【摘要】：甲烷(CH4)是一種影響全球氣候變化和大氣化學(xué)的重要溫室氣體,近年來由于甲烷源匯的失衡,大氣中CH4含量逐漸升高。河流是大氣CH4的自然源,隨著工業(yè)化的進(jìn)程,城市黑臭河道更為突出,城市黑臭河道由于受到人為活動的影響,生活污水和工業(yè)污水的排入,CH4釋放異常活躍,對大氣CH4貢獻(xiàn)顯著。因此,研究城市黑臭河道甲烷排放規(guī)律及其環(huán)境影響因子之間的關(guān)系,有助于深入認(rèn)識各種水體甲烷排放通量,從而為全球甲烷估算提供一定的參考和數(shù)據(jù)支持,通過現(xiàn)場調(diào)查及實驗室實驗探究環(huán)境因子對產(chǎn)甲烷速率的影響,獲得主要成果如下：(1)本文通過對城市黑臭河道—南寧市朝陽溪現(xiàn)場進(jìn)行調(diào)查,利用靜態(tài)箱法測定南寧市上、中、下游產(chǎn)甲烷通量,并測定水體中CODCr、TN. TP、NH4+-N、溫度、pH及底泥有機碳的含量,結(jié)果表明：朝陽溪是重要的甲烷排放源,夏季甲烷排放通量平均值為12.2mg/(m2·h),上游、中游、下游排放通量變化不顯著。利用偏最小二乘法進(jìn)行相關(guān)性分析可得,甲烷通量與溫度、化學(xué)需氧量、底泥有機碳呈顯著正相關(guān),與溶解氧呈顯著負(fù)相關(guān),與總氮、氨氮、總磷、pH相關(guān)性較小。(2)利用頂空瓶測定底泥及水體甲烷生成量可得,水體產(chǎn)甲烷很微小,幾乎為零,底泥產(chǎn)甲烷速率呈現(xiàn)先增加后減少的趨勢,且底泥在第5天產(chǎn)甲烷速率最大,為0.0056mg·g-1。底泥在第15天后產(chǎn)甲烷的速率很小。根據(jù)本實驗數(shù)據(jù)可得南寧市朝陽溪底泥在厭氧和25℃的條件下底泥甲烷初始釋放量與培養(yǎng)時間的數(shù)學(xué)關(guān)系y=0.4558×d0.7280。(3)在不同溫度條件下對底泥產(chǎn)甲烷的影響實驗中,設(shè)置3組不同的溫度分別為15℃、25℃、35℃。溫度對底泥產(chǎn)甲烷具有顯著的影響,且隨著溫高的升高產(chǎn)甲烷速率增大,在35℃時產(chǎn)甲烷速率比15℃產(chǎn)甲烷速率大1.9倍。溫度對底泥污染物的釋放具有顯著的影響,溫度越高底泥污染物釋放的速率越快,溫度在35℃時底泥CODCr、TN、TP釋放速率為15℃的2、4.5和3.8倍,底泥有機碳的降解速率在35℃為15℃的1.7倍,溫度對水體溶解氧降低的速率具有重要的影響,當(dāng)水體有機物含量較高時,水體中溶解氧的含量對底泥產(chǎn)甲烷的影響較少。在隔絕空氣條件下底泥甲烷生成量與培養(yǎng)時間及溫度的數(shù)學(xué)關(guān)系為CMethane=0.4182·T0.9509·log10(0.091t+1)。隔絕空氣條件下底泥的甲烷生成量與底泥所釋放出的CODCr、TP呈正相關(guān)關(guān)系,與底泥所釋放出TN和水體溶解所消耗速率的相關(guān)性較少,隔絕空氣條件下底泥所降解的有機碳與底泥甲烷生成量呈顯著的正相關(guān)關(guān)系。(4)在不同的水體初始pH條件下對底泥產(chǎn)甲烷的影響實驗中,設(shè)置3組不同的水體初始pH分別為6、7.5、9。pH對底泥產(chǎn)甲烷具有重要的影響,不同pH甲烷生成量不同,其中在pH為9最大,pH為7.5時次之,pH為6時最小。當(dāng)水體初始pH為9有利于底泥向底泥——水界面中水體體釋放TP、CODCr。當(dāng)水體初始pH為7.5時有利于底泥向底泥—水界面中水體釋放TN。甲烷生成量與上覆水CODCr含量呈正相關(guān),與泥水界面TN、TP濃度不具相關(guān)性。不同pH條件下底泥甲烷生成量與培養(yǎng)時間的數(shù)學(xué)關(guān)系可表示為：CMethane=0.8472·pH1.577·log10(0.036d+1)。
[Abstract]:Methane (CH4) is an important greenhouse gas that affects global climate change and atmospheric chemistry. In recent years, the content of CH4 in the atmosphere is increasing due to the imbalance of the source of methane. The river is the natural source of the atmospheric CH4. With the process of industrialization, the city's black-smelling channel is more prominent. The city's black-smelling channel is affected by man-made activities, and the discharge of domestic sewage and industrial sewage, CH4 release is abnormal, and the contribution of CH4 to the atmosphere is significant. Therefore, the study of the relationship between the methane emission law and the environmental impact factors in the urban black-smelling channel can help to understand the methane emission flux in various water bodies, thus providing some reference and data support for the global methane estimation. The effect of environmental factors on the rate of methane production was investigated by on-site investigation and laboratory experiments. The main results are as follows: (1) The main results are as follows: (1) In this paper, the methane flux in the upper, middle and lower reaches of Nanning city is determined by the static tank method. And the CODCr and TN in the water body are measured. The organic carbon content of TP, NH 4 +-N, temperature, pH and bottom mud shows that the average of methane emission is 12.2 mg/ (m2 路 h), and the change of emission flux in the upstream, middle reaches and downstream is not significant. The correlation between the methane flux and the temperature, the chemical oxygen demand and the organic carbon of the sediment is positively correlated with the dissolved oxygen, and the correlation with the total nitrogen, the ammonia nitrogen, the total phosphorus and the pH is small. (2) The methane production rate of the bottom mud and the water body is obtained by using the top empty bottle, the methane production rate of the water body is very small, almost zero, the methane production rate of the bottom mud is increased, and the methane production rate of the bottom mud is at the maximum of 0.0056 mg 路 g-1 at the fifth day. The rate of methane production after the 15th day was very small. Under the condition of anaerobic and 25 鈩，

本文編號：2487139