本文關(guān)鍵詞： 水力條件 生物膜 胞外聚合物 表面附著 給水管網(wǎng)　出處：《合肥工業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：給水管網(wǎng)是一個(gè)復(fù)雜的、時(shí)刻變化的生態(tài)反應(yīng)系統(tǒng),其中的細(xì)菌會(huì)通過(guò)表面附著和聚集的方式(多以生物膜出現(xiàn))以適應(yīng)不斷變化的環(huán)境條件,嚴(yán)重威脅供水水質(zhì)安全。目前,關(guān)于水力條件對(duì)給水管網(wǎng)生物膜形成影響的研究仍存在較多爭(zhēng)議,其中水力條件如何調(diào)控細(xì)菌個(gè)體行為進(jìn)而影響初期生物膜形成的機(jī)理尚不清晰。本文以給水管網(wǎng)細(xì)菌為研究對(duì)象,解析不同流速條件下細(xì)菌胞外聚合物的分泌、種群分布以及初期附著和聚集機(jī)制,揭示生物膜的形成機(jī)制,以期為給水管網(wǎng)細(xì)菌生長(zhǎng)控制提供理論指導(dǎo)和新的思路。首先,本文研究了恒定水力條件下流速對(duì)給水管網(wǎng)細(xì)菌胞外聚合物分泌與初期生物膜形成的影響。結(jié)果表明:在流速較低(0.0-1.0 m/s)時(shí),增大流速會(huì)刺激細(xì)菌胞外聚合物的分泌進(jìn)而促進(jìn)其附著聚集;但當(dāng)流速過(guò)高(1.0 m/s)時(shí),增大流速抑制細(xì)菌胞外聚合物的分泌從而抑制其附著聚集。主體水懸浮細(xì)菌胞外聚合物分泌量與表面Zeta電位和疏水性的相關(guān),進(jìn)一步說(shuō)明了水力條件調(diào)控了細(xì)菌胞外聚合物的分泌,改變了細(xì)菌表面特征,進(jìn)而影響其在管壁表面的初期附著行為。其次,研究了流速波動(dòng)對(duì)給水管網(wǎng)細(xì)菌胞外聚合物分泌和初期生物膜形成的影響。結(jié)果表明:相較于恒定水流流速條件,給水管網(wǎng)流速波動(dòng)促進(jìn)管壁初期生物膜的形成和主體水懸浮細(xì)菌數(shù)量的增長(zhǎng),且流速波動(dòng)幅度和頻率越大越有利于管壁生物膜的形成;同時(shí),給水管網(wǎng)水流流速波動(dòng)促進(jìn)了細(xì)菌EPS的分泌,且隨著波動(dòng)幅度和頻率的增大,細(xì)菌EPS的分泌量進(jìn)一步提高;水流流速波動(dòng)調(diào)控著細(xì)菌EPS的分泌,改變細(xì)菌表面Zeta電位和疏水性,從而影響給水管網(wǎng)初期生物膜的形成。最后,研究了水流流速對(duì)給水管網(wǎng)生物膜種群結(jié)構(gòu)和多樣性的影響。結(jié)果表明:中等流速條件(1.0 m/s)下,生物膜群落結(jié)構(gòu)呈現(xiàn)較高的多樣性。在不同流速條件下,銅綠假單胞菌菌屬始終為生物膜優(yōu)勢(shì)菌種,且在中等流速(1.0 m/s)條件下,其優(yōu)勢(shì)最明顯。
[Abstract]:The water supply network is a complex and ever-changing ecological response system in which bacteria can adapt to changing environmental conditions by means of surface adhesion and aggregation (mostly as biofilms). At present, there are still many controversies on the influence of hydraulic conditions on biofilm formation in water supply networks. It is not clear how hydraulic condition can regulate the individual behavior of bacteria and then affect the formation of biofilm in the early stage. In this paper, the bacteria in water supply network were taken as the research object to analyze the secretion of extracellular polymer under different flow rates. Population distribution and initial attachment and aggregation mechanism to reveal the biofilm formation mechanism in order to provide theoretical guidance and new ideas for the control of bacterial growth in water supply networks. The effect of flow rate on extracellular polymer secretion and biofilm formation of bacteria in water supply network was studied under constant hydraulic conditions. The results showed that at a low velocity of 0.0-1.0 m / s. Increasing the flow rate stimulates the secretion of extracellular polymers and promotes the aggregation of extracellular polymers. But when the velocity is too high (1.0 m / s). The increase of flow rate inhibited the secretion of extracellular polymers and thus inhibited the aggregation of extracellular polymers. The amount of extracellular polymers secreted by water suspension bacteria was related to the surface Zeta potential and hydrophobicity. It is further explained that hydraulic conditions regulate the secretion of extracellular polymers of bacteria, change the surface characteristics of bacteria, and then affect the initial adhesion behavior of bacteria on the surface of tube wall. Secondly. The effect of flow rate fluctuation on extracellular polymer secretion and biofilm formation of bacteria in water supply network was studied. The velocity fluctuation of water supply network promotes the formation of biofilm in the initial stage of the pipe wall and the increase of bacteria number in the main water suspension, and the greater the fluctuation amplitude and frequency of the velocity is, the more favorable the biofilm is. At the same time, the fluctuation of water flow velocity in water supply network promoted the secretion of bacterial EPS, and with the increase of fluctuation amplitude and frequency, the secretion of bacterial EPS was further increased. The fluctuation of flow velocity regulates the secretion of bacterial EPS, changes the surface Zeta potential and hydrophobicity of bacteria, thus affects the formation of biofilm in the initial stage of water supply network. The effect of flow velocity on the population structure and diversity of biofilm in water supply network was studied. Under different flow rates, Pseudomonas aeruginosa was always the dominant biofilm species, and the dominant biofilm was the most obvious under the medium velocity of 1.0 m / s.
【學(xué)位授予單位】：合肥工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TU991.33

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