發(fā)布時(shí)間：2018-01-11 06:10

  本文關(guān)鍵詞：大連某TPH污染場(chǎng)地原位強(qiáng)化過(guò)硫酸鈉修復(fù)技術(shù)研究　出處：《沈陽(yáng)大學(xué)》2017年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 原位化學(xué)氧化 過(guò)硫酸鈉 TPH污染土壤 土壤修復(fù)

【摘要】：石油類污染場(chǎng)地是指由于人類活動(dòng)產(chǎn)生的石油類污染物(TPH,Total petroleum hydrocarbon)超過(guò)一定閾值,對(duì)環(huán)境介質(zhì)造成污染,且對(duì)人體健康造成危害的場(chǎng)地,具有成分復(fù)雜,污染濃度高、分布廣、環(huán)境危害性強(qiáng)的特點(diǎn)。由于對(duì)污染場(chǎng)地的二次利用以及對(duì)土壤安全性的需求,如何快速有效的修復(fù)TPH污染場(chǎng)地是必要解決的問(wèn)題,也是難點(diǎn)問(wèn)題。化學(xué)氧化技術(shù)是修復(fù)TPH污染土壤的一個(gè)快速而有效的方法,其關(guān)鍵在于氧化劑的選擇以及高效安全的應(yīng)用方式。本研究以大連某TPH污染場(chǎng)地為研究對(duì)象,通過(guò)場(chǎng)地調(diào)查和風(fēng)險(xiǎn)評(píng)估確定需要修復(fù)的污染物類型、濃度、分布范圍和修復(fù)目標(biāo),篩選適合該場(chǎng)地修復(fù)用的氧化劑組合,研究其最佳的應(yīng)用方式、影響因素和降解機(jī)制等,并利用自制的土壤修復(fù)設(shè)備模擬氧化劑對(duì)該場(chǎng)地表層及深層污染土壤的修復(fù),探明化學(xué)氧化過(guò)程中TPH的遷移轉(zhuǎn)化規(guī)律,為設(shè)計(jì)本場(chǎng)地原位化學(xué)氧化修復(fù)技術(shù)方案提供數(shù)據(jù)支撐和理論依據(jù)。主要研究結(jié)果如下:(1)通過(guò)對(duì)污染場(chǎng)地自然地理環(huán)境、水文地質(zhì)特征、企業(yè)生產(chǎn)情況的調(diào)查以及土壤和地下水中可能存在的有機(jī)污染物和重金屬的監(jiān)測(cè)分析,確定本場(chǎng)地需修復(fù)的污染物類型、范圍和濃度。結(jié)果表明地下水中20種污染物均未超過(guò)篩選值,場(chǎng)地主要為土壤TPH污染,濃度范圍19.8~52500 mg/kg。修復(fù)區(qū)域?yàn)閳?chǎng)地溶劑庫(kù)房表層(0~20cm)、廢液庫(kù)房(0~430 cm)及油泥處理區(qū)表層(0~60 cm),修復(fù)土方量合計(jì)3168.4m_3,其中重點(diǎn)修復(fù)區(qū)域?yàn)閺U液庫(kù)房,所需修復(fù)面積615.7 m2,修復(fù)土方量2647.5m_3。(2)通過(guò)理論計(jì)算與小試實(shí)驗(yàn)對(duì)比了不同氧化劑的修復(fù)效率和氧化劑的需求量,并以此為基礎(chǔ),綜合考慮土壤自然氧化劑需求、氧化劑的穩(wěn)定性、地下環(huán)境傳質(zhì)特性、修復(fù)成本以及場(chǎng)地自然條件等因素,選擇過(guò)硫酸鈉(Na_2S_2O_8)為本場(chǎng)地修復(fù)用氧化劑;研究了不同方法活化時(shí)Na_2S_2O_8對(duì)TPH污染土壤的氧化處理效果:添加Fe~(2+)/檸檬酸(CA)活化的效果最佳,Na_2S_2O_8的投加量在2 mmol/g土較為適宜,且一次添加的去除效果比序批添加降解效率更高,土壤TPH的去除率為40.8%;利用探針化合物研究了不同時(shí)間節(jié)點(diǎn)內(nèi)Fe~(2+)活化Na_2S_2O_8去除土壤中TPH的機(jī)理:Fe~(2+)/CA活化反應(yīng)較快,30 min內(nèi)反應(yīng)基本完成,其降解TPH的主要物質(zhì)是SO4-·、·OH等自由基,土壤中天然存在以及反應(yīng)中產(chǎn)生的還原性物質(zhì)促進(jìn)了TPH的降解。(3)采用Na_2S_2O_8/過(guò)氧化鈣(CaO_2)/Fe~(2+)/CA的組合修復(fù)場(chǎng)地表層TPH污染土壤,以克服單獨(dú)使用Fe~(2+)/CA活化帶來(lái)的水溶性氧化劑/活化劑流失嚴(yán)重、土壤酸化、副產(chǎn)物SO42-過(guò)高的缺陷。結(jié)果表明:使用Na_2S_2O_8/CaO_2的組合,摩爾用量比為2.5較為合適,反應(yīng)7天TPH去除率為67.4%。使用Na_2S_2O_8/Ca O_2/Fe~(2+)/CA的方法,當(dāng)摩爾用量比為5/2/1/1時(shí),TPH降解率為82.1%,反應(yīng)比較溫和,反應(yīng)后土壤體系pH呈中性。土壤水相中TPH和SO42-的濃度均低于篩選值,對(duì)環(huán)境的影響較小。利用探針化合物對(duì)Na_2S_2O_8/CaO_2/Fe~(2+)/CA體系去除土壤TPH的機(jī)制研究表明,TPH降解過(guò)程中不僅有SO4-·、OH·等自由基的作用,CaO_2也參與了直接氧化,168 h內(nèi)反應(yīng)基本完成。(4)通過(guò)自制的土壤修復(fù)模擬設(shè)備,采集污染場(chǎng)地土壤,按照實(shí)際地層狀況進(jìn)行按比例縮小重塑。采用表層土壤混合、淋濾、下層土壤注射井注入/抽出地下水配制氧化劑溶液循環(huán)利用等方式,對(duì)大連某TPH污染場(chǎng)地土壤進(jìn)行原位Na_2S_2O_8氧化修復(fù)模擬。結(jié)果表明:上層土壤混合Ca O_2和Na_2S_2O_8后噴灑FeSO_4/CA可以有效修復(fù)表層污染土壤,20天后土壤TPH降解率達(dá)到最高,平均值為98.5%;下層土壤注射井注入Na_2S_2O_8/FeSO_4/CA,在蠕動(dòng)泵壓力0.2 Mpa,流速10 mL/min,地下水流速0.08 m/d條件下,Na_2S_2O_8在模擬土體中的傳輸能力較強(qiáng),持續(xù)注入3天,氧化劑遷移至飽和層,影響半徑約為0.2 m。持續(xù)注入7天時(shí)氧化劑影響半徑約為0.4 m,氧化劑基本充滿飽和層,此時(shí)土壤TPH降解率達(dá)到最高,平均為95.6%。土壤溶液pH和土壤溫度監(jiān)測(cè)值分別為5.9~7.6和7~21℃,表明該方法的環(huán)境次生影響較小。(5)根據(jù)場(chǎng)地調(diào)查和中試模擬所得技術(shù)參數(shù),設(shè)計(jì)本場(chǎng)地TPH污染土壤原位化學(xué)氧化修復(fù)工程技術(shù)方案。對(duì)于溶劑庫(kù)房表層(0~20 cm)、油泥處理區(qū)表層(0~60 cm)和廢液庫(kù)房表層污染土壤,采取原位混合淋濾的方法,修復(fù)藥劑為Na_2S_2O_8/CaO_2/Fe~(2+)/CA;對(duì)于廢液庫(kù)房深層污染土壤(60~430 cm)采取原位注射的方法,修復(fù)藥劑為Na_2S_2O_8/Fe~(2+)/CA。井間距4米,初始注入壓力1 Mpa,修復(fù)期為60天。
[Abstract]:Oil pollution site is due to human activities have petroleum pollutants (TPH, Total petroleum hydrocarbon) exceeds a certain threshold, pollute the environment and harm to the media sites on human health, has complex composition, high concentration of pollution, wide distribution, environmental hazards and strong characteristics. Because the two use of pollution the site and the demand for the safety of the soil, how to quickly and effectively repair TPH contaminated sites is necessary to solve the problem, which is also a difficult problem. Chemical oxidation technology is a rapid and effective method for the remediation of TPH contaminated soil, the key lies in the application of oxidants and high safety. The study in Dalian Province TPH contaminated sites as the research object, through the site investigation and risk assessment to determine the need to repair the pollutant type, concentration, distribution and repair, suitable for the screening of site remediation Combination of oxidizing agent, studied the best application mode, influencing factors and degradation mechanisms, and the use of soil remediation equipment homemade oxidation repair agent on the ground simulation of surface and deep soil pollution, migration and transformation regularity of chemical oxidation process of TPH, provide data support and theoretical basis for the design of repair technology field in situ chemical oxidation. The main results are as follows: (1) based on the contaminated natural geographical environment, hydrogeological characteristics, analysis of possible production situation investigation and soil and groundwater organic pollutants and heavy metals monitoring, determine the site to repair the types of pollutants, and the concentration range. The results showed that 20 kinds of contaminants in groundwater did not exceed the value of screening, the main venue for soil TPH pollution, the concentration range of 19.8~52500 mg/kg. repair area for site surface (0~20cm) solvent storeroom The warehouse (0~430 cm), wastewater sludge treatment and surface area (0~60 cm), total repair of earthwork 3168.4m_3, which focus on the repair area for waste storeroom, the required repair area of 615.7 m2, 2647.5m_3. repair earthwork (2) by comparing the theoretical calculation and experiment of the repair efficiency and oxidant different oxidant demand the amount, and on this basis, considering the soil natural oxidant demand, the stability of the oxidant, the underground environment and mass transfer characteristics, the cost of repair and site factors such as natural conditions, selection of sodium persulfate (Na_2S_2O_8) as oxidant for the site repair; studied the activation of Na_2S_2O_8 in TPH contaminated soils: add oxidation treatment Fe~ (2+) / citric acid (CA) activation of the best effect, the dosage of Na_2S_2O_8 2 mmol/g in the soil is suitable, and an added removal effect than batch add higher degradation efficiency, soil TPH The removal rate was 40.8%; of different time node using Fe~ probe compound (2+) removal mechanism of soil TPH activation in Na_2S_2O_8: Fe~ (2+) /CA activation reaction rapidly, within 30 min was completed, the main substance of the degradation of TPH is SO4-, OH and other free radicals, reducing substances from natural there are soil and in response to promote the degradation of TPH. (3) using Na_2S_2O_8/ calcium peroxide (CaO_2) /Fe~ (2+) /CA composite repair site surface TPH contaminated soil, in order to overcome the single use of Fe~ (2+) /CA activation of water soluble oxidant / activator erosion, soil acidification that defect by-product SO42- high. The results show that the combination of Na_2S_2O_8/CaO_2, molar ratio of 2.5 is more appropriate, reaction 7 days the removal rate of TPH using Na_2S_2O_8/Ca O_2/Fe~ 67.4%. (2+) /CA method, when the molar ratio was 5/2/1/1, the degradation rate of TPH was 82.1%, the reaction Mild reaction after soil system pH is neutral. The concentration of TPH and SO42- in soil solution was lower than the value of screening, less impact on the environment. Using Na_2S_2O_8/CaO_2/Fe~ probe compound (2+) mechanism of /CA system for removal of soil TPH showed that the degradation process of TPH is not only in the SO4-, OH and other free radicals CaO_2, is also involved in the direct oxidation reaction basically completed within 168 H. (4) through soil remediation selfmade simulation equipment, acquisition of contaminated soil, were scaled according to the actual situation. The remodeling of formation of surface soil mixing, leaching, soil injection wells injection / extraction of groundwater prepared oxidant solution recycling etc. Na_2S_2O_8, in situ oxidation repair simulation of a Dalian TPH contaminated soil. The results showed that: Ca O_2 and Na_2S_2O_8 mixed soil after spraying FeSO_4/CA can effectively repair the surface of polluted soil After 20 days of soil, soil degradation rate of TPH reached the highest, the average value of 98.5%; lower soil injection wells of Na_2S_2O_8/FeSO_4/CA injection on the peristaltic pump pressure of 0.2 Mpa, a flow rate of 10 mL/min, the underground water flow rate under the condition of 0.08 m/d, transmission capacity of Na_2S_2O_8 in the simulation of soil in strong, continuous injection of 3 days, the oxidant migration to the saturated layer the influence radius is about 0.2 M., continuous injection of 7 days oxidant influence radius is about 0.4 m, oxidant basic saturated layer, the soil degradation rate of TPH reached the highest, the average 95.6%. pH of soil solution and soil temperature monitoring value were 5.9~7.6 and 7~21 C, that this method has a smaller environment (secondary effects. 5) according to the simulation results of site investigation and test technical parameters, design the site of TPH contaminated soil remediation technology for in situ chemical oxidation. For the solvent warehouse (0~20 cm), the surface area of the surface of sludge treatment (0~60 cm) and waste water The storehouse surface contaminated soil, adopt the method of in situ leaching mixed, repair agent for Na_2S_2O_8/CaO_2/Fe~ (2+) /CA; for the waste warehouse deep contaminated soil (60~430 cm) by in situ injection, repair agent for Na_2S_2O_8/Fe~ (2+) /CA. well spacing of 4 meters, the initial injection pressure of 1 Mpa, the repair period is 60 days.

【學(xué)位授予單位】：沈陽(yáng)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：X53

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