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871.
Yong-Jin Park Hiroshi Tsuno Taira Hidaka Ji-Hoon Cheon 《Journal of Material Cycles and Waste Management》2008,10(1):46-52
In this study, the effect of operational parameters, such as solids retention time (SRT), pH, and substrate total solids (TS)
concentration, on acid fermentation efficiency was investigated. From batch tests, it was shown that the appropriate pH range
for thermophilic acidogens was around 6–7 and that the optimum pH condition was 6. From the continuous experiment, pH and
SRT were shown to be the most important operational parameters for solubilization and organic acid production. In contrast,
TS concentration did not show any obvious effect on chromium chemical oxygen demand (CODcr) solubilization when TS was in
the range 3.5%–10%. The optimum operational conditions for thermophilic acid fermentation were an SRT of 2 days and a pH of
6.
This research was carried as a part of the CREST project of Japan Science and Technology Agency. 相似文献
872.
873.
Geographical and pedological drivers of distribution and risks to soil fauna of seven metals (Cd, Cu, Cr, Ni, Pb, V and Zn) in British soils 总被引:1,自引:0,他引:1
Spurgeon DJ Rowland P Ainsworth G Rothery P Long S Black HI 《Environmental pollution (Barking, Essex : 1987)》2008,153(2):273-283
Concentrations of seven metals were measured in over 1000 samples as part of an integrated survey. Sixteen metal pairs were significantly positively correlated. Cluster analysis identified two clusters. Metals from the largest (Cr, Cu, Ni, V, Zn), but not the smallest (Cd, Pb) cluster were significantly negatively correlated with spatial location and soil pH and organic matter content. Cd and Pb were not correlated with these parameters, due possibly to the masking effect of recent extensive release. Analysis of trends with soil properties in different habitats indicated that general trends may not necessarily be applicable to all areas. A risk assessment indicated that Zn poses the most widespread direct risk to soil fauna and Cd the least. Any risks associated with high metal concentrations are, however, likely to be greatest in habitats such as arable and horticultural, improved grassland and built up areas where soil metal concentrations are more frequently elevated. 相似文献
874.
K. Wyat Appel Prakash V. Bhave Alice B. Gilliland Golam Sarwar Shawn J. Roselle 《Atmospheric environment (Oxford, England : 1994)》2008,42(24):6057-6066
This paper is Part II in a pair of papers that examines the results of the Community Multiscale Air Quality (CMAQ) model version 4.5 (v4.5) and discusses the potential explanations for the model performance characteristics seen. The focus of this paper is on fine particulate matter (PM2.5) and its chemical composition. Improvements made to the dry deposition velocity and cloud treatment in CMAQ v4.5 addressing compensating errors in 36-km simulations improved particulate sulfate (SO42−) predictions. Large overpredictions of particulate nitrate (NO3−) and ammonium (NH4+) in the fall are likely due to a gross overestimation of seasonal ammonia (NH3) emissions. Carbonaceous aerosol concentrations are substantially underpredicted during the late spring and summer months, most likely due, in part, to a lack of some secondary organic aerosol (SOA) formation pathways in the model. Comparisons of CMAQ PM2.5 predictions with observed PM2.5 mass show mixed seasonal performance. Spring and summer show the best overall performance, while performance in the winter and fall is relatively poor, with significant overpredictions of total PM2.5 mass in those seasons. The model biases in PM2.5 mass cannot be explained by summing the model biases for the major inorganic ions plus carbon. Errors in the prediction of other unspeciated PM2.5 (PMOther) are largely to blame for the errors in total PM2.5 mass predictions, and efforts are underway to identify the cause of these errors. 相似文献
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