好氧颗粒污泥强化解体实验与机理研究

在120r／min的搅拌及pH=1的强酸条件下,进行好氧颗粒污泥的强化解体实验,研究颗粒污泥的总数、平均粒径和粒径分布的变化情况。在15h实验时间内,搅拌强化解体的颗粒平均粒径从1230μm降至320μm,颗粒总数从30个／mL增至193个／mL。强酸强化解体结果类似,但解体时间为110h。搅拌比强酸对颗粒解体的强化作用更明显。粒径分布结果显示,小颗粒所占比例明显增加。颗粒解体过程中粒径分布均符合对数正态分布,但颗粒粒径的期望值石,随解体时间明显减小。根据颗粒的解体机理,即4种解体类型：破碎、破裂、剥落和研磨,结合实验结果,将解体过程分为对数期、平缓期、二次对数期和稳定期。     

湖域工业初始排污权纳什议价模型研究——以江苏省太湖流域纺织行业为例

针对湖域工业初始排污权定价问题,文章从多利益相关者合作视角出发,结合我国现阶段基本国情,利用合作博弈理论构建了基于多利益相关者合作的湖域工业初始排污权纳什议价(Nash-Bargaining)定价模型。即在满足湖域水环境排污权总量控制及区域产业规划调整方案的前提下,通过政府主体与行业主体之间考虑议价能力系数λ影响的Nash-Bargaining,求解符合价格约束的行业初始排污权价格的最大满意解。其中,价格约束通过求解行业治污成本函数的Aumann-Shapley值给出。并以江苏省太湖流域纺织染整行业为例,针对湖域工业点源氨氮初始排污权定价问题,对比分析了Nash-Bargaining定价模型与江苏省太湖流域现行氨氮类资源价格,结果表明:议价能力系数λ对Nash-Bargaining定价模型影响显著,λ的合理区间为0.5≤λ≤0.7,现行氨氮初始排污权价格对应于0.3<λ<0.4时的情况,不利于初始排污权资源的可持续利用;现行氨氮初始排污权价格的标准化系数ξ=0.91,以λ=0.6时的价格为例,Nash-Bargaining定价模型所给出的价格的标准化指数ξ=0.85,具有比现行价格更强的资源补偿性能,考虑到太湖流域污染现状,Nash-Bargaining定价模型所得价格可行性更强。因此,建议适当调高氨氮初始排污权价格。     

An economic evaluation and assessment of environmental impact of the municipal solid waste management system for Taichung City in Taiwan

Municipal solid waste management (MSWM) is an important environmental challenge and subject in urban planning. For sustainable MSWM strategies, the critical management factors to be considered include not only economic efficiency of MSW treatment but also life-cycle assessment of the environmental impact. This paper employed linear programming technique to establish optimal MSWM strategies considering economic efficiency and the air pollutant emissions during the life cycle of a MSWM system, and investigated the correlations between the economical optimization and pollutant emissions. A case study based on real-world MSW operating parameters in Taichung City is also presented. The results showed that the costs, benefits, streams of MSW, and throughputs of incinerators and landfills will be affected if pollution emission reductions are implemented in the MSWM strategies. In addition, the quantity of particulate matter is the best pollutant indicator for the MSWM system performance of emission reduction. In particular this model will assist the decision maker in drawing up a friendly MSWM strategy for Taichung City in Taiwan. Implications: Recently, life-cycle assessments of municipal solid waste management (MSWM) strategies have been given more considerations. However, what seems to be lacking is the consideration of economic factors and environmental impacts simultaneously. This work analyzed real-world data to establish optimal MSWM strategies considering economic efficiency and the air pollutant emissions during the life cycle of the MSWM system. The results indicated that the consideration of environmental impacts will affect the costs, benefits, streams of MSW, and throughputs of incinerators and landfills. This work is relevant to public discussion and may establish useful guidelines for the MSWM policies.     

沸石粉在污泥生态床中的应用研究

研究了不同沸石粉投加比例对污泥脱水、沉降、干化时间、污泥生态床中植物根部干重的影响,最终选定沸石粉投加比例为6%。在此投加比例下,对污泥生态床中的氮磷含量进行了测定,结果表明,黄花鸢尾床与芦苇床,总磷含量下降分别为13.2%和12.2%;总氮含量下降分别为48.3%和49.2%;硝氮含量下降分别为67.2%和70.2%。     

Short-chain chlorinated paraffins (SCCPs) in surface soil from a background area in China: occurrence, distribution, and congener profiles

Short-chain chlorinated paraffins (SCCPs) are extremely complex technical mixtures of polychlorinated n-alkanes with carbon chain lengths from C₁₀ to C₁₃ and chlorine content between 49 and 70 %. SCCPs are under consideration for inclusion in the Stockholm Convention on persistent organic pollutants. SCCPs have been used extensively in industrial production, but little is known about the pollution level in soil environment in China. In this study, levels and distribution of SCCPs in soil samples from Chongming Island were analyzed. Concentrations of total SCCPs in soil samples ranged from 0.42 to 420 ng?g^?1, with a median of 9.6 ng?g^?1. The ubiquitous occurrence of SCCPs in Chongming Island implied that long-range atmospheric transport and soil–air exchange may be the most important pathways for SCCP contamination in the background area. The localized SCCP contamination could be derived from an unidentified source. Hierarchical cluster analysis indicated that C₁₃- and C₁₁-congeners were predominant in most soils and C₁₀- and C₁₂-congeners dominated in the remaining soils. Cl₇- and Cl₈-congeners were on the average the most dominant chlorine congeners in nearly all soils. Principal component analysis suggested that the separation of even and odd carbon chain congeners occurred during long-range atmospheric transport and aging in soil in the study area.     

D006树脂对Cd(Ⅱ)的吸附性能研究

通过树脂筛选实验,选用大孔强酸性阳离子树脂D006作为Cd(Ⅱ)的吸附材料,通过静态实验考察吸附时间、振荡转速、溶液pH和树脂用量对吸附效果的影响,并探讨了吸附的热力学和动力学性能,同时对树脂进行了再生实验。结果表明,D006树脂对Cd(Ⅱ)的平衡吸附量可达20.98mg/g;D006树脂吸附Cd(Ⅱ)的最佳条件为吸附时间120min、振荡转速120r/min、溶液pH 2.9左右、树脂用量0.20g;D006树脂对Cd(Ⅱ)的吸附过程符合Langmuir方程,为单分子层吸附;准二级动力学模型能较好地描述Cd(Ⅱ)在D006树脂上的吸附行为,吸附的活化能为5.46kJ/mol,该吸附过程主要为物理吸附;于30℃下采用1mol/L硫酸对吸附后的D006树脂进行脱附,脱附率可达到96%以上,可实现对Cd(Ⅱ)的富集与回收。     

Development and Pilot Plant Evaluation of Silica- Enhanced Lime Sorbents for Dry Flue Gas Desulfurization

EPA’s efforts to develop low cost, retrofitable flue gas cleaning technology include the development of highly reactive sorbents. Recent work addressing lime enhancement and testing at the bench-scale followed by evaluation of the more promising sorbents in a pilot plant are discussed here.

The conversion of Ca(OH)₂ with SO₂ increased several-fold compared with Ca(OH)₂ alone when Ca(OH)₂ was slurrled with fly ash first and later exposed to SO₂ in a laboratory packed bed reactor. Ca(OH)₂ enhancement increased with the increased fly ash amount. Dlatomaceous earths were very effective reactivity promoters of lime-based sorbents. Differential scanning calorimetry of the promoted sorbents revealed the formation of a new phase (calcium silicate hydrates) after hydration, which may be the basis for the observed Improved SO₂ capture.

Fly ash/lime and diatomaceous earth/lime sorbents were tested in a 100 m³/h pilot facility incorporating a gas humidifier, a sorbent duct injection system, and a baghouse. The inlet SO₂ concentration range was 1000-2500 ppm. With once-through dry sorbent injection into the humidified flue gas [approach to saturation 10–20°C (18–36°F) in the baghouse], the total SO₂ removal ranged from 50 to 90 percent for a stoichiometric ratio of 1 to 2. Recycling the collected solids resulted in a total lime utilization exceeding 80–90 percent. Increased lime utilization was also investigated by the use of additives.     

Urban CO Concentrations and Vehicle Emissions

The effect of the general growth of CO vehicular emissions in urban areas on the CAMP station measurements in downtown areas, where vehicular traffic is saturated is considered. With the assumption that the street-level CO concentration is derived from the sum of an urban background term and a local street-effect term, the urban background CO concentration is computed with a diffusion model by introducing a simple area source distribution. The local street-effect term is taken to be constant at a saturation emission level corresponding to a saturation traffic density when the emission per vehicle-mile and meteorological conditions are fixed. The present analysis indicates that the local street-effect term, AC, has a major role in determining street-level concentrations for pollutants, such as CO, whose air quality standard is based on maximum concentrations with averaging times of 1 hour and 8 hours. The relevance of this analysis to the abatement requirements of the Clean Air Amendments and to the driving cycle adopted is discussed.     

An Equilibrium Analysis of Some Chlorinated Hydrocarbons in Stoichiometric to Fuel-rich Post-flame Combustion Environments

The equilibrium composition of product gases from the combustion of chlorinated hydrocarbons (CHC) has been studied for varying ratios of C, H, Cl, and O under stoichiometric to fuel-rich conditions. An interactive, PC-compatible FORTRAN program, STANJAN, was utilized in conjunction with thermochemical data sources to calculate equilibrium compositions of gas mixtures as a function of temperature. The predicted results, when judiciously Interpreted, assist in the understanding of the potential for formation of residual organic substance emissions (ROSEs) in post-flame environments of an incinerator.

Arguments are presented for the potential formation of chlorinated species, which are stable at ambient temperature, if locally fuel-rich mixtures penetrate into the lower temperature zones of an incinerator. ROSEs that have been observed in field tests of incinerators burning chlorinated compounds are predicted to form under the fuel-rich condition. Furthermore, when the equivalence ratio is greater than unity by even a slight amount, the degree of chlorination of product gases increases markedly when the Cl/H ratio also exceeds unity. In that case, time, temperature, turbulence and an overall fuel-lean stoichiometry may not be sufficient to guarantee elimination of measurable levels of chlorinated products. Possible implications of the equilibrium calculations are discussed. Further systematic studies with additional CHCs, nitrogen?, sulfur?, and heavy metal-bearing compounds are recommended as well as continued efforts to carry out kinetic studies.