Mechanisms of granular activated carbon anaerobic fluidized-bed process for treating phenols wastewater

Granular activated carbon (GAC) anaerobic fluidized bed reactor was applied to treating phenols wastewater. When influent phenol concentration was 1000 mg/L, volume loadings of phenol and COD Cr were 0 39 kg/(m 3·d) and 0 98 kg/(m 3·d), their removal rates were 99 9% and 96 4% respectively. From analyzing above results, the main mechanisms of the process are that through fluidizing GAC, its adsorption is combined with biodegradation, both activities are brought into full play, and phenol in wastewater is effectively decomposed. Meanwhile problems concerning gas liquid separation and medium plugging are well solved.

Characteristics of high-sulfate wastewater treatment by two-phase anaerobic digestion process with Jet-loop anaerobic fluidized bed

A new anaerobic reactor, Jet-loop anaerobic fluidized bed （JLAFB）, was designed for treating high-sulfate wastewater. The treatment characteristics, including the effect of influent COD/SO42 ratio and alkalinity and sulfide inhibition in reactors, were discussed for a JLAFB and a general anaerobic fiuidized bed （AFB） reactor used as sulfate-reducing phase and methane-producing phase, respectively, in two-phase anaerobic digestion process. The formation of granules in the two reactors was also examined. The results indicated that COD and sulfate removal had different demand of influent COD/SO4^2- ratios. When total COD removal was up to 85%, the ratio was only required up to 1.2, whereas, total sulfate removal up to 95% required it exceeding 3.0. The alkalinity in the two reactors increased linearly with the growth of influent alkalinity. Moreover, the change of influent alkalinity had no significant effect on pH and volatile fatty acids （VFA） in the two reactors. Influent alkalinity kept at 400-500 mg/L could meet the requirement of the treating process. The JLAFB reactor had great advantage in avoiding sulfide and free-H2S accumulation and toxicity inhibition on microorganisms. When sulfate loading rate was up to 8. 1 kg/（m^3.d）, the sulfide and free-H2S concentrations in JLAFB reactor were 58.6 and 49.7 mg/L, respectively. Furthermore, the granules, with offwhite color, ellipse shape and diameters of 1.0-3.0 mm, could be developed in JLAFB reactor. In granules, different groups of bacteria were distributed in different layers, and some inorganic metal compounds such as Fe, Ca, Mg etc. were found.

Performance of Anammox granular sludge bed reactor started up with nitrifying granular sludge

The anaerobic ammonia oxidation(Anammox) granular sludge bed reactor was started up successfully with nitrifying granular sludge. During the operation, the nitrifying granular sludge was gradually converted into Anammox granular sludge with good settling property and high conversion activity. The Anammox reactor worked well with the shortest HRT of 2 43 h. Under the condition that HRT w as 6 39 h and influent concentration of ammonia and nitrite was 10 mmol/L, the removal of ammonia and nitrite was 97 17% and 100 00%, respectively. Corresponding volumetric total nitrogen loading rate and volumetric total nitrogen conversion rate were 100 83 mmol/(L·d) and 98 95 mmol/(L·d). The performance of Anammox reactor was efficient and stable.

Anaerobic tapered fluidized bed reactor for starch wastewater treatment and modeling using multilayer perceptron neural network

treatability of synthetic sago wastewater was investigated in a laboratory anaerobic tapered fluidized bed reactor （ATFBR） with a mesoporous granular activated carbon （GAC） as a support material. The experimental protocol was defined to examine the effect of the maximum organic loading rate （OLR）, hydraulic retention time （HRT）, the efficiency of the reactor and to report on its steady- state performance. The reactor was subjected to a steady-state operation over a range of OLR up to 85.44 kg COD/（m^3·d）. The COD removal efficiency was found to be 92% in the reactor while the biogas produced in the digester reached 25.38 m^3/（m^3·d） of the reactor. With the increase of OLR from 83.7 kg COD/（m^3·d）, the COD removal efficiency decreased. Also an artificial neural network （ANN） model using multilayer perceptron （MLP） has been developed for a system of two input variable and five output dependent variables. For the training of the input-output data, the experimental values obtained have been used. The output parameters predicted have been found to be much closer to the corresponding experimental ones and the model was validated for 30% of the untrained data. The mean square error （MSE） was found to be only 0.0146.

Stability of expanded granular sludge bed process for terylene artificial silk printing and dyeing wastewater treatment

Terylene artificial silk printing and dyeing wastewater(TPD wastewater), containing averaged 710 mg/L terephthalic acid(TA) as the main carbon source and the character pollutant, was subjected to expanded granular sludge bed(EGSB) process. The stability of the EGSB process was firstly conducted by laboratory experiment. TA ionization was the predominated factor influencing the acid-base balance of the system. High concentration of TA in wastewater resulted in sufficient buffering capacity to neutralize the volatile fatty acids(VFA) generated from substrate degradation and provided strong base for anaerobic system to resist the pH decrease below 6.5. VFA and UFA caused almost no inhibition on the anaerobic process and biogas production except that pH was below 6.35 and VFA was at its maximum value. Along with the granulating of the activated sludge, the efficiency of organic removal and production rate of biogas increased gradually and became more stable. After start-up, the efficiency of COD removal increased to 57%—64%, pH stabilized in a range of 7.99—8.04, and production rate of biogas was relatively high and stable. Sludge granulating, suitable influent of pH and loading were responsible for the EGSB stability. The variation of VFA concentration only resulted in neglectable rebound of pH, and the inhibition from VFA could be ignored in EGSB. The EGSB reactor was stable for TPD wastewater treatment.

Start-up and Performance of a Novel Reactor----Jet Biogas Inter-loop Anaerobic Fluidized Bed

A novel anaerobic reactor, jet biogas inter-loop anaerobic fluidized bed （JBILAFB）, was designed and constructed. The start-up and performance of the reactor was investigated in the Process. of .artificial glucose wastewater treatment. With the wastewater recycle ratio of 2.5 ： 1, the recycled wastewater with biogas could mix sludge and wastewater in the JBILAFB reactor completely. The start-up of the JBILAFB reactor could be completed in less than 70 d through maintenance of hydraulic retention time （HR^I＂） and stepwise increase of feed total organic carbon （TOC） concentration. After the start-up, with the volumetric TOC loadings of 14.3 kg·m ^-3·d^-1, the TOC removal ratio, the effluent pH, and the volatile fatty acids （VFA）/alkalinity of the JBILAFB reactor were more than 80%, close to 7.0 and less than 0.4, respectively. Moreover, CH4 was produced at more than 70% of the theoretical value, The reactor exhibited high stability under the condition of high volumetric TOC loading. Sludge granules in the JBILAFB reactor were developed during the start-up and their sizes were enlarged with the stepwise increase of volumetric TOC loadings from 0.8 kg.m^-3.d ^-1 to 14.3 kg.m^-3.d^-1. Granules, an offwhite color and a similar spherical shape, were mainly comprised of global-like bacteria. These had good methanogenic activity and settleability, which were formed probably through adhesion of the bacteria. Some inorganic metal compounds such as Fe, Ca, Mg, Al, etc. were advantageous to the formation of the granules.

Production and application of anaerobic granular sludge produced by landfill

Sludge granulation is considered to be the most critical parameter governing successful operation of an upflow anaerobic sludge blanket and expanded granular sludge bed （EGSB） reactors. Pre-granulated seeding sludge could greatly reduce the required startup time. Two lab-scale and a pilot-scale EGSB reactors were operated to treat Shaoxing Wastewater Treatment Plant （SWWTP） containing wastewater from real engineering printing and dyeing with high pH and sulfate concentration. The microbiological structure and the particle size distribution in aerobic excess sludge, sanitary landfill sludge digested for one year, and the granular sludge of EGSB reactor after 400 d of operation were analyzed through scanning electron microscopy （SEM） and sieves. The lab-scale EGSB reactor seeded with anaerobic sludge after digestion for one year in landfill showed obviously better total chemical oxygen demand （TCOD） removal efficiency than one seeded with aerobic excess sludge after cation polyacrylamide flocculation-concentration and dehydration. The TCOD removed was 470.8 mg/L in pilot scale EGSB reactor at short hydraulic retention time of 15 h. SEM of sludge granules showed that the microbiological structure of the sludge from different sources showed some differences. SEM demonstrated that Methanobacterium sp. was present in the granules of pilot-scale EGSB and the granular sludge produced by landfill contained a mixture of anaerobic/anoxic organisms in abundance. The particle size distribution in EGSB demonstrated that using anaerobic granular sludge produced by sanitary landfill as the seeding granular sludge was feasible.

Startup and operation of anaerobic EGSB reactor treating palm oil mill effluent

A bench-scale expanded granular sludge bed （EGSB） reactor was applied to the treatment of palm oil mill effluent （POME）. The reactor had been operated continuously at 35℃ for 514 d, with organic loading rate （OLR） increased from 1.45 to 17.5 kg COD/（m^3·d）. The results showed that the EGSB reactor had good performance in terms of COD removal on the one hand, high COD removal of 91% was obtained at two days＇ of hydraulic retention time （HRT）, and the highest OLR of 17.5 kg COD/（m^3·d）. On the other hand, only 46% COD in raw POME was transformed into biogas in which the methane content was about 70% （V/V）. A 30-d intermittent experiment indicated that the maximum transformation potential of organic matter in raw POME into methane was 56%. Volatile fatty acid （VFA） accumulation was observed in the later operation stage, and this was settled by supplementing trace metal elements. On the whole, the system exhibited good stability in terms of acidity and alkalinity. Finally, the operational problems inherent in the laboratory scale experiment and the corresponding countermeasures were also discussed.

Concept and application of anaerobic suspended granular sludge bed （SGSB） reactor for wastewater treatment

Bed expansion serves an important function in the design and operation of an upflow anaerobic reactor. An analysis of the flow pattern of expanded granular sludge bed （EGSB） reactors shows that most EGSB reactors do not behave as expanded bed reactors, as is widely perceived. Rather, these reactors behave as fluidized bed reactors based on the classic chemical reactor theory. In this paper, four bed expansion modes, divided as static bed, expanded bed, suspended bed, and fluidized bed, for bioreactors are proposed. A high-rate anaerobic suspended granular sludge bed （SGSB） reactor was then developed. The SGSB reactor is an upflow anaerobic reactor, and its expansion degree can be easily controlled within a range to maintain the suspended status of the sludge bed by controlling upfiow velocity. The results of the full-scale reactor confirmed that the use of SGSB reactors is advantageous. The full-scale SGSB reactor runs stably and achieves high COD removal efficiency （about 90%） at high loading rates （average 40 kg-COD·m^-3·d^-1, maximum to 52 kg·COD·m^-3 ·d^-1） based on the SGSB theory, and its expansion degree is between 22% and 37%.

废水处理硝酸盐异化还原与厌氧氨氧化/反硝化耦合工艺构建

采用厌氧膨胀颗粒污泥床反应器(EGSB)处理含COD、氨氮和硝氮的模拟废水,旨在高浓度有机废水处理系统中快速构建厌氧氨氧化(Anammox)运行工艺。通过接种少量Anammox污泥和逐步提高氨氮浓度的操作方式,在连续运行58d后,系统成功启动Anammox反应,此时的总氮和COD去除率稳定在97%和98%以上。物料衡算显示,Anammox反应途径对氮的去除贡献逐渐增加,硝酸盐异化还原(DNRA)耦合Anammox和反硝化共同促进了系统的同步脱氮除碳。对微生物群落分析发现,Candidatus Kuenenia相对丰度由0.27%快速升高至35.87%,DNRA菌(Ignavibacterium、Thermogutta)及反硝化菌(Azospira、Gp3)在体系内共存。通过基因注释法,检测出了Anammox、DNRA、硝酸盐还原及亚硝酸盐还原关键基因。运行过程中,颗粒污泥颜色变红且粒径增大;胞外聚合物(EPS)分析表明多糖(PS)和蛋白质(PN)含量增加而PN/PS下降;三维荧光光谱发现腐殖酸类物质增多。研究结果为高浓度有机含氮废水高效处理提供了一种新的工艺途径。

EGSB反应器中颗粒污泥床工作状况及污泥性质研究

研究了处理低浓度有机废水的EGSB反应器中颗粒污泥床状况及颗粒污泥的性质 ,结果表明 ,液体表面上升流速 (Vup)是影响EGSB反应器效能的重要参数 ,当进水COD为 6 0 0～ 80 0mg L时 ,较佳的液体表面上升流速 (Vup)为 1 5～ 4 5m h ,在此条件下 ,EGSB反应器COD负荷为2 4 5～ 2 5 7kg (m3·d) ,COD去除率大于 85 % ;同时还发现 ,经过一定时间的运行后 ,反应器中颗粒污泥粒径分布、沉降速度、胞外聚合物 (ECP)等性质都发生了明显变化 ,颗粒污泥的平均粒径由 0 85mm增加到 1 78mm ,平均沉降速度由 41 2m h提高到 83 2m h ,而胞外聚合物 (ECP)的含量则由接种污泥的 32 5mg g增加到 5 7 8mg g。

连续流气提式流化床启动过程中好氧颗粒污泥的形成机制

探讨连续流气提式好氧颗粒污泥流化床(CAFB)反应器的运行特征,对该工艺颗粒污泥形成过程、形成机理和颗粒性质进行分析。以市政污泥为接种污泥,以醋酸钠为碳源,在连续运行方式下培养好氧颗粒污泥。研究结果表明:CAFB反应器启动的第4-5天即有大量颗粒污泥形成,颗粒直径800～1 000μm,比重1.006,生物相丰富,能够分泌大量胞外聚合物。当COD有机负荷高达8和13kg/(m3.d)时,对COD处理效率均维持在93%～97%,COD出水质量浓度仅为30～80mg/L,引起启动后期丝状菌的大量繁殖,污泥流失。进一步提高污泥负荷有望控制污泥膨胀。

溶解氧对厌氧颗粒污泥活性的影响

采用血清瓶培养法,以厌氧膨胀颗粒污泥床(EGSB)反应器中接种的厌氧颗粒污泥为对象,研究了溶解氧(DO)对其产甲烷活性的影响.结果表明,水中溶解氧的升高会致使厌氧颗粒污泥的活性降低.常温22℃下,当溶解氧浓度从0.00 mg/L上升到7.00 mg/L时,其最大比产甲烷速率(SMA)值先后两次分别由75.9 mL.(g.d)-1,91.1 mL.(g.d)-1下降到47.6 mL.(g.d)-1,71.4mL.(g.d)-1.但温度的升高可以显著提高其活性并削弱这种变化趋势.与第1次产气实验结果相比,恒温28℃与35℃时,SMA值分别平均提高了54.0%和114.4%.进水中溶解氧的存在并不会对处理系统的运行造成不利影响,厌氧颗粒污泥对溶解氧有较强的耐受性和适应能力.因此,在工程实践中可以不考虑溶解氧因素的影响.

厌氧氨氧化反应器性能的稳定性及其判据

The stability of performance of anaerobic ammonium oxidation (ANAMMOX) reactors was studied and the indices of performance stability were compared.The results showed that under different types of shock load, the reactors with different configurations displayed different stability.The biofilm reactor stood first in stability towards substrate shock load, followed by anaerobic sequencing batch reactor (SBR) and the granular sludge bed.And the biofilm reactor took the first place towards hydraulic shock load, followed by the granular sludge bed and SBR.The three ANAMMOX reactors were more tolerant to hydraulic shock load than to substrate shock load.When different kinds of stability assessment indices(i.e., sensitivity ratio, mean variance ratio and derivative regression function) were used, inconsistent assessment conclusions were reached.It was suggested that the mean deviation ratio and derivative regression function were more effective and universal.

射流循环厌氧流化床两相厌氧处理高浓度硫酸盐有机废水

设计了射流循环新型厌氧生物流化床反应器（JLAFB），以该反应器为酸化相（或称硫酸盐还原相），厌氧颗粒污泥流化床（AGSFB）为产甲烷相组成两相厌氧工艺处理高浓度硫酸盐有机废水。在培养出耐酸性硫酸盐还原厌氧颗粒污泥基础上，成功实现了硫酸盐还原菌（SRB）和产甲烷菌（MPB）的相分离，消除了SRB对MPB的基质竞争性抑制。在进水SO4^2-负荷达12．0kg·m^-3·d^-1条件下，JLAFB和AGSFB反应器内硫化物浓度分别为78．3mg·L^-1和92．4mg·L^-1，远小于200mg·L^-1的抑制浓度，消除了硫化物在反应器内的积累和对微生物的毒性作用。在稳态运行条件下，当进水COD和SO4^2-负荷分别为26．0和8．5kg·m^-3·d^-1时，工艺总的COD和SO4^2-去除率分别达到86．9％和97．6％。试验确定工艺的最优运行条件为：进水COD／SO4^2-〉3．0；碱度为400-500mg·L^-1；JLAFB反应器吹脱气体流量为0．04L·min^-1，水力回流比为5：1。

厌氧-好氧处理变性淀粉生产废水工程实例

利用膨胀颗粒污泥床(EGSB)和活性污泥好氧处理工艺相结合处理高浓度变性淀粉生产废水,处理水质可达到国家污水综合排放一级标准。工程实践表明该工艺具有投资与占地面积少,运行效果稳定,可回收能源等优点,具有很高推广价值。

EGSB处理玉米淀粉生产废水中试研究

研究了厌氧膨胀颗粒 (EGSB)反应器处理玉米生产废水的运行过程现象 ,结果表明 ,液体表面上升流速是影响EGSB反应器效能的重要参数 ,当进水CODCr为 35 0 0～ 6 5 0 0mg L时 ,液体表面上升流速为 1～ 3 5m h时 ,EGSB反应器处理始终保持在 85 %以上 ,污泥经过选择后能够适应EGSB反应器的运行条件。

EGSB反应器处理抗生素制药废水的性能研究

构建颗粒污泥膨胀床(EGSB)反应器处理高浓度抗生素制药废水,考察其对该废水的处理性能及抗冲击能力。运行结果表明,EGSB反应器通过逐步提高容积负荷的方式运行90 d可成功启动。在9.5 kgCOD/(m3·d)(HRT为40 h)的最适容积负荷下,COD平均去除率可达91.4%±0.8%,甲烷产率为(2.56±0.05)L/(L·d)。在pH为5.8的低p H冲击下,EGSB反应器对COD的去除率仍可达到83.4%±1.3%。Geobacter和Methanomassiliicoccus分别为污泥中的优势产酸菌群和产甲烷菌种。

常温EGSB去除有机物的性能与机理

将厌氧污泥膨胀床(EGSB)分别与厌氧生物滤池、好氧生物滤池和活性污泥法串联并用其处理城市污水,考察了EGSB在常温下的工艺性能和去除有机物的机理。结果表明,在常温和较短水力停留时间下,EGSB的厌氧生化过程主要停留在水解阶段,对有机物的去除主要以颗粒污泥的吸附、吸收作用为主;影响EGSB处理效果的主要因素有温度、上升流速、水力停留时间、进水浓度及容积负荷等。

厌氧颗粒污泥反应器处理中药废水性能

以硅藻土为厌氧颗粒污泥的支撑材料,构建上流式厌氧污泥床(UASB)系统,考察其对中药废水的处理性能。运行结果显示:与空白组相比,添加硅藻土的UASB系统具有更高的有机物去除能力。启动成功后,硅藻土组的COD去除率达到(90.8±1.1)%,高于空白组(82.5±1.9)%。硅藻土的投加能有效提高UASB系统对pH变化的耐受性。在低pH条件(5.8)下,硅藻土组的COD去除率可达到(88.9±1.6)%,高于空白组的(76.6±3.2)%。在硅藻土组污泥中,Geobacter和Candidatus是产酸菌种的优势菌群,Methanomassiliicoccus是产甲烷菌种的优势菌群,且菌群比例的稳定性高于空白组。