臭氧-曝气生物滤池深度处理印染制革园区废水

针对浙江省某印染制革园区污水处理厂二级生化出水,开展了处理规模36~120 t/d的臭氧-曝气生物滤池中试研究,对臭氧预处理进行优化,考察了臭氧预处理优化后与不同填料BAF组合对污染物的去除情况。结果表明,当臭氧预处理条件为投加量25 mg/L,三点投加且投加比为6：3：1,臭氧接触时间为42 min时,处理效果较好且最经济;在此臭氧预处理条件下,臭氧-活性炭BAF的出水COD能稳定在50 mg/L,色度稳定在5度,满足《城镇污水厂污染物排放标准》（GB 18918-2002）中的一级B排放要求;臭氧-混合填料BAF的出水COD和色度也能基本达到一级B排放要求;而臭氧-陶粒BAF出水COD和色度都未能达到一级B排放要求。     

The importance of skillful community leaders: understanding municipal pesticide policy change in Calgary and Halifax

This paper focuses on policy change under scientific uncertainty. This is done by exploring two case studies of Canadian pesticide policy evolution applied to Sabatier's ‘Advocacy Coalition Framework’. ‘Stakeholder’ and ‘narrative policy’ analyses are emphasised to understand pesticide policy changes in Calgary (public education without a restrictive by-law) and Halifax (restrictive by-law). The parallel case studies consist of qualitative interviews with members of pesticide policy advisory committees in each city and a content analysis of local newspaper articles. Key resources mobilised by coalitions to achieve their policy goals include skillful leadership, and the use by those leaders of the media to disseminate coalition narratives. Further, the context of policy change contributed to the scenarios whereby pro-by-law grassroots activists were particularly successful in Halifax and anti-by-law city employees were most influential in Calgary.     

复配介质去除地下水中腐殖酸

以模拟地下水为研究对象,进行了复配介质去除地下水中腐殖酸的实验研究。探讨了配比、粒径、固液比、pH和温度对腐殖酸去除效果的影响。腐殖酸的浓度通过紫外分光光度法测定。结果表明:在不加活性炭的条件下,H物质∶X物质∶Q物质=1∶8∶8时,其硬度较好;在初始pH=6.34、反应时间为4 h时,去除率可达到95%以上;当反应时间≤1 h时,去除率随粒径增大而减小,而当反应时间为2～6 h时,小粒径和中等粒径复配介质对腐殖酸去除率略高于大粒径;一定浓度范围内,腐殖酸的去除率与固液比呈正相关,但固液比增大时,并不能无限提高去除率,当固液比为1∶200～1∶50时,去除率呈现平台;pH对复配介质去除效果影响不大,而温度对腐殖酸的去除有显著影响,较低温度(16.8℃)下的去除率比较高温度(35.0℃)下的去除率高5%。该复配介质去除地下水中腐殖酸是有效可行的,可作为PRB(permeable reactive barrier,渗透反应格栅)的潜在反应介质。     

鼠李糖脂对不同菌株降解柴油污染物的影响

通过一系列实验分析了鼠李糖脂对柴油污染物生物降解的影响。单菌株柴油降解实验结果表明,在添加生物表面活性剂鼠李糖脂后,各菌株细胞表面疏水性均发生不同程度的增加,并且对柴油的降解率均有所提高。在混合菌的柴油污染物降解实验中,发现当向土壤中添加了200 mg/L鼠李糖脂时,对柴油的降解才有较大的提高;而当添加100 mg/L的鼠李糖脂到水体中时,对柴油的降解就有较大的提高,而当鼠李糖脂浓度提高为200 mg/L时,柴油的降解率却没有进一步明显的提高。这说明鼠李糖脂对柴油降解的影响程度不仅与环境介质有关,还与添加的鼠李糖脂浓度有关。进一步分析表明,添加适当浓度的鼠李糖脂不仅可以提高对柴油的降解率,而且可加速其降解速度,缩短生物修复所需时间。     

Effect of fluorescent silica nanoparticles in embryo and larva of Oryzias latipes: sonic effect in nanoparticle dispersion

We characterized fluorescent silica nanoparticles (FNPs), which had been applied in many biological systems, in fish embryo rearing media (ERM) solution and evaluated the potential toxicity to the early development of Oryzias latipes embryos. Distribution of FNPs in embryos and larvae of O. latipes was studied by fluorescent and confocal laser scanning microscopic studies. Embryos exposed to three different concentrations of FNPs in stirred or sonicated ERM solutions were observed up to 2 d after hatching. FNPs had a negligible effect on the hatchability of O. latipes embryos; however, compared to controls, more than 30% of eggs were abnormal in 10 and 50 mg FNP L⁻¹ solutions. We found that the toxic effect was increased in sonicated FNP solution, which seems to be related with the dissolution of FNPs in ERM solutions that could be accelerated by sonication. Further study found that the CaCl₂ included in ERM solution might enhance the dissolution of the FNPs and the silicate ion released from FNPs partially contributed to larval toxicity. This study showed that some nanoparticles may not be stable in biological fluids even if they are stable in water. Dissolution factors such as sonication and cellular components should be considered in biological application of nanoparticles.     

Scaling of spontaneous imbibition data with wettability included

Wettability is a dominant parameter governing spontaneous imbibition. However less attention has been paid to the effect of wettability on the scaling of spontaneous imbibition data. Actually few models can include wettability in scaling of spontaneous imbibition data. To this end, a scaling model has been developed for NAPL (oil)-saturated porous media with different wettability based on the fluid flow mechanisms in porous media. Relative permeability, capillary pressure, initial water saturation, and wettability are considered in the scaling model. Theoretically this scaling model is suitable for both cocurrent and countercurrent spontaneous imbibition. The experimental data of countercurrent spontaneous water imbibition at different wettability cannot be scaled using the frequently used scaling model but can be scaled satisfactorily using the scaling model developed in this study. An analytical solution to the relationship between recovery and imbibition time for linear spontaneous imbibition has also been derived in the case in which gravity is ignored. The analytical solution predicts a linear correlation between the recovery by spontaneous water imbibition and the square root of imbibition time, which has been verified against experimental data.     

处理含油地表水体的潜流湿地填料筛选及其性能评价

采用包括填料表面微观特征、元素构成、吸附性能、微生物附着生长性、经济性等因素的填料性能评价方法,对处理含油地表水的潜流湿地填料进行评价与筛选.静态吸附试验表明,各种填料对磷的吸附能力为炉渣＞陶粒＞沸石＞砾石＞砖块＞卵石,对石油类的吸附能力为炉渣＞陶粒＞砖块＞沸石＞砾石＞卵石;动态吸附试验表明,各种填料床对石油类的去除效果为炉渣床＞砾石床＞湖泊底泥床;放置在污染水体中的填料表面微生物总数和烃降解菌数量为砖块＞沸石＞砾石,陶粒和炉渣＞卵石.根据上述评价结果,选择总体性能较好的砾石、炉渣、砖块和沸石作为潜流湿地现场试验系统的填料.     

化学混凝与曝气生物滤池组合工艺用于再生水处理中试研究

将化学混凝与曝气生物滤池(BAF)结合,利用混凝处理和生物膜过滤的双重作用,对城市污水处理厂二级处理出水进行深度处理,以实现污水的回用.结果表明:在原水ρ(COD_Cr),ρ(SS)和ρ(氨氮)分别为78,11和13 mg/L,色度为12倍时,出水ρ(COD_Cr),ρ(SS)和ρ(氨氮)分别为38,3和7mg/L左右,色度为2倍左右.相对于单独使用BAF,组合工艺对COD_Cr的去除率有所提高,色度去除率提高明显(50%左右).膨胀聚丙烯(EPP)填料最佳SS和COD_Cr去除率对应的滤层高度分别为1.0和2.5 m,在较高滤层处,氨氮去除率上升较快.      

悬浮填料优化试验研究

试验系统利用某城市污水厂生产工艺回流污泥为系统悬浮污泥,探讨了悬浮填料投配比、投配方式和中试硝化效果之间的关系。试验结果表明,悬浮填料最小投配比为15％即可满足系统硝化功能的要求;悬浮填料的投配方式宜采用集中投配并布置于曝气池的末端,这样既可提高系统的生物膜量,又有利于硝化反应的实现。而且,控制适当的溶解氧浓度,悬浮填料的投加有助于同步硝化反硝化更充分的进行。     

Characterizing the trophy hunting debate on Twitter

Social media is an arena of debate for contentious political and social topics. One conservation topic debated online is the acceptability of trophy hunting, a debate that has implications for national and international policy. We used a mixed-methods approach (grounded theory and quantitative clustering) to identify themes in the trophy hunting debate on Twitter. We examined commonly co-occurring categories that describe people's stances on trophy hunting. We identified 12 categories and 4 preliminary archetypes opposing trophy hunting—activism, scientific, condemning, and objecting—whose opposition derived from different moral reasoning. Few tweets (22) in our sample of 500 supported trophy hunting, whereas 350 opposed it. The debate was hostile; 7% of tweets in our sample were categorized as abusive. Online debates can be unproductive, and our findings may be important for stakeholders wishing to effectively engage in the trophy hunting debate on Twitter. More generally, we contend that because social media is increasingly influential, it is important to formally contextualize public responses to contentious conservation topics in order to aid communication of conservation evidence and to integrate diverse public perspectives in conservation practice.