| Biogas project is an effective engineering technology for treatment of organic waste, especially for animal manure treatment and high-concentration organic water waste treatment. At present, this technology has been actively applied at home and abroad. In recent years, with the development of aquaculture, the processing of agricultural products as well as the utilization of new energy methane, Biogas project is moving forward in the direction of large-scale and industrialization development in China. In treatment of organic waste, biogas project can produce clean energy, and the processed biogas slurry and biogas residue may also be used as organic manure. However, in practical projects these wastes are unable to "get used on spot" as expected, but cause a number of negative effects.First, Biogas contains large amounts of N, P, K nutrients, physiologically active substances (BAC), a huge number of microbial flora, some other inorganic ions and very few elements of heavy metal etc. These substances are complicated and their content is still unknown. If they are directly used as fertilizer for irrigation, it is difficult to make them most effective, which will do more harm than good.Second, the season changes have a direct effect on agricultural use of biogas slurry. Due to reasons of storage and transport, there are not enough fields to absorb the biogas slurry, which can only be directly discharged and pollute the environment.Besides, when we use the liquid methane and biogas residue in farmland, without a normative technical guidance, it can lead to secondary pollution once the daily use highly exceeds the capacity of land and crop utilization. Therefore, liquid methane and biogas residue problem has become the bottleneck which restricts the development of large-scale biogas engineering. This article focuses on the development of biogas engineering research, which has achieved the following innovative results.Through systematically analyzing and monitoring, this paper has found the biogas major components and physiologically active substances (Major Components and Bioactive Components, MCBAC) and their physical, chemical and biological properties. Pig slurry is first detected and isolated in a variety of plant growth promoting hormone composition and content:cytokinin iPR, content 0.00194μg/L; gibberellin GA4 content 0.857 μg/L, GA19 content of 1.47 μg/L, GA53 content 0.271 μg/L. GA content in higher plants is generally 0.001-1 ng/kg fresh weight, biogas gibberellin concentration of three orders of magnitude, indole acetic acid (IAA) in auxin content of plants is very low, usually per gram fresh weight of 10-100 ng, detected in this study that, biogas IAA content in 332 ug/L, the concentration ratio of 3-30 times higher plants, IAA promote the plant growth and induce the flower bud of differentiation, and also have a significant impact role on promoting photosynthesis; The content of ICA indole carboxylic acid was 397μg/L, by detecting two kinds of insecticidal and antibacterial ingredient content:8-hydroxy-3, 4-dihydro-quinoline-2-one, the concentration of slurry was 0.7375mg/L, 3,4-dihydro-quinolin-2-one, the slurry concentration was 0.1775mg/L; identified and indole-3-carboxylic acid,8-hydroxy-3,4-dihydro-quinoline-2-,3,4-dihydro-2-structure ketone. All these provide a theoretical basis for explaining that applying slurry can help crops insect-resistant and growth promoting. They also provide theoretical support for the subsequent high-value biogas slurry nutrient solution use research.In aspect of biogas reduction technology research, we proposed anaerobic fermentation process for high-solids anaerobic digestion of high concentrations of reflux ratio and also solved the key technical problems of reflux inhibition effects on anaerobic fermentation process so that we determined the maximum reflux ratio. Applying disc tubular reverse osmosis membrane (DTRO) technology, we established biogas concentrated nutrients and water recovery system. Through experiments we studied to explored the long-term stable operation parameters and economical personality of biogas concentration. Based on the above, the overall reduction in biogas emissions can achieve over 80%, meanwhile water discharge and recycling will meet the government requirement.In aspect of artificial substrates technology and product development of biogas residue, we make use biogas’rich nutrients and pro-life components and discover artificial breeding matrix effect of cow manure, chicken manure and pig manure through compared experiments:cattle manure biogas can completely replace peat, pig manure biogas and manure biogas can partially replace peat. The effects of raising seedlings are better than the effects of using fertilizer made of nursery.As to evaluation of biogas land carrying capacity, we establish an accurate soil column simulation system. In the natural environment by planting different crop varieties and biogas application level, it can monitor the leachate quality changes at different depths in soil through the whole year (nitrogen, nitrate, ammonia nitrogen, total phosphorus, etc.). The system can also assess the environmental risk for biogas using and land carrying capacity of crop consuming biogas. This paper reveals that different forms crops and climatic factors have a significant impact on biogas land carrying capacity.In summary, combining and applying high concentrations of solids anaerobic digestion technology and high reflux ratio super-concentrated slurry technology can significantly reduce emissions of biogas slurry and biogas residue. By producing high quality water, the system can bare the unrestraint Effect from reflux anaerobic systems. Making biogas into organic nutrient, making biogas residue into organic fertilizer and artificial matrix solves the absorbing problem of biogas slurry and biogas residue, at the same time it improves their additional use value and promotes the sustainable development of large-scale biogas projects. |
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