19.3, ? 19.3 m in 1.5 m above the ground level and the ratio of H/W is 1:1, 1:2 and 2:1, respectively. The flow around the top of the building and clearance flow between the buildings in street canyon influence by different H/W, which affected the diffusion of fine particulate matters. The largest PM2.5 concentrations are 88.1, 31.6 and 33.7 µg/m3 when x = 148.0, ? 92.3 and ? 186.7 m above the ground level of 1.5 m height and the building gap of 0, 20 and 40%, respectively. The air flows are cut by the clearance in the street canyons, and present the segmental characteristics. The largest PM2.5 concentrations are 10.6, 11.2 and 16.0 µg/m3 when x = 165.3 m, x = 58.0 and 1.5 m above the ground level of 1.5 m height and wind direction of the parallel to the street, perpendicular to the street and southwest, respectively. Modelled PM2.5 concentrations are basic agreement with measured PM2.5 concentrations for southwest wind direction. These results can help analyze the difussion of PM2.5 concentration in street canyons and urban planning.
Environmental Science and Pollution Research - As a kind of solid waste with a high silicon content, electrolytic manganese residue (EMR) can be utilized as silicon source by plants through... 相似文献