固定化三维电极-生物膜法去除污水中硝酸盐氮

本研究将固定化细胞技术用于三维电极-生物膜反应器的阴极微生物挂膜,对现有的三维电极-生物膜反应器进行了改进。同时,以城市污水二级生化处理系统的出水为研究对象,利用自制的固定化三维电极-生物膜反应器进行了反硝化深度脱氮试验。考察了电流强度、HRT、不同C/N值等因素对硝态氮和COD去除率的影响,并通过对比试验证实了固定化细胞技术的使用可提高反应器的反硝化性能。试验结果表明,在电流强度30mA,进水流量9mL/min时,COD的去除率为50%,硝态氮的去除率可达82.03%,反应器NO3--N负荷为0.297mg NO3--N(/cm2.d);同等操作条件下,采用固定化方法挂膜的反应器的脱氮效率可比普通反应器提高20%以上。     

污水厂二沉池出水化学除磷实验研究

在原水总磷较高的情况下,生物除磷已不能满足除磷要求。化学除磷作为生物除磷的重要补充显得非常重要。液体硫酸铝是一种很好的化学除磷药剂,在二沉池出水总磷大于2．00mg／L的情况下,60．00mg／L液体硫酸铝投加量可以使TP降至0．50mg／L以下,去除率达到80．00％以上。适宜的水动力条件是除磷效果的保证。     

Effect of illumination intensity and light application time on secondary organic aerosol formation from the photooxidation of α-pinene

Secondary organic aerosol (SOA) formation from hydroxyl radical (OH.) initiated photooxidation of α-pinene was investigated in a home-made smog chamber. The size distribution of SOA particles was measured using aerodynamic particle sizer spectrometer. The effects of illumination intensity and light application time on SOA formation for α-pinene were evaluated. Experimental results show that the concentration of SOA particles increased significantly with an increasing of illumination intensity, and the light...     

Modeling of secondary treated wastewater disinfection by UV irradiation: Effects of suspended solids content

This work aimed to study UV-resistant strains of Pseudomonas aeruginosa, to propose a formulation of the kinetics of secondary treated wastewater disinfection and to underline the influence of suspended solids on the inactivation kinetics of these strains. Some investigations were carried out for the validation of some simulation models, from the simplest, the kinetics model of Chick-Watson reduced to first order, to rather complex models such as multi-kinetic and Collins-Selleck models. Results revealed that the involved processes of UV irradiation were too complex to be approached by a simplified formulation, even in the case of specific strains of microorganisms and the use of nearly constant UV radiation intensity. In fact, the application of Chick-Watson model in its original form is not representative of the kinetics of UV disinfection. Modification, taking into account the speed change during the disinfection process, has not significantly improved results. On the other hand, the application of Collins-Selleck model demonstrates that it was necessary to exceed a least dose of critical radiation to start the process of inactivation. To better explain the process of inactivation, we have assumed that the action of disinfectant on the survival of lonely microorganisms is faster than its action on suspended solids protected or agglomerated to each others. We can assume in this case the existence of two inactivation kinetics during the processes (parallel and independent) of the first-order. For this reason, the application of a new kinetic model by introducing a third factor reflecting the influence of suspended solids in water on disinfection kinetics appeared to be determinant for modeling UV inactivation of P. aeruginosa in secondary treated wastewater.     

废旧锂离子电池回收处理技术研究进展

通过介绍废旧锂离子电池的构成及近年来废旧锂离子电池回收处理技术的研究进展,综述了目前主要回收方法有溶解分离法和直接回收正极材料的新型方法等,并对现有研究中存在的二次污染、安全性问题进行了初步探讨。     

京津冀区域气溶胶中无机水溶性离子污染特征分析

在北京、天津、石家庄、承德城区和北京上甸子区域本底站共设置5个采样点,2009～2010年分季节采集环境PM<,2.5>,并分析其中的无机水溶性离子,进而研究京津冀区域气溶胶中离子组分的污染特征.研究表明,京津冀PM<,2.5>污染较重,北京、天津和石家庄年均浓度均超过了100 μg/m<'3>;5个站点二次离子(SO...     

热泵蒸发及其在浓缩垃圾渗滤液中应用的初探

在热泵蒸发过程中,二次蒸汽压缩比是个至关重要的参数,它直接关系到热泵蒸发的经济程度。对热泵蒸发中的传热过程及可利用的余热作了全面分析。最后对热泵蒸发在浓缩垃圾渗滤液中的应用进行了探讨。     

Effects of two forest types on the dynamics of four base cations along with rainfall partitioning in middle subtropical forests北大核心CSCD

盐基离子随穿透雨和树干茎流的迁移成为森林元素输入的重要组成部分.在迁移过程中,冠层淋溶、树干冲刷等改变了盐基离子含量,而不同林型的林冠特征、树皮性质等存在差异,因此盐基离子含量在不同林型中可能存在差异对米槠次生林和杉木人工林穿透雨、树干茎流进行为期4年的监测,对比研究4种盐基离子(K+、Ca2+、Na+、Mg2+)浓度和输入量的动态特征.结果显示:(1)米槠次生林树干茎流Ca2+、Mg2+浓度显著低于杉木人工林而K+浓度显著高于杉木人工林;穿透雨除Na+浓度外均为米槠次生林显著高于杉木人工林.穿透雨和树干茎流Na+浓度林型差异不显著.(2)两种林型盐基离子季节动态变化基本一致,在雨季旱季各有一个峰值,雨季浓度普遍低于旱季.米槠次生林盐基离子浓度稳定性普遍高于杉木人工林.(3)分析盐基离子浓度与降雨强度的关系发现:Ca2+、K+、Mg2+浓度随雨量级的增加而降低,Na+浓度随雨量级的增加而增加.(4)观测期间米槠次生林穿透雨累计输入Ca2+、K+、Mg2+和Na+总量分别为47.97、35.17、7.15和12.94 kg/hm2,树干茎流累计输入Ca2+、K+、Mg2+和Na+总量分别为11.38、6.21、1.54和3.00 kg/hm2;杉木人工林穿透雨累计输入Ca2+、K+、Mg2+和Na+总量分别为47.24、26.63、6.43和11.55 kg/hm2,树干茎流累计输入Ca2+、K+、Mg2+和Na+总量分别为4.11、1.20、0.50和0.83 kg/hm2.米槠次生林的林内雨盐基离子输入量大于杉木人工林.总体而言,米槠次生林比杉木人工林有更高的养分输入,能更好地维持生态系统养分的供应;上述结果有助于进一步认识森林物质随水文过程的流动,可为人工林经营管理提供一定科学基础数据.(图6表1参36)     

Dynamic characteristics of woody plant regeneration in karst secondary forests in central Guizhou北大核心CSCD

Based on community data (2012, 2020) of the Tianlong Mountain evergreen and deciduous broadleaved mixed forest plot in central Guizhou, China, the species composition, importance value index, diversity, and dynamic changes were estimated to explore the renewal and change characteristics of karst secondary forests. The results showed that: (1) the number of individual species in the investigated two hm2 plot encompassing 33 families and 55 genera, totaling 69 species decreased from 10 276 to 7837. Five families, 10 genera, and 18 species were newly added, while seven families, nine genera, and 11 species disappeared. The difference between the importance value indices of the species was obvious; that of Lithocarpus confinis (20.97–23.26) was much higher than that of other species. Except for some species, the overall inter-annual differences were not large, and the status of mesophytic and shaded species has increased. Life forms were dominated by small trees and shrubs or small trees, and the plant number density of different life forms is reduced. (2) The Margalef and Shannon-Wiener indices of shrubs were the largest, and the Pielou indices of shrubs or small trees were the largest. The composition of most life forms has increased; the diversity became richer; and the uniform distribution of individual species has increased, but the change was small. (3) With respect to the spatial distribution pattern, the species were generally clustered, and only a few were randomly distributed. The Cx, I, m*, CA, and G indices of the species were reduced, and those of some species were quite different. A tendency for aggregated distribution was observed over random distribution, but the aggregation degree of Lithocarpus sphaerocephala was still high. The PAI index of most species increased but was not obvious, whereas the K value changed irregularly. Overall, the species composition, importance value index, diversity, and spatial distribution pattern of the main species in this community have changed to some extent but without any significant fluctuations. L. sphaerocephala was still the dominant species in succession, and the species composition of the flora was stable. The restoration of vegetation and the development of the entire community are slow. © 2022 Science Press. All rights reserved.     

地下停车场VOCs污染特征与健康风险评价

机动车尾气和蒸发排放的VOCs在地下停车场的半密闭环境中不断积累,威胁居民健康.为探究停车场内挥发性有机物（VOCs）浓度水平和变化特征与车队活动水平之间的关系,阐明其对居民健康的影响,选取天津市某居民小区地下停车场,开展了为期9d的VOCs样品采集,利用臭氧生成潜势（OFPs）,·OH反应速率（L_·OH）和二次有机气溶胶生成潜势（SOAPs）综合评价停车场内VOCs大气反应活性,对人体健康风险进行评价.结果表明：①停车场内VOCs浓度和组分变化主要受车队活动影响,工作日和周末的浓度峰值均与进场和出场车流峰值同步出现,即早晚高峰时段,工作日和周末早高峰浓度分别为（463.76±148.42）μg·m^-3和（391.47±135.37）μg·m^-3,晚高峰为（334.29±176.57）μg·m^-3和（416.20±134.64）μg·m^-3.停车场夜间几乎没有车辆活动,但夜间ρ（VOCs）［工作日（320.33±115.57）μg·m^-3;周末（364.77±155.32）μg·m^-3］仍高于午间［工作日（255.76±103.65）μg·m^-3;周末（350.91±108.73）μg·m^-3］,且夜间时段烯炔烃质量分数明显高于其他时段,这是由于夜间车辆静置时发生昼间排放产生较多的烯烃.②烯炔烃和芳香烃对OFPs和L_·OH贡献率最大（84.10%~88.04%）,芳香烃对各时间段的SOAPs贡献率最大（98.03%~98.99%）,说明芳香烃和烯炔烃的大气反应活性强且广泛存在于机动车源,是提高排放标准、升级油品时需首要考虑降低的关键组分.③健康风险评价结果表明,停车场内VOCs非致癌风险危险指数（HI）：0.19~0.55,暂无健康风险.而各时间段致癌风险均超过阈值（1×10^-6）1.56~3.11倍,停车场作为居民每天必经场所,应开启机械通风措施保证其中空气流通性.