污水廠水質(zhì)變化對(duì)超濾膜的影響及其改進(jìn)
發(fā)布時(shí)間：2018-08-03 06:59
【摘要】：近些年水資源短缺、城市缺水問題突出的國(guó)家,都將單純水污染控制轉(zhuǎn)變?yōu)槿轿坏乃h(huán)境可持續(xù)發(fā)展。我國(guó)也采取了多種措施來緩解城市用水的危機(jī),其中最主要的就是再生水回用。本研究通過污水廠不同因素對(duì)膜的影響,主要從膜通量的衰減和跨膜壓差的增大,判斷膜污染的主要原因;通過分析膜對(duì)胞外聚合物和溶解性微生物產(chǎn)物的過濾行為及對(duì)污染物的截留情況,評(píng)價(jià)膜污堵的情況,研究過濾過程中膜對(duì)胞外聚合物和溶解性微生物產(chǎn)物的截留和沉積情況,為優(yōu)化膜的清洗策略提供技術(shù)指導(dǎo);通過對(duì)比不同的運(yùn)行方式,觀察膜通量的衰減和跨膜壓差的變化,從而改善運(yùn)行方式,為超濾膜系統(tǒng)穩(wěn)定正常的運(yùn)行提供依據(jù),同時(shí)為優(yōu)化超濾系統(tǒng)的設(shè)計(jì)和操作參數(shù)提供有效的方法;在冬季污水廠的生化系統(tǒng)變化,水中出現(xiàn)的絮狀物質(zhì),這種物質(zhì)有極強(qiáng)的附著能力和聚集能力,在冬季需將自清洗過濾器進(jìn)行調(diào)整,不能讓其到了設(shè)定的自清洗壓力再進(jìn)行清洗,將自清洗過濾器調(diào)整為固定時(shí)間進(jìn)行自清洗,根據(jù)多次的試驗(yàn),最后將時(shí)間調(diào)整為15分鐘。調(diào)整之后,自清洗過濾器在之后的冬季運(yùn)行良好。但過了冬季仍需將自清洗過濾器調(diào)整回根據(jù)壓差清洗,這樣能保證系統(tǒng)的長(zhǎng)時(shí)間穩(wěn)定運(yùn)行。超濾膜隨著夏季進(jìn)水水溫的上升,微生物的數(shù)量增加和繁殖,造成了膜的污堵,進(jìn)而造成了秋季超濾膜污堵情加劇。在進(jìn)水端上加裝一臺(tái)計(jì)量泵,由計(jì)量泵向進(jìn)水管路中輸送進(jìn)1Oppm的次氯酸鈉,進(jìn)而抑制細(xì)菌的繁殖,減少其對(duì)膜孔附著的幾率,降低超濾膜系統(tǒng)的污堵。在超濾膜運(yùn)行過程中,必須對(duì)超濾系統(tǒng)的反洗水進(jìn)行跟蹤化驗(yàn),從而更進(jìn)一步的了解水質(zhì)的變化、主要污染物的形式、反洗是否徹底等關(guān)鍵因素。當(dāng)發(fā)現(xiàn)水質(zhì)發(fā)生變化,從而造成反洗去污染物的去除降低,應(yīng)當(dāng)適時(shí)的增加反洗時(shí)間。污水處理廠的超濾中水回用系統(tǒng),其在夏季超濾膜已經(jīng)開始污堵,只是由于進(jìn)水水溫的原因,造成超濾系統(tǒng)的產(chǎn)水水量上升,進(jìn)水壓力未有明顯的上升,但到了秋冬季后,進(jìn)水水溫的降低,造成進(jìn)水壓力急劇上升,同時(shí)產(chǎn)水水量下降,若仍保持系統(tǒng)的到了清洗壓力再進(jìn)行化學(xué)清洗,會(huì)導(dǎo)致超濾膜無法將污染物洗出,同時(shí)由于污染積聚較多,需要使用大量NaOH和次氯酸鈉對(duì)超濾膜進(jìn)行清洗,而且清洗效果也不能達(dá)到最佳,超濾膜無法恢復(fù)到最初。造成化學(xué)清洗的頻率越高,使超濾膜表面發(fā)生膜孔擴(kuò)張和斷裂現(xiàn)象。會(huì)造成超濾膜的不可逆的傷害,減少超濾膜的使用年限。
[Abstract]:In recent years, the shortage of water resources and the outstanding problems of urban water shortage have transformed the pure water pollution control into all-around sustainable development of water environment. China has also adopted a variety of measures to alleviate the crisis of urban water use, the most important of which is the reuse of recycled water. According to the influence of different factors on the membrane in the wastewater treatment plant, the main reasons of membrane fouling can be judged from the attenuation of membrane flux and the increase of transmembrane pressure difference. By analyzing the filtration behavior of membrane on extracellular polymer and soluble microbial products and the retention of pollutants, the situation of membrane fouling was evaluated, and the retention and deposition of membrane to extracellular polymer and soluble microbial product during filtration were studied. It can provide technical guidance for optimizing the cleaning strategy of membrane, observe the attenuation of membrane flux and the change of transmembrane pressure difference by comparing different operation modes, so as to improve the operation mode and provide the basis for the stable and normal operation of UF membrane system. At the same time, it provides an effective method for optimizing the design and operation parameters of the ultrafiltration system. It is necessary to adjust the self-cleaning filter in winter so that it cannot be cleaned to the set self-cleaning pressure. The self-cleaning filter is adjusted to a fixed time for self-cleaning. According to many experiments, the time is adjusted to 15 minutes. After adjustment, the self-cleaning filter works well in the following winter. But after winter, the self-cleaning filter should be adjusted back to clean according to the pressure difference, which can ensure the system to run steadily for a long time. With the increase of water temperature in summer, the number and propagation of microorganism increased, which resulted in fouling and blocking of membrane, which resulted in the fouling of ultrafiltration membrane in autumn. A metering pump was installed on the inlet end, from which the sodium hypochlorite (1Oppm) was transported to the inlet line, thus inhibiting the propagation of bacteria, reducing the probability of adhesion to the membrane pore, and reducing the fouling and plugging of the ultrafiltration membrane system. In the process of ultrafiltration membrane operation, it is necessary to trace and test the backwash water of the ultrafiltration system, so as to further understand the key factors, such as the change of water quality, the form of main pollutants, and whether the backwash is thorough or not. When it is found that the water quality changes, resulting in the reduction of backwash pollutants, it is necessary to increase the backwash time. The UF water reuse system of the sewage treatment plant has started fouling in the summer. It is only because of the water temperature of the influent that the water yield of the UF system increases, but the influent pressure does not increase significantly, but after autumn and winter, With the decrease of inlet water temperature, the influent pressure rises sharply, and the water yield decreases. If the system is kept at the cleaning pressure and then chemically cleaned, the ultrafiltration membrane will not be able to wash out the pollutants, and because of the accumulation of pollution, there will be a lot of pollution. A large amount of NaOH and sodium hypochlorite were used to clean the ultrafiltration membrane, and the cleaning effect was not optimal, and the ultrafiltration membrane could not be restored to the original. The higher the frequency of chemical cleaning, the larger the expansion and fracture of the membrane surface. UF membrane will cause irreversible damage, reduce the UF membrane service life.
【學(xué)位授予單位】：蘇州科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：X703
，
本文編號(hào)：2160932
[Abstract]:In recent years, the shortage of water resources and the outstanding problems of urban water shortage have transformed the pure water pollution control into all-around sustainable development of water environment. China has also adopted a variety of measures to alleviate the crisis of urban water use, the most important of which is the reuse of recycled water. According to the influence of different factors on the membrane in the wastewater treatment plant, the main reasons of membrane fouling can be judged from the attenuation of membrane flux and the increase of transmembrane pressure difference. By analyzing the filtration behavior of membrane on extracellular polymer and soluble microbial products and the retention of pollutants, the situation of membrane fouling was evaluated, and the retention and deposition of membrane to extracellular polymer and soluble microbial product during filtration were studied. It can provide technical guidance for optimizing the cleaning strategy of membrane, observe the attenuation of membrane flux and the change of transmembrane pressure difference by comparing different operation modes, so as to improve the operation mode and provide the basis for the stable and normal operation of UF membrane system. At the same time, it provides an effective method for optimizing the design and operation parameters of the ultrafiltration system. It is necessary to adjust the self-cleaning filter in winter so that it cannot be cleaned to the set self-cleaning pressure. The self-cleaning filter is adjusted to a fixed time for self-cleaning. According to many experiments, the time is adjusted to 15 minutes. After adjustment, the self-cleaning filter works well in the following winter. But after winter, the self-cleaning filter should be adjusted back to clean according to the pressure difference, which can ensure the system to run steadily for a long time. With the increase of water temperature in summer, the number and propagation of microorganism increased, which resulted in fouling and blocking of membrane, which resulted in the fouling of ultrafiltration membrane in autumn. A metering pump was installed on the inlet end, from which the sodium hypochlorite (1Oppm) was transported to the inlet line, thus inhibiting the propagation of bacteria, reducing the probability of adhesion to the membrane pore, and reducing the fouling and plugging of the ultrafiltration membrane system. In the process of ultrafiltration membrane operation, it is necessary to trace and test the backwash water of the ultrafiltration system, so as to further understand the key factors, such as the change of water quality, the form of main pollutants, and whether the backwash is thorough or not. When it is found that the water quality changes, resulting in the reduction of backwash pollutants, it is necessary to increase the backwash time. The UF water reuse system of the sewage treatment plant has started fouling in the summer. It is only because of the water temperature of the influent that the water yield of the UF system increases, but the influent pressure does not increase significantly, but after autumn and winter, With the decrease of inlet water temperature, the influent pressure rises sharply, and the water yield decreases. If the system is kept at the cleaning pressure and then chemically cleaned, the ultrafiltration membrane will not be able to wash out the pollutants, and because of the accumulation of pollution, there will be a lot of pollution. A large amount of NaOH and sodium hypochlorite were used to clean the ultrafiltration membrane, and the cleaning effect was not optimal, and the ultrafiltration membrane could not be restored to the original. The higher the frequency of chemical cleaning, the larger the expansion and fracture of the membrane surface. UF membrane will cause irreversible damage, reduce the UF membrane service life.
【學(xué)位授予單位】：蘇州科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：X703
，
本文編號(hào)：2160932
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