本文選題：聚丙烯酰胺 + 脫水污泥��； 參考：《西北大學(xué)》2016年博士論文

【摘要】：脫水污泥含水率高是我國污泥處置目前普遍存在的問題,直接影響脫水污泥的后續(xù)處理。造成這一問題的原因有多種,其中之一是由目前在污水與污泥處理中大量使用的,以聚丙烯酰胺(PAM)為代表的高分子有機(jī)絮凝劑引起的。在污泥脫水過程中,被PAM吸附絮凝的污泥顆粒聚集后會形成膠狀物聚合體,造成脫水后的污泥不易分散,內(nèi)部水分蒸發(fā)困難,使得自然條件下污泥干化需要更長時間。本研究為解決這一問題,篩選可降解PAM的菌株,研究其降解特性,并以固體菌劑的形式對脫水污泥干化過程進(jìn)行生物強(qiáng)化,降解脫水污泥中的PAM,加快污泥干化速度。主要有以下結(jié)論：從四個來源的脫水污泥中分離出11株可在PAM培養(yǎng)基上生長的菌株,經(jīng)過重金屬耐受性和耐鹽性實(shí)驗,篩選出一株菌株H13以PAM為唯一營養(yǎng)源生長,7 d內(nèi)PAM降解率可達(dá)35.9%。結(jié)合形態(tài)學(xué)特征、全自動微生物分析系統(tǒng)儀鑒定及16S rRNA基因序列分析,確定為惡臭假單胞菌(Pseudomonas putida)。對菌株的生長和PAM降解的影響因素進(jìn)行了研究。凝膠過濾色譜(GPC)分析顯示微生物降解后PAM的分子量下降,培養(yǎng)21 d后,聚合物重均分子量從6.44×10~6 Da減小到1.85×10~4 Da。PAM中的高分子量組分經(jīng)過生物降解變?yōu)橹械头肿恿拷M分,進(jìn)一步作為菌株生長所需的碳源被轉(zhuǎn)化利用。紅外光譜(FT-IR)分析顯示,微生物生長過程中,PAM側(cè)鏈酰胺基轉(zhuǎn)化為羧基,水解的氨基作為生長所需的氮源被微生物吸收利用。液質(zhì)聯(lián)用分析(LC-MS)分析顯示,PAM降解前和降解后的產(chǎn)物中,含CH_3-C=C-CHO基團(tuán)及其衍生基團(tuán)的化合物較多。經(jīng)SDS-PAGE分析,通過硫酸銨沉淀、DEAE-Sepharose FF離子交換層析和SephadexG-200分子篩層析純化得到了PAM誘導(dǎo)產(chǎn)生的胞外酰胺酶。酶的最適溫度為44℃C,最適pH為7.8,低濃度的Mg~(2+)、Ca~(2+)、Mn~(2+)對酶活性有激活作用,Fe~(2+)、Zn~(2+)、Cu~(2+)、Ni~(2+)等金屬離子會抑制酶活性,碘乙酸可使酶徹底失活。該酶對短鏈的脂肪族酰胺類化合物也具有水解能力,對腈類化合物則沒有水解能力。通過CODEHOP方法針對該酶氨基序列保守區(qū)域設(shè)計簡并引物,克隆并鑒定了酰胺酶的基因片段,確定分離酶為脂肪族酰胺水解酶。通過單因素實(shí)驗及正交分析,確定了菌株的固體菌劑發(fā)酵最適營養(yǎng)源及條件。污泥生物干化的實(shí)驗室實(shí)驗及小試實(shí)驗顯示,菌劑可有效降低污泥中PAM濃度,促進(jìn)污泥含水率下降,縮短了干化所需時間。在污水廠實(shí)地進(jìn)行了脫水污泥的生物干化及好氧發(fā)酵中試實(shí)驗,結(jié)合好氧發(fā)酵設(shè)備,可在15d內(nèi)將污泥轉(zhuǎn)化為符合國家標(biāo)準(zhǔn)的有機(jī)肥料產(chǎn)品,所需時間遠(yuǎn)少于傳統(tǒng)污泥堆肥,是一套具有參考意義的污泥穩(wěn)定化、資源化示范工藝。
[Abstract]:High moisture content of dewatered sludge is a common problem in sludge disposal in China, which directly affects the subsequent treatment of dewatered sludge. There are many reasons for this problem, one of which is caused by the high molecular organic flocculant, which is widely used in sewage and sludge treatment and represented by polyacrylamide (PAM). In the process of sludge dewatering, the flocculated sludge particles adsorbed by PAM will form a colloidal polymer, which results in the sludge being difficult to disperse and the internal water evaporation difficult, which makes it take longer for the sludge to dry under natural conditions. In order to solve this problem, the strain that can degrade PAM was screened, its degradation characteristics were studied, and the drying process of dewatered sludge was biostrengthened in the form of solid bacteria agent, the PAM in dewatered sludge was degraded, and the drying rate of sludge was accelerated. The main conclusions are as follows: 11 strains which can grow on PAM medium were isolated from dewatered sludge from four sources and tested for heavy metal tolerance and salt tolerance. A strain H13 with PAM as the sole nutrient source was screened. The degradation rate of PAM could reach 35.9g within 7 days. Combined with morphological characteristics, automatic microbiological analysis system and 16s rRNA gene sequence analysis, Pseudomonas putida was identified as Pseudomonas putida. The factors affecting strain growth and PAM degradation were studied. Gel filtration chromatography (GPC) analysis showed that the molecular weight of PAM decreased after microbial degradation. After 21 days of culture, the average molecular weight of PAM decreased from 6.44 脳 10 ~ (-6) Da to 1.85 脳 10 ~ (4) Da.PAM. It is further used as a carbon source for the growth of the strain. FT-IR analysis showed that PAM side chain amide group was converted to carboxyl group during microbial growth and hydrolyzed amino group was absorbed by microorganism as the nitrogen source for growth. LC-MS analysis showed that the compounds containing CH3-CnC-CHO group and their derivatives were more in the products before and after the degradation of PAM. By SDS-PAGE, the extracellular acylase induced by PAM was purified by DEAE-Sepharose FF ion exchange chromatography and Sephadex G-200 molecular sieve chromatography. The optimum temperature of enzyme is 44 鈩，

本文編號：2036514