好氧颗粒污泥膜生物反应器的运行特性

以人工合成模拟废水对好氧颗粒污泥膜生物反应器(MBR)的运行特性和膜污染进行了研究.结果表明:在HRT为6h,溶氧浓度为4～6mg.L^-1,COD的容积负荷为7.24kg·(m³·d)^-1的条件下,COD的去除率可达96%以上.当NH₃-N的容积负荷为0.17kg·(m³·d)^-1时,NH₃-N的去除率可达60%.COD/N比的变化,对好氧颗粒污泥MBR的COD及NH₃-N去除率基本没有影响.稳定运行过程时,MBR中好氧颗粒污泥浓度(MLSS)基本维持在14～16mg·L^-1.较高的污泥浓度和颗粒污泥内部缺氧和厌氧环境的存在,使MBR中硝化和反硝化过程能同时存在.同时,比较了2种不同形态的活性污泥(颗粒污泥和絮状污泥)在MBR运行过程中膜通量的变化趋势,结果表明,颗粒污泥MBR膜通量的下降速度明显比絮状污泥MBR的下降速度慢很多,且通过空气反冲或用水清洗即可使通量基本恢复.     

活性污泥性质对短期膜污染影响的解析研究

采用统计分析方法研究了16种不同性质活性污泥混合液对膜生物反应器膜污染的影响机理.结果表明,胞外聚合物(extracellular polymeric substances,EPS)、溶解性有机物(soluble microbial products,SMP)、上清液胶体颗粒(suspended solids insupernatant,SS_s)、污泥混合液粘度(μ)、相对疏水性(relative hydrophobicity,RH)、Zeta电位(Zeta potential)均对膜生物反应器膜渗透性能有显著的影响作用,其与膜污染阻力的皮尔逊相关系数r_p分别为:0.898、0.712、0.810、0.691、0.837、-0.881;同时发现,胞外聚合物是影响活性污泥中溶解性有机物含量(r_p=0.682)、污泥粘度大小(r_p=0.633)、上清液胶体颗粒含量(r_p=0.783)、Zeta电位(r_p=-0.953)及相对疏水性大小(r_p=0.877)的主要因素;在活性污泥性质中胞外聚合物是影响膜污染的根本原因,是膜生物反应器膜污染的重要影响因素.     

内置转盘式膜-生物反应器处理污水的工艺条件研究

对内置转盘式膜-生物反应器(SRMBR)处理污水工艺进行了研究.进水COD 160～368 mg/L时,出水COD在运行1d后降低到20 mg/L以下,去除率大于90%;转盘式膜组件的转速在0～25 r/min范围内,平衡膜通量随转速增大而快速增加,继续增大转速则平衡膜通量的增加变得不显著;在一定范围(0～1min)内延长停抽时间有助于缓解膜污染;SRMBR在较低的气水比(15∶1)下运行,也可达到较高的平衡膜通量.研究表明,SRMBR在最佳组合操作条件(转速为25r/min,抽/停为9min/1min,气水比为15∶1,抽吸压力为25kPa)下运行,其平衡膜通量高达53.75L/(m²·h).     

好氧膜生物反应器的硝化性能研究

以含有高浓度氨氮的垃圾渗滤液为对象,针对好氧膜生物反应器的硝化性能进行了研究。结果表明:当进水氨氮<1000mg/L和负荷<1.5kgNH4+-N/m3d时,氨氮去除率保持在80%～99.7%之间,表明好氧MBR具有良好的硝化性能;硝酸菌在进水氨氮浓度>600mg/L时受到了抑制,而亚硝酸菌在进水氨氮浓度>1200mg/L时才受到抑制;在试验过程中,MBR污泥经历了由以异养细菌为主到自养细菌为主的转型过程。以硝化菌为主的污泥具有良好的沉淀性能,污泥的SV和SVI分别稳定在20%～30%之间和40～70mL/g之间。     

无过氧化氢添加Fenton氧化法降解有机物的可行性研究

Fenton反应可以氧化分解有机物,在反应中的关键氧化剂羟基自由基(HO·)是通过亚铁离子与过氧化氢作用生成的,因此,传统的Fenton氧化必须由外部添加过氧化氢.研究了一种新的方法,即采用Nafion膜固定化亚铁离子,并通过光催化反应提供Fenton氧化所需的过氧化氢,使得Fenton反应在不添加过氧化氢的条件下也能够连续进行.结果表明,以甲酸为代表有机物,该方法可以在不添加过氧化氢的条件下起到分解甲酸的作用.而且,通过对负载亚铁离子Nafion膜的再生,可以使该方法的降解能力保持在稳定的范围.     

膜组合工艺对地下水中铀的去除及其微生物群落特征

含铀地下水因具有放射性和化学毒性对人类健康构成严重威胁,常规工艺有时无法有效去除地下水铀故需增加处理工艺以满足饮用水水质要求.以我国某地膜组合工艺处理工程为研究对象,监测了6个月运行过程中铀去除效果及常规水质参数,并对各工艺阶段出水及生物膜进行样品采集.结合水质分析与高通量测序探讨了不同工艺段出水水质参数变化,微生物群...     

Mitochondrial toxicity and in vitro biological effects of ambient PM2.5 from an urban site in China

Abstract

The roles of PM_2.5-induced mitochondrial damage and oxidative stress on mast cell degranulation were examined in vitro. Mast cells were treated with suspensions of PM_2.5 in Dulbecco’s modified Eagle’s medium at concentrations from 25 to 200?mg/L in the absence or presence of 10?mmol/L N-acetyl-L-cysteine. Biological effects and mitochondrial function were assessed by determining cell viability, β-hexosaminidase release, interleukin-4 secretion, reactive oxygen species generation, adenosine triphosphate production, potential alteration of mitochondrial membrane, and activities of mitochondrial electron transport chain complexes I and III. Exposure of mast cells to PM_2.5 induced reduction of adenosine triphosphate production, collapse of mitochondrial membrane potential, and inhibition of the activity of complex III. Co-treatment of mast cells exposed to PM_2.5 with N-acetyl-L-cysteine attenuated cytotoxicity and the production of reactive oxygen species, and decreased the release of β-hexosaminidase and interleukin-4. Evidently, PM_2.5-induced oxidative stress plays an essential role in mitochondrial toxicity and mast cell activation.     

Metabolic uncoupler, 3,3′,4′,5-tetrachlorosalicylanilide addition for sludge reduction and fouling control in a gravity-driven membrane bioreactor

• Effects of metabolic uncoupler TCS on the performances of GDMBR were evaluated. • Sludge EPS reduced and transformed into dissolved SMP when TCS was added. • Appropriate TCS increased the permeability and reduced cake layer fouling. • High dosage aggravated fouling due to compact cake layer with low bio-activity. The gravity-driven membrane bioreactor (MBR)system is promising for decentralized sewage treatment because of its low energy consumption and maintenance requirements. However, the growing sludge not only increases membrane fouling, but also augments operational complexities (sludge discharge). We added the metabolic uncoupler 3,3′,4′,5-tetrachlorosalicylanilide (TCS) to the system to deal with the mentioned issues. Based on the results, TCS addition effectively decreased sludge ATP and sludge yield (reduced by 50%). Extracellular polymeric substances (EPS; proteins and polysaccharides) decreased with the addition of TCS and were transformed into dissolved soluble microbial products (SMPs) in the bulk solution, leading to the break of sludge flocs into small fragments. Permeability was increased by more than two times, reaching 60–70 L/m²/h bar when 10–30 mg/L TCS were added, because of the reduced suspended sludge and the formation of a thin cake layer with low EPS levels. Resistance analyses confirmed that appropriate dosages of TCS primarily decreased the cake layer and hydraulically reversible resistances. Permeability decreased at high dosage (50 mg/L) due to the release of excess sludge fragments and SMP into the supernatant, with a thin but more compact fouling layer with low bioactivity developing on the membrane surface, causing higher cake layer and pore blocking resistances. Our study provides a fundamental understanding of how a metabolic uncoupler affects the sludge and bio-fouling layers at different dosages, with practical relevance for in situ sludge reduction and membrane fouling alleviation in MBR systems.     

烟气脱碳技术进展

介绍了吸收法、吸附法、低温法、膜分离法回收烟道气中CO2的研究和应用现状,并对这些方法进行了比较,指出了适用范围。     

有机废气中VOC的回收方法

介绍了炭吸附法、冷凝法和膜分离法回胥机废报中ＶＯＤ的原理、工艺流程和工业应用情况，并对这些方法进行了比较，指出了适用范围。