| 6种农业废弃物初期碳源及溶解性有机物释放机制 |
| 摘要点击 2083 全文点击 679 投稿时间：2020-10-24 修订日期：2020-11-06 |
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| 中文关键词 农业废弃物 反硝化碳源 二次污染物 溶解性有机物(DOM) 释放机制 |
| 英文关键词 agricultural wastes denitrification carbon source secondary pollutant dissolved organic matter(DOM) release mechanism |
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| 中文摘要 |
| 针对农业废弃物作为反硝化碳源初期有机物释放过多，N、P和色度物质释放以及溶解性有机物成分、释放机制及潜在影响不清楚等问题，选取水稻秸秆、小麦秸秆、玉米秸秆、玉米芯、大豆秸秆和大豆壳作为反硝化碳源，研究其碳源、二次污染物及溶解性有机物的释放情况，并分析其可能产生的影响.结果表明，6种材料均可作为反硝化碳源，小麦秸秆中C元素含量最高，而玉米芯释放二次污染的风险最低；6种材料在1~120 h的碳源释放过程符合二级反应动力学和Ritger-Peppas方程，二级反应动力学拟合结果表明玉米芯因具有适中的cm值和较大的t1/2值更适合作为反硝化碳源，Ritger-Peppas方程拟合结果表明释放机制为扩散过程；水稻秸秆浸出液中NH4+-N、TN和TP浓度显著高于其他5种材料，小麦秸秆和玉米秸秆在浸泡过程中释放色度严重，玉米芯释放的N、P和色度物质均最少；玉米芯和大豆秸秆浸出液的可生化性好，造成出水二次污染的风险较低；浸出液中DOM芳香性和分子量随时间逐渐增大，腐殖化程度较低；利用平行因子法分析出5种荧光组分，主要为以类酪氨酸和类色氨酸为主的类蛋白物质，类胡敏酸为主的类腐殖酸含量较少，对后续水处理过程可能存在不利影响.本研究结果能为农业废弃物作为反硝化碳源时对初期阶段的出水水质影响及风险评估提供理论支撑. |
| 英文摘要 |
| As carbon sources for the denitrification process, agricultural wastes have some problems, such as excess release of organic carbon; unclear release characteristics of nitrogen, phosphorus, and colorimetric substances; and unclear components, release mechanisms, and potential effects of the released dissolved organic matter (DOM) in the start-up period. To resolve those problems, rice straw, wheat straw, corn stalk, corncob, soybean stalk, and soybean hull were selected as denitrification carbon sources to investigate the release mechanisms and potential influences of the organic matter, secondary pollutants, and DOM. The results showed that the six agricultural wastes could be used as the denitrification carbon source. The carbon content in the wheat straw was the highest and the secondary pollution risk from the corncob was the lowest. For the six carbon sources, the second-order kinetic equation and Ritger-Peppas equation were followed during the 1-120 h carbon release process. The fitting results demonstrated that corncob was more suitable for use as the denitrification carbon source because of its moderate cm value and longer t1/2 value, and the release mechanisms of the six types of carbon sources were mainly controlled by the diffusion process. The NH4+-N, TN, and TP contents in the immersion water of the rice straw were higher than those of the five other agricultural wastes, and there was heavy chromaticity in the immersion water of the wheat straw and corn stalk. The amounts of nitrogen, phosphorus, and chromatic substances released from the corncob were the lowest. The leachates of the corncob and soybean hull had higher biodegradability and lower risks of secondary pollution than those of the other sources. The aromaticity and molecular weight of DOM increased as the reaction time increased, and the humification of DOM was low. Five components were identified by PARAFAC. The main component was protein-like matter, which was mainly composed of tyrosine-like and tryptophan-like substances. There was less humic acid-like matter in the immersion water. The component characteristics of DOM might have had an adverse effect on the subsequent water treatment process. These results could provide theoretical support for the impact on effluent water quality and risk assessment when the agricultural wastes are used as an additional denitrification carbon source at the start-up stage. |
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