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61.
62.
为了研究温度分化对固定床厌氧反应器(anaerobic packed bed reactor,APBR)牛粪发酵处理效果及产甲烷菌群落的影响,反应器发酵温度从室温(22℃±1℃)阶梯式分化到低温(15℃±1℃)、中温(37℃±1℃)和高温(55℃±1℃).温度变化的过程中,温度越高COD(chemical oxygen demand)去除率和日总产气量越高,分化后COD去除率分别为25%、45%、60%,相应的日产气量为2.3、4.0、8.5 L·d-1,但是甲烷含量基本保持不变(~60%);温度突然变化造成挥发性脂肪酸含量骤然增加,并处于波动状态.16S r RNA基因克隆文库法分析表明,室温时包含广古菌门中的常见重要产甲烷菌MBT(甲烷杆菌目)、Mst(甲烷鬃菌科)、Msc(甲烷八叠球菌科)和MMB(甲烷微菌目),以及嗜热菌,也有少部分泉古生菌门,发酵温度分化后,产甲烷菌多样性减少,中温条件下产甲烷菌种类相对较少.定量PCR表明Mst、MMB和Msc总基因浓度都有所减少,并且温度越高减少越多,各菌数量相对比例变化较大,但Mst仍为优势产甲烷菌. 相似文献
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水解酸化—气浮—SBR工艺处理乳品废水的研究 总被引:10,自引:2,他引:10
分析了水解酸化时间对CODCr处理效果的影响,以及SBR池内CODCr去除率、溶解氧、生物相的变化规律。对实际的生产废水进行了试验研究,结果表明,当进水CODCr浓度为1860~2740mg/L,常温条件下,水解酸化水力停留时间为4h,SBR池排出比为1∶3,反应时间为8h,CODCr去除率可达95%以上。 相似文献
65.
日益增强的乳品行业竞争使乳品企业不断加强环境管理和实行清洁生产成为必然.文章阐述了在乳品行业没有国家清洁生产标准的情况下如何以ISO14001环境管理体系标准为基础开展清洁生产工作,同时提出了乳品企业开展清洁生产的方向,对乳品企业开展清洁生产工作具有一定的指导意义. 相似文献
66.
Bridget Guerrero Rachel Owens Steve Amosson Kunlapath Sukcharoen John Richeson Lal Almas 《Journal of the American Water Resources Association》2019,55(3):670-679
The dairy industry in the Texas High Plains has experienced rapid expansion in the past two decades. This study assesses the impact of the increased presence of dairies on overall water use, crop composition, and the local economy. The increase in water use related to the dairy industry from 2000 to 2015 was primarily due to an increase in demand for drinking by the cows (direct water) as well as an increased demand for silage (indirect water). However, a comparative analysis (dairy presence vs. no dairy presence) from a single year indicates minimal impacts on total water use due to dairies. During the same time period, the number, size, and employment of related local business establishments have increased economic activity in rural areas. Editor's note : This paper is part of the featured series on Optimizing Ogallala Aquifer Water Use to Sustain Food Systems. See the February 2019 issue for the introduction and background to the series. 相似文献
67.
Asha Srinivasan Ping H. Liao 《Journal of environmental science and health. Part. B》2016,51(12):840-846
A newly designed continuous-flow 915 MHz microwave wastewater treatment system was used to demonstrate the effectiveness of the microwave enhanced advanced oxidation process (MW/H2O2-AOP) for treating dairy manure. After the treatment, about 84% of total phosphorus and 45% of total chemical oxygen demand were solubilized with the highest H2O2 dosage (0.4% H2O2 per %TS). The reaction kinetics of soluble chemical oxygen demand revealed activation energy to be in the range of 5–22 kJ mole?1. The energy required by the processes was approximately 0.16 kWh per liter of dairy manure heated. A higher H2O2 dosage used in the system had a better process performance in terms of solids solubilization, reaction kinetics, and energy consumption. Cost-benefit analysis for a farm-scale MW/H2O2-AOP treatment system was also presented. The results obtained from this study would provide the basic knowledge for designing an effective farm-scale dairy manure treatment system. 相似文献
68.
Effect of the Carbohydrate Composition of feed Concentratates on Methane Emission from dairy Cows and Their Slurry 总被引:1,自引:0,他引:1
Hindrichsen IK Wettstein HR Machmüller A Jörg B Kreuzer M 《Environmental monitoring and assessment》2005,107(1-3):329-350
Dietary carbohydrate effects on methane emission from cows and their slurry were measured on an individual animal basis. Twelve dairy cows were fed three of six diets each (n = 6 per diet) of a forage-to-concentrate ratio of 1:1 (dry matter basis), and designed to cover the cows’ requirements. The forages consisted of maize and grass silage, and hay. Variations were exclusively accomplished in the concentrates which were either rich in lignified or non-lignified fiber, pectin, fructan, sugar or starch. To measure methane emission, cows were placed into open-circuit respiration chambers and slurry was stored for 14 weeks in 60-L barrels with slurry being intermittently connected to this system. The enteric and slurry organic matter digestibility and degradation was highest when offering Jerusalem artichoke tubers rich in fructan, while acid-detergent fiber digestibility and degradation were highest in cows and slurries with the soybean hulls diet rich in non-lignified fiber. Multiple regression analysis, based on nutrients either offered or digested, suggested that, when carbohydrate variation is done in concentrate, sugar enhances enteric methanogenesis. The methane emission from the slurry accounted for 16.0 to 21.9% of total system methane emission. Despite a high individual variation, the methane emission from the slurry showed a trend toward lower values, when the dietwas characterized by lignified fiber, a diet where enteric methane release also had been lowest. The study disproved the assumption that a lower enteric methanogenesis, associated with a higher excretion of fiber, will inevitably lead to compensatory increases in methane emission during slurry storage. 相似文献
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70.
Eric William McMillan Earl Downey Brill 《Journal of the American Water Resources Association》1976,12(5):985-994
ABSTRACT: The cost of the liquid wast treatment measures required to meet federal as well as typical state and local regulations was examined for dairy processing plants of various sizes. Federal effluent standards were found to produce higher estimated capital costs per unit of raw material for smaller plants, even with relaxed requirements for smaller plants. State regulations limiting the effluent BOD5- concentration were also found to result in inequitable costs for smaller processors. These inequities result from economies of scale and not such factors as level of process technology employed or amount of waste produced per unit of raw material. In contrast, applying an example sewer surcharge formula did not produce inequities from economies of scale. 相似文献