健康住宅的降噪问题与技术措施

健康住宅的噪声控制,包括对噪声源的认识、进行降噪的方法设计、技术措施实施效果的分析等内容。笔者在研究健康住宅噪声种类和控制标准、分析控制噪声基本措施的基础上,认为健康住宅噪声控制的难点在于设计方法和技术措施两方面,解决问题的思路是将降噪手段视为系统工程,包括住区户外和住宅室内两大系统;综合设计降噪控制技术,才能达到健康住宅声环境的控制标准。     

Phosphorus Load Reduction Goals for Feitsui Reservoir Watershed, Taiwan

The present paper describes an effort for developing the total maximum daily load (TMDL) for phosphorus and a load reduction strategy for the Feitsui Reservoir in Northern Taiwan. BASINS model was employed to estimate watershed pollutant loads from nonpoint sources (NPS) in the Feitsui Reservoir watershed. The BASINS model was calibrated using field data collected during a 2-year sampling period and then used to compute watershed pollutant loadings into the Feitsui Reservoir. The simulated results indicate that the average annual total phosphorus (TP) loading into the reservoir is 18,910 kg/year, which consists of non-point source loading of 16,003 kg/year, and point source loading of 2,907 kg/year. The Vollenweider mass balance model was used next to determine the degree of eutrophication under current pollutant loading and the load reduction needed to keep the reservoir from being eutrophic. It was estimated that Feitsui Reservoir can becoming of the oligotrophic state if the average annual TP loading is reduced by 37% or more. The results provide the basis on which an integrated control action plan for both point and nonpoint sources of pollution in the watershed can be developed.     

利用人工湿地系统深度处理城市污水尾水

利用垂直复合流模拟人工湿地系统对城市污水厂尾水进行深度处理实验研究,植物床选用美人蕉、菖蒲、茭草、芋头和象草混合栽种,采用石英砂为主体填料。实验研究表明:人工湿地系统在停留时间为24h,水力负荷为0.4m3(m2·d)的运行条件处理效果较佳,在此条件下连续稳定运行10个月,处理后的尾水主要指标达到(GBT189212002)标准。     

生物滴滤塔处理氯苯废气的工艺性能

将活性污泥培养及驯化后接种于生物滴滤塔中,挂膜启动后处理模拟氯苯废气（简称氯苯废气）,考察了生物滴滤塔在挂膜启动阶段及稳定运行阶段的性能。实验结果表明：接种41 d后生物滴滤塔成功挂膜,此时氯苯去除率稳定在90%以上;生物滴滤塔稳定运行阶段,随着进气中氯苯质量浓度由303.82 mg/m³逐渐增至1 489.05 mg/m³,氯苯去除率从85.1%降至70.1%。处理氯苯废气适宜的工艺条件为：空塔停留时间超过45 s,喷淋液流量31.8 mL/min,氯苯负荷23.97~128.01 g/（m³·h）。生物滴滤塔对喷淋液的酸性环境有较好的适应性,喷淋液pH的变化对氯苯去除率无显著影响。     

丹阳市宅基地使用权流转意愿的影响因素及相互作用

通过丹阳市4个村320户农户实地问卷调查,分析了丹阳市宅基地使用权流转意愿的影响因素,由Logistic回归分析模型,给出了影响因素的驱动力、贡献率的数学表达。结果表明：文化程度、宅基地个数、家庭总收入等影响因素对流转意愿呈正相关;户主年龄、家庭人口数量等影响因素对流转意愿呈负相关。同一农户的影响因素在不同阶段对流转意愿度的贡献率不同,家庭收入和户主年龄是影响宅基地流转的主要因素,他们对宅基地流转分别起着推力和阻力作用,在相互作用过程中,两者之间彼此消长。实地抽样结果分析表明,丹阳农村户主文化程度若为初中且年龄在35岁时,家庭收入能达到34 000元的话,宅基地使用权流转意愿度超过50%。以后每年家庭收入能有一定增速的话,农户流转意愿度将持续保持在50%以上。     

生物滴滤塔处理模拟甲硫醚废气

在常温条件下,采用生物滴滤塔处理模拟甲硫醚废气,考察了气体空床停留时间(EBRT)、容积负荷、喷淋密度及营养液pH对生物滴滤塔性能的影响。实验结果表明:当EBRT为90 s、进气甲硫醚质量浓度为150 mg/m~3、喷淋密度为0.65 m~3/(m~2·h),营养液pH为6.8时,甲硫醚去除率为90%;容积负荷高于15 g/(m~3·h)时,对生物滴滤塔的性能产生抑制作用;EBRT为90 s及60 s时,最佳喷淋密度分别为0.56~0.65 m~3/(m~2·h)及0.65~0.75 m~3/(m~2·h);降解甲硫醚的微生物对pH的变化较敏感,最适营养液pH为6~7。     

以焦炭为填料的生物滴滤塔处理含挥发性脂肪酸臭气

在以焦炭为填料的生物滴滤塔对挥发性脂肪酸臭气的处理研究中考察了空床停留时间、臭气浓度、体积负荷以及进气温度等参数对净化效果的影响。结果表明,空床停留时间较长时对臭气降解有利。在停留时间超过97 s时,能实现完全降解;此外,净化率随臭气浓度和体积负荷的不断增加呈先增加后降低的趋势。当臭气浓度为24.29 mg/m³即臭气的体积负荷为3 g/（m³·h）时,去除率约为96%;当臭气浓度增至1 345.74 mg/m³即体积负荷增至18 g/（m³·h）,去除率达100%;然而,当臭气浓度增至4 934.38 mg/m³即体积负荷增至66 g/（m³·h）时,去除率降至73.1%。另外,进气温度对净化率也有一定程度影响。当进气温度较低时,净化效率相对较高。     

PHYSICAL PROCESSES AND EUTROPHICATION1

ABSTRACT: Biological responses to physical-chemical processes were examined in Toronto and Hamilton Harbours of Lake Ontario. Nutrient loadings to the harbors are large and are of similar magnitude, yet the trophic conditions of the harbors were considerably different. Lake oscillations were found to determine the flushing rates and environmental stability of the harbors. LOW residence times (<10 days) resulted in homogenous chemical conditions in Toronto Harbour, and prevented the establishment of large phytoplankton crops. The longer retention time of Hamilton Harbour permitted the establishment of huger phytoplankton crops. There probably exists a critical retention time where nutrient input events persist for a sufficient period of time for the algal community to adapt to and exploit the environmental conditions of nearshore areas.     

停留时间对滴滴涕农药热处理特性的影响研究

利用高温管式炉研究停留时间对滴滴涕农药热处理特性的影响。结果表明,600℃时ηDDT在15 min内迅速增长,在15 min后稳定在85%上下;900℃时,当停留时间≥15 min,ηDDT≥99%;1 200℃时,各时段的ηDDT≥99.9%。在滴滴涕农药残渣中,DDTs在600℃和900℃时的配比随停留时间的增加变化甚微,在1 200℃时,p,p’-DDD、DDT和o,p’-DDT分别占DDTs总量的比例随时间增加明显降低,p,p’-DDE则大幅增加。在尾气中,DDTs在600℃时的配比随停留时间的增加无明显变化,DDT为主要尾气残留物质,900℃时DDTs在尾气中配比变化混乱,1 200℃时,p,p’-DDE的比例随停留时间的增长迅速增加,并成为尾气中的主要DDTs残留物质。     

Environmental Persistence of Chemicals

- DOI: http://dx.doi.org/10.1065/espr2006.01.008 Background The hazard criterion of persistence as it applies to chemicals in the environment is reviewed and discussed. This quantity can not be measured directly in the environment, thus it must be estimated using models that synthesise information on chemical half-lives and partitioning properties, the nature of the environment and how the chemical is released into the environment. Main Features It is suggested that the preferred criterion is the average residence time of the chemical in the environment, i.e. conceptually the sum of the life-times of all molecules (attributable only to losses by degrading reactions) divided by the number of molecules. If all chemical fate processes are first order, this persistence is independent of the quantity of chemical introduced and whether introduction is steady- or unsteady-state in nature. It is shown that in a multimedia environment persistence is affected not only by degradation kinetics, but also by mode-of-entry and partitioning. For screening level purposes a Level II equilibrium model may be adequate but a Level III model is generally preferable for estimating the average persistence. If a distribution of persistences is required a dynamic Level IV model must be used. Discussion The implications for regulating chemicals on the basis of persistence are discussed. Conclusion It is concluded that the preferred strategy is to use Level II, III, and IV models and that the use of only degradation kinetics or media-specific half-lives can be misleading and uneconomical.