有机固废好氧发酵过程中的pH变化与原材料性质对产物pH的影响

发布时间：2018-07-02 23:01

本文选题：有机固废 + 污泥堆肥　；参考：《扬州大学》2017年硕士论文

【摘要】：随着我国农业和工业的快速发展以及城市生活水平的提高,我国有机固体废弃物的产量逐年增加。有机固废来源十分广泛,种类繁多,成分复杂,产生量巨大。有机固废乱堆乱排乱放,得不到合理有效的处理处置,一方面会造成大量土地资源被占用和有机资源的浪费,另一方面会造成严重的环境污染以及对人体健康的危害。好氧堆肥是目前国内外应用比较广泛的污泥处置方式,是解决可生物降解有机固废的有效途径之一。好氧堆肥化过程是一个较为复杂的生物发酵过程。不同有机物转化过程中,由于其本身物质组成的不同和C/N的不同,产生的中间产物种类和量也会有所不同。pH值对参与发酵过程的微生物区系组成和作用效率均有较大影响,通过对原料的合理配置从而将pH值控制在合理的范围内不仅影响到发酵的过程,也会影响到产物的性质特别是包括产物的pH,但有关这方面的研究很少。本文通过以下三个不同规模的试验对有机固废好氧发酵过程的pH变化规律进行了探究。(1)在实验室条件下对三种具有不同C/N比的有机固废材料(小麦秸秆、毛豆叶、牛粪)进行的单独好气矿化培养试验:将麦秸秆、毛豆叶和牛粪三种材料分别以1:20质量比与石英砂充分混合均匀,加入相同体积的土壤提取液,调至最大持水量的50%,于恒温30℃进行为期30天的培养试验,测定培养过程中的pH、全氮、铵态氮、硝态氮、CO2释放速率。(2)利用木屑、水稻秸秆、玉米秸秆与污泥混合进行小堆体好氧发酵试验:设置污泥与材料的湿重比为6:1,好氧发酵全过程60天,发酵过程中测定温度、pH、TOC、DOC、全氮、铵态氮、硝态氮。(3)工厂化生产条件下进行的药渣与污泥不同混合比发酵试验:设置药渣与污泥的体积比分别为0.5:1、1:1、1.5:1和2:1共四个处理,发酵堆肥全长58天,测定堆肥过程中的温度、pH、铵态氮、硝态氮、有机碳等。通过三个不同规模的试验,初步得到以下结论:(1)试验室单独好气培养发现,有机碳的矿化与有机材料本身总有机碳和可溶性有机碳的含量有关。高含量总有机碳和可溶性有机碳会增加材料的有机碳分解和CO2释放量。有机材料的氮释放与含氮量及C/N比有一定的联系:较高的氮含量和较低的C/N比会促进氮的释放,并且在培养初期释放量最多,释放速率最快。(2)试验室单独好气培养结果显示,在好气培养过程中,C/N比较小的牛粪与毛豆叶处理的铵态氮和硝态氮呈现此消彼长的状态,意味着铵态氮向硝态氮的转化。但C/N比较大的麦秸秆在培养过程中,其铵态氮和硝态氮之间这种关系不够明显。材料在培养初期发生的氨化作用会导致pH的上升,随后的铵态氮向硝态氮的转化会导致pH值的下降。C/N最低的毛豆叶在培养结束时的pH增加最多。(3)由于矿化过程中有机酸的脱羧作用属于消耗H+的过程,会导致pH值的升高,因此材料体内的DOC含量和有机酸含量对产物pH有着极大的影响。试验的结果证实,三种材料最终pH的升高程度是毛豆叶麦秸秆牛粪,这与它们体内可溶性有机碳与有机酸的含量顺序是一致的。(4)三种材料的小堆体污泥发酵试验表明,由于堆体中的污泥部分含氮量较高,其中的氮释放后最终会大部分转化成硝酸根,释放出大量H+,因此添加三种材料后的污泥堆肥的最终堆体pH均低于最初的堆体pH。(5)小堆体好氧发酵试验显示,随着铵态氮的下降和硝态氮的上升,堆体的pH呈现相应的下降趋势。堆体的最终pH是玉米秸秆处理水稻秸秆处理木屑处理,这与它们体内的有机酸含量顺序一致,与实验室单独材料培养试验的结果也一致,再次证实了原料中可溶性有机酸根的含量越高,由于脱羧基的过程的存在,最终产物的pH也越高。(6)工厂化生产条件下有机物料好氧堆肥过程中pH的变化与铵态氮和硝态氮的产生和转化有关,氨化作用较强时,铵态氮上升,pH上升;硝化作用较强时,铵态氮转化为硝态氮,pH下降。堆肥起始阶段的原料pH影响最终的产物pH,但堆肥过程的进行总体上缩小了它们之间的差异。
[Abstract]:With the rapid development of agriculture and industry in China and the improvement of urban living standards, the production of organic solid wastes in China is increasing year by year. The organic solid waste sources are very wide, various kinds, complex components and huge amount of production. Organic solid waste piles are disorderly arranged and disorderly and disorderly and effective treatment and disposal, on the one hand, a large amount of land capital will be caused. The waste of source and organic resources, on the other hand, will cause serious environmental pollution and harm to human health. Aerobic composting is widely used at home and abroad and is one of the effective ways to solve biodegradable organic solid waste. Aerobic composting is a more complex biological fermentation process. In the process of different organic matter transformation, because of the different composition of the material and the difference of C/N, the type and quantity of the intermediate products produced by the different.PH values have great influence on the microbial flora and the efficiency of the fermentation process. The pH value is controlled in a reasonable range by the rational allocation of the raw materials. The only influence of the process of fermentation will also affect the properties of the products, especially the pH of the products, but there are few studies on this. In this paper, the pH changes in aerobic fermentation process of organic solid waste are investigated by the following three different scales. (1) three kinds of organic solid waste with different C/N ratios under the laboratory conditions. The individual aerobic mineralization culture test (wheat straw, pea leaf, cow dung) was carried out. The three materials of wheat straw, pea leaf and cow dung were mixed evenly with the 1:20 mass ratio and quartz sand, and the same volume of soil extract was added to 50% of the maximum water holding capacity. The culture test was carried out at the constant temperature of 30 C for 30 days, and the cultivation was determined. PH, total nitrogen, ammonium nitrogen, nitrate nitrogen, CO2 release rate. (2) the use of wood chips, rice straw, corn straw and sludge mixed aerobic fermentation test: the wet weight ratio of the sludge and material is 6:1, the whole process of aerobic fermentation is 60 days, the fermentation process of temperature, pH, TOC, DOC, total nitrogen, ammonium nitrogen, nitrate nitrogen. (3) factory production strip The volume ratio of dregs and sludge under different mixed ratio fermentation tests: the volume ratio of dregs and sludge is 0.5:1,1:1,1.5:1 and 2:1 respectively four treatments, the total length of the composting is 58 days, and the temperature, pH, ammonium nitrogen, nitrate nitrogen and organic carbon in the composting process are measured. Through three different scale experiments, the following conclusions are obtained: (1) test room The mineralization of organic carbon is related to the content of organic carbon and soluble organic carbon in organic material itself. The high content of total organic carbon and soluble organic carbon will increase the organic carbon decomposition and CO2 release of the material. The nitrogen release of organic materials is related to the nitrogen content and the C/N ratio: higher nitrogen content and lower C The /N ratio will promote the release of nitrogen, and the release rate is the fastest at the early stage of culture. (2) the results of the aerobic culture in the laboratory show that in the aerobic culture, the ammonium nitrogen and nitrate nitrogen treatment of the smaller cow dung and the pea leaf in the aerobic culture shows a state of extinction, which means the conversion of ammonium nitrogen to nitrate nitrogen. But the C/N is larger. In the process of wheat straw culture, the relationship between ammonium nitrogen and nitrate nitrogen is not obvious. The ammoniation of the material in the early stage of culture will lead to the rise of pH. The subsequent transformation of ammonium nitrogen to nitrate nitrogen will lead to the decrease of pH value.C/N at the lowest pH at the end of culture. (3) due to the Organic Mineralization Process The decarboxylation of acid belongs to the process of consuming H+, which leads to the increase of pH value. Therefore, the content of DOC and the content of organic acids in the material have a great influence on the product pH. The results of the experiment confirm that the increase of the three materials is the final degree of pH in the soybean leaf wheat straw cow dung, which is in the order of the content of soluble organic carbon and organic acids in their bodies. (4) the small heap sludge fermentation test of three kinds of materials showed that due to the high nitrogen content in the sludge in the heap, most of the nitrogen release would eventually turn into nitrate and release a large amount of H+. Therefore, the final heap of the sludge compost after adding three kinds of materials was lower than the initial pH. (5) small heap aerobic fermentation test. The results showed that with the decrease of ammonium nitrogen and the increase of nitrate nitrogen, the pH of the heap showed a corresponding decline. The final pH of the heap body was treated with corn straw to treat the sawdust, which was in the same order as the organic acid content in the body. It was also consistent with the results of the laboratory test for individual materials in the laboratory, and confirmed the solubility in the raw material again. The higher the content of sexual organic acid root, the pH of the final product is higher because of the decarboxylic process. (6) the change of pH in the aerobic composting process of organic materials is related to the production and transformation of ammonium nitrogen and nitrate nitrogen during the process of industrial production. When the ammoniation effect is strong, the ammonium nitrogen rises and pH rises; when the nitrification is strong, the ammonium nitrogen is converted to the ammonium nitrogen. Nitrate nitrogen and pH decreased. The raw material pH of the initial stage of composting affected the final product pH, but the composting process reduced their differences in general.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X705;S141.4

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