共查询到20条相似文献，搜索用时 62 毫秒
1.
针对市政脱水污泥直接厌氧消化产气率低等问题,文章探究了脱水污泥在不同温度(150℃,180℃,210℃)水热预处理下COD溶解度、氨氮、VFAs浓度等的变化规律,结果表明水热预处理可破坏污泥絮体结构和污泥细胞,溶解胞内物质,水解大分子有机物。150℃,180℃,210℃处理后的SCOD由2522 mg·L-1分别升至14902,23245,23895 mg·L-1,COD溶解度分别达到20.34%,34.05%,35.12%,氨氮和挥发性有机酸浓度均显著增加。180℃与210℃处理效果差异较小,建议采用180℃,此时VFA浓度和理论产甲烷量最大。 相似文献
2.
沼液预处理玉米秸秆与牛粪混合厌氧消化产气性能的研究 总被引：2，自引：0，他引：2
文章用沼液预处理玉米秸秆后与牛粪按3∶1混合,进行中温(35℃±1℃)批式厌氧消化实验,考察沼液预处理玉米秸秆对混合厌氧消化产气性能的影响。通过全因素实验设计,对不同沼液浓度(过5目,10目,20目,40目滤网的沼液)和不同沼液固体含量(10%,15%,20%,25%)条件下预处理的玉米秸秆与牛粪混合厌氧消化的产甲烷性能进行分析。结果表明:不同浓度的沼液在不同的固体浓度下预处理玉米秸秆后与牛粪混合厌氧消化的负荷产甲烷量较未预处理组显著提高,消化时间明显缩短。当沼液过5 M筛网,预处理固体浓度为15%时可获最大负荷产甲烷量238.35 mL·g~(-1)VS,相比未预处理组173.43 mL·g~(-1)VS提高37.43%,而厌氧消化周期T90(26天)相对未预处理组(39天)缩短33.33%。 相似文献
3.
《中国沼气》2018,(6)
为了探讨餐厨垃圾中各类组分的厌氧消化特性,对比其产气效率的高低,该试验对餐厨中的4种主要组成成分进行了中温厌氧消化研究。通过对比4种组分的累计产气量、每克挥发性固体的产气率、甲烷含量及消化液pH值的变化,研究餐厨垃圾不同组分厌氧消化的效率。结果表明:厌氧消化产气性能较好的组分为油脂类及蛋白质类,其次为碳水化合物类,最差的组分为蔬菜类。每克挥发性固体(VS)的累计产气量最高的为油脂类,达到了454 mL·g-1VS;最低的为蔬菜类,只有215 mL·g-1VS。4种餐厨组分在厌氧消化过程中所产沼气中的气体组成及含量差异不大,甲烷的含量均在45%～65%之间变化。在整个45 d的厌氧消化期间,各组分消化液的pH值基本保持稳定。 相似文献
4.
通过对预处理污泥的微观形态,破解度(DDCOD),挥发性脂肪酸(VFAs)含量,产气性能等方面进行分析,比较了高压均质和超声波两种预处理方法对剩余污泥厌氧消化性能的影响。研究结果表明:高压均质和超声波预处理都显著地破坏了污泥的絮体结构,但前者破坏作用更加强烈。经过高压均质预处理,污泥VFAs提高206.5%,DDCOD达5.4%,厌氧消化12 h后VFAs较对照组提高589.4%,20 d底物产气量和产气率分别提高57.2%和51.4%;经过超声波预处理,污泥VFAs提高22.9%,DDCOD达2.0%,厌氧消化12 h后VFAs较对照组提高507.0%,20 d底物产气量和产气率分别提高18.5%和17.3%。试验结果证明采用高压均质预处理对污泥厌氧消化性能提高更显著。 相似文献
5.
利用微生物处理技术对经聚丙烯酰胺脱水后的污泥进行不同方式微生物预处理,研究进料总固体(TS)质量分数为3%、发酵温度为35℃时厌氧消化过程中累积产气量与产甲烷含量、p H值、氨氮和化学需氧量(TCOD)等参数的变化趋势,探索真菌宛氏拟青霉不同预处理方式对脱水污泥厌氧消化过程特性的影响。试验结果表明:微生物预处理脱水污泥厌氧消化技术具有较好的可行性。直接添加宛氏拟青霉和添加宛氏拟青霉预处理2 d的污泥进行厌氧消化反应能够有效提高产气量和产甲烷量,加快水解速率,促进污泥中有机物的有效降解,使产甲烷过程顺利进行。直接添加宛氏拟青霉处理的产甲烷效果最优,其净累积产气量和产甲烷量较纯污泥分别提高85.79%和42.76%,且1 kg污泥可产甲烷12.69 L,较纯污泥提高42.74%。 相似文献
6.
在中温35℃条件下,对番茄废物进行半连续式厌氧消化试验.对不同负荷率下的番茄废物产气率及稳定状态下消化液的碱度、挥发性有机酸(VFA),总固体(TS),挥发性固体(VS),氨氮等参数进行了测定.随着负荷率(OLR)从1.0～3.0 g·L-1的增加,出料消化液中VFA的浓度和VS浓度有所上升,同时单位原料产气率(y)和甲烷含量均有下降,通过曲线拟合可以得到最大原料产气率(ym).在拟合出一级反应常数k和ym的情况下,可以计算出预期达到消化产气率效果时的水力停留时间(HRT)以及OLR.根据试验结果,可以得到ym=0.61 L·g-1以及k=0.345 d-1.该模型可以应用于蔬菜废物的半连续厌氧消化过程工艺参数的优化. 相似文献
7.
试验采用餐厨垃圾与市政污泥混合共厌氧消化的方法,在中温条件下(35℃±0.5℃),控制餐厨垃圾(F)与市政污泥(S)挥发性有机物(VS)的比例分别为0∶1,2∶1,1∶1,1∶2和1∶3,研究了不同混合比条件下,系统的产气性能,VS去除率以及对溶解性COD、溶解性蛋白质、溶解性碳水化合物的转化情况。结果表明,与市政污泥单独厌氧消化相比,混合共厌氧消化在提高产气量的同时也提高了系统内溶解性有机物的转化率。其中混合比例为2∶1组效果最佳,沼气产量达到451.29 mL·g~(-1) VS,相对于市政污泥单独厌氧消化提高了55.09%;VS去除率为66.51%,较市政污泥单独厌氧消化提高了20.51%;溶解性COD、溶解性蛋白质及溶解性碳水化合物转化率分别达到80.00%,94.38%和63.32%,比市政污泥单独厌氧消化分别提高了15.91%,42.17%及11.24%。说明餐厨垃圾和市政污泥混合共厌氧消化确实可以显著提高厌氧消化的效率。 相似文献
8.
水热预处理对提高牛粪厌氧产甲烷性能的研究 总被引：1，自引：0，他引：1
《中国沼气》2019,(4)
为了研究水热预处理对牛粪厌氧产甲烷性能的影响,文章采用不同的温度(50℃,70℃,90℃,100℃,150℃和200℃)分别对牛粪进行预处理(5 min～3 d),再进行中温批式厌氧消化实验。结果表明:最优的预处理条件是70℃预处理3 d,牛粪的甲烷产量最高,达到176.36 m L·g~(-1)VS,比未经处理的提高了21.00%;VS去除率为39.64%,比未经处理的提高了6.34%。此外,牛粪经不同水热预处理后的VS水解率达到2.78%～16.25%。部分预处理组的还原糖和VFAs浓度分别达到66.20～118.51 mg·L~(-1)和8230.14～12135.72 mg·L~(-1),分别比对照组提高了7.31%～92.11%和8.03%～59.29%。所以水热温度和时间是预处理过程中的重要影响因素,并且在较低温度下预处理效果最好。 相似文献
9.
文章以茶树叶为发酵原料,厌氧活性污泥为接种物,在接种量为25%,配料TS浓度为7%和恒温35℃下,研究了纤维素酶预处理、高温蒸煮处理与Na OH预处理3种预处理方法对茶树叶厌氧发酵产气性能的影响。试验数据经过改Modified Gompertz模型处理,获得相应的厌氧消化动力学参数(最大累积产气量、最大产气速率和滞留时间),并计算出TS和VS评价指标。分析结果表明:经纤维素酶与Na OH预处理可以不同程度提高产气能力,并缩短发酵启动时间。Modified Gompertz模型拟合不同预处理茶树叶厌氧发酵累积产气量随时间变化具有较好相关性,拟合结果中质量分数4%的Na OH预处理茶树叶产气效果最好,发酵累积产气量2860 m L,最大产气速率127.9m L·d-1,总固体产气率、挥发性固体产气率分别为109.58 m L·g-1,116.73 m L·g-1,优于其他实验组与对照。因此,碱处理可能成为今后茶树叶沼气工程较理想的预处理方法。 相似文献
10.
《中国沼气》2017,(3)
文章以牛粪和超声预处理污泥为发酵原料,在恒温35℃±1℃及底物浓度为15 gVS·L~(-1)的条件下,采用正常运行的大型沼气池沼液作为接种物,研究不同配比(VS_(污泥)∶VS_(牛粪)分别为1∶0,2∶1,1∶1,1∶2,0∶1)对混合厌氧消化效果的影响。研究表明,在35℃±1℃条件下,超声预处理污泥与牛粪的比例为1∶2时累积产气量高于其他4种比例,VS产气率达到了470.33 mL·g~(-1),甲烷产量在发酵稳定后达到了58.68%。发酵过程中pH值,NH_4~+-N,COD的变化表明了混合厌氧消化能够平衡营养物质,稀释有毒物质,具有协同作用,发酵过程中未出现酸抑制以及氨抑制。进一步研究得出,将超声预处理污泥与牛粪按一定比例混合发酵可以将产气高峰提前,并出现"双峰",提升产气速率,大幅提升了原料的产气潜力。 相似文献
11.
Overland water and salt flows in a set of rice paddies 总被引：1，自引：0，他引：1
E. Playn O. Prez-Coveta A. Martínez-Cob J. Herrero P. García-Navarro B. Latorre P. Brufau J. Garcs 《Agricultural Water Management》2008,95(6):645-658
Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m−1) and an infiltration rate of 5.8 mm day−1. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day−1), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day−1 was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration. 相似文献
12.
瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。 相似文献
13.
对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。 相似文献
14.
对《种子法》存在问题的探讨 总被引：1，自引：0，他引：1
李鹏 《农业机械化与电气化》2011,(6):129-130
《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。 相似文献
15.
About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered. 相似文献
16.
在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。 相似文献
17.
Gunter Wriedt Marijn van der Velde Alberto Aloe Fayçal Bouraoui 《Agricultural Water Management》2009,96(5):771-789
We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications. 相似文献
18.
在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。 相似文献
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20.
车辆ABS控制算法的研究及探讨 总被引：1，自引：0，他引：1
对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。 相似文献