本文選題：懸沙 + 顆粒磷��； 參考：《長江科學院》2014年碩士論文

【摘要】：三峽水庫是舉世矚目的大型水利樞紐，研究三峽水庫蓄水以來長江中游河段懸浮泥沙環(huán)境效應，具有重要的學術價值。本文在前人研究的基礎上，通過設計完整的室內(nèi)動態(tài)吸附實驗，分析了長江中游懸浮泥沙粒徑、含沙量以及磷濃度對泥沙吸附顆粒磷的影響，并系統(tǒng)分析了未來20年長江中游顆粒磷通量的變化情況，指出三峽水庫淤積泥沙影響營養(yǎng)鹽的輸移，對長江中下游生態(tài)環(huán)境也產(chǎn)生一定影響。主要研究內(nèi)容及結(jié)論包括以下幾個方面： （1）總結(jié)了長江中游水體懸沙與顆粒磷的時空分布現(xiàn)狀。水庫蓄水以來，長江中游懸沙和顆粒磷通量大幅降低，宜昌至漢口河段，蓄水后均值低于蓄水前，壩下均值低于庫區(qū)均值；蓄水前后，懸沙和顆粒磷通量都具有季節(jié)性變化，豐水期輸送通量占了全年的80%以上，但是建庫后季節(jié)性變化幅度較小，，峰值較低。 （2）通過長江中游泥沙與顆粒磷的室內(nèi)吸附實驗，揭示了總吸附量和單位質(zhì)量泥沙吸附量隨懸沙含量、粒徑、磷酸鹽濃度和溫度改變的規(guī)律。可得總吸附量隨著含沙量和初始磷濃度的增加而增加；單位質(zhì)量泥沙吸附量隨含沙量和粒徑的增加而遞減，隨溫度和初始磷濃度的增加而增大，有最大吸附容量。 （3）泥沙吸附磷達到平衡狀態(tài)時，磷在水沙兩相之間的分配關系可以分別用Freundfich吸附等溫式和Langmuir吸附等溫式來表達，兩種吸附等溫模型擬合結(jié)果均滿足精度要求，Langmuir模型只考慮兩個變量，含沙量和平衡時水相磷濃度，擬合方便簡單。 （4）基于實測資料，率定并驗證了長江中游顆粒磷與懸沙的定量關系式，Cs=k*S~(1-n)*C_w(1+k'*S~(-n)*C_w)，并依據(jù)該方程，對未來20年長江中游顆粒磷通量變化情況進行了預測。結(jié)果表明，短時間內(nèi)長江中游顆粒磷通量仍然低于蓄水以前的水平，因而造成壩下水體磷缺失，這在一定程度上會抑制四大家魚等水生生物的生長。 （5）對進一步研究溫度和粒徑對泥沙吸附磷的影響，以及兩岸排污、農(nóng)村面源污染等的影響進行了展望。
[Abstract]:The three Gorges Reservoir is a large water conservancy project that attracts worldwide attention. It is of great academic value to study the environmental effect of suspended sediment in the middle reaches of the Yangtze River since the three Gorges Reservoir was impounded. On the basis of previous studies, the effects of suspended sediment particle size, sediment content and phosphorus concentration on the adsorption of particulate phosphorus by sediment in the middle reaches of the Yangtze River are analyzed by designing a complete indoor dynamic adsorption experiment. The change of particulate phosphorus flux in the middle reaches of the Yangtze River in the next 20 years is analyzed systematically. It is pointed out that sediment deposition in the three Gorges Reservoir affects the transport of nutrients and the ecological environment in the middle and lower reaches of the Yangtze River. The main contents and conclusions include the following: The temporal and spatial distribution of suspended sediment and particulate phosphorus in the middle reaches of the Yangtze River are summarized. Since the reservoir was impounded, suspended sediment and particulate phosphorus fluxes in the middle reaches of the Yangtze River have been greatly reduced. The mean values of suspended sediment and particulate phosphorus fluxes in the reach of Yichang to Hankou are lower than those before and after impounding, and the mean value under the dam is lower than that in the reservoir area before and after impounding. In the high water period, the transport flux accounted for more than 80% of the whole year, but the seasonal variation range was small and the peak value was lower after the establishment of the reservoir. 2) through the indoor adsorption experiments of sediment and particulate phosphorus in the middle reaches of the Yangtze River, the regularity of the change of total adsorption capacity and sediment adsorption capacity per unit mass with suspended sediment content, particle size, phosphate concentration and temperature was revealed. The total adsorption capacity increases with the increase of sediment content and initial phosphorus concentration, and decreases with the increase of sediment content and particle size, and increases with the increase of temperature and initial phosphorus concentration, with the maximum adsorption capacity. 3) when phosphorus adsorption reaches equilibrium, the distribution of phosphorus between water and sediment phases can be expressed by Freundfich adsorption isotherm and Langmuir adsorption isotherm, respectively. The fitting results of the two isothermal adsorption models meet the precision requirements. The Langmuir model only considers two variables, sediment content and phosphorus concentration in water phase at equilibrium. The fitting is convenient and simple. Based on the measured data, the quantitative relationship between particulate phosphorus and suspended sediment in the middle reaches of the Yangtze River is determined and verified. Based on this equation, the variation of particulate phosphorus flux in the middle reaches of the Yangtze River in the next 20 years is predicted. The results show that the particulate phosphorus flux in the middle reaches of the Yangtze River is still lower than that before the water storage in a short period of time, resulting in phosphorus deficiency under the dam, which to some extent inhibits the growth of aquatic organisms such as the four big domestic fish. The effects of temperature and particle size on phosphorus adsorption by sediment, sewage discharge from both banks and non-point source pollution in rural areas are prospected.
【學位授予單位】：長江科學院
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TV14

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