Conversion regular patterns of acetic acid,propionic acid and butyric acid in UASB reactor

On the basis of continuous tests and batch tests, conversion regular patterns of acetate, propionate and butyrate in activated sludge at different heights of the UASB reactor were conducted. Results indicated that the conversion capacity of the microbe is decided by the substrate characteristic when sole VFA is used as the only substrate. But when mixed substrates are used,the conversion regulations would have changed accordingly. Relationships of different substrates vary according to their locations. In the whole reactor, propionate's conversion is restrained by acetate and butyrate of high concentration. On the top and at the bottom of the reactor, conversion of acetate, but butyrate, is restrained by propionate. And in the midst, acetate's conversion is accelerated by propionate while that of butyrate is restrained. It is proved, based on the analysis of specific conversion rate, that the space distribution of the microbe is the main factor that affects substrates' conversion. The ethanol type fermentation of the acidogenic phase is the optimal acid type fermentation for the two phase anaerobic process.

Population dynamics on anaerobic sludge granulation in UASB reactors

Three UASB reactors were operated to investigate the population dynamics of anaerobic sludge granulation. It is found that the increase of bacterial population relates to the bacterial status in anaerobic food chain and relates to sludge organic loading rates. In order to form granular sludge, it is necessary to have sufficient amount of different groups of bacteria in the sludge. In our experiment, the population of fermentative bacteria, propionate degraders, butyrate degraders and methanogens is about 107-8, 105-7, 105-7 and 105-7 cells/ml respectively at the appearance of granular sludge. Filamentous methanogenic bacteria are found to be the important species in sludge granulation. Based on the results obtained, a descriptive model is proposed to describe the microbial characteristics of granulation.

Application of UASB Reactor in Leachate Treatment of Beijing Asuwei Waste Sanitary Landfill Site

The UASB reactor was used to reconstruct leachate treatment project of Beijing Asuwei Waste Sanitary Landfill Site,and the commissioning with the UASB reactor was executed.Water quality indicators were determined in the debugging process,and the results showed that the VFA content in the anaerobic tank was controlled within 600 mg/L,which indicated that the water quality did not have the acidified phenomenon.The COD removal efficiency was 50%approximately and NH_3-N concentration showed as light decline when operation stability in anaerobic system.

Economic Analysis of a Large UASB Reactor Producing Biogas from Baggase Wash Water

This paper concerns with the treatment of bagasse wash water, which is generated after washing the stored bagasse before its use in the paper manufacture. The bagasse wash water, treated earlier in open lagoons, is now treated by the anaerobic process using UASB reactor. This study, based upon an operating unit, shows that the UASB reactor reduces COD of wash water by 85% - 90%, and results in significant emission reductions. Economic analysis carried out by using financial indicators such as DSCR, Payback period and IRR reveals very attractive rate of returns and thus, greatly reduces the risks in financing such projects by the financial institutions.

UASB和MBR组合工艺处理生活垃圾焚烧发电厂渗滤液的研究

上升式厌氧污泥床(Upward Anaerobic Sludge Bed,UASB)和膜生物反应器(Membrane Bio-Reactor,MBR)是目前较为流行的渗滤液处理技术,其组合工艺可有效处理渗滤液。生活垃圾焚烧发电厂可以综合运用两种技术,提升渗滤液处理能力,降低渗滤液对环境的危害。本文结合生活垃圾焚烧发电厂渗滤液产生量与设计进出水水质,设计渗滤液处理工艺,确定关键构筑物和设备参数,然后开展应用案例分析,验证渗滤液处理效果。经现场测试,UASB和MBR组合工艺可有效降低渗滤液的氨氮浓度,明显改善出水水质。

Biological sulfate removal from acrylic fiber manufacturing wastewater using a two-stage UASB reactor

A two-stage UASB reactor was employed to remove sulfate from acrylic fiber manufacturing wastewater.Mesophilic operation（35±0.5℃） was performed with hydraulic retention time（HRT） varied between 28 and 40 hr.Mixed liquor suspended solids（MLSS） in the reactor was maintained about 8000 mg/L.The results indicated that sulfate removal was enhanced with increasing the ratio of COD/SO24-.At low COD/SO42-,the growth of the sulfate-reducing bacteria（SRB） was carbon-limited.The optimal sulfate removal efficiencies were 75% when the HRT was no less than 38 hr.Sulfidogenesis mainly happened in the sulfate-reducing stage,while methanogenesis in the methane-producing stage.Microbes in sulfate-reducing stage performed granulation better than that in methaneproducing stage.Higher extracellular polymeric substances（EPS） content in sulfate-reducing stage helped to adhere and connect the flocculent sludge particles together.SRB accounted for about 31% both in sulfate-reducing stage and methane-producing stage at COD/SO42-ratio of 0.5,while it dropped dramatically from 34% in sulfate-reducing stage to 10% in methane-producing stage corresponding to the COD/SO42-ratio of 4.7.SRB and MPA were predominant in sulfate-reducing stage and methane-producing stage respectively.

Formation process and properties of hydrogen-producing granular sludge in UASB reactor

The granular sludge of microbial fermentation systems includes various biomass-degrading enzymes and different microflora,which have significant impacts on the degradation of biomass and the stability of the system.An up-flow anaerobic sludge blanket(UASB)reactor was used to grow hydrogen-producing granular sludge.The results showed that the formation of the granular sludge underwent four stages,i.e.,flocculation of the sludge,formation of the flocculent sludge,swelling of the flocculent sludge,and formation of the granular sludge.The formed granular sludge mostly had regular spherical and ellipsoidal shapes with a fractal dimension of 2.08±0.4;the settling velocities were 0.84 cm/s to 1.96 cm/s in water,the porosity was 0.67-0.95.The shear sensitivity(Kss)of the granular sludge was 0.1152.The granular sludge had a culture cycle of approximately 70 d and a hydrogen yield of 1.09 mol H2/mol glucose.

Impact of roxarsone on the UASB reactor performance and its degradation

Roxarsone （3-nitro-4-hydroxyphenylarsonic acid, ROX） has been widely used for decades as an organoarsenic feed additive to control intestinal parasites and improve feed efficiency in animal production. However, most of the ROX is excreted into the manure, causing arsenic contamination in wastewater. The arsenic compounds are toxic to microorganisms, but the influence of continuous ROX loading on upflow anaerobic sludge blanket （UASB） reactor is still unknown. In this study, the impact of ROX and its degradation products on the performance of the UASB reactor and the degradation and speciation of ROX in the reactor were investigated. The UASB reactor （hydraulic retention time： 1.75 d） was operated using synthetic wastewater supplemented with ROX for a period of 260 days. With continuous ROX addition at 25.0 mg.L-1, severe inhibition to methanogenic activity occurred after 87 days operation accompanied with an accumulation of volatile fatty acids （VFAs） and a decline in pH. The decrease of added ROX concentration to 13.2 mg.L-1 did not mediate the inhibition. As（III）, As （V）, MMA（V）, DMA（V）, HAPA and an unknown arsenic compound were detected in the reactor, and a possible biotransformation pathway of ROX was proposed. Mass balance analysis of arsenic indicated that 60%-70% of the arsenic was discharged into the effluent, and 30%-40% was precipitated in the reactor. The results from this study suggest that we need to pay attention to the stability in the UASB reactors treating organoarsenic-contaminated manure and wastewater, and the effluent and sludge from the reactor tO avoid diffusion of arsenic contamination.

UASB处理垃圾渗滤液的试验研究

以柠檬酸厂IC反应器的颗粒污泥为接种污泥启动UASB反应器处理垃圾渗滤液,探讨了启动后不同阶段容积负荷、水力停留时间、p H等主要运行参数对COD去除率的影响。低容积负荷接种污泥逐步适应废水水质,随着容积负荷提高,COD去除率也逐步提高,容积负荷为8~9 kg COD/(m~3·d),水力停留时间为18 h,p H控制在6.8~7.2,产酸菌和产甲烷菌的活性高,COD去除率大于70%。

UASB处理垃圾渗滤液影响因素分析

采用垃圾渗滤液驯化接种污泥,分析UASB反应器处理渗滤液的影响因素。渗滤液的处理效能和UASB反应器内温度、pH值、容积负荷、水力停留时间、进水营养物配比等密切相关。反应器内温度控制在35℃±2℃,COD∶N∶P=(200~300)∶5∶1,容积负荷从低逐步提高到9 kg/(m3·d)时,COD去除率稳定且超过70%,容积负荷超过9 kg/(m3·d)去除率锐减;进水通过碳酸氢钠调节pH值在6.8~7.2时,COD的去除率稳定在70%以上,pH<6.5或>8.2,产甲烷菌受到抑制,COD去除率下降;水力停留时间18 h时,COD去除率好,且出水水质较好。

UASB处理技术在化企业废水处理中的重要作用

为了解决化工企业废水治理问题,本文对UASB处理技术在化工企业废水处理中的应用进行了研究,通过分析UASB反应器应用过程中的影响因素,包括水力停留时间、温度、碱度、进水浓度、pH值等,提出最佳工艺操作条件。经试验研究表明,处于最佳工艺操作条件下,利用UASB技术处理化工企业废水,COD去除率可以达到75%,能够满足我国有关废水处理的规定要求,因而本研究可以为相关工作人员提供参考。

混凝气浮+混凝沉淀+UASB+A/O+MBR工艺处理化妆品废水工程应用实例

文章介绍了某化妆品企业生产废水处理工程,该工程综合废水采用“混凝气浮+混凝沉淀+UASB厌氧塔+水解酸化+好氧+沉淀+MBR”工艺。综合废水处理后满足广东省《水污染物排放限值》(DB44/26-2001)第二时段三级排放标准,具有良好的应用前景。

UASB反应器中颗粒污泥的沉降性能与终端沉降速度

从流体力学角度,通过建立沉降速度模型探讨了UASB反应器中颗粒污泥的沉降性能与终端沉降速度.计算结果表明,(1)绝大多数颗粒污泥的沉降过程属于过渡区(1<Re<100)而非层流区,其沉降速度与直径成正比,可用Allen公式进行计算;(2)颗粒污泥的终端沉降速度远高于厌氧反应器中废水的上流速度,其良好的沉降性能解决了在高负荷情况下污泥的流失问题.所建模型能较好地反映实际条件下的情况,为厌氧反应器的工艺设计与正常运行提供理论依据.

UASB反应器中影响污泥颗粒化的工程因素

研究了具有不同微生物群系的接种污泥、流动方式和流速对上流式厌氧污泥床（ＵＡＳＢ）反应器中活性污泥粒化的影响。颗粒化过程包括：微生物絮凝体的形成、亚核的形成，亚核增长和颗粒成熟四个阶段。微絮凝体的形成取决于酸化菌的作用。流体的动量传递和流体对悬浮物的剪切作用是影响亚核形成的关键性工程因素。为此提出最低流速概念，即形成污泥膨胀床的最低流速。合适的进料速率、污泥负荷。

厌氧氨氧化工艺在UASB反应器中的启动运行研究

利用UASB反应器进行了厌氧氨氧化工艺的启动运行研究。以自配高氮低碳废水为进水,普通厌氧污泥为接种污泥,在温度35℃,pH7.5～8.0的条件下连续运行220d,成功实现了厌氧氨氧化工艺的启动,氨氮容积负荷为0.43kg/(m^3·d)时,氨氮的去除率最高达88.3％,扫描电镜的观察结果表明,厌氧氨氧化污泥中的细菌以形状不规则的短杆菌为主。

进水浓度对UASB颗粒污泥形成的影响研究

采用人工葡萄糖配水,在相同的操作条件下,研究了进水浓度对UASB反应器颗粒污泥形成的影响。试验结果表明,9000mg/L COD的高浓度进水能够培养出良好的颗粒污泥,颗粒直径1.0—2.5mm(大多为2.0mm),SVI 16.03 ml/g,沉降性能良好.颗粒化过程在二个多月的试验周期内基本完成。反应器容积负荷达30.8kg COD/m^3·d,COD去除率大于85％.而采用1000mg/L COD的低浓度进水,也能培养出颗粒污泥但过程较慢,颗粒直径较小,约0.5—1.5mm,反应器容积负荷最高为10.2kg COD/m^3·d,COD去除率约75％。本文还就处理实际废水时的操作控制技术进行了分析讨论。

UASB反应器处理酒精废液颗粒污泥形成过程的研究

采用中温（３５１℃）ＵＡＳＢ反应器处理酒精废液，通过启动、运行，成功地培养出了颗粒污泥，取得了良好的处理效果。试验在运行的不同时间对反应器污泥中不同营养类群细菌进行了分类计数；分析了颗粒污泥形成中细菌数量的变化规律；并通过扫描电镜观察了颗粒污泥的表面情况．

UASB反应器处理淀粉废水试验研究

利用UASB反应器中温条件下处理高浓度淀粉废水 ,在COD容积负荷保持在 10kg/ (m3 ·d)时 ,COD去除率可达到 90 %以上。试验结果还充分证明 。

厌氧UASB－好氧工艺处理染料废水的研究

报道厌氧－好氧工艺处理染料废水的试验结果。厌氧段采用ＵＡＳＢ反应器，好氧段采用普通活性污泥法。试验结果表明，进水ＣＯＤ１１５０—１３００ｍｇ／Ｌ、色度５００倍的染料废水，在厌氧段停留６—１０ｈ，可获得６０％以上的ＣＯＤ去除率，色度降到５０—１００倍。后续曝气６ｈ，总ＣＯＤ去除率可达８５％－９０％，色度降至２０倍左右。进出水的光谱分析揭示，染料废水的脱色主要发生在厌氧段．并且通过生物降解作用来实现。从这些结果得出，ＵＡＳＢ－好氧工艺是处理染料废水的一种经济有效的方法。

外循环UASB的结构与设计方法

阐述了外循环升流式厌氧污泥床反应器(UASB)的整体结构和分部结构及其主要作用,以某化工厂的废水处理工程为实例,对各部分的具体参数、设计方法、工艺特点,作了详尽的介绍。用此方法设计建成的外循环UASB反应器在30～35℃时,采用污水处理厂的消化污泥接种,启动一个多月,在污泥区就形成了1～2mm的颗粒污泥,COD去除率>90%,并可有效分离出直径>5×10-3cm的沼气气泡,证明该设计方法是切实可行的。