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21.
城市高污染水体生物生态处理技术研究   总被引:2,自引:0,他引:2  
针对城市高污染水体的特点,建成了粉煤灰基质滤料生物过滤与复合水生植物滤床组合处理系统。生物过滤在有机物和氨氮的去除方面起主要作用,磷则主要是通过人工湿地去除。运行结果表明,组合工艺出水COD、TP、NH3-N、TN平均浓度分别为16.35 mg/L、0.08 mg/L、2.68 mg/L、15.63 mg/L,均满足《城市污水再生利用——城市杂用水水质》(GB/T18920-2002)标准要求。  相似文献   
22.
城市热力景观格局季节变化特征分析及其应用   总被引:1,自引:0,他引:1  
热岛效应是城市发展过程中所产生的特有的环境问题,已经成为一种城市环境公害,对其形成和演变规律的研究有助于人们提出有效的应对措施。热力景观是分析城市热岛空间格局的一种新方法。以厦门为研究对象,利用2002年1、2、3、8、12月的Landsat ETM+影像数据进行地表温度反演,在此基础上使用景观格局指数分析厦门城市热力景观格局的季节变化特征。结果表明:厦门城市热岛在夏季(8月)最强,春秋次之,冬季(1月)最弱。该变化特征是城市地表吸收太阳辐射和人为废热排放随季节变化的共同结果。应用该方法对2002年厦门热污染源进行调查,发现当年共有热污染源26个,其中工业热污染源18个。该研究可为环保、能源等部门乃至于整个城市的规划管理提供有力的决策依据。  相似文献   
23.
吴昊  孙丽娜  王辉  王晓旭 《环境化学》2016,35(4):623-628
本文探讨了利用过氧化钙活化过硫酸钠氧化修复实际污染场地长期高浓度石油类(TPH)污染土壤的可行性.研究了过氧化氢、过氧化钙、过氧化钙/Fe2+等活化方法对TPH降解效率的影响.结果表明,对于TPH污染较重的土壤(浓度15000 mg·kg-1),过氧化钙较过氧化氢活化过硫酸钠降解的效果更好,使用过氧化氢活化方法,TPH最高降解率仅为25.6%,而当过氧化钙/过硫酸钠的用量(物质的量之比)为1/5时,反应7 d,TPH去除率达到67.4%,反应不需要添加额外的活化剂.当Fe2+/过氧化钙/过硫酸钠的用量为1/2/5时,反应7 d,TPH降解率为82.1%,较不添加Fe2+高14.6%,反应后体系呈中性.进一步增加过氧化钙的用量,TPH去除率和体系pH均增加.研究表明,CaO2/Fe2+活化过硫酸钠氧化修复石油类污染土壤效果较好,考虑到实际场地后续利用的可行性,Fe2+/过氧化钙/过硫酸钠的用量为1/2/5较为合适.  相似文献   
24.
    
● MSWNet was proposed to classify municipal solid waste. ● Transfer learning could promote the performance of MSWNet. ● Cyclical learning rate was adopted to quickly tune hyperparameters. An intelligent and efficient methodology is needed owning to the continuous increase of global municipal solid waste (MSW). This is because the common methods of manual and semi-mechanical screenings not only consume large amount of manpower and material resources but also accelerate virus community transmission. As the categories of MSW are diverse considering their compositions, chemical reactions, and processing procedures, etc., resulting in low efficiencies in MSW sorting using the traditional methods. Deep machine learning can help MSW sorting becoming into a smarter and more efficient mode. This study for the first time applied MSWNet in MSW sorting, a ResNet-50 with transfer learning. The method of cyclical learning rate was taken to avoid blind finding, and tests were repeated until accidentally encountering a good value. Measures of visualization were also considered to make the MSWNet model more transparent and accountable. Results showed transfer learning enhanced the efficiency of training time (from 741 s to 598.5 s), and improved the accuracy of recognition performance (from 88.50% to 93.50%); MSWNet showed a better performance in MSW classsification in terms of sensitivity (93.50%), precision (93.40%), F1-score (93.40%), accuracy (93.50%) and AUC (92.00%). The findings of this study can be taken as a reference for building the model MSW classification by deep learning, quantifying a suitable learning rate, and changing the data from high dimensions to two dimensions.  相似文献   
25.
Snakehead fish (Ophiocephalus argus cantor), silver carp (Hypophthalmichthys molitrtix), crucian carp (Carassius carassius), and common carp (Cyprinus carpio) are four common freshwater fish species in China. In this study, the level of methylmercury (MeHg), total mercury (T-Hg), and total selenium (T-Se) in muscle samples of these four fish species from Ya-Er Lake, China, were analyzed using atomic fluorescence spectrometry coupled with high-performance liquid chromatography, and inductively coupled plasma mass spectrometry. The concentrations of MeHg in all the fish species were significantly correlated with those of T-Hg. Higher T-Hg and MeHg concentrations had accumulated in the snakehead fish, which is a strongly predatory fish, than in the other three species. The concentration ratios of MeHg and T-Hg in the muscles of these four fish species were almost equal. Conversely, there was negative correlation between the concentrations of T-Hg and T-Se, which implies that there is a competition between these two elements with respect to bioaccumulation. It is noteworthy that of all the muscle samples tested, the level of T-Hg exceeded the maximum allowable limit in fish [0.4 mg kg−1 (w/w) recommended by the World Health Organization] in 38.46% of those of the silver carp, 18.18% of those of the crucian carp, and 100% of those of snakehead fish. These results show that the consumption of contaminated fish is a potential threat to human health and that necessary preventive measures to safeguard public health should be emphasized.  相似文献   
26.
    
With scholars paying increasing attention to energy sustainability, integrating energy sustainable utilization into the energy-related assessment framework is particularly useful for achieving SDG7. This study empirically assesses the energy-related efficiency (EE) comprised of the energy utilize stage and energy sustainable stage in China using a dynamic two-stage data envelopment analysis model, and its influencing factors including digital economy with fixed-effect models. The findings reveal a slight downward trend of EE from 2011 to 2020, primarily due to the poor performance of energy utilize stage. The subregional analysis illustrates that increasing clean energy use (CEU) is more beneficial to energy efficiency than reducing carbon emissions (CER). Dagum Gini coefficients indicate a growing disparity between regions. Additionally, a “U-shaped” relationship between digital economy and EE is found, but two-thirds provinces of China have not yet surpassed the turning point. Moreover, different degrees of CEU and CER will influence the impact of digital economy on EE. Environmental regulations and green technology innovation play positive moderating roles in the “U-shaped” relationship. This study recommends to stimulate the energy sustainable use through higher adoption of clean energy sources and carbon emissions reduction, as well as highlight the green value of the digital economy.  相似文献   
27.
Environmental Science and Pollution Research - In this study, the degradation performance of nutrients in zeolite trickling filter (ZTF) with different influent C/N ratios and aeration conditions...  相似文献   
28.
Environmental Science and Pollution Research - Over the last decades, the demographic changes have all altered the population structure and influenced the social, economic, and political...  相似文献   
29.
The focus of this study, carried out on mudflat and mangrove sediments of Ulhas Estuary and Thane Creek in Mumbai, India, documents how sediment analysis in different ecosystems can help in understanding metal behaviour and pollution status of the region. Based on the the geoaccumulation index (I geo ), the study shows that the estuarine and creek regions, being recipients of industrial and domestic wastes, display moderate pollution. Ulhas Estuary with higher clay and organic matter contents, exhibits higher amounts of metals than Thane Creek. Furthermore, using correlation and cluster analyses, the creek projects stable subenvironments with similar types of metal associations, with Fe and total organic carbon as the dominant metal carriers. By contrast, in the estuarine subenvironments, the metal associations do not reveal any distinct trend, which may be attributed to the disturbance caused by dredging activities routinely carried out in the region. Factor analysis carried out on I geo data in both regions further helped in identifying polluted metal groups.  相似文献   
30.
China has the fifth largest forest area in the world and any change in China's forestry development will have inevitable impacts on global ecological sustainability. China has undergone excessive logging of natural forests and also made tremendous efforts in afforestation during the past half century. China's forestry is now going through a variety of transitions and several forestry programs have been implemented to drive forestry transitions. The goal of these actions is to protect ecological services of forests and sustain China's forestry development. These forestry programs are spatially sophisticated and cannot be successfully implemented without accurate and transparent forest/forestry information. A variety of digital technologies, including forest modeling, remote sensing, geographic information systems, global positioning systems, and visualization, have been applied in handling diverse information in China's forestry. Digital forestry is not just a theoretical concept in China. Our digital forestry experience in northeast China suggests that digital technology is both usable and useful in China's forestry development. Digital technology is playing an important interactive role in China's top-down forestry administration system. The analog-to-digital transition in technology is expected to lead to the success of forestry programs and forestry transitions in China.  相似文献   
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