Analysis of Influences between the Energy Structure Change and Energy Intensity in China

In this article, based on the data of the energy statistics from 1980 to 2004, we analyze the relationship between the primary energy structures, technique, management, and the energy use per unit of GDP based on the path analysis approach and present the degree of the direct, indirect, and the overall influences of the primary energy structures on the energy use per unit of GDP. The results show that the technical change and management level play a decisive role in the energy use per unit of GDP, and the ratio of oil consumption was the major limiting factor to energy use per unit of GDP. We then found the model of the energy use per unit of GDP and the structures of the primary energy consumption, eliminated the multicollinearity in the model with the path analysis result, and finally, analyzed the influence of the primary energy structure on the energy conservation.     

主成分分析法优化治理黑臭水体的碳素纤维铺设密度

在治理黑臭水体的碳素纤维铺设密度优化研究中,借助统计学软件(SIMCA-P),以4个指标(COD、TP、NH3-N、TN)作为分析变量,探讨了单指标优化法与主成分分析法分析样本数据的差别。结果表明:单指标优化法可以确定4个指标各自的最优铺设密度,而主成分分析法能综合4个指标的信息进行分析,并优选出碳素纤维的最优铺设密度为40 cm2/L,为碳素纤维的综合运用提供参考依据。     

Threat of heavy metal contamination in eight mangrove plants from the Futian mangrove forest,China

Mangrove plants play an important role in heavy metal maintenance in a mangrove ecosystem. To evaluate the characteristics of heavy metal contamination in the Futian mangrove forest, Shenzhen, China, eight heavy metals in mangrove sediments and plants were monitored, including essential elements such as Cu and Zn, and non-essential elements such as Cr, Ni, As, Cd, Pb and Hg. The results showed that the heavy metals exhibited the following scheme: Zn > As > Cu ≈ Cr > Pb > Ni > Cd ≈ Hg in sediment cores, among which Cd, As, Pb and Hg contents were nearly ten times higher than the background values. There was no significant difference in metal maintenance capability between native and exotic species. In mangrove plants’ leaves and stems, concentrations of Cu, Zn and As were higher than other heavy metals. The low bioconcentration factors for most heavy metals, except for Cr, implied the limited ability of heavy metal accumulation by the plants. Mangrove plants seem to develop some degree of tolerance to Cr. The factor analysis implies that anthropogenic influences have altered metal mobility and bioavailability.     

Enhanced dewatering characteristics of waste activated sludge with Fenton pretreatment: effectiveness and statistical optimization

In this work, the enhanced dewaterabing characteristics of waste activated sludge using Fenton pretreatment was investigated in terms of effectiveness and statistical optimization. Response surface method （RSM） and central composite design （CCD） were applied to evaluate and optimize the effectiveness of important operational parameters, i.e., H202 concentrations, Fe2＋ concentrations and initial pH values. A significant quadratic polynomial model was obtained （R2= 0.9189） with capillary suction time （CST） reduction efficiency as the response. Numerical optimization based on desirability function was carried out. The optimum values for H202, Fe2, and initial pH were found to be 178 mg-g-1 VSS （volatile suspended solids）, 211mg.gI VSS and 3.8, respectively, at which CST reduction efficiency of 98.25% could be achieved. This complied well with those predicted by the established polynomial model. The results indicate that Fenton pretreatment is an effective technique for advanced waste activated sludge dewatering. The enhancement of sludge dewaterability by Fenton＇s reagent lies in the migration of sludge bound water due to the disintegration of sludge flocs and microbial cells lysis.     

北京市东北城区夏季环境空气中苯系物的污染特征与健康风险评价

于2013年8月2日至31日,利用Airmo VOC在线分析仪开展了北京市东北城区环境空气中挥发性有机物(VOCs)的在线监测,分析了其中16种苯系物的污染水平、变化特征、来源及其臭氧形成潜势(OFP),并采用US EPA的健康风险评价模型对BTEX(苯、甲苯、乙苯、间-对二甲苯、邻二甲苯)和苯乙烯的人体健康风险进行了评价。结果表明,16种苯系物在观测期间总平均质量浓度为10.36μg·m-3,其中BTEX的质量浓度均值为7.45μg·m-3,约占总的苯系物质量浓度的72%。苯系物的质量浓度呈现明显的一次污染物日变化特征,即早晚较高,中午较低。苯与甲苯的质量浓度比值(B/T)平均为0.39,说明除机动车尾气外,涂料和溶剂的挥发释放对大气中苯系物也可能具有重要贡献。间-对二甲苯、1,2,4-三甲苯和甲苯的OFP值较高,对北京市大气臭氧光化学形成具有显著贡献。BTEX和苯乙烯对人体的非致癌风险危害商值在8.70E-05至3.76E-02之间,危害指数为6.19E-02,对暴露人群尚不存在明显的非致癌风险;而苯的致癌风险值为8.80E-06,超过了US EPA的建议值1.00E-06,显示苯对研究区居民身体健康存在潜在的致癌风险。     

饮水型砷中毒病区人群砷暴露量及尿砷的季节变化

地下水高砷暴露的健康危害是环境与健康领域面临的巨大挑战。水砷含量及暴露人群饮水量参数的季节性变化可能影响饮水砷暴露评估的准确性。本研究选择内蒙古饮水砷中毒病区为研究区,测定丰水期(2013年5月)和枯水期(2013年12月)居民饮用水和尿液各形态砷(三价无机砷iAs~(3+)、五价无机砷iAs~(5+)、一甲基砷MMA~(5+)和二甲基砷DMA~(5+)+)含量,研究砷暴露量和尿砷的季节变化。结果表明,丰水期水砷含量(134.4±25.8)μg·L~(-1)显著低于枯水期的(163.2±38.1)μg·L~(-1),且丰水期水中iAs~(3+)的含量(58.9±51.2)μg·L~(-1)也显著低于枯水期的(100.1±49.0)μg·L~(-1)。研究人群丰水期通过饮水的摄砷量为313.1μg·d~(-1),低于枯水期的378.6μg·d~(-1)。此外,丰水期居民尿液总砷含量(218.6μg·L~(-1))显著低于枯水期(283.1μg·L~(-1))。丰水期女性居民尿液iAs、MMA~(5+)和总砷含量随当季饮水iAs~(5+)含量的升高而显著降低,枯水期女性尿液MMA5+含量随当季饮水iAs~(3+)及iAs含量的升高而显著升高。可见,病区居民饮水砷暴露量与尿砷含量具有明显的季节差异性,饮水砷与尿砷的关系受饮水砷形态、季节变化及性别等因素影响。     

Effects of Modified Starch and Different Molecular Weight Polyvinyl Alcohols on Biodegradable Characteristics of Polyvinyl Alcohol/Starch Blends

The common biodegradable properties of polymer make them an excellent pair for blending, and the water solubility of polyvinyl alcohol (PVA) makes it easy to mix evenly with the starch. In this study, PVAs with different molecular weights were blended with various compositions of cross-linked starch (CLS) to explore the effects of molecular weight of PVA on the biodegradable characteristics of the PVA/starch blends. Comparing the biodegradability of all the various PVA/starch blends, a PVA was singled out from the PVA/starch blends of higher biodegradability. Further, the chosen PVA was then blended with the acid-modified starch (AMS) to systematically investigate the effects of the modified processing of starch on the biodegradable characteristics of the PVA/starch blends. Differential scanning calorimetry (DSC) analysis of PVA and PVA/starch specimens reveal that the T_m values of PVA/starch specimens reduce gradually as their CLS or AMS contents increase. After the CLS is blended in PVAs of different molecular weights, the tensile strength (??_f) and elongation at break (??_f) values of (P₁₀₀S₀)G₂₀M₁ specimen increase and simultaneously reduce, respectively, as their molecular weights of PVA increase from about 80,000 (PVA_BF-17) to 120,000 (PVA_BF-26). The ??_f and ??_f values of the PVA/modified-starch blends decrease with an increase in the modified starch contents. The ??_f values of the PVA/AMS specimens decrease with an increase in the concentrations of hydrochloric acid. Comparing the ??_f values of the PVA/CLS specimens with those of the PVA/AMS specimens, the ??_f values of the PVA/CLS specimens are better than those of the PVA/AMS specimens. On the contrary, the ??_f values of the PVA/AMS specimens are better than those of the PVA/CLS specimens. According to the biodegradability of all the PVA/starch blends, PVA with higher molecular weights displays higher biodegradability. The biodegradability of the PVA/modified-starch blends increase as the modified starch contents of the PVA/modified-starch blends increase. As evidenced by the results of the biodegradability test, the biodegradability of the PVA/modified-starch blends, therein PVA is blended with 1N AMS, shows better biodegradability. The result of bio-reaction kinetics experiment can evaluate the decomposition tendency of the PVA/starch blends up to any biodegradable rate under ambient environment. Using the kinetic model of the first order reaction, it is estimated that 16.20?years and 12.47?years will be needed for the PVA_BF-17/starch blends, containing 20 and 40% of CLS respectively, to be degraded up to 70% under ambient environment. In addition, it is 1.68?years for the PVA_BF-26 blends with the 40% 2N AMS under decomposition environment while it is 1.94?years for the 40% 1N AMS. Overall, the decomposition potential of PVA/AMS specimens is better than PVA/CLS specimens. Furthermore, the 1N(26P₆₀AS₄₀)₁₀₀G₂₀M₁ specimen is coincidence the biodegradable material criteria of Environmental Protection Administration (EPA) of Taiwan.     

Leaching of heavy metals from solidified waste using Portland cement and zeolite as a binder

This study investigated the properties of solidified waste using ordinary Portland cement (OPC) containing synthesized zeolite (SZ) and natural zeolite (NZ) as a binder. Natural and synthesized zeolites were used to partially replace the OPC at rates of 0%, 20%, and 40% by weight of the binder. Plating sludge was used as contaminated waste to replace the binder at rates of 40%, 50% and 60% by weight. A water to binder (w/b) ratio of 0.40 was used for all of the mixtures. The setting time and compressive strength of the solidified waste were investigated, while the leachability of the heavy metals was determined by TCLP. Additionally, XRD, XRF, and SEM were performed to investigate the fracture surface, while the pore size distribution was analyzed with MIP. The results indicated that the setting time of the binders marginally increased as the amount of SZ and NZ increased in the mix. The compressive strengths of the pastes containing 20 and 40wt.% of NZ were higher than those containing SZ. The compressive strengths at 28 days of the SZ solidified waste mixes were 1.2-31.1MPa and those of NZ solidified waste mixes were 26.0-62.4MPa as compared to 72.9MPa of the control mix at the same age. The quality of the solidified waste containing zeolites was better than that with OPC alone in terms of the effectiveness in reducing the leachability. The concentrations of heavy metals in the leachates were within the limits specified by the US EPA. SEM and MIP revealed that the replacement of Portland cement by zeolites increased the total porosity but decreased the average pore size and resulted in the better containment of heavy ions from the solidified waste.     

地理信息系统在环境安全中的应用与发展

随着社会的发展,环境安全的呼声日益高涨,信息时代的到来,使随之发展起来的地理信息系统成为解决环境问题的重要方法。从环境安全的角度出发,论述了地理信息系统在环境安全领域的应用及其在环境领域的发展。     

A new method of inhibiting pollutant release from source water reservoir sediment by adding chemical stabilization agents combined with water-lifting aerator

A new method of adding chemical stabilization agents combined with water-lifting aerator can inhibit pollutant release from source water reservoir sediment effectively.