山区浆体管道跨越设计

在尖山铁矿－－太原钢铁公司矿浆管道设计中,针对山区的特殊地理环境,提出了采取开凿隧洞使管道穿山通过的方法,而被汾河或深谷隔离的隧洞出口之间采用水中不设墩的悬索、悬缆结构方案,将管道连通。结合各隧洞口的实际情况,对各种跨越常采用的标准式争分夺秒了简化改进,使其更有利于山高壁陆的自然特征和地形状态变化复杂的客观环境。     

双燃料发动机燃烧噪声特性及影响因素分析

从时域和频域两方面综合评价双燃料发动机的燃烧噪声,分析转速、负荷、供油提前角以及生物质气替代率等因素对燃烧噪声的影响,并与柴油机的相关数据进行比较,结果表明:在21℃A供油提前角时,转速对整个频率范围内气缸压力级的影响较小,在相同转速下随负荷的增加,生物质气替代率下降,燃烧总声压级普遍增大;而当供油提前角增大至24℃A时,两种机型的气缸压力级频谱曲线变化强烈,转速的增大使其在高频范围内呈振荡式发展,负荷的增加使其在低、中频范围内增大.     

Effect of different pig feeding strategies on the nitrogen fertilizing value of slurry for Lolium multiflorum

The objective of this study was to evaluate the extent to which altering pig nutrition for environmental reasons could affect the N fertilizing value of slurry. This was assessed by studying the nitrification of NH₄-N and the N use efficiency of slurries obtained from growing pigs offered feeds either with commonly applied contents of crude protein (CP) and bacterially fermentable substrates (BFS) or reduced CP levels and/or elevated BFS levels. Soil/slurry mixtures were incubated for 16 weeks at 20°C using 0.2 g total slurry N addition per kg soil. In a 15 weeks lasting pot experiment with Lolium multiflorum, N derived from the same slurries was applied at two N doses with overall either 0.4 or 0.8 g total slurry N/kg soil. In the pot experiment the effect of slurry on plant growth and N uptake was compared with a mineral N fertilizer (NH₄NO₃) treatment and a non-fertilized control. Slurries obtained from pigs fed at reduced CP content had lower pH, total N content and proportion of NH₄-N than slurries obtained from pigs fed at higher CP. Accordingly incubation of soil/slurry mixtures using slurries obtained from low CP feeds resulted in lower NO₃-N concentration in the soil. Furthermore, a lower proportion of the added NH₄-N was nitrified in treatments involving slurries derived from low CP feeds. Modifying the BFS content in feeds had minor effects both on slurry characteristics and on slurry NH₄-N nitrification in soil. Although reduced CP and, to a lesser extent, elevated BFS altered the N release pattern to plants, slurry N use efficiency during the four cuts following the first fertilization ranged at a similar level of 32 to 33% for all types of slurry. This apparent use was significantly lower than that of the mineral N fertilizer which amounted to 72 to 75% of the added N. Nitrogen balance showed that less than 22% of the added mineral N fertilizer was lost from the soil/plant systems while from 32 to 47% of the N added with the slurries was lost independently of the type of slurry. So overall N utilization by crop and rate of slurry N recovery did not significantly differ which indicates that the investigated modifications of pig feeding appear to have no short term negative effect on the N fertilizing value of slurries.     

沼液预处理玉米秸秆产沼气工艺参数优化

沼液作为厌氧发酵的废弃物处理存在困难,但沼液可以对秸秆类原料进行预处理,为沼液的综合利用提供可能。为优化沼液预处理玉米秸秆的条件,提高玉米秸秆厌氧消化产气量,该文以沼液预处理前后的纤维素、半纤维素、木质素含量以及产气量为指标,根据CCD(centralcompositedesign)试验设计原理,选取沼液添加比例、温度和时间为因素,建立三者之间的模型。试验结果表明:随着预处理TS(total solid)的降低,时间的延长,木质纤维素的降解率越高,而温度在30℃时木质纤维素的降解率达到最大。从产气量来看木质纤维素降解率并不是越高越好,过分的追求木质纤维素的降解会对产气量产生影响,经过响应面法优化产气量后得出最佳的预处理工艺为:沼液添加比例19.08%、预处理温度(30±1)℃、预处理时间为5 d,总产气量可提高30.76%。     

畜禽粪便与秸秆混合发酵及贮藏阶段沼液中碳氮元素变化

为研究沼液从产生到贮藏期间碳氮元素的变化规律,将猪粪、鸡粪和秸秆混合,进行中温厌氧发酵,并在常温下以密闭静置、密闭搅拌、敞口静置、敞口搅拌等4种方式贮藏沼液,跟踪并分析了猪、鸡粪和秸秆混合发酵沼液在厌氧发酵及贮藏期间碳、氮元素的形态和含量变化。结果表明:厌氧发酵阶段,沼液中的总有机碳(TOC)和总氮(TN)浓度均有所增加,增加幅度在15.0%~36.1%之间,其中TOC在第18 d达到最高浓度(6467 mg·L~(-1)),TN在第23 d达到最高浓度(4181 mg·L~(-1))。贮藏阶段,沼液中的TOC、TN浓度均有所降低,TOC先下降后升高,总体降低幅度较小(2.9%~12.0%),降幅顺序为敞口静置敞口搅拌密闭静置密闭搅拌;TN先升高后降低,总体降低幅度较大(4.2%~56.2%),降幅顺序为密闭静置密闭搅拌敞口静置敞口搅拌。综上,厌氧发酵18~23 d的沼液碳氮元素含量最高,采用密闭静置方式并缩短贮藏时间可减少沼液贮藏过程氮元素的损失。     

Fenton法对沼液中三种四环素类和三种磺胺类抗生素氧化去除的研究

近年来各类抗生素广泛地用于畜禽养殖,经动物代谢后随粪便和尿液排出体外。代谢物通过沼气工程处理后,得到的沼液又多用于灌溉,使得抗生素进入环境被农作物吸收,通过食物链的传递对人体产生危害。因而沼液中抗生素的去除尤为重要。采用Fenton氧化技术去除沼液中的三种四环素类和三种磺胺类抗生素,通过设置单因素实验考察了pH值、H_2O_2浓度、摩尔比n(H_2O_2)/n(Fe~(2+))对抗生素去除的影响。结果表明,最佳反应条件为pH=4,H_2O_2浓度为0.4 mol·L~(-1),n(H_2O_2)/n(Fe~(2+))=10∶1,在此条件下,四环素、土霉素、金霉素去除率分别为91.83%、92.38%、80.52%,磺胺甲恶唑、磺胺甲基嘧啶、磺胺嘧啶去除率分别为93.60%、91.97%、91.60%。同时TN、TP、TK的保留率分别为96.0%、97.7%、97.2%。可见,Fenton氧化法对沼液中抗生素的去除有良好的效果,同时又保证其养分的保留,为沼液中抗生素的去除提供了一条可能的途径。     

生物炭配施沼液对淋溶状态下土壤养分的影响

为探讨生物炭配施沼液对土壤养分淋失的影响,通过室内土柱试验,采用三因素三水平正交试验方法,系统研究了生物炭添加量、淋溶强度、沼液施加量对土壤养分淋失及土壤养分垂直分布的影响规律。结果表明,土壤养分淋失主要集中在前8次,后期淋失量均维持在较低水平并趋于稳定。各因素对氨态氮、速效磷、速效钾淋失的影响由大到小依次为淋溶强度、生物炭添加量、沼液施加量,而对硝态氮淋失量的影响由大到小依次为生物炭添加量、沼液施加量、淋溶强度。添加生物炭能明显减少养分淋失,且添加生物炭的0～20cm深度土壤的养分明显高于未添加生物炭的20～40cm土壤,各因素对氨态氮、硝态氮、速效钾在土壤中的含量影响差异显著,而对速效磷的影响则无显著差异。     

The Effect of Spraying Concentrated Biogas on Growth and Physiological Characteristics of Cotton Seedling

[Objective] The effect of concentrated biogas slurry on growth and physiological characteristics of cotton seedlings was studied in this experiment, and theoretical basis for the rational application of concentrated biogas slurry was provided. [Method] Potted cotton seedlings was sprayed by five different dosages of concentrated biogas slurry, the impact of different spraying quantity (163 mL·hm^－2, 326 mL·hm^－2, 489 mL·hm^－2, 668 mL·hm^－2, 815 mL·hm^－2) after spraying time (after spraying 2nd day, 4th day, 6th day) on cotton seedlings growth and physiological indexes were studied. [Results] The results showed that the suitable quantity of spraying of concentrated biogas slurry had promoting effect to the cotton growth and development, the excess concentrated biogas slurry could inhibit the growth of cotton seedlings. The plant height, dry weight per plant and leaf area of spraying 489 mL·hm^－2 processing are the highest, the average of two batches on the 6th day after spraying are 21.15%, 35.95%, 18.84% higher than CK, respectively. Spraying concentrated biogas slurry can improve cotton seedlings chlorophyll content, soluble sugar contents, soluble protein content. Spraying 489 mL·hm^－2 processing is the highest in both batches, the average of two batches is 18.84%, 24.03%, 3.16% higher than CK, respectively. The result of concentrated biogas slurry onseedlings leaves took effect quickly, especially in 0～4th days. [Conclusion] It is concluded that the suitable amount of concentrated biogas slurry has a positive effect on the growth and physiological characteristics of cotton seedlings, which is beneficial to the formation of strong seedlings of cotton and provides the basis for the later growth of cotton.     

酸化处理对猪场原水和沼液存储过程中气体排放的影响

为探索酸化处理对猪场原水和沼液存储过程中温室气体(CH_4、N_2O、CO_2)以及NH_3排放的影响,采用浓硫酸酸化处理猪场污水,利用动态箱法在线监测存储75 d内各气体排放通量。试验分别设置一个对照组和两个酸化处理组:原水对照组p H为6.5(RCK),加酸处理后p H分别为5.1(RT1)和5.7(RT2);沼液对照组p H为7.8(BCK),加酸处理后p H分别为5.7(BT1)和6.5(BT2)。对于原水组,RCK、RT1、RT2的CH4排放通量分别为32.2、2.37、3.10 g·m~(-3)·d~(-1),N_2O排放通量分别为336.45、23.36、29.79 mg·m~(-3)·d~(-1),NH_3排放通量分别为1.01、0.82、1.63 g·m~(-3)·d~(-1),CO2排放通量分别为109.14、99.66、110.55 g·m~(-3)·d~(-1),酸化处理显著降低原水CH_4和N_2O排放量;对于沼液组,BCK、BT1、BT2的CH_4排放通量分别为0.24、0.86、0.63 g·m~(-3)·d~(-1),N_2O排放通量分别为2.54、73.43、268.66mg·m~(-3)·d~(-1),NH_3排放通量分别为8.02、1.35、1.51 g·m~(-3)·d~(-1),CO_2排放通量分别为48.9、44.3、44.0 g·m~(-3)·d~(-1),酸化沼液显著增加CH_4和N_2O排放通量,但NH3排放可显著降低81%~83%,同时酸化组内氨氮含量较对照组增加40%~54%。根据CH_4和N_2O在100年尺度上的全球增温潜势计算各组的综合温室效应,猪场原水酸化后CO_2-eq降低91%~92%,沼液酸化后温室气体增加5~11倍。结果表明:酸化处理原水能够有效降低温室气体排放,而酸化处理沼液则一定程度上增加了温室气体排放,但可有效降低NH_3排放,同时保留沼液中氮养分。     

猪场废弃物对Cd超标土壤生菜生长及Cd含量的影响

为了比较同一猪场废弃物对Cd超标土壤生菜生长及其Cd含量的影响,从广东省博罗县某规模化养猪场同时采集猪粪、沼液与沼渣,通过在Cd超标土壤中添加不同用量猪场废弃物(按每千克土壤0.1、0.2、0.3、0.4、0.5、0.6 g氮用量计算)的盆栽试验(连续2茬生菜),研究生菜生物量与Cd吸收对这3种废弃物的响应关系。结果表明:猪场废弃物种类或用量均显著影响生菜地上部的生物量,其贡献大小为废弃物用量废弃物种类;第1茬生菜生物量随猪场废弃物用量的增加而降低,第2茬生菜生物量与沼液或沼渣用量之间呈"Λ"形关系,但随猪粪用量增加而显著提高。猪场废弃物种类和用量均显著影响生菜地上部Cd含量,其贡献大小为废弃物种类废弃物用量。猪粪与沼渣降低生菜Cd含量,沼液提高生菜Cd含量;生菜Cd含量随猪粪用量增加而显著降低,随沼液用量增加而显著提高。生菜Cd含量的变化主要受生物量稀释效应的影响(猪粪处理第1茬例外),每千克该土壤的沼液、猪粪、沼渣用量分别≤370 m L、10 g、15 g时,生菜正常生长。