栽植寒富苹果防风固沙修复土壤的效益分析

通过台安县西平林场大兴村栽植寒富苹果防风固沙修复土壤实验,证明在北方沙化土地上种植寒富苹果是可行的.以内蒙古"十五"林业生态建设所产生的生态效益为依据,寒富苹果基地建设,一方面促进农民增收,另一方面具有防风固沙修复土壤、涵养水源,保持水土的作用.能获得生态效益和经济效益双赢,在适宜地区具有广泛的推广价值.     

化工建设规划生态环境影响评价研究

规划环境影响评价是以可持续发展的思想为出发点,通过调整规划布局或规模从规划源头预防环境污染和生态破坏.文章探讨了化工建设规划的生态环境影响评价理论和方法学体系,并以武汉化工新城为例,对该理论方法体系进行探讨.     

双碱法烟气脱硫技术影响因素分析

双碱法在中小型燃煤锅炉的烟气脱硫上有着较广泛的应用,它克服了其他湿法脱硫容易结垢的缺点,且脱硫效率高。主要介绍近几年国内双碱法烟气脱硫效率主要影响因素的理论和实验研究现状,分析了pH值、钠离子浓度、液气比、硫酸根离子的比例和进口二氧化硫浓度等因素对该技术的脱硫效果的影响,提出了该技术目前存在的问题及其今后的发展方向。     

Characterization of submicron particles during autumn in Beijing, China

In this study, we performed a highly time-resolved chemical characterization of nonrefractory submicron particles(NR-PM_1) in Beijing by using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer(HR-ToF-AMS). The results showed the average NR-PM_1 mass concentration to be 56.4 ± 58.0 μg/m~3, with a peak at 307.4 μg/m~3. Due to the high frequency of biomass burning in autumn, submicron particles significantly increased in organic content, which accounted for 51% of NR-PM_1 on average. Secondary inorganic aerosols(sulfate + nitrate + ammonium) accounted for 46% of NR-PM_1, of which sulfate,nitrate, and ammonium contributed 15%, 20%, and 11%, respectively. To determine the intrinsic relationships between the organic and inorganic species, we used the positive matrix factorization(PMF) model to merge the high-resolution mass spectra of the organic species and NO+and NO_2~+ions. The PMF analysis separated the mixed organic and nitrate(NO+and NO_2~+) spectra into four organic factors, including hydrocarbon-like organic aerosol(HOA), oxygenated organic aerosol(OOA), cooking organic aerosol(COA), and biomass burning organic aerosol(BBOA), as well as one nitrate inorganic aerosol(NIA) factor. COA(33%) and OOA(30%) contributed the most to the total organic aerosol(OA) mass, followed by BBOA(20%) and HOA(17%). We successfully quantified the mass concentrations of the organic and inorganic nitrates by the NO+and NO2+ions signal in the organic and NIA factors. The organic nitrate mass varied from 0.01-6.8 μg/m~3, with an average of 1.0 ±1.1 μg/m~3, and organic nitrate components accounted for 10% of the total nitrate mass in this observation.     

Phytotoxicity and groundwater impacts of leaching from thermal treatment residues in roadways

The use of coal fly ash (CFA), municipal solid waste incinerator bottom ash (MSWIBA) and flue gas desulfurization residue (FGDR) in road construction has become very common owing to its economical advantages. However, these residues may contain toxic constituents that pose an environmental risk if they leach out and flow through the soil, surface water and groundwater. Therefore, it is necessary to assess the ecotoxicity and groundwater impact of these residues before decisions can be made regarding their utilization for road construction. In this study, the physico-chemical characteristics, leaching and phytotoxicity of these residues were investigated. Specifically, multivariate analyses were used to evaluate the contributions of the leaching constituents of the CFA, MSWIBA and FGDR leachates to the germination index of wheat seeds. B, Ba, Cr, Cu, Fe and Pb were found to be more toxic to the wheat seeds than the other heavy metals. Furthermore, the leached concentrations of the constituents from the CFA, MSWIBA and FGDR were below the regulatory threshold limits of the Chinese identification standard for hazardous wastes. Analyses conducted using a numerical groundwater model (WiscLEACH) indicated that the predicted field concentrations of metals from the CFA, MSWIBA and FGDR increased with time up to about 30 years at the point of compliance, then decreased with time and distance. Overall, this study demonstrated that the risks resulting from MSWIBA, CFA and FGDR leaching could be assessed before its utilization for road construction, providing crucial information for the adoption of these alternative materials.     

甬江水质控制规划研究

甬江流经经济腾飞的宁波市,污染日趋严重;新老工业混杂,老城区排水系统落后,是沿海开放城市实施水污染控制的共同问题。采取对有毒有害污染物实行浓度控制、对可降解污染物实行总量控制相结合的原则,因地制宜确定水质目标的指标体系,全面分析新老企业的污染治理状况、环境的纳污能力及经济响应关系,给出污染负荷-环境治理投资-甬江水质关系图线。由此可确定,宁波市只需投资1.9亿元,从重点污染源治理中去除BOD_3负荷2.5t/d,即可使甬江水质维持1987年状况,并较原分区二级治理方案节省投资2.5亿元。     

用传递矩阵法计算消声器插入损失的理论探讨

采用声电类比的传递矩阵法，本文对消声器插入损失进行了理论探讨，所推导的理论公式准确地反映了整个内燃机排气系统对消声器插入损失的影响，克服了其它学者在研究此问题中的不足，考虑了声源声阻抗对传递损失的影响，对消声器的整体优化设计具有重要的指导意义。     

Feedforward control for nitrogen removal in a pilot-scale anaerobic-anoxic-oxic plant for municipal wastewater treatment

To improve the efficiency of nitrogen removal with lower energy consumption, the study of feedforward control was carried out on a pilot-scale anaerobic-anoxicoxic (AAO) plant for the treatment of municipal wastewater. The effluent qualities of the pilot plant under different control strategies were investigated. The results indicated that the change of external recycle was not a suitable approach to regulate the sludge concentration of plug-flow reactors; adjusting the aeration valve and dissolved oxygen set-point according to ammonia load could overcome the impact of influent fluctuation; and the denitrification potential could be estimated based on the transit time of anoxic zone and the relative content of carbon resource entering the anoxic zone. Simple feedforward control strategies for aeration and internal recycle were subsequently proposed and validated. The nitrogen removal was successfully improved in the pilot plant. The effluent total nitrogen had decreased by 29.9% and was steadily controlled below 15 mg·L⁻¹. Furthermore, approximately 38% of the energy for aeration had been saved.