高台位旱地石灰性紫色土培肥研究

本文研究了高台位旱地石灰性紫色土的肥力退化因子,并针对紫色母岩矿质养分丰富、易风化成土的特点,以一种培肥耕作法-聚土免耕耕作法培肥土壤。结果表明,采用此耕作法的土壤具有防蚀、抗旱、培肥和自调能力,能提高系统生产力。     

Field dissipation of acetochlor in two New Zealand soils at two application rates

The persistence of pesticides in soils has both economic and environmental significance and is often used as a key parameter in pesticide risk assessment. Persistence of acetochlor [2'-ethyl-6'-methyl-N-(ethoxymethyl)-2-chloroacetylanilide] in two New Zealand field soils was measured over two years and the data were used to identify models that adequately describe acetochlor persistence in the field. Acetochlor was sprayed onto six fallow plots (3 x 9 m each) at each site at the recommended rate (2.5 kg a.i. ha(-1)) and at twice that rate. Acetochlor concentrations were measured in soil cores. Simple first-order kinetics (Model 1) adequately described acetochlor persistence in Hamilton clay loam soil (Humic Hapludull, Illuvial Spadic) at the high application rate, but overestimated it at the low application rate. A quadratic model (Model 2), a first-order double-exponential model (Model 3), a first-order biphasic model (Model 4), or a two-compartment model (Model 5) better described acetochlor persistence at the low application rate. The time for 50% (DT50) and 90% (DT90) of initial acetochlor loss was approximately 9 and 56 d, and 18 and 63 d at low and high application rates, respectively. The more complex Models 2 through 5 also better described the biphasic dissipation of acetochlor in Horotiu sandy loam soil (Typic Orthic Allophanic) than Model 1, with Model 1 significantly underestimating acetochlor concentrations on the day of application at both application rates. The DT50 and DT90 values were 5 and 29 d and 7 and 31 d at low and high application rates, respectively. Overall, application rate significantly affected the DT50 and DT90 values in the Hamilton soil, but not in the Horotiu soil. Faster acetochlor loss in the Horotiu soil possibly resulted from the higher soil organic carbon content that retained more acetochlor near the soil surface where higher temperature and photolysis accelerated the loss.     

Effects of sample storage on biosolids compost stability and maturity evaluation

Compost stability and maturity are important parameters of compost quality. To date, nearly all compost characterization has been performed using samples freshly collected because sample storage can affect compost stability and maturity evaluation. However, sample preservation is sometimes necessary, especially for scientific research purposes. There is little information available on the effects of sample storage on compost stability and maturity. Samples of biosolids compost with different levels of stability and maturity were collected from four compost facilities in Florida (referred to as Register, Winslow, Sunset, and Meadow). Comparisons of CO2 evolution, seed germination rate, and water-soluble organic carbon (WSOC) were made between fresh samples with short storage at 4 degrees C for less than 1 wk and air-dried or frozen compost samples stored for 1 yr. The effects of storage (air-dry or frozen) on the measured parameters depended on compost stability and maturity and on the compost material source. Frozen storage reduced the peak CO2 evolution of Register samples by 12 to 29%, while accumulated CO2 evolution was reduced by 43 to 64% and 110 to 277% with air-dry and frozen storage, respectively. The storage effect on CO2 evolution with more stable compost was inconsistent. Storage did not affect compost phytotoxicity, except for samples from the Sunset facility. Air-drying reduced the WSOC by up to 35%, and freezing increased it by up to 34%, while both storage methods had no significant effect on samples of low WSOC. Despite all these variations, WSOC had a significant and consistent relation to CO2 evolution and seed germination rates with R2 of 0.78 and 0.57, respectively, regardless of storage methods.     

Solar drying of granulated waste blends for dry biofuel production

Environmental Science and Pollution Research - In the paper, results of drying biofuels from sewage sludge using solar energy are presented. Drying rates of biofuels made from sewage sludge and...     

Influence of filtration velocity on DON variation in BAF for micropolluted surface water treatment

Biological aerated filters (BAFs) are widely used for the treatment of micropolluted surface water. However, the biological process produces dissolved organic nitrogen (DON), which, as precursors of nitrogenous disinfection by-products, pose potential threats to drinking water safety. Therefore, to control DON in BAF effluent, it is necessary to study the influence of BAF operation parameters on DON production. In this study, the influence of filtration velocity in a BAF on DON production was investigated. Under different filtration velocity (0.5, 2, and 4 m/h) conditions, profiles of DON concentrations along the media layer were measured. The profile at a filtration velocity of 0.5 m/h showed a decreasing trend, and the ones under filtration velocities of 2 and 4 m/h fluctuated in a small range (from 0.1 to 0.4 mg/L). Moreover, the relatively high filtration velocities of 2 and 4 m/h resulted in a lower level of DON concentration. Additionally, 3D excitation-emission matrix fluorescence spectroscopy was used to characterize DON. It is found that the patterns of DON at a relatively high filtration velocity condition (4 m/h) were obviously different from the ones under low filtration velocity conditions (0.5 and 2 m/h).     

煤气脱硫废料综合利用新工艺

针对煤气脱硫废料（简称废料）的成分（硫、碳、萘及少量其他有机物）,提出了一种处理废料的新工艺,先用乙酸乙酯提取废料中的萘和少量其他有机物,再用复合溶剂B加热溶解废料,热过滤得碳粉,最后将溶液冷却结晶分离出硫。实验结果表明：在乙酸乙酯与废料的质量比（R1）为3.75,提取温度为60℃,提取时间为4h的条件下,萘回收率为98%,纯度大于等于70%,在复合溶剂B与提取剩余物的质量比（R2）为2.69,过滤温度为100℃的条件下,硫回收率接近100%,纯度大于等于99%,碳回收率和纯度为100%。     

Study on macro-meso mechanical properties of cemented tailings backfill with high fly ash content

Environmental Science and Pollution Research - The use of cement and fly ash (FA) to prepare cemented tailings backfill (CTB) lowers backfill mining costs while also reducing pollution caused by...     

Does haze pollution affect public health in China from the perspective of environmental efficiency?

Environment, Development and Sustainability - This study attempts to introduce haze pollution into the environmental efficiency evaluation framework and measures PM2.5 environmental efficiency in...     

黄河宁蒙河段突发性水污染事件中应急监测探讨

介绍了黄河宁蒙河段近几年突发性水污染事件应急监测基本情况,总结了应急监测的特点、作用,对突发性水污染事件中应急监测中存在的问题进行了重点分析,提出了解决的对策。     

2000年1月15日姚安6.5级地震余震序列震源机制解与震源区应力场分析

本文利用垂直向的Pg和Sg波的最大振幅比方法,计算2000年1月15日云南姚安6.5级地震后余震序列震源机制解,通过统计和系统聚类分析,再结合震中分布图,综合分析了云南姚安6.5级地震的震源机制解和震源区应力场破裂特征,研究结果表明震源断层的走向为SEE-NWW占主导,其平均解为120°,震区主压应力轴平均解为145°,即SSE向,与震源区现今构造应力场主压应力方向一致,表明余震的应力场主要受区域应力场的控制.