本文關(guān)鍵詞： 底泥 疏浚 污染特征 化學(xué)鈍化　出處：《重慶交通大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：疏浚不僅是維護(hù)航道水深和通航的一種重要措施，而且也屬于一種能去除底泥污染物的方法，但是由于疏浚過程中挖泥船的機(jī)械擾動(dòng)、溢流、灑漏，，使得底泥中的污染物重新釋放，造成二次污染。所以疏浚能否從根本上解決環(huán)境的污染，一直存在很大爭議。從而選擇行之有效的疏浚方案，包括疏浚方式、疏浚深度、疏浚時(shí)節(jié)都是當(dāng)今研究的熱點(diǎn)問題。 化學(xué)鈍化技術(shù)是指通過向水體投加化學(xué)鈍化劑來去除或者轉(zhuǎn)化為其他無毒無害，相對(duì)穩(wěn)定的物質(zhì)，從而達(dá)到凈化底泥以及水體的作用。本文則是將化學(xué)鈍化技術(shù)運(yùn)用到航道疏浚中來從而達(dá)到以改變疏浚方式為目的，使底泥中的污染物造成的二次污染最低。本實(shí)驗(yàn)以三峽水庫常年回水區(qū)忠縣黃花城河段的底泥為研究對(duì)象，通過實(shí)驗(yàn)室的模擬，研究了化學(xué)鈍化劑在抑制疏浚底泥中污染物的釋放規(guī)律，主要研究結(jié)論如下： ①隨著時(shí)間的增加，各類污染物釋放量總體越來越大。在0-8h釋放速率最快，8-24h釋放量趨于穩(wěn)定，達(dá)到底泥對(duì)污染物的吸附解吸平衡。解吸曲線擬合符合Langmuir公式。COD、TP、氨氮的最大釋放量分別為104mg/L、0.94mg/L、1.96mg/L。由此說明，三峽典型淤積河段忠縣黃花港地區(qū)疏浚底泥中存在大量污染物，如果不進(jìn)行有效控制，在底泥擾動(dòng)后，將會(huì)造成二次污染。 ②最佳鈍化劑為PAC和硝酸鈣。雖然5種鈍化劑對(duì)于COD、TP都有一定的鈍化效果，對(duì)于COD而言，效果最好的是PAC和硝酸鈣，過氧化鈣和雙氧水次之，高錳酸鉀再次之，但是從鈍化速度來講，雙氧水的速度最快，在2天就能達(dá)到很好的抑制率，但是長期性較差。對(duì)于TP，5種鈍化劑的效果都比較理想，控制速度快，且效果良好。其中以PAC和硝酸鈣效果最佳，釋放量均低于0.1mg/L。對(duì)于氨氮而言，5種鈍化劑均無明顯效果，雙氧水與高錳酸鉀反而有很強(qiáng)的促進(jìn)氨氮釋放能力，且隨著投加量的增加，促進(jìn)效果越強(qiáng)。 ③PAC的最佳投加量為4g/kg干泥、硝酸鈣的最佳投加量為6g/kg干泥。 ④擾動(dòng)情況下， PAC與硝酸鈣能讓泥沙迅速沉降，能在4小時(shí)達(dá)到50NTU以下，過氧化鈣和高錳酸鉀次之，雙氧水反而促進(jìn)了底泥向上覆水中擴(kuò)散。 ⑤通過注入底泥內(nèi)部的方式能更好的達(dá)到控制底泥污染物釋放的目的，且注入方式對(duì)硝酸鈣的影響較PAC更大。 ⑥溫度的升高對(duì)于COD、總磷和氨氮有促進(jìn)作用。 ⑦溫度的升高對(duì)于PAC抑制底泥中COD、 TP和氨氮解吸影響不大；溫度的升高對(duì)硝酸鈣抑制底泥污染物的釋放均起促進(jìn)作用，且30℃效果遠(yuǎn)大于10℃18.2℃。夏季疏浚過程中，用硝酸鈣效果更好。
[Abstract]:Dredging is not only an important measure to maintain waterway depth and navigation, but also a method to remove sediment pollutants. However, due to the mechanical disturbance, overflow and leakage of dredging vessels during dredging, So whether dredging can fundamentally solve the pollution of the environment has always been controversial. Therefore, it has been very controversial to select effective dredging schemes, including dredging methods and depth of dredging. Dredging season is a hot topic in current research. Chemical passivation technology refers to the removal or conversion into other non-toxic and relatively stable substances by adding chemical passivating agents to water bodies. In this paper, the chemical passivation technology is applied to the dredging of waterway to change the dredging mode. The secondary pollution caused by pollutants in sediment is the lowest. This experiment takes the sediment of Huanghuacheng reach, Zhongxian County, as the research object, through the laboratory simulation. The regulation of the release of pollutants from dredged sediment by chemical passivating agent was studied. The main conclusions are as follows:. (1) with the increase of time, the release of various pollutants became more and more large, and the release rate was the fastest in 0-8 h, and the release rate of 8-24 h tended to be stable. The desorption curve fitted with Langmuir formula. The maximum release of ammonia nitrogen was 104mg / L 0.94 mg / L 0.94 mg / L 1.96 mg / L respectively. This shows that there are a lot of pollutants in dredged sediment of Huanghua Port area, Zhongxian County, three Gorges typical silt. If no effective control is carried out, secondary pollution will be caused after sediment disturbance. 2 the best passivating agents were PAC and calcium nitrate. Although the five passivating agents had certain passivation effect for COD, the best ones were PAC and calcium nitrate, calcium peroxide and hydrogen peroxide, and potassium permanganate again. But in terms of passivation speed, hydrogen peroxide is the fastest, it can reach a good inhibition rate in 2 days, but the long-term is poor. The results showed that PAC and calcium nitrate had the best effect, and the release amount was less than 0.1 mg / L. there was no obvious effect on ammonia nitrogen, but hydrogen peroxide and potassium permanganate had a strong ability to promote the release of ammonia nitrogen, and with the increase of the amount of ammonia nitrogen, the effect of hydrogen peroxide and potassium permanganate on the release of ammonia nitrogen was higher than that of potassium permanganate. The stronger the promotion effect. 3The optimum dosage of PAC is 4 g / kg dry mud, and the best dosage of calcium nitrate is 6 g / kg dry mud. (4) under disturbance, PAC and calcium nitrate can precipitate the sediment rapidly, reaching less than 50NTU in 4 hours, followed by calcium peroxide and potassium permanganate, and hydrogen peroxide can promote the diffusion of sediment to the overlying water. (5) the method of injecting into sediment can better control the release of pollutants from sediment, and the effect of injection on calcium nitrate is greater than that of PAC. 6 the increase of temperature can promote COD, total phosphorus and ammonia nitrogen. (7) the increase of temperature has little effect on the inhibition of COD, TP and ammonia nitrogen desorption in sediment by PAC, and the increase of temperature can promote the inhibition of pollutant release from sediment by calcium nitrate, and the effect at 30 鈩

本文編號(hào)：1545466