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991.
沱江流域综合整治规划   总被引:2,自引:1,他引:2  
施为光 《四川环境》1996,15(3):67-71
本文首先在描述了沱江流域的水质问题,沱江干流的几个主要水质指标与10年前相比呈继续恶化的趋势,于流的水污染仍未得到控制,工业点源污染和流域非点源是造成流域水污染的主要原因,沱江流域水环境潜在问题陆生生态恶化和水资源贫乏两大难题,文章提出了工业污染源控制,修建城市污水厂,增加枯水流量和提高森林覆盖率等综合防治措施。  相似文献   
992.
Decomposition of soil organic carbon (SOC) is a critical component of the global carbon cycle, and accurate estimates of SOC decomposition are important for forest carbon modeling and ultimately for decision making relative to carbon sequestration and mitigation of global climate change. We determined the major pools of SOC in four sites representing major forest types in China: temperate forests at Changbai Mountain (CBM) and Qilian Mountain (QLM), and sub-tropical forests at Yujiang (YJ) and Liping (LP) counties. A 90-day laboratory incubation was conducted to measure CO(2) evolution from forest soils from each site, and data from the incubation study were fitted to a three-pool first-order model that separated mineralizable soil organic carbon into active (C(a)), slow (C(s)) and resistant (C(r)) carbon pools. Results indicate that: (1) the rate of SOC decomposition in the sub-tropical zone was faster than that in the temperature zone, (2) The C(a) pool comprised approximately 1-3% of SOC with an average mean residence time (MRT) of 219 days. The C(s) pool comprised approximately 25-65% with an average MRT of 78 yr. The C(r) pool accounted for approximately 35-80% of SOC, (3) The YJ site in the sub-tropical zone had the greatest C(a) pool and the lowest MRT, while the QLM in the temperature zone had the greatest MRT for both the C(a) and C(s) pools. The results suggest a higher capacity for long-term C sequestration as SOC in temperature forests than in sub-tropical forests.  相似文献   
993.
厌氧-吹脱-好氧-吸附法处理酱油废水   总被引:5,自引:0,他引:5  
针对酱油废水的高CODCr、高色度、高挥发酸以及含盐的特点,设计了用厌氧-吹脱-好氧-吸附法处理酱油废水的工艺。实验结果表明,该工艺对酱油废水的处理有较好的处理效果。当厌氧进水的CODCr分别为6000~8000和1500~2000mg/L,色度分别为5000和1800倍左右时,厌氧反应的水力停留时间(HRT)分别为3~4和2d,吹脱池的停留时间为16h,气水比为0.01m^3/L,好氧反应器和煤渣吸附池的停留时间分别为14~18和14~16h时,该流程对废水CODCr的总平均去除率分别达到90%和82.7%左右,对色度的总平均去除率分别为76.7%和86.5%。  相似文献   
994.
Journal of Polymers and the Environment - Although polyvinyl alcohol (PVA) membranes are commonly used for CO2 separation, there is still large development space in mechanical properties and high...  相似文献   
995.
本文研究了沱江流域水资源的开发利用问题。由于流域内水资源贫乏和开发利用程度较高,枯水期中下游区无法保证水资源的需要。随着工业的发展,沱江水质污染将日趋严重致使枯水期有限的水资源变成不能使用的污水。因此,本文较详细地研究了沱江水质保护规划。在水目标、水污染控制最优方案、总量控制标准、流域水质保护区划等方面进行了探讨,文中从水量和水质两方面着手,根据系统工程原理求得解决水资源问题的最佳方案。  相似文献   
996.
Shi  En  Wang  Xinyu  Zhang  Miao  Wang  Xin  Gao  Jianchun  Zheng  Yunbin 《Environmental Chemistry Letters》2022,20(4):2253-2259
Environmental Chemistry Letters - Wastewater treatment generates increasing amounts of unwanted sewage sludges, calling for advanced recycling methods. Here, we transformed sewage sludge into...  相似文献   
997.
Environmental Science and Pollution Research - Good surface water quality is critical to human health and ecology. Land use determines the surface water heat and material balance, which cause...  相似文献   
998.
999.
The effects of free chlorine disinfection of tap water and wastewater effluents on the infectivity, gene integrity and surface antigens of rotaviruses were evaluated by a bench-scale chlorine disinfection experiments. Plaque assays, integrated cell culture-quantitative RT-PCR (ICC-RT-qPCR), RT-qPCR, and enzyme-linked immunosorbent assays (ELISA), respectively, were used to assess the influence of the disinfectant on virus infectivity as well as genetic and antigenic integrity of simian rotavirus SA11 as a surrogate for human rotaviruses. The ICC-RT-qPCR was able to detect rotaviruses survival from chlorine disinfection at chlorine dose up to 20 mg/L (60 min contact), which suggested a required chlorine dose of 5 folds (from 1 to 5 mg/L) higher than that indicated by the plaque assay to achieve 1.8 log10 reductions in tap water with 60 min exposing. The VP7 gene was more resistant than the infectivity and existed at chlorine dose up to 20 mg/L (60 min contact), while the antigencity was undetectable with chlorine dose more than 5 mg/L (60 min contact). The water quality also impacted the inactivation efficiencies, and rotaviruses have a relatively higher resistant in secondary effluents than in the tap water under the same chlorine disinfection treatments. This study indicated that rotaviruses have a higher infectivity, gene and antigencity resistance to chlorine than that previously indicated by plaque assay only, which seemed to underestimate the resistance of rotaviruses to chlorine and the risk of rotaviruses in environments. Present results also suggested that re-evaluation of resistance of other waterborne viruses after disinfections by more sensitive infectivity detection method (such as ICC-RT-qPCR) may be necessary, to determine the adequate disinfectant doses required for the inactivation of waterborne viruses.  相似文献   
1000.
Objective: Safety performance at bus stops is generally evaluated by using historical traffic crash data or traffic conflict data. However, in China, it is quite difficult to obtain such data mainly due to the lack of traffic data management and organizational issues. In light of this, the primary objective of this study is to develop a quantitative approach to evaluate bus stop safety performance.

Methods: The concept of level-of-safety for bus stops is introduced and corresponding models are proposed to quantify safety levels, which consider conflict points, traffic factors, geometric characteristics, traffic signs and markings, pavement conditions, and lighting conditions. Principal component analysis and k-means clustering methods were used to model and quantify safety levels for bus stops.

Results: A case study was conducted to show the applicability of the proposed model with data collected from 46 samples for the 7 most common types of bus stops in China, using 32 of the samples for modeling and 14 samples for illustration. Based on the case study, 6 levels of safety for bus stops were defined. Finally, a linear regression analysis between safety levels and the number of traffic conflicts showed that they had a strong relationship (R2 value of 0.908).

Conclusions: The results indicated that the method was well validated and could be practically used for the analysis and evaluation of bus stop safety in China. The proposed model was relatively easy to implement without the requirement of traffic crash data and/or traffic conflict data. In addition, with the proposed method, it was feasible to evaluate countermeasures to improve bus stop safety (e.g., exclusive bus lanes).  相似文献   

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