Extracellular polymeric substances (EPS) properties and their effects on membrane fouling in a submerged membrane bioreactor

A pilot-scale submerged membrane bioreactor (MBR) for real municipal wastewater treatment was operated for over one year in order to investigate extracellular polymeric substances (EPS) properties and their role in membrane fouling. The components and properties of bound EPS were examined by the evaluation of mean oxidation state (MOS) of organic carbons, Fourier transform infrared (FT-IR) spectroscopy, three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy, and gel filtration chromatography (GFC), etc. Test results showed that MOS of organic carbons in the bound EPS was ranging from −0.14 to −0.51, and major components could be assessed as proteins and carbohydrates. FT-IR analysis confirmed the presence of proteins and carbohydrates in the bound EPS. The organic substances with fluorescence characteristics in the bound EPS were identified as proteins, visible humic acid-like substances and fulvic acid-like substances by EEM technology. GFC analysis demonstrated that EPS had part of higher MW molecules and a broader MW distribution than the influent wastewater. It was also found that a high shear stress imposed on mixed liquor could result in the release of EPS, which would in turn influence membrane fouling in MBRs. Bound EPS solution was observed to have a stronger potential of fouling than mixed liquor. During long-term operation of the MBR, bound EPS demonstrated positive correlations with membrane fouling while temperature was verified as a negative factor affecting EPS concentration. Compared to tightly bound EPS (TB-EPS), loosely bound EPS (LB-EPS) showed more significant correlations with membrane fouling. This critical investigation would contribute towards a better understanding of the behavior, composition and fouling potential of EPS in MBR operation.     

Recent advances in membrane bioreactors (MBRs): Membrane fouling and membrane material

Membrane bioreactors (MBRs) have been actively employed for municipal and industrial wastewater treatments. So far, membrane fouling and the high cost of membranes are main obstacles for wider application of MBRs. Over the past few years, considerable investigations have been performed to understand MBR fouling in detail and to develop high-flux or low-cost membranes. This review attempted to address the recent and current developments in MBRs on the basis of reported literature in order to provide more detailed information about MBRs. In this paper, the fouling behaviour, fouling factors and fouling control strategies were discussed. Recent developments in membrane materials including low-cost filters, membrane modification and dynamic membranes were also reviewed. Lastly, the future trends in membrane fouling research and membrane material development in the coming years were addressed.     

严寒地区粘贴EPS板外墙外保温薄抹灰面层施工质量控制

针对严寒地区粘EPS板外墙外保温薄抹灰系统应用以来出现的质量问题,提出材料控制、基层控制、粘贴控制、锚栓加设、系统终端控制、面层及滴水线控制、嵌缝胶施工等质量控制措施并提出建议。     

利用EPS2008制作宗地图

叙述了利用EPS2008生成宗地图的方法,通过比对不同软件输出的宗地图,指出利用EPS2008软件自动输出宗地图,不仅可以提高宗地图的制作效率,而且还能保持数据的高度统一。     

EPS蓄电池组巡检模块设计

蓄电池是EPS的重要的储能部件,蓄电池在充电时可能会产生过压现象,在放电时可能会产生欠压现象,长时间的过压或欠压都会直接影响EPS正常工作。为了实时检测蓄电池运行状态,便于维护、检修或更换蓄电池,本设计以MSP430F149单片机为核心,设计EPS蓄电池组巡检模块,并利用DSP作为主机、利用LCD1602进行显示。     

基于MC9S08JM60的电动助力转向控制系统设计

采用Freescale高性能微处理器MC9S08JM60来设计EPS控制系统,同时采用模糊控制策略、增量式PID算法、综合补偿控制以及分层结构模块化设计思想,并利用基于软件冗余技术的容错方法来对系统进行改进,最后给出该控制系统的设计方案和相关设计内容,并进行相关的试验对控制效果进行检验。     

三菱PLC在电动汽车控制系统上的应斥

采用三菱Q系列PLC和CC—Link总线,建立了电动汽车控制系统和控制模型。控制系统中包括动力控制单元、EPS转向控制单元、PWM调速控制单元和车身电器控制单元,通过CC—Link总线对控制系统进行了优化,使电动汽车控制系统能够平滑、稳定地运行,能够适应复杂的交通路况。     

Quality Control of Malt: Turbidity Problems of Standard Worts Given by the Presence of Microbial Cells

Since the main effect on beer colour originates from the chemical composition of malt, the measurement of the colour of wort obtained from malt is one of the most important quality parameters to be controlled. Malt colour determination is usually performed spectrophotometrically on EBC Congress worts, which are generally bright. The quality control on the malt harvested in the year 2007 highlighted a problem of turbid Congress wort, for a part of Northern Europe samples analyzed, and therefore the spectrophotometric determination of the colour of wort was not possible. Thus both analytical screening of the quality parameters of malt and the scanning electron microscope (SEM) were used to identify the nature of the turbidity in the worts. The results obtained suggested that the nature of the turbidity of Congress worts could have been due to microbial contamination of the barley, enhanced in particular by the rainy harvest and the consequent formation of exopolysaccharides (EPS) by stressed yeast and bacteria during malting.     

Design and construction of lightweight EPS geofoam embedded geomaterial embankment system for control of settlements

This paper presents a research study on a bridge site located along US highway 67 over SH 174 in Cleburne, Texas, where bridge approach slabs have experienced more than 0.4 m (17 in.) of settlement within a span of 16 years after construction. Many treatment methods attempted to mitigate this problem had proven to be ineffective. As part of novel rehabilitation works, the top of existing fill soil on the embankment was replaced with lightweight expanded polystyrene (EPS) geofoam blocks to alleviate the approach slab settlements. This paper describes initial design and construction details of the rehabilitation works performed on the embankment system along with a focus on the early performance details. Field monitoring studies were conducted for almost three years to study the bump/settlements under the EPS geofoam embankment system. Short term measured settlement data was analyzed with hyperbolic model to predict the long term settlements. Numerical finite element studies attempted in this study showed that settlements could be reasonably predicted by modeling these geofoam embankments. Based on the monitoring and modeling studies, the effectiveness of utilizing EPS geofoam as an embankment fill material was addressed to mitigate the differential settlements under a bridge approach slab.     

Feasibility of CANON process for treating nitrogenous wastewater containing heavy metals

The appearance of heavy metals in wastewater brings a major burden to wastewater treatment plants, due to the high toxicity to microorganisms. Several commonly used heavy metals, including Zn(II), Cd(II), Hg(II), and Pb(II) were adopted to clear the individual and joint toxicity to the completely autotrophic nitrogen removal over nitrite (CANON) process in six sequencing batch reactors. The obtained results suggested that the nitrogen removal performances were transiently inhibited, but rapidly recovered. The restoration period under the stress of Hg(II) and Pb(II) was shorter than that under Zn(II), Cd(II), and the joint heavy metals. During the long-term exposure, Cd(II) in 1mg L⁻¹ slightly inhibited the nitrogen removal, while Zn(II), Hg(II), Pb(II), and mixture showed a negligible impact on CANON process. The defense of extracellular polymeric substances (EPS), the good adaptability of functional bacteria, and the inducement of resistant genera by heavy metals all contributed to the robustness and stability of CANON process. Therefore, it is feasible to treat nitrogenous wastewater containing low heavy metals using CANON process. © 2020 Society of Chemical Industry