Non-stop industries were the main source of air pollution during the 2020 coronavirus lockdown in the North China Plain

Environmental Chemistry Letters - Despite large decreases of emissions of air pollution during the coronavirus disease 2019 (COVID-19) lockdown in 2020, an unexpected regional severe haze...     

2种好氧颗粒污泥反应器工艺处理城市污水

以低浓度城市污水作为原水,絮状污泥作为接种污泥,分别采用序批式生物反应器(SBR)与气升式间歇反应器(SBAR)培养好氧颗粒污泥.分别考察2种工艺中好氧污泥颗粒化过程中的污泥特性以及对污染物的去除效果,结果表明2种工艺均成功培养出稳定的好氧颗粒污泥.SBR工艺中好氧颗粒污泥的污泥容积指数(SVI)、挥发性组分所占比例(...     

再生资源价格波动的形成机理初探——基于蛛网模型

从供需关系的视角发出,利用蛛网模型分析再生资源价格波动的形成机理.再生资源的价格波动在一定程度上可以用供需的内部传导来解释,影响供求关系的因素主要有3个:再生资源的异质替代效应、生产成本的变动以及市场体系的不完备.厘清再生资源价格波动的形成机理,对于完善再生资源的价格机制有着重要意义.     

Land-Cover Changes and Its Impacts on Ecological Variables in the Headwaters Area of the Yangtze River, China

Land cover changes affect ecological landscape spatial pattern, and evolving landscape patterns inevitably cause an evolution in ecosystem functionality. Various ecological landscape variables, such as biological productivity (plant biomass and stock capacity), soil nutrients (organic matter and N content) and water source conservation capacity are identified as landscape function characteristics. A quantitative method and digital model for analyzing evolving landscape functionality in the headwaters areas of the Yangtze River, China were devised. In the period 1986–2000, patch transitions of the region's evolving landscapes have been predominantly characterized by alpine cold swamp meadow, with the highest coverage tending to be steppified meadow or steppe, and desertification landscape such as sand and bare rock land expansion. As the result of such changes, alpine swamp areas decreased by 3.08 × 10³ km² and the alpine cold sparse steppe and bare rock and soil land increased by 6.48 × 10³ km² and 5.82 × 10³ km², respectively. Consequently, the grass biomass production decreased by 2627.15 Gg, of which alpine cold swamp meadows accounted for 55.9% of this loss. The overall stock capacity of the headwaters area of the Yangtze River decreased by 920.64 thousand sheep units, of which 502.02 thousand sheep units decreased in ACS (Alpine cold swamp) meadow transition. Soil organic matter and N contents decreased significantly in most alpine cold meadow and swamp meadow landscape patches. From 1986 to 2000 the total losses of soil organic matter and total N in the entire headwaters region amounted to 150.2 Gkg and 7.67 Gkg. Meanwhile, the landscape soil water capacity declined by 935.9 Mm³, of which 83.9% occurred in the ACS meadow transition. In the headwater area of the Yangtze River, the complex transition of landscape resulted in sharp eco-environmental deterioration. The main indication for these changes involved the intensity of the climate in this region is becoming drier and warmer, resulting in a gradual degradation of the permafrost.     

不同稳定剂对污泥蛋白发泡特性的影响研究

污泥含有蛋白质,经过高温水解可产生水解蛋白液(简称污泥蛋白),该蛋白具有发泡特性,经通风搅拌可产生泡沫;由于污泥蛋白所产生的泡沫具有不稳定、易破裂的特点,因此,设计了不同稳定剂对污泥蛋白发泡特性的影响研究实验,解决污泥蛋白所产生泡沫的稳定性问题。结果表明,在测定污泥蛋白的基本发泡特性实验中,10 mL污泥蛋白稀释10倍时,初始泡沫量较大,达到2 153 mL,但泡沫半衰期相对较短,时间为27 min;在10 mL污泥蛋白中分别加入0.2 g十六烷基三甲基溴化氨(CTAB)、羧甲基纤维素钠(CMC)、GP-1,并用水稀释10倍,制成泡沫后的初始泡沫量分别为1 380、1 400和1 248 mL,相对降低了773、753和905 mL;泡沫半衰期分别为31、76和509 min,相对提高了4、49和482 min,尤其是GP-1作为稳定剂时,泡沫的半衰期与不加稳定剂时相比提高了15倍;在10 mL污泥蛋白中加入0.2 g十六烷基三甲基溴化氨与0.2 g GP-1的复配稳定剂,用水稀释10倍,制成泡沫后的初始泡沫量为1 525 mL,相对降低了628 mL;泡沫半衰期为95 min,相对提高了68 min。因此,GP-1是污泥蛋白最好的泡沫稳定剂。     

Nutrient depletion is the main limiting factor in the crude oil bioaugmentation process

The biodegradation was considered as the prime mechanism of crude oil degradation. To validate the efficacy and survival of the crude oil-degrading strain in a bioremediation process, the enhanced green fluorescent protein gene (egfp) was introduced into Acinetobacter sp. HC8–3S. In this study, an oil-contaminated sediment microcosm was conducted to investigate the temporal dynamics of the physicochemical characterization and microbial community in response to bacterium amendment. The introduced strains were able to survive, flourish and degrade crude oil quickly in the early stage of the bioremediation. However, the high abundance cannot be maintained due to the ammonium (NH₄⁺-N) and phosphorus (PO₄^3?-P) contents decreased rapidly after 15 days of remediation. The sediment microbial community changed considerably and reached relatively stable after nutrient depletion. Therefore, the addition of crude oil and degrading cells did not show a long-time impact on the original microbial communities, and sufficient nitrogen and phosphorus nutrients ensures the survive and activity of degrader. Our studies expand the understanding of the crude oil degradative processes, which will help to develop more rational bioremediation strategies.     

新型复合垃圾衍生燃料的制备及性能分析

为了提高城市生活垃圾资源化利用的效率,采用室温冷压有粘结剂成型的方法将城市生活垃圾和煤按一定的配比制成新型复合垃圾衍生燃料,研究了成型压力、配比对衍生燃料的热稳定性、机械强度、粘结性以及发热量的影响.试验结果表明,在生活垃圾中加入煤可有效改善衍生燃料性能,增加其热值,在成型压力为25 MPa,煤配比为20%时复合衍生燃料的性能最优.     

Air pollution and inhalation exposure to particulate matter of different sizes in rural households using improved stoves in central China

Household air pollution is considered to be among the top environmental risks in China.To examine the performance of improved stoves for reduction of indoor particulate matter(PM) emission and exposure in rural households, individual inhalation exposure to size-resolved PM was investigated using personal portable samplers carried by residents using wood gasifier stoves or improved coal stoves in a rural county in Central China.Concentrations of PM with different sizes in stationary indoor and outdoor air were also monitored at paired sites. The stationary concentrations of size-resolved PM in indoor air were greater than those in outdoor air, especially finer particles PM0.25. The daily averaged exposure concentrations of PM0.25, PM1.0, PM2.5 and total suspended particle for all the surveyed residents were 74.4 ± 41.1, 159.3 ± 74.3, 176.7 ± 78.1 and 217.9 ± 78.1 μg/m3,respectively. Even using the improved stoves, the individual exposure to indoor PM far exceeded the air quality guideline by WHO at 25 μg/m3. Submicron particles PM1.0 were the dominant PM fraction for personal exposure and indoor and outdoor air. Personal exposure exhibited a closer correlation with indoor PM concentrations than that for outdoor concentrations. Both inhalation exposure and indoor air PM concentrations in the rural households with gasifier firewood stoves were evidently lower than the reported results using traditional firewood stoves. However, local governments in the studied rural areas should exercise caution when widely and hastily promoting gasifier firewood stoves in place of improved coal stoves, due to the higher PM levels in indoor and outdoor air and personal inhaled exposure.     

基于贝叶斯网络的地震次生燃气管道泄漏事件链构建

地震次生燃气管道泄漏事件是导致地震灾害影响扩大的主要原因之一,为了解建 筑物内地震次生燃气管道泄漏事件的发展过程,参考国内外相关的文献和统计资料,确 定建筑物内地震次生燃气管道泄漏事件贝叶斯网络的节点变量和取值范围。根据节点变 量及其逻辑关联性构建贝叶斯网络结构图,通过对国内外研究数据的统计并结合专家经 验估算确定各节点变量的条件概率。利用贝叶斯网络工具计算建筑物属性和环境变量在 不同状态取值下建筑物遭受破坏、燃气泄漏、燃气扩散引发二次灾害等关键节点变量的 后验概率。通过实例分析得出,建筑结构和地震烈度是建筑物遭受破坏的主要影响因素 ,风速、大气稳定度对燃气扩散引发二次灾害有显著影响。     

煤炭工业资源—环境—经济耦合协调分析——以榆林市为例

耦合协调发展水平的测度对于研究煤炭工业可持续发展具有重要意义.根据煤炭工业资源—环境—经济系统耦合机制,构建了该系统的评价指标体系,利用熵权法和TOPSIS法计算煤炭工业资源—环境—经济系统以及各子系统的评价值,通过耦合协调度模型计算耦合协调度,评估煤炭工业的资源—环境—经济系统的耦合协调水平.结果表明:2008-20...