无机碳源对零价铁介导的自养脱氮序批式反应器处理高氨氮废水的影响

无机碳源作为自养微生物的能量来源,是影响自养脱氮细菌富集的重要因素。文章通过添加不同量的KHCO3作为ZVI介导的自养脱氮体系中无机碳源,研究反应体系的脱氮效果影响趋势以及适宜的无机碳源添加量。结果如下:1)KHCO3作为无机碳源可以显著提高NH^+4-N去除率,KHCO3添加量越多,其NH^+4-N去除率越高。KHCO3添加量分别为2 g,1 g,0.5 g的SBR反应器R2,R1,R0.5的NH^+4-N去除率分别为98.39%,65.18%,44.56%,相较不添加KHCO3的R0分别提高86.5%,53.29%,32.67%。ZVI的添加会降低KHCO3对NH^+4-N氧化的促进作用。2)KHCO3可明显提高TIN去除效果,促进总氮脱除的高低顺序是R1>R0.5>R2,SBR反应器R2,R1,R0.5的平均TIN去除率分别为19.01%,32.04%,27.62%,相较于空白组R0分别提高了10.60%,23.63%,19.21%。3)KHCO3可中和硝化反应产生的H^+,对反应体系具有缓冲作用,可使微生物处于较适宜的酸碱环境中,更有利于反应器的稳定运行。4)适量的无机碳源KHCO3可以促进氨氧化细菌和厌氧氨氧化细菌的活性。该研究探讨了无机碳源在零价铁脱氮体系中的影响趋势,为铁型脱氮技术提供了理论支撑。     

1例犬畸胎瘤的诊疗报告

2018年12月内蒙古农业大学动物医院接收一病犬,其外阴异常增大,生殖道口有淡红色液体流出,触诊阴门内有一肿瘤硬物,表面光滑,呈淡粉色,不规则形状,初步诊断为阴道肿瘤。手术切除后经组织病理学检查,证实为未成熟的畸胎瘤。     

Microbial remediation of a pentachloronitrobenzene-contaminated soil under Panax notoginseng: A field experiment

Pentachloronitrobenzene (PCNB) is an organochlorine fungicide that is mainly used in the prevention and control of diseases in crop seedlings. Microbial removal is used as a promising method for in-situ removal of many organic pesticides and pesticide residues. A short-term field experiment (1 year) was conducted to explore the potential role of a PCNB-degrading bacterial isolate, Cupriavidus sp. YNS-85, in the remediation of a PCNB-contaminated soil on which Panax notoginseng was grown. The following three treatments were used:i) control soil amended with wheat bran but without YNS-85, ii) soil with 0.15 kg m^-2 of solid bacterial inoculum (A), and iii) soil with 0.30 kg m^-2 of solid bacterial inoculum (B). The removal of soil PCNB during the microbial remediation was monitored using gas chromatography. Soil catalase and fluorescein diacetate (FDA) esterase activities were determined using spectrophotometry. In addition, cultivable bacteria, fungi, and actinomycetes were counted by plating serial dilutions, and the microbial biodiversity of the soil was analyzed using BIOLOG. After 1 year of in-situ remediation, the soil PCNB concentrations decreased significantly by 50.3% and 74.2% in treatments A and B, respectively, when compared with the uninoculated control. The soil catalase activity decreased in the presence of the bacterial isolate, the FDA esterase activity decreased in treatment A, but increased in treatment B. No significant changes in plant biomass, diversity of the soil microbial community, or physicochemical properties of the soil were observed between the control and inoculated groups (P<0.05). The results indicate that Cupriavidus sp. YNS-85 is a potential candidate for the remediation of PCNB-contaminated soils under P. notoginseng.     

菌剂挂膜3D-RBC联合BCO工艺处理养猪沼液废水

针对养猪沼液废水寡营养、高氨氮的水质特征，该研究采用耐高氨氮、适应贫营养生长的异养硝化-好氧反硝化（Heterotrophic Nitrification-Aerobic Denitrification，以下简称HN-AD）菌挂膜启动三维结构生物转盘+生物接触氧化反应器（3D-RBC+BCO）组合工艺对沼液进行处理。该文研究了3D-RBC+BCO组合工艺在真实沼液条件下的启动过程及污染物去除效果，重点考察了溶解氧（Dissolved Oxygen，DO）浓度和C/N比2个关键因素对组合工艺污染物去除效果的影响。同时，借助高通量测序技术对DO和C/N比优化过程中微生物群落结构的变化规律进行解析。结果表明：在真实沼液条件下，采用HN-AD菌剂挂膜启动方法，仅用12和18 d就分别完成3D-RBC和BCO反应器的挂膜启动，同时组合工艺对COD、NH4+-N和TN的去除率分别稳定在94.8%、95.7%和80.1%，出水优于城镇污水厂排放一级B标准。在对3D-RBC反应器DO和C/N比的优化过程中，增设底曝后COD、NH4+-N和TN等指标的去除率分别降低了25.4%、15.4%和15.5%。高通量测序结果显示，增加底曝后3D-RBC盘片生物膜中微生物菌属的数量小幅下降，但HN-AD优势菌属的种类与丰度显著降低，导致脱氮效率下降；贫营养型Acinetobacter、Pseudomonas菌属是3D-RBC可以对真实沼液高效脱氮的关键，提高C/N比会显著降低其丰度，进而影响脱氮效果。     

鲜食玉米果穗收获负压除杂装置参数优化与试验

针对现有鲜食玉米收获机在收获果穗时，果穗中含有茎叶等杂质，影响运输、贮存和后续加工等问题，采用轴流风机负压除杂技术去除果穗中的茎秆和茎叶等杂质，同时在除杂装置内增加动、定刀，切碎杂质，便于后续的打包回收利用，并对风机负压除杂装置进行了性能分析和参数优化。通过对动、定刀进行动力学分析，对动、定刀数和刀间隙进行分析，确定了该装置的风机转速范围为1326~1573r/min，动、定刀间隙20mm，定刀数为3~8。采用二次回归正交组合试验方案，以风机转速、定刀数、喂入量为试验因素，以果穗含杂率和茎秆切碎长度合格率为试验指标进行台架试验，通过分析各因素对指标贡献率，得到影响茎秆切碎长度合格率的主次顺序为喂入量、风机转速、定刀数，影响果穗含杂率的主次顺序为风机转速、喂入量、定刀数。建立了参数优化数学模型，利用Optimization模块优化得出，当风机转速为1524r/min、单排定刀数为4、喂入量为7.6kg/s时，茎秆切碎长度合格率为96.8%，果穗含杂率为0.69%。对优化后的参数组合进行了5组验证试验，得到茎秆切碎长度合格率平均值为96.2%，果穗含杂率平均值为0.71%。相比于传统收获机，该装置使果穗含杂率降低了23.3%，说明该优化参数能够满足鲜食玉米果穗收获和茎叶青贮相关技术要求。     

复合潜流人工湿地对农村生活污水的净化效果 及其微生物群落结构特征

试验探究了复合潜流人工湿地对农村生活污水的净化效果及其微生物群落结构特征。结果表明，当水力负荷为0.35 m³·(m²·d）^-1时，系统对TN、NH₄⁺-N、COD和TP去除效率分别为（89.84±7.64）%、（98.67±1.31）%、（61.63±16.01）%和（70.21±8.00）%。湿地中一共发现11个主要菌门、18个主要菌纲和33个主要菌属，变形菌门（Proteobacteria）、蓝藻门（Cyanobacteria）、拟杆菌门（Bacteroidetes）、厚壁菌门（Firmicutes）、绿弯菌门（Chloroflexi）、酸杆菌门（Acidobacteria）、放线菌门（Actinobacteria）是其中的优势菌门，它们在各级湿地中表层和底层的相对丰度分别是57.26%、61.37%、91.60%、93.22%、88.78%、88.02%。蓝藻菌纲（Cyanobacteria）、α-变形菌纲(Alphaproteobacteria) 、芽孢杆菌纲(Bacilli)和γ-变形菌纲(Gammaproteobacteria)、β-变形菌纲(Betaproteobacteria)是其中优势菌纲，约占主要菌纲的70%。共有17个优势菌属，在各级湿地中的分布情况不同，其中芽孢杆菌属（Bacillus）相对丰度最高，集中分布于第三级湿地，其次是Leptolyngbya、席藻属（Phormidium），在第一、二级湿地中广泛分布。复合潜流人工湿地具有良好污水净化效果，系统中有机物和氮素的去除主要依靠微生物作用，磷素的去除主要依靠基质吸附沉淀作用。     

Influence of race and crossbreeding on casein micelles size

Casein (CN) micelles are colloidal aggregates of protein dispersed in milk, the importance of which in the dairy industry is related to functionality and yield in dairy products. The objective of this work was to investigate the correlation of milk CN micelles diameter from Holstein and Zebu crossbreds with milk composition (protein, fat, lactose, total and nonfat solids and milk urea nitrogen), somatic cell count (SCC), age, lactation stage and production. Average casein micelles diameters of milk samples obtained from 200 cows were measured using photon correlation spectroscopy and multiple regression analysis was used to find relationship between variables. CN micelle diameter, SCC and nonfat solids were different between animals with different Holstein crossbreed ratios, which suggests influence of genetic factors, mammary gland health and milk composition. Overall, results indicate the potential use of CN micelle diameter as a tool to select animals to produce milk more suitable to cheese production.     

黑龙江几种桑果品质的测定分析

不同品种的桑果其可溶性固形物、总酸、固酸比、氨基态氮含量存在差异 ,可作为评价桑果品质的重要参考指标.经测试 :龙椹2号和龙椹3号可溶性固形物的百分含量高出对照品种4个百分点 ;总酸的百分含量远低于对照品种 ;固酸比远大于对照品种 ;氨基态氮的含量小于对照品种.初步认为龙椹2号和龙椹3号桑果品质优于野生对照品种.     

木材的变色

本文论述了木材变色的特征及其防治措施 ,介绍了有代表性色调的变色特征、除色和防变色方法 ,同时探讨了已变色木材的普通除色方法、变色木材的利用以及药液处理时应注意的事项     

The impact of beaver dam removal on the chemical properties of water in drainage ditches in peatland forests

ABSTRACT

Despite near-extinction in the nineteenth century, after efficient restoration measures the population of Eurasian beaver (Castor fiber L.) in Latvia currently is viable and growing. While the ecological effect of the species on water quality and biodiversity is generally positive, the high number of animals in production forests often creates challenges for management. Drainage ditches are among the most favoured habitats of beavers resulting in flooded stands, reduced tree growth and economical losses. The aim of the study was to evaluate the chemical properties of water in forest drainage ditches, affected by beaver activity, and their changes after the dam removal. Chemical composition of surface water in ditches was analysed in sampling points above dam, below dam and in the ditch itself after removal of the dam; results compared to pristine beaver site nearby on a small stream. Results did not show significant differences between concentrations above and below dams. After removal of the dams, significant increase in DOC, N-NO₃ ^-, N-NH₄ ⁺ and TSS concentrations and significant decrease in TP concentrations were observed in some of the sites. Observed concentrations of all measured parameters were significantly lower in pristine beaver site than in beaver sites on drainage ditches.