生物流化床反应器生物膜特性研究进展

生物流化床技术应用于废水处理领域具有广阔的发展前景。生物流化床反应器对污染物的降解主要依赖于活性生物膜 ,研究生物膜的特性是提高反应器效率的重要手段。本文对描述生物膜特性的主要参数进行了综述 ,其中 ,生物膜种群构成的差异是影响反应器效率的最重要因素 ,本文重点探讨了生物膜中微生物的种群分布特征、种群的生态演替过程与反应器性能的关系。在此基础上 ,提出了对生物流化床生物膜特性进行强化的几种手段     

生物流化床反应器生物膜特性研究进展

生物流化床技术应用于废水处理领域具有广阔的发展前景，生物流化床反应器对污染物的降解主要依赖于活性生物膜，研究生物膜的特性是提高反应器效率的重要手段。本文对描述生物膜特性的主要参数进行了综述，其中，生物膜种群构成的差异是影响反应器效率的最重要因素，本文重点探讨了生物膜中微生物的种群分布特征，种群的生态演替过程与反应器性能的关系，在此基础上，提出了对生物流化床生物膜特性进行强化的几种手段。     

亲水性多孔载体在流化床中的生物膜形成过程分析

采用实验制备的一种新型亲水性多孔聚合物作为流化床反应器中生物膜附着生长的载体,实现流态化水力条件下的生物挂膜过程.在3个结构尺寸相同的流化床反应器中考察了接种污泥浓度、进水有机负荷及载体粒径对亲水性多孔载体生物挂膜量的影响,试验结果表明,接种污泥浓度为30 g VSS/L、进水TOC值为350 mg/L、载体粒径为5～8 mm时载体表面的附着生物量最大,反应器运行12 d的载体附着生物量达到4.45 g VSS/L,膜结构稳定,表现出较活性污泥法更高的活性.在进水TOC、氨氮浓度分别为350 ms/L、50 mg/L,HRT为6 h的情况下,两者的去除率分别达到了97.1%和64.3%,表明载体上的生物膜对污水中TOC及氨氮的去除表现出高效率.挂膜后载体表面上的微生物以丝状菌为主,孔壁上的微生物以球菌和杆菌为主要生物相,证明载体内外表面皆适宜微生物的生长,并且形成合理的生物相分布.     

膜生物反应器中生物膜的生长特性

实验采用经甲苯培养驯化而成的单一假单胞菌菌种,通过分析平板式生物膜反应器内,不同阶段假单胞细菌生物膜干重、厚度、活性生物量和生物种群分布的变化,研究生物膜特性与降解效率之间的关系。实验结果表明,在挂膜初期生物膜迅速生长,生物量以及生物膜干重增长很快,有利于甲苯及营养物质的传输,降解效率也快速提升。随着生物膜的生长,生物量及干重也逐步增加,厚度逐渐增加使传质阻力不断增大,生物膜上层微生物的有机底物供应不足,使生物膜上层结构稀疏,最终维持一个甲苯的总传输量与生化降解量的平衡,生物量的生长与衰亡也达到动态平衡,形成了一个较高且稳定的降解效率。     

生物膜微环境和传质现象研究进展

生物膜法污水处理工艺对污染物的降解去除主要依赖活性生物膜,研究生物膜的结构和传质特性是揭示反应机理和提高反应器处理效率的重要手段.综述了近年来国外在生物膜微环境和微观传质过程中的研究进展,包括对生物膜微观结构的解析、膜内不同菌系的分布特征及其功能以及生物膜的传质现象和数学模型.在此基础上,提出了生物膜研究领域今后应开展的研究方向.     

生物膜微环境和传质现象研究进展

生物膜法污水处理工艺对污染物的降解去除主要依赖活性生物膜,研究生物膜的结构和传质特性是揭示反应机理和提高反应器处理效率的重要手段.综述了近年来国外在生物膜微环境和微观传质过程中的研究进展,包括对生物膜微观结构的解析、膜内不同菌系的分布特征及其功能以及生物膜的传质现象和数学模型.在此基础上,提出了生物膜研究领域今后应开展的研究方向.     

在线超声对流化床膜生物反应器污泥混合液性能影响的研究

在流化床膜生物反应器中引入在线超声辐射来控制膜污染,超声功率为300 W、频率分别为中频(50 kHz)和中低频(50 kHz和25 kHz)混合频率,考察了在线超声对反应器内混合液性能的影响及对膜污染的控制效果。结果表明,中频超声辐射不会对反应器内混合液的污泥浓度和粘度产生显著影响,而中低频超声辐射会降低混合液的污泥浓度并造成混合液粘度的升高。2种频率的超声辐射对污泥混合液的过滤性能和污泥活性都有一定的改善作用。连续运行26 d和29d后,在中频和中低频超声辐射的作用下,超声流化床膜生物反应器比普通流化床膜生物反应器的跨膜压差分别低8 kPa和14 kPa,说明2种频率的在线超声均可显著延缓膜污染。     

秸秆粉煤灰基颗粒填料生物膜特性的比较

为提高曝气生物滤池处理效率、研发新型具有结构和功能优势的颗粒填料,采用间歇式完全混合循环流态化反应器,探究了自制复合颗粒A、自制复合颗粒B、中劲陶粒及石英砂颗粒填料在4个水力停留时间下的挂膜性能、动力学参数及生物膜活性等生物膜特性,建立了生物膜微生物动力学参数实验测定的新方法。结果表明：当水力停留时间为8～12 h时,自制复合颗粒A、B挂膜性能优于石英砂和中劲陶粒,生物膜增殖速率分别为95.83、63.75 mg·(L·h)^-1(以COD去除率标准评价)和54.13、29.23 mg·(L·h)^-1(以氨氮降解率标准评价);装填复合颗粒A的完全混合循环流态化反应器氨氮降解效率最高,相应生物膜表观产率系数最低,剩余污泥量最少;当水力停留时间超过8 h后,复合颗粒附着生长生物膜的脱氢酶活性、表面蛋白质、多糖含量最高。由此可知,以自制复合颗粒A、B为颗粒填料能优化曝气生物滤池的处理效率。本研究结果可为新型生物滤池技术的发展提供参考。     

Ca~(2+)对生物膜形态结构及其组分的影响

通过向序批式生物膜反应器(SBBR)中投加Ca2+,考察Ca2+对生物膜形态结构及其组分的影响,探究Ca2+在生物膜形成中的作用影响规律及其对生物膜反应器运行的影响,以期能为含钙废水处理及优化废水处理效果提供理论指导。研究结果表明,Ca2+浓度增加有助于生物膜形成,并提高生物膜结构致密性;连续少量增加Ca2+(1~2 mg/L)有助于挂膜初期(约10 d)有机物去除;然而Ca2+浓度过高则会抑制生物膜活性,影响其降解性:当Ca2+浓度超过120 mg/L时,氨氮去除率出现下降,当Ca2+浓度超过280 mg/L时,有机物和总氮去除率显著下降。对生物膜及其胞外多聚物(EPS)组分的分析表明,Ca2+不会刺激微生物分泌产生更多EPS,但会导致生物膜干重增加。     

在线超声作用下流化床膜生物反应器的膜污染机制

在流化床膜生物反应器中引用在线超声技术来控制膜污染,考察了在线超声对污泥混合液特性的影响,探讨了在线超声作用下的膜污染机制。结果表明：在线超声流化床膜生物反应器的跨膜压差（TMP）增长速度明显慢于普通流化床膜生物反应器,可延长膜清洗周期约51％。在线超声作用下,污泥平均粒径降低约70μm,污泥胞外聚合物（EPS）含量增加（14±5）mg／g,混合液溶解性微生物产物（SMP）有所降低;同时,在线超声使得污泥浓度和混合液粘度降低,从而改善了混合液的过滤性,有助于膜污染的控制。分析表明,在线超声能够减少膜表面不可逆污染的发生,膜的主要污染机制为泥饼层污染。     

基于膨胀特性的厌氧流化床反应器的设计和运行控制

生物流化床的床层膨胀行为直接与生化反应区的水动力学和效率相关 ,床层膨胀特性是进行合理设计和运行的重要依据。目前流化床设计一般没有考虑生物膜的影响 ,但生物颗粒的流化行为有别于光滑载体 ,因此需要对曳力系数Cd 和膨胀特性方程中的ui 进行必要的修正。在综合分析基础上 ,探讨了优化两相流化床设计和运行的程序和方法     

流动床生物膜反应器在污水处理中的应用研究现状

给出了流动床生物膜反应器的定义、分类及其特点 ,并对各种流动床生物膜反应器的优缺点及近年来在污水处理中的应用状况进行了总结 ,根据实际应用效果 ,提出了各类反应器的适用处理对象     

微污染水源水生物处理工艺中IAL-CHS与三相流化床的初步比较

初步比较气升式内循环蜂窝陶瓷反应器(IAL-CHS)和内循环三相流化床反应器(ITFB)对微污染水源水进行生物预处理的效果。IAL-CHS反应器比ITFB反应器挂膜启动速度快,但是在挂膜期承受冲击负荷能力较ITFB反应器差。在进水相同条件下,两者所能达到的最小水力停留时间、最大体积负荷和容积负荷相差不大,但是ITFB反应器的曝气强度却为IAL-CHS反应器的3.33倍,并且比IAL-CHS反应器出水SS高,浊度去除率低,单位载体的生物量及活性生物量小。     

Photocatalytic oxidation of methyl orange in a three-phase fluidized bed reactor

The photocatalytic oxidation of methyl orange under weak illumination conditions was carried out in two different types of fluidized bed reactors. TiO2 powder was employed as the photocatalysts and a 15 W low pressure mercury lamp was used as the light source and the reactor volume was 2.5 l. The parametric study of photocatalytic oxidation of methyl orange in two different types of fluidized beds was investigated; effect of catalyst loadings, pH, air flow rate, initial concentration and oxygen concentration on the oxidation reaction rate. The experimental results were analyzed in conjunction with the characteristics of fluidized bed and the reactor geometry effect on the reaction rate was analyzed.     

Treatment of wastewater from red and tropical fruit wine production by zeolite anaerobic fluidized bed reactor

A study of the anaerobic treatment of wastewaters derived from red (RWWW) and tropical fruit wine (TFWWW) production was carried out in four laboratory-scale fluidized bed reactors with natural zeolite as bacterial support. These reactors operated at mesophilic temperature (35 degrees C). Reactors R1 and R2 contained Chilean natural zeolite, while reactors R3 and R4 used Cuban natural zeolite as microorganism support. In addition, reactors R1 and R3 processed RWWW, while reactors R2 and R4 used TFWWW as substrate. The biomass concentration attached to zeolites in the four reactors studied was found to be in the range of 44-46 g volatile solids (VS)/L after 90 days of operation time. Both types of zeolites can be used indistinctly in the fluidized bed reactors achieving more than 80%-86% chemical oxygen demand (COD) removals for organic loading rates (OLR) of up to at least 20 g COD/L d. pH values remained within the optimal range for anaerobic microorganisms for OLR values of up to 20 and 22 g COD/L d for RWWW and TFWWW, respectively. Toxicity and inhibition levels were observed at an OLR of 20 g COD/L d in reactors R1 and R3 while processing RWWW, whereas the aforementioned inhibitory phenomena were not observed at an OLR of 24 g COD/L d in R2 and R4, treating TFWWW as a consequence of the lower phenolic compound content present in this substrate. The volatile fatty acid (VFA) levels were always lower in reactors processing TFWWW (R2 and R4) and these values (< 400 mg/L, as acetic acid) were lower than the suggested limits for digester failure. The specific methanogenic activity (SMA) was twice as high in reactors R2 and R4 than in R1 and R3 after 120 days of operation when all reactors operated at an OLR of 20 g COD/L d.     

Treatment of wastewater from red and tropical fruit wine production by zeolite anaerobic fluidized bed reactor

A study of the anaerobic treatment of wastewaters derived from red (RWWW) and tropical fruit wine (TFWWW) production was carried out in four laboratory-scale fluidized bed reactors with natural zeolite as bacterial support. These reactors operated at mesophilic temperature (35°C). Reactors R1 and R2 contained Chilean natural zeolite, while reactors R3 and R4 used Cuban natural zeolite as microorganism support. In addition, reactors R1 and R3 processed RWWW, while reactors R2 and R4 used TFWWW as substrate. The biomass concentration attached to zeolites in the four reactors studied was found to be in the range of 44–46 g volatile solids (VS)/L after 90 days of operation time. Both types of zeolites can be used indistinctly in the fluidized bed reactors achieving more than 80%–86% chemical oxygen demand (COD) removals for organic loading rates (OLR) of up to at least 20 g COD/L d. pH values remained within the optimal range for anaerobic microorganisms for OLR values of up to 20 and 22 g COD/L d for RWWW and TFWWW, respectively. Toxicity and inhibition levels were observed at an OLR of 20 g COD/L d in reactors R1 and R3 while processing RWWW, whereas the aforementioned inhibitory phenomena were not observed at an OLR of 24 g COD/L d in R2 and R4, treating TFWWW as a consequence of the lower phenolic compound content present in this substrate. The volatile fatty acid (VFA) levels were always lower in reactors processing TFWWW (R2 and R4) and these values (< 400 mg/L, as acetic acid) were lower than the suggested limits for digester failure. The specific methanogenic activity (SMA) was twice as high in reactors R2 and R4 than in R1 and R3 after 120 days of operation when all reactors operated at an OLR of 20 g COD/L d.     

Relationship between pressure fluctuations and generation of organic pollutants with different particle size distributions in a fluidized bed incinerator

The hydrodynamic behaviors of fluidization perhaps significantly influence the uniformity of fluidization in fluidized bed incinerator. Good uniformity of fluidization expressed the air across uniformly through the bed and the particles being distributed well in the fluid stream. The aggregates, flocs and channels of particles do not happen during fluidization. The Good uniformity will maintain high heat and mass distribution to improve reaction efficiency. These parameters include the height of static bed, gas velocity, mixing and distribution of bed particle, which have rarely been studied in previous investigations. Consequently, this study examines how the hydrodynamic parameters affect the generation of organic pollutants (BTEXs and PAHs) during incineration. The statistical and power spectral analysis of the measured pressure fluctuation during incineration are used to elucidate the relationship between behaviors of fluidization and generation of pollutants during incineration. Experimental results show the organic concentration does not increase with uniformity of fluidization decreasing. The reason may be the explosion of the gas and the consequent thermal shock destroy the coalescent bubbles to form small bubbles again and enhance the efficiency of transfer of oxygen to increase combustion efficiency. Additionally, the mean amplitude and fluidized index of pressure fluctuation similarly vary with the concentration of organic pollutants. These two indices can be used to assess the efficiency of combustion. The four particle size distributions could be divided into two groups by statistical analysis. The Gaussian and narrow distributions belong to one group and the binary and flat the other. The organic concentration of the Gaussian and narrow distributions are lower than that of the other distributions. Consequently, the bed materials should maintain narrow or Gaussian distributions to maintain a good combustion efficiency during incineration.     

流化床中污泥干燥特性

以湿污泥为原料在气固流动流化床干燥器内进行了污泥干燥特性的实验研究,考察流化风速、送风温度、联合干燥热量配比的变化对干燥强度、干燥热效率及平均传热系数的影响。实验结果表明,流化床污泥干燥最佳流化风速为1.48 m/s左右;随着流化风温的升高,干燥强度和干燥热效率逐渐增大,但增幅减小;单独的加热管干燥和流化风干燥的干燥热效率均较低,分别为33%和45%左右。在相同总输入热量下,随着内置加热管输入热量的比重越来越大,干燥热效率、干燥强度和平均传热系数均先增大后减小。