本文關(guān)鍵詞：上海城市河網(wǎng)沉積物硝酸鹽異化還原過程及其環(huán)境影響因素研究　出處：《華東師范大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 反硝化 厭氧氨氧化 硝酸鹽異化還原為銨 影響因素 上海市河網(wǎng)

【摘要】：氮是影響水生生態(tài)系統(tǒng)的環(huán)境惡化的主要因素之一。近些年,由于化石燃料的燃燒、生活污水排放和工業(yè)排放等人類活動(dòng)導(dǎo)致大量氮素排放進(jìn)入城市河流,這些人為輸入的活性氮進(jìn)入到城市河流環(huán)境。進(jìn)入到河流環(huán)境的氮以硝態(tài)氮的形體存在于河流水環(huán)境中。河流環(huán)境中氮的高度富集造成了水環(huán)境質(zhì)量惡化、水體酸化和生物多樣性減少等一系列的生態(tài)環(huán)境問題,給河流生態(tài)環(huán)境造成嚴(yán)重威脅。城市河流水環(huán)境氮高度富集現(xiàn)象已引起人們的廣泛關(guān)注,也是當(dāng)今城市環(huán)境研究的熱點(diǎn)科學(xué)問題。然而,現(xiàn)階段關(guān)于城市河流氮循環(huán)及活性氮去除機(jī)制的研究鮮有報(bào)道。因此,開展城市河流沉積物氮的削減途徑、歸宿和生態(tài)環(huán)境效應(yīng)研究,對(duì)加強(qiáng)城市河流氮循環(huán)過程的作用機(jī)制深入認(rèn)識(shí)具有重要的意義。基于此,本研究以上海城市河網(wǎng)為研究對(duì)象,研究上海城市河網(wǎng)沉積物硝酸鹽異化還原過程,揭示上海城市河網(wǎng)氮素污染狀況和硝態(tài)氮去除削減機(jī)制及其歸宿。硝酸鹽異化還原過程主要包括反硝化、厭氧氨氧化和硝酸鹽異化還原為銨(DNRA)過程。其中反硝化和厭氧氨氧化是分別將硝酸鹽和氨氮通過微生物作用轉(zhuǎn)化為氮?dú)饷撾x水體,長(zhǎng)期以來被認(rèn)為是自然環(huán)境中最重要的活性氮去除過程。DNRA過程不同于反硝化和厭氧氨氧過程,它是將硝酸鹽轉(zhuǎn)化為生物可利用性更高的銨鹽,進(jìn)而繼續(xù)留存在自然環(huán)境中,在氮轉(zhuǎn)化和歸宿中也具有非常重要的作用。本研究采用同位素示蹤技術(shù)結(jié)合泥漿培養(yǎng)試驗(yàn)上海城市河網(wǎng)沉積物反硝化、厭氧氨氧化和DNRA過程及其影響因素,并探討硝酸鹽異化還原生態(tài)效應(yīng)。主要研究成果包括以下幾方面:(1)上海城市河網(wǎng)沉積物硝酸鹽異化還原過程具有明顯的季節(jié)變化和空間差異特征。冬季,反硝化潛在速率為0.19-16.9 nmol N g-1 h-1(以干重計(jì)),夏季為1.98-987 nmol N g-1 h-1;厭氧氨氧化潛在速率范圍冬季和夏季分別為0.0404-23.7 nmol N g-1 h-1 和 0.243-12.9nmol N g-1 h-1;DNRA 冬季和夏季的潛在速率范圍分別為0-7.28 nmol N g-1 h-和0-10.3 nmol N g-1 h-1。研究區(qū),夏季反硝化和DNRA過程速率高于冬季,而冬季的厭氧氨氧化速率冬季速率高于夏季。(2)上海城市河網(wǎng)沉積物硝酸鹽異化還原過程受多種環(huán)境因子的影響,溶解氧、總有機(jī)碳、硝態(tài)氮、氨氮、硫化物和活性鐵對(duì)三種硝酸鹽還原過程具有顯著的影響。其中,反硝化過程主要受到溶解氧、硝酸鹽、二價(jià)鐵、三價(jià)鐵、硫化物和總有機(jī)碳影響;厭氧氨氧化過程與氨氮、三價(jià)鐵和溶解氧顯著相關(guān);硝態(tài)氮含量和C/N是DNRA過程的主要影響因素。(3)上海城市河網(wǎng)沉積物的反硝化和厭氧氨氧化過程在總硝酸鹽異化還原過程中的比例范圍為11.5-99.5%和0.343-81.6%,DNRA過程在硝酸鹽還原過程貢獻(xiàn)率只有0-52.3%。三種過程對(duì)硝酸鹽異化還原量的平均值來看,反硝化、厭氧氨氧化和DNRA貢獻(xiàn)率分別為50.2%、40.5%和9.3%。相較于DNRA過程,反硝化與厭氧氨氧化是上海城市河網(wǎng)沉積物中主要的硝酸鹽削減過程。經(jīng)估算,上海城市河網(wǎng)沉積物反硝化和厭氧氨氧化過程的脫氮量約為每年8.86×104t和4.45× 104t,總脫氮量為1.33× 105t,占河流每年氮輸入量的20.1%。
[Abstract]:Nitrogen is one of the main factors affecting the aquatic ecosystem environment deterioration. In recent years, due to the burning of fossil fuels, sewage emissions and industrial emissions and other human activities lead to a large number of nitrogen discharged into the river city, the anthropogenic input of reactive nitrogen into the environment into the river. The river city environment of nitrogen in nitrate form exists on the river water environment in river environment. Nitrogen in high concentration caused the deterioration of water environmental quality, water acidification and the loss of biodiversity and a series of ecological environment problems, causing a serious threat to the ecological environment of the river. The city river water environment nitrogen high enrichment phenomenon has aroused widespread concern and hot science problem is the city study on the environment. However, few studies on city river at this stage the nitrogen cycle and the activity of nitrogen removal mechanisms reported. Therefore, to carry out the city of river sediment Cut the way nitrogen, study on the effect of fate and ecological environment, strengthen the understanding of mechanism of city river nitrogen cycle has important significance. Based on this, this study takes Shanghai City River as the research object, the reduction process of Shanghai city river sediment nitrate dissimilation, revealed Shanghai city river pollution and nitrate nitrogen nitrogen removal mechanism and cut end. Dissimilatory nitrate reduction process including denitrification, anaerobic ammonium oxidation and reduction of nitrate to ammonium alienation (DNRA) process. The denitrification and anammox is respectively nitrate and ammonia nitrogen by microorganisms into nitrogen from water, has long been considered the most important activity of nitrogen the natural environment in the removal process of.DNRA is different from the process of denitrification and anaerobic ammonia oxidation process, it is the conversion of nitrate to bioavailable ammonium salt into the higher. And continue to exist in the natural environment, but also has a very important role in the nitrogen transformation and fate. In this study by using isotope tracer technique combined with mud cultivation test of Shanghai city river sediment denitrification, factors of anaerobic ammonia oxidation and DNRA process and its effects, and to explore the ecological effects of dissimilatory nitrate reduction. The main results include the following aspects: (1) Shanghai city river sediments dissimilatory nitrate reduction process with different distinct seasonal and spatial characteristics. In winter, the denitrification rate of 0.19-16.9 nmol N g-1 potential H-1 (dry weight), 1.98-987 nmol N g-1 H-1 in summer; anaerobic ammonia oxidation potential rate range in winter and summer respectively 0.0404-23.7 nmol N g-1 H-1 and 0.243-12.9nmol N g-1 H-1; the potential range of DNRA rate in winter and summer were 0-7.28 nmol N g-1 h- and 0-10.3 nmol N g-1 h-1. in study area. Denitrification and DNRA rate is higher than that in winter, while in winter, the anaerobic ammonia oxidation rate is higher than that in summer. The winter rate (2) of Shanghai city river sediments dissimilatory nitrate reduction process is affected by many environmental factors, dissolved oxygen, total organic carbon, nitrate nitrogen, ammonia nitrogen, has a significant effect on three kinds of iron sulfide and activity the nitrate reduction process. The denitrification process is mainly affected by dissolved oxygen, nitrate, ferric iron, two iron sulfide and total organic carbon; anaerobic ammonia oxidation process and ammonia nitrogen were significantly related to ferric iron and dissolved oxygen; the nitrate nitrogen content and C/N are the main factors affecting the DNRA process (3). Shanghai city river sediment denitrification and anammox process in dissimilatory nitrate reduction process in the ratio range of 11.5-99.5% and 0.343-81.6%, DNRA during the reduction process of the contribution rate of only 0-52.3%. three in the process of nitrate nitrate The average amount of salt dissimilatory reduction, denitrification, anaerobic ammonium oxidation and DNRA contribution rate were 50.2%, 40.5% and 9.3%. compared with DNRA process, denitrification and anaerobic ammonium oxidation is the main process of nitrate reduction in Shanghai city river sediments. It is estimated that the denitrification capacity of Shanghai city river sediment denitrification and anaerobic the ammonia oxidation process was approximately 8.86 * 104t and 4.45 * 104t, the total nitrogen amount to 1.33 * 105T, accounting for the annual n input 20.1%. River

【學(xué)位授予單位】：華東師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：X52

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