旋流板塔内石灰湿法烟气脱硫的试验研究

试验研究了在旋流板塔内以石灰湿法进行烟气脱硫率的影响，并对试验结果进行了分析讨论，得出了回归关联式。本研究为工业装置的设计、操作和运行提供了所必需的基础数据。     

珠江三角洲表层土壤中的多环芳烃

多环芳烃是一类主要由人类活动排放的有毒有机污染化合物,对人和生物体具有致癌、致畸和致突变效应,是评价土壤生态污染的重要内容之一。文章利用螺旋钻采样、索氏抽提、硅胶氧化铝净化和GC-MS分析,研究了珠江三角洲不同功能区(城市点、郊区点、乡村点)的76个表层土壤样品(耕作土、非耕作土)中多环芳烃(PAHs)的含量、分布特征及其影响因素。结果表明,16种优控PAHs的总质量分数范围为31.5~791.6ng·g-1(平均279.1ng·g-1,以干质量计),以萘(44.4%)、菲(13.7%)、荧蒽(8.4%)、芘(4.9%)、■(6.6%)等化合物为主。与国内外其它地区的城市相比较,珠江三角洲地区土壤PAHs的污染程度较低,在组成上也表现出亚热带地区独特的中、低环化合物为主的特征。受人类经济活动的影响,地处珠江三角洲中部的经济工业中心地带,土壤中PAHs含量相对较高。珠三角表层土壤PAHs含量和组成分布主要受大气沉降控制,而与土壤有机碳、pH的相关性较小。高温潮湿的亚热带季风气候是影响珠三角土壤PAHs的降解和迁移的重要环境因素。     

Efficacy of a Biomonitoring (Moss Bag) Technique for Determining Element Deposition Trends on a Mid-Range (375 Km) Scale

National networks detect multi-state trends in element deposition using direct measurement methods. Biomonitoring techniques have been used to examine deposition in local areas and around point sources. We sought to determine the efficacy of a moss bag technique to detect element deposition trends on a mid-range (state) scale, and to compare these results with those of the National Acid Deposition Program/National Trends Network (NADP/NTN, 1999). We sampled heavy metals, sulfur, and nitrogen deposition (21 elements) using mesh bags containing Sphagnum russowii at nine sites, over a 375 km transect crossing southern Wisconsin (upper Midwest, USA). We found statistically significant trends of decreasing deposition in a northwesterly direction for 13 elements: Al, B, Ca, Cd, Co, Cu, Cr, Fe, Mg, Mn, Ni, S, and Zn. Six of these have moderate to large changes in concentration (14–37%). The trends for Ca, Mg, and S are consistent with regional deposition patterns in 1998 isopleth maps from the NADP/NTN (1999) which are derived from a sampling array far less dense than the transect sites. This national network indicates that Ca and Mg increase to the southeast, beyond Wisconsin borders. The fact that the present study demonstrates strong correlations between both of these elements (Ca and Mg) and Al, B, Cr, Cu, Fe, Mn, Ni, and Zn (mean r for all correlations = 0.75, p < 0.02) implies that these correlated elements also increase to the southeast in neighboring states.     

Losses of nitrogen and phosphorus from agricultural and forest areas in Finland during the 1980s and 1990s

The temporal changes and spatial variability of phosphorus andnitrogen losses and concentrations in Finland during the period1981–1997 were studied in 15 small agricultural and forestedcatchments. In addition, four coastal river basins with highagricultural land use located in southern Finland were includedin the study in order to assess the representativeness ofagricultural loss estimates from small agricultural catchments.The mean annual loss specific for agricultural land was estimatedto be on average 110 kg km^-2 a^-1 for total phosphorusand 1500 kg km^-2 a^-1 for total nitrogen. The resultsfrom small agricultural catchments were in agreement with thecorresponding loss estimates from rivers, with an average of137 kg km^-2 a^-1 for total phosphorus and 1800 kg km^-2a^-1 for total nitrogen. The results from the studiedagricultural catchments and rivers during the period 1981–1997suggest that weather-driven fluctuation in discharge was usuallythe main reason for changes in nutrient losses, and little or noimpact of changes in agricultural production or managementpractises can be observed. In forested areas the total phosphorusloss (average 9 kg km^-2 a^-1) and total nitrogen loss(average 250 kg km^-2 a^-1) were lower than inagricultural areas. In forested catchments the impact of forestryoperations, such as clear-cutting and fertilization, and theimpact of atmospheric nitrogen deposition can be seen in changesin nutrient losses.     

Transport,deposition and biodegradation of particle bound polycyclic aromatic hydrocarbons in a tidal basin of an industrial watershed

Polycylic aromatic hydrocarbons (PAHs) are commoncontaminants in industrial watersheds. Their origin,transport and fate are important to scientists,environmental managers and citizens. The Philadelphia NavalReserve Basin (RB) is a small semi-enclosed embayment nearthe confluence of the Schuylkill and Delaware Rivers inPennsylvania (USA). We conducted a study at this site todetermine the tidal flux of particles and particle-boundcontaminants associated with the RB. Particle traps wereplaced at the mouth and inside the RB and in the Schuylkilland Delaware Rivers. There was net particle deposition intothe RB, which was determined for three seasons. Spring andfall depositions were highest (1740 and 1230 kg ofparticles, respectively) while winter deposition wasinsignificant. PAH concentrations on settling particlesindicated a net deposition of 12.7 g PAH in fall and 2.1 gPAH in spring over one tidal cycle. There was nosignificant PAH deposition in the winter. Biodegradationrates, calculated from ¹⁴C-labeled PAH substratemineralization, could attenuate only about 0.25% of the PAHdeposited during a tidal cycle in fall. However, in thespring, biodegradation could be responsible for degrading50% of the settling PAHs. The RB appears to be a sink forPAHs in this watershed.     

干湿交替对自然沟渠沉积物反硝化速率的影响

以川中丘陵区自然沟渠沉积物为研究对象,设置低强度、中强度、高强度的干湿交替频率和长期淹水对照处理,运用室内原状土柱-乙炔抑制培养法和实时荧光定量PCR技术,研究了干湿交替对自然沟渠沉积物反硝化速率及相关功能基因的影响.结果表明：在试验模拟过程中,干湿交替显著降低了沉积物中NH₄⁺-N和DOC含量,沉积物中NO₃^--N含量则表现为先增加后减少的趋势.沉积物反硝化速率均值表现为中强度（266.42 μg·m^-2·h^-1） > 高强度（199.10 μg·m^-2·h^-1） > 低强度（152.93 μg·m^-2·h^-1） > 长期淹水（9.57 μg·m^-2·h^-1）.干湿交替增加了反硝化功能基因的拷贝数（p<0.05）,nosZ基因拷贝数在实验前后无显著差异;低强度和中强度处理的nirK基因拷贝数在实验前后差异显著,中强度处理的nirS基因拷贝数在实验前后差异显著.Pearson相关分析结果表明,沉积物的反硝化速率与NO₃^--N含量、ORP和nirK基因拷贝数呈显著正相关（p<0.05）.干湿交替可能主要通过改变沉积物的NO₃^--N含量、ORP和nirK基因拷贝数影响沉积物反硝化速率.     

城市污水管网污染物沉积与冲刷释放规律研究

为明确城市污水管网中污染物沉积、冲刷释放及微生物降解作用对有机物去除的贡献,以管网中城市污水为研究对象,通过建立有沉积与无沉积的模拟管道,在首次冲刷的理论基础上得到管道污染物沉积释放计算模型,进而研究了不同流量下有机污染物的沉积与冲刷释放规律,并对不同流量下进出水的粒径分布及颗粒组成进行分析。结果表明,在管道6 h水力循环条件下,当流速为0.32 m/s时,污水中有机物变化以沉积贡献为主;当流速增加为管网最小设计流速0.6 m/s时,污染物沉积现象得到显著改善,冲刷释放效应增强;当流速进一步增加为0.9 m/s时,冲刷释放成为主要作用,生物降解作用微弱。     

Deposition behavior of residual aluminum in drinking water distribution system: Effect of aluminum speciation

Finished drinking water usually contains some residual aluminum.The deposition of residual aluminum in distribution systems and potential release back to the drinking water could significantly influence the water quality at consumer taps.A preliminary analysis of aluminum content in cast iron pipe corrosion scales and loose deposits demonstrated that aluminum deposition on distribution pipe surfaces could be excessive for water treated by aluminum coagulants including polyaluminum chloride（PACl）.In this work,the deposition features of different aluminum species in PACl were investigated by simulated coil-pipe test,batch reactor test and quartz crystal microbalance with dissipation monitoring.The deposition amount of non-polymeric aluminum species was the least,and its deposition layer was soft and hydrated,which indicated the possible formation of amorphous Al（OH）₃.Al₁₃ had the highest deposition tendency,and the deposition layer was rigid and much less hydrated,which indicated that the deposited aluminum might possess regular structure and self-aggregation of Al₁₃could be the main deposition mechanism.While for Al₃₀,its deposition was relatively slower and deposited aluminum amount was relatively less compared with Al₁₃.However,the total deposited mass of Al₃₀ was much higher than that of Al₁₃,which was attributed to the deposition of particulate aluminum matters with much higher hydration state.Compared with stationary condition,stirring could significantly enhance the deposition process,while the effect of pH on deposition was relatively weak in the near neutral range of 6.7 to 8.7.     

基于CWPO法处理垃圾渗滤液的CuO/TiO_2催化剂的制备及其性能研究

采用过量浸渍的方法制备CuO/TiO_2催化剂,以垃圾转运站的渗滤液为对象评价催化剂的活性及稳定性。采用XRD、SEM、BET对催化剂进行了表征,并利用催化湿式氧化法处理垃圾渗滤液。考察了制备过程中煅烧温度、煅烧时间、负载比以及浸渍液浓度对垃圾渗滤液处理效果的影响。结果表明:煅烧温度为300℃,煅烧时间为2 h,负载比为16.5%,浸渍液浓度为0.8 mol/L条件下,渗滤液COD去除率达到78.6%,脱色率达到88.2%。     

湿式电除尘器给排水技术的研究与应用

湿式电除尘器是作为燃煤电厂大气污染治理的终端精处理设备的首选,但湿式电除尘器存在耗水量巨大、排出的灰水存在二次污染、内部件腐蚀严重等问题,严重影响了湿式电除尘器在国内燃煤电厂上的大型化应用。为此,对湿式电除尘器的喷淋给水、水质、灰水循环利用、废水排放等进行了研究分析并结合实际工程应用经验加以阐述,提出了科学合理的给水和排水方式,实现了湿式电除尘器在燃煤电厂工艺系统上的零水耗,有效解决了内部件腐蚀问题。