大气污染物对流垂直输送作用的探讨

利用一个欧拉型硫沉降模式探讨了积云对硫污染物的对流垂直输送作用．结果表明,积云引起的垂直气流是造成大气污染物浓度分布及输送通量变化的重要因素．对流垂直输送可使硫污染物在高层出现大浓度区,浓度的增加率为５０％—４００％,中层和低层的浓度相应也有所变化．积云区内南北剖面上的通量也因对流输送作用在高层出现了大值中心．     

Vertical and temporal distribution of nitrogen and phosphorus and relationship with their influencing factors in aquatic-terrestrial ecotone： a case study in Taihu Lake, China

Vertical and temporal distributions of N and P in soil solution in aquatic-terrestrial ecotone （ATE） of Taihu Lake were investigated, and the relations among N, P, ORP （oxidation reduction potential）, TOC, root system biomass and microorganism were studied. As a whole, significant declines in TN, NO3^--N, DON （dissolved organic nitrogen） and TP concentration in soil solution have occurred with increase of the depth, and reached their minima at 60 cm depth, except for NH4^＋-N, which increased with depth. The concentration of TP increased gradually from spring to winter in the topsoil, the maximum 0.08 mg/L presented in the winter while the minimum 0.03 mg/L in spring. In the deeper layer, the concentration value of TP fluctuated little. As for the NO3^--N, its seasonal variation was significant at 20 cm depth, its concentration increased gradually from spring to autumn, and decreased markedly in winter. Vertical and temporal distribution of DON is contrary to that of NO3^--N. The results also show that the variation of N and P in the percolate between adjacent layers is obviously different. The vertical variation ofTN, TP, NO3^--N, NH4^＋-N and DON is significant, of which the variation coefficient of NO3^--N along the depth reaches 100.23%, the highest; while the variation coefficient of DON is 41.14%, the smallest. The results of correlation analysis show that the concentration of nitrogen and phosphorus correlate significantly with TOC, ORP, root biomass and counts of nitrifying bacteria. Most nutrients altered much from 20 to 40 cm along the depth. However, DON changed more between 60 and 80 cm. Results show that soil of 0-60 cm depth is active rhizoplane, with strong capability to remove the nitrogen and phosphorus in ATE. It may suggest that there exists the optimum ecological efficiency in the depth of above 60 cm in reed wetland. This will be very significant for ecological restoration and reestablishment.     

活性污泥数学模型中异养菌产率系数的测定研究

利用活性污泥数学模型预测污水生物处理系统,首先必须确定其参数和水质组分。采用间歇活性污泥法和呼吸计量法对活性污泥数学模型中异养菌产率系数γ_H进行测定研究。结果表明,间歇活性污泥法测定结果重现性较差,试验控制条件比较严格;呼吸计量法测定结果准确性较高,重现性良好,因而,呼吸计量法是比较可行的γ_H测定方法。     

青海共和盆地降尘观测与137Cs测定的初步结果

通过对1998～1999年共和盆地的降尘观测和尘样的¹³⁷Cs分析,测定了降尘速率及其月分配;对尘源进行了¹³⁷Cs示踪,并从理论上估算出降尘产生的¹³⁷Cs再分配,对沉积速率的计算模型进行了讨论.作为采用¹³⁷Cs法研究沙尘暴降尘的一次尝试,这些初步结果对沙尘暴测定及其强度评估等方面研究有一定的借鉴作用.     

Oxidation inhibition of sulfite in dual alkali FGD system

A laboratory-scale well-mixed thermostatic reactor with continuously blasting air was used to investigate the oxidation inhibition of sulfite in dual alkali flue gas desulfurization （FGD） system. The effects of operating parameters such as pH value and catalyst concentration on the oxidation were studied. Sodium thiosulfate was used in the system, and was found that it significantly inhabited the sulfite oxidation. In the absence of catalyst, sodium thiosulfate at 12.67 mmol/L had an inhibition efficiency of approximately 98%. While in the presence of catalyst, sodium thiosulfate at 26.72 mmol/L had an inhibition efficiency less than 85.0%. The oxidation reaction order of sulfite in the sodium thiosulfate was determined to be -1.90 and 4）.55 in the absence and presence of the catalyst, respectively. Apparent activation energy of oxidation inhibition was calculated to be 53.9 kJ/mol. Pilot tests showed that the consumption rate of thiosulfate agreed well with the laboratory-scale experimental results.     

油松排放萜烯类化合物浓度的日变化及排放速率的研究

 采用封闭式采样和气相色谱法分析监测了北京主要树种油松排放的萜烯类化合物，其中包括α和β蒎烯、蒈烯、松油烯、柠檬烯和罗勒烯，以及少量异戊二烯。松油烯、B蒎烯、柠檬烯和蒈烯的排放量之和占油松排放碳氢总量的94％以上。萜烯和异戌二烯排放速率随日照和温度的升高而增加。萜烯等浓度的日变化表明在正午和午夜油松有两个排放高峰。在日均气温为18℃时油松的碳氢化合物平均总排放速率约为8.7μh/h.g。     

强化启动对内循环生物流化床硝化效果的影响

通过改变内循环生物流化床的启动水质,提高N/C组成以强化流化床后期的硝化作用.结果表明,高N/C和低进水COD强化启动后处理生活污水,在HRT为2h时,可以同时高效去除COD和氨氮,氨氮的平均去除率为74%.耗氧速率试验表明,强化启动后,流化床中生物膜的异养菌活性大幅度降低,氨氧化细菌活性明显提高,硝化细菌活性变化不大.对反应系统微生物醌进行的跟踪分析表明,强化启动后,生物膜中的硝化细菌数量明显增加,微生物种群的分布均匀性变化较小,以革兰氏阴性菌为主.扫描电镜观察显示,低N/C启动条件下,生物膜厚且致密,异养菌所占比例高;高N/C启动条件有利于硝化细菌的生长,生物膜相对稀薄.     

降雨对香溪河库湾主要藻种原位生长的影响

为明晰蓄水期降雨对三峡库区香溪河支流主要藻种原位生长的影响因素,本文在三峡水库降雨前后采用原位培养装置(培养笼)对铜绿微囊藻、小球藻和栅藻生物量变化特征进行原位培养实验.结果表明:①研究期间(2017年10月4～18日)降雨期与非降雨期水动力条件存在显著性差异(ANOVA,P 0. 05),降雨期间3种主要藻种Chl-a总量、比生长速率均显著小于非降雨期(ANOVA,P 0. 05),表明降雨对藻类生长起一定的抑制作用;相关分析结果指出,表征垂向掺混的4个水动力参数与3种藻种比生长速率呈显著/极显著负相关关系,表明水动力条件中剪切力τ、垂向紊流黏性系数Vr和垂向紊流扩散系数Vt的改变是导致藻类迅速衰亡的关键因素;②降雨前培养装置内混合层深度较低(1～2 m),降雨后(10月10～18日)混合层深度明显上升(大于5 m),同时降雨期叶绿素a(Chl-a)浓度显著低于非降雨期(ANOVA,P 0. 05).相关分析结果表明,光混比与3种藻种的比生长速率呈显著/极显著正相关,表明降雨导致水体垂向扰动增强,混合层不断扩大,打破了水体原有的水温分层从而抑制藻类的生长增殖;③降雨量、水温、光照强度、总氮(TN)和溶解性总氮(DTN)在降雨期与非降雨期均存在显著差异(ANOVA,P 0. 05),相关分析表明,降雨带来降雨量、水温、光照强度、总氮(TN)和溶解性总氮(DTN)改变是影响3种主要藻种比生长速率的关键环境参数.     

两种新型涂铁改性砂的过滤性能及反冲洗条件研究

以两种新型涂铁改性石英砂(纳米氧化铁改性砂,Nano-OCS;氧化铁改性砂,IOCS)及普通石英砂(RQS)为研究对象,考察了两种新型改性砂对沉后水腐殖酸及浊度的直接过滤效果,对其反冲洗条件进行优化研究,并对3种滤料的过滤效果进行了比较.结果表明,1滤层厚度为45 cm时,最佳滤速为6 m·h-1;3种滤料对腐殖酸和浊度的直接过滤效果依次为:Nano-OCSIOCSRQS,其中两种涂铁砂对腐殖酸的去除率分别为71.70%和61.61%;2Nano-OCS和IOCS滤柱的反冲洗流程分4步,对应的流程及最佳操作条件为:首先,用0.5 mol·L-1NaOH的溶液浸泡,气冲强度13 L·s-1·m-2,气冲时间6 min;然后,用0.075 mol·L-1的NaOH溶液与空气同时反冲洗,NaOH溶液冲洗强度为8 L·s-1·m-2,气冲强度13 L·s-1·m-2,冲洗时间3 min;接着用0.015 mol·L-1的FeCl3溶液与空气同时反冲洗,FeCl3溶液冲洗强度为8 L·s-1·m-2,气冲强度13L·s-1·m-2,冲洗时间2 min;最后,用清水冲洗,冲洗强度8 L·s-1·m-2,冲洗时间4 min.两种涂铁砂反冲洗前后表面形态结构更加复杂、粗糙度增加,对腐殖酸去除率进一步提高.3当滤层厚度由45 cm增加到80 cm时,Nano-OCS对腐殖酸直接过滤的最高去除率由74.6%提高至80.3%,平均去除率由57.9%提高至68.5%.     

大别山超高压变质杂岩的折返

作为世界上规模最大的一个超高压变质带，大别山超高压变质杂岩是扬子板块 与中朝板块在三叠纪碰撞造山的产物，表现为扬子板块呈北北东向斜向俯冲到中朝板块之下。 超高压变质杂岩的折返机制是个复杂的动力学过程，折返速率也随时间推移而变慢。早期阶段 （三叠纪－早侏罗纪）同碰撞期浮力驱动下高压－超高压变质杂岩在俯冲带内沿道冲－韧性剪 切断裂快速挤侵（ｅｘｔｒｕｓｉｏ）到地壳层位，折返速率高达４ｍｍ／年；中期伴随着巨厚造山带山根的 拆沉，上部发生拉张塌陷，使超高压变质杂岩进一步减压，但折返速率缓慢，～(４０)Ａｒ／~(３９)Ａｒ年代学显 示１１７Ｍａ前它们仍处在地壳的较深部；晚期伴随着晚侏罗－早白垩纪花岗质岩浆的上升侵位， 超高压变质杂岩进一步抬升，同时低角度正断层发育，此阶段的折返机制类似于变质核杂岩模 型。整个折返过程中剥蚀一直在起作用。