【作者】 韩雪利；

【导师】 张建； 梁爽；

【作者基本信息】 山东大学 ， 环境工程， 2011， 硕士

【摘要】 自生动态膜生物反应器(Self-forming dynamic membrane bioreactor, SFDMBR)利用过滤初期在廉价微网基材上自然吸附/沉积形成自生动态膜(SFDM)取得与微滤膜近似的泥水分离效果,构成新型低成本膜生物反应器,具有广阔的应用前景。SFDM的形成和污染是制约SFDMBR运行成本和能耗的重要参数。作为SFDM的主要构成成分,活性污泥性质的变化会对SFDM的形成和污染产生重要影响。本文选取了20种不同性质的活性污泥,在两台平行运行的反应器中开展批式过滤实验,考察了12种污泥性质对SFDM的形成时间(Tf)、过滤阻力(Rsm)及其污染倾向(kR)的影响。所研究的污泥性质包括：胞外聚合物(Extracellular polymeric substance, EPS)及构成EPS的蛋白质(Protein, EPSp)和多糖(Polysaccharide, EPSC)的含量及二者的比值(EPSp/EPSc)、污泥的颗粒粒径分布(Particle size distribution, PSD)、相对疏水性(Relative hydrophobic, RH)、溶解性微生物产物(soluble microbial products, SMP)、比好氧速率(Specific oxygen uptake rate, SOUR)、污泥粘度(Viscosity)、污泥毛细吸收时间(Capillary suction time)、污泥沉积指数(SVI)及污泥表面电荷(Zeta potential)。利用SPSS对实验结果进行统计分析。研究结果表明：污泥的EPS浓度与污泥的SOUR显著负相关(rp=-0.751),与viscosity正相关(rp=0.560),这两个性质主要受污泥的EPS。浓度的影响(rp=-0.709；0.684),EPS的浓度还与Zeta potential负相关(rp=-0.520),与SVI显著正相关(rp=0.736),这两个性质主要受EPSp浓度的控制(rp=-0.767；0.672)。因此,在研究污泥性质对SFDM的形成与污染的影响时,将EPS浓度及其他与EPS无关的污泥性质作为独立因素进行分析。结果表明：污泥的PSD与Tf显著正相关(rp=-0.808),与Rsm显著负相关(rp=-0.690)。除PSD外,污泥的RH与Tf负相关(rp=-0.578),这表明,污泥颗粒愈大,疏水性越强,SFDM越易形成；且污泥的颗粒越大,SFDM的过滤阻力越小。污泥的EPS与kR呈正相关关系(rp=0.723),其中,污泥的EPSc浓度与kR正相关(rp=0.760),而EPSp与之无关。表明污泥的EPS浓度,具体为EPSc浓度增加,SFDM的污染程度加重。虽然污泥的EPSp浓度与kR无关,但是EPSp也是SFDM的污染物质之一。除此之外,污泥的viscosity与kR显著正相关(rp=0.801),SOUR与kR负相关(rp=-0.642),后者相关系数的绝对值略低于前者。由于这二者与污泥的EPS和EPS。浓度相关,且粘度与kR的相关系数最高,因此,污泥的粘度可以作为SFDM污染程度的指示参数。更多还原

【Abstract】 Recently, a low-cost membrane bioreactor (MBR), termed self-forming dynamic membrane bioreactor (SFDMBR), has emerged as an innovative and cost-effective wastewater treatment system. The basic idea is to utilize the filtration modules made of cheap coarse-pore materials such as non-woven fabric, nylon mesh, and industrial filter-cloth instead of microfiltration (MF)/ultrafiltration (UF) membranes to reduce capital cost, and take advantage of the self-forming dynamic membranes (SFDMs) (i.e. initial "desired" sludge layers developed on the coarse-pore materials) to achieve required solid-liquid separation efficiency. Since the development of SFDM is essentially a result of sludge deposition/adsorption on coarse-pore materials, the characteristics of SFDM including formation and fouling are reasonably expected to be significantly affected by sludge properties.This study investigated the impacts of sludge properties on the formation time (Tf), filtration resistance (Rsm) and fouling propensity (KR) of SFDM. Sludge properties includes the extracellular polymeric substances (EPS) content which is considered as the sum of polysaccharides (EPSc) and protein (EPSp), soluble microbial products (SMP) content, particle size distribution (PSD), relative hydrophobicity (RH), zeta potential, specific oxygen uptake rate (SOUR), dynamic viscosity, capillary suction time(CST) and sludge volume index (SVI). Statistical analyses were conducted to determine the effects of sludge properties on each SFDM characteristic. The results showed EPS content presents positive/negative correlations with SOUR, Zeta potential, viscosity and SVI with rp=-0.751,-0.520,0.560,0.736, respectively. Especially, EPSc content was the major factor affecting SOUR and viscosity of the sludge (rp=-0.709; 0.684) while EPSp content affecting Zeta potential and SVI (rp=-0.767; 0.672). As a result, the EPS content and other sludge properties except these four should be considered as independent factors to conduct this study.In the sequent study, it is found that PSD was the major factor affecting both SFDM formation rate and filtration resistance with rp=-0.808; -0.690, P=0.000; 0.001, respectively, while RH displayed as a sub-factor affecting SFDM formation time (rp=-0.578; P=0.052). The EPS content contributed to SFDM fouling propensity (rp=0.723, P=0.000). In particular, increasing EPSc concentration (rp=0.760, P=0.000) could result in serious SFDM fouling while no correlation was found between EPSP and SFDM fouling propensity. The SFDM formation and fouling mechanisms was proposed based on these analyses. In addition, dynamic viscosity demonstrated a considerably positive correlation with SFDM fouling propensity (rp=0.801, P=0.004) while SOUR appeared a relatively lower negative correlation (rp=-0.642, P=0.032). Consequently, dynamic viscosity could be chosen as an indicator for examining SFDM fouling.更多还原