本文關(guān)鍵詞：印染廢水對超濾膜污染的機理及防控工藝研究　出處：《浙江理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 印染廢水 超濾 膜污染 混凝 臭氧氧化 清洗

【摘要】：紡織印染廢水作為最主要的水體污染源,具有有機物含量高、成分復(fù)雜、色度高、水質(zhì)變化大等特點,且回用率低。隨著水資源的日益短缺,印染廢水回用技術(shù)勢必逐漸推廣,而超濾/反滲透雙膜技術(shù)是目前對印染廢水進行深度處理和回用的有效技術(shù)之一,但是超濾作為反滲透的預(yù)處理很容易被污染,導(dǎo)致超濾的分離效率和使用壽命降低。如何在保證出水水質(zhì)的前提下降低膜污染,是膜技術(shù)領(lǐng)域研究的重點和難點。本文利用阻力串聯(lián)模型研究超濾膜過濾印染廢水過程中膜污染的阻力分布,分析印染廢水對超濾膜的污染機理,確定印染廢水中造成超濾膜污染的主要污染物。在此基礎(chǔ)上,系統(tǒng)研究了混凝預(yù)處理和臭氧氧化預(yù)處理對降低超濾膜污染的效果、以及不同清洗工藝對超濾膜通量的恢復(fù)效果,確定最佳的預(yù)處理及清洗工藝,減輕和控制超濾膜過濾印染廢水過程中的膜污染。得出以下結(jié)論:(1)利用阻力串聯(lián)模型,通過分析超濾處理印染廢水過程中的污染阻力的分布,發(fā)現(xiàn)印染廢水對超濾膜的污染主要集中于超濾膜表面,其污染機理主要為膜表面濾餅層的形成,膜表面污染阻力占總污染阻力的75.3%,而超濾膜孔內(nèi)污染阻力僅占24.7%。通過單因素實驗,發(fā)現(xiàn)印染廢水對超濾膜的污染主要源自于廢水中所含的漿料和助劑中的大分子有機物如PAM、PVA、CMC等。(2)混凝預(yù)處理實驗表明:氯化鐵混凝劑與聚丙烯酰胺助凝劑結(jié)合使用,混凝效果明顯優(yōu)于其他混凝劑。氯化鐵的混凝效果隨其用量的增大而增大,當氯化鐵和聚丙烯酰胺用量分別為300 mg/L和2 mg/L時,其對印染廢水COD和UV254的去除率分別可達26.8%和13.1%。確定混凝的最佳工藝參數(shù)為:廢水pH為堿性、溫度為20~30℃、沉降時間為100 min。印染廢水經(jīng)300 mg/L三氯化鐵混凝處理后,在75 L/(m2h)的恒膜通量模式下進行超濾,可使超濾跨膜壓差的上升速率由55 kPa/h降至6 kPa/h左右。(3)臭氧氧化對有機物的去除率隨pH的增大而增大,當pH達到11時其上升速率減慢,因此控制原水pH為11進行氧化。溫度對氧化效果的影響并不明顯,因此控制臭氧氧化溫度為常溫。臭氧投加量為80 mg/L時,廢水COD和UV254的去除率分別達到26.8%和44.8%左右,但是印染廢水經(jīng)臭氧氧化后,在75 L/(m2h)恒定膜通量下進行超濾,超濾跨膜壓差的上升速率僅由55 kPa/h降至32 kPa/h左右,表明臭氧氧化對降低超濾膜污染不如混凝。(4)用經(jīng)過混凝處理后的印染廢水的上清液,在0.03 MPa恒定操作壓力下進行超濾,研究不同清洗工藝的清洗效率。確定最佳清洗工藝為:每運行1小時用超濾產(chǎn)水在0.1 MPa下反洗2 min,選用pH值為12的2000 mg/L的次氯酸鈉+氫氧化鈉溶液作為清洗劑對超濾系統(tǒng)進行化學(xué)清洗,化學(xué)清洗周期為10小時。在此清洗工藝條件下,超濾系統(tǒng)可以長期穩(wěn)定運行。
[Abstract]:Textile printing and dyeing wastewater, as the main water pollution source, has the characteristics of high organic content, complex composition, high chroma, great water quality change, and low reuse rate. With the increasing shortage of water resources, textile printing and dyeing wastewater is characterized by high organic content, complex composition, high chroma, and low reuse rate. The reuse technology of printing and dyeing wastewater will be popularized gradually, and ultrafiltration / reverse osmosis dual-membrane technology is one of the effective technologies for advanced treatment and reuse of printing and dyeing wastewater. However, as the pretreatment of reverse osmosis, ultrafiltration is easy to be contaminated, resulting in the separation efficiency and service life of ultrafiltration reduced. How to ensure the quality of effluent under the premise of reducing membrane fouling. In this paper, resistance series model is used to study the resistance distribution of membrane fouling in the process of UF membrane filtration of dyeing wastewater, and the mechanism of UF membrane fouling by printing and dyeing wastewater is analyzed. On the basis of this, the effects of coagulation pretreatment and ozone oxidation pretreatment on the reduction of ultrafiltration membrane fouling were studied systematically. As well as the recovery effect of different cleaning processes on the flux of ultrafiltration membrane, determine the best pretreatment and cleaning process. To reduce and control the membrane fouling in the process of ultrafiltration membrane filtration printing and dyeing wastewater. The following conclusion is drawn: 1) by using the resistance series model, the distribution of pollution resistance in ultrafiltration treatment of printing and dyeing wastewater is analyzed. It was found that the fouling of UF membrane by printing and dyeing wastewater was mainly concentrated on the surface of UF membrane, and the fouling mechanism was mainly the formation of filter cake layer on the membrane surface, and the fouling resistance of membrane surface accounted for 75.3% of the total fouling resistance. The fouling resistance of UF membrane is only 24.7. through the single factor experiment, it is found that the pollution of UF membrane from printing and dyeing wastewater is mainly caused by the macromolecular organic matter such as PAM in the slurry and auxiliaries contained in the wastewater. The experiment of coagulation pretreatment showed that ferric chloride coagulant combined with polyacrylamide coagulant. The coagulation effect of ferric chloride increased with the increase of its dosage, when the dosage of ferric chloride and polyacrylamide were 300 mg/L and 2 mg/L, respectively. The removal rates of COD and UV254 in printing and dyeing wastewater were 26.8% and 13.1.The optimum parameters of coagulation were determined as follows: the pH of wastewater was alkaline and the temperature was 2030 鈩，

本文編號：1375605