The Effect of Non-acidified Wastewater on Expanded Granular Sludge Bed （EGSB） Reactors Performance

The textile processing plants utilize a wide variety of dyes and other chemicals such as acids, bases, salts, detergents, sizes, oxidants, mercerizing and finishing chemicals. Many of these are not retained in the final product and are discharged in the effluent. Therefore, the objective of this study was to assess the performance of EGSB （Expanded Granular Sludge Bed） reactor to treat non-acidifie wastewater. Several experiments using starch and volatile fatty acids as model substrates were conducted. The problems of piston formation were evaluated at a variety of relevant operational conditions, such as substrate concentration, organic and hydraulic loading rates. The results showed that newly grown acidogenic biomass diluted original methanogenic biomass and the granular sludge in the EGSB reactor deteriorated. The piston formation in the EGSB reactor that was fed with non-acidified wastewater occurred due to high growth of acidogenic biomass and high upflow velocity applied in the system.

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.

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.

Optimizing Conditions of Enhancing Granule Sludge Concentration and Performance

An expanded granular sludge bed （EGSB） reactor was adopted to study the influence factors and rule of enhancing granular sludge concentration and performance. The experiment was performed at 33 ℃, pH 6.0-8.0 with continuous flow by adding proper quantity of nutritional trace elements. The results show that SLR was the key of steady operation of EGSB reactor. The increment of the granular sludge was influenced by volume loading rate （VLR）, liquid up-flow velocity and sludge loading rate （SLR）. Concentration of granular sludge increased rapidly when liquid up-flow velocity was over 0.94 m · h^-1 with SLR being at 1.0-2.0 d ^-1. With the propriety parameters： liquid up-flow velocity 2.52 m · h^-1, SLR 1.0-2.2 d^-1 and VLR 8.2-13.1 kg · m ^3 · d^-1, 23 days＇ continuous operation resulted in an increment by over 80% of granular sludge concentration in the EGSB reactor, plus good granular sludge property.

Performance and microbial diversity of an expanded granular sludge bed reactor for high sulfate and nitrate waste brine treatment

The disposal of waste brines has become a major challenge that hinders the wide application of ion- exchange resins in the water industry in recent decades. In this study, high sulfate removal efficiency （80%-90%） was achieved at the influent sulfate concentration of 3600 mg/L and 3% NaC1 after 145 days in an expanded granular sludge bed （EGSB） reactor. Furthermore, the feasibility of treating synthetic waste brine containing high levels of sulfate and nitrate was investigated in a single EGSB reactor during an operation period of 261 days. The highest nitrate and sulfate loading rate reached 6.38 and 5.78 kg/（m3-day） at SO42--S/NO3-N mass ratio of 4/3, and the corresponding removal efficiency was 99.97% and 82.26% at 3% NaC1, respectively. Meanwhile, 454-pyrosequencing technology was used to analyze the bacterial diversity of the sludge on the 240th day for stable operation of phase X. Results showed that a total of 9194 sequences were obtained, which could be affiliated to 14 phyla, including Proteobacteria, Firmicutes, Chlorobi, Bacteroidetes, Synergistetes and so on. Proteobacteria （77.66%） was the dominant microbial population, followed by Firmicutes （12.23%） and Chlorobi （2.71%）.

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。

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.

Integration of biological method and membrane technology in treating palm oil mill effluent

Palm oil industry is the most important agro-industry in Malaysia, but its by-product-palm oil mill effluent （POME）, posed a great threat to water environment. In the past decades, several treatment and disposal methods have been proposed and investigated to solve this problem. A two-stage pilot-scale plant was designed and constructed for POME treatment. Anaerobic digestion and aerobic biodegradation constituted the first biological stage, while ultrafiltration （UF） and reverse osmosis （RO） membrane units were combined as the second membrane separation stage. In the anaerobic expanded granular sludge bed （EGSB） reactor, about 43% organic matter in POME was converted into biogas, and COD reduction efficiency reached 93% and 22% in EGSB and the following aerobic reactor, respectively. With the treatment in the first biological stage, suspended solids and oil also decreased to a low degree. All these alleviated the membrane fouling and prolonged the membrane life. In the membrane process unit, almost all the suspended solids were captured by UF membranes, while RO membrane excluded most of the dissolved solids or inorganic salts from RO permeate. After the whole treatment processes, organic matter in POME expressed by BOD and COD was removed almost thoroughly. Suspended solids and color were not detectable in RO permeate any more, and mineral elements only existed in trace amount （except for K and Na）. The high-quality effluent was crystal clear and could be used as the boiler feed water.

Development of a novel modified EGSB reactor for municipal sewage treatment at ambient temperatures

A novel modified expanded granular sludge bed(EGSBm) reactor was developed for anaerobic treatment of municipal sewage with mixed liquid recirculation instead of effluent recirculation commonly adopted by a conventional EGSB(EGSBc) reactor.Performances of these two reactors were compared in treating municipal sewage at ambient temperatures ranging from 8 to 26 ℃.At an upflow liquid velocity(Vup) of 10.3 m/h,the mean concentrations of filtrated COD(CODfilt) and COD of the EGSBm effluent were determined to be 59.4 and 95.9 mg/L,respectively,which were significantly lower than those of the EGSBc effluent operated under identical experimental conditions.When the organic loading rate was suddenly increased from 1.2 to 7.2 kg COD/(m3·d),the EGSBm regained the removal efficiency of previous operation phase in 10 d.Hydrodynamic characteristics of the reactors were compared using the residence time distribution(RTD) model.It was found that the treatment efficiency of EGSBm kept increasing as the Vup increased.The polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis(PCR-DGGE) technique was used to analyze the microbial diversity in EGSBm.Fingerprinting pattern indicated that some species in the inoculating sludge were still reserved in the granular sludge of EGSBm,moreover,several new species occurred.

High rate production of concentrated sulfides from metal bearing wastewater in an expanded bed hydrogenotrophic sulfate reducing bioreactor

Metallurgical wastewaters contain high concentrations of sulfate,up to 15 g L^(-1).Sulfate-reducing bioreactors are employed to treat these wastewaters,reducing sulfates to sulfides which subsequently coprecipitate metals.Sulfate loading and reduction rates are typically restricted by the total H2S concentration.Sulfide stripping,sulfide precipitation and dilution are the main strategies employed to minimize inhibition by H2S,but can be adversely compromised by suboptimal sulfate reduction,clogging and additional energy costs.Here,metallurgical wastewater was treated for over 250 days using two hydrogenotrophic granular activated carbon expanded bed bioreactors without additional removal of sulfides.H2S toxicity was minimized by operating at pH 8±0.15,resulting in an average sulfate removal of 7.08±0.08 g L^(-1),sulfide concentrations of 2.1±0.2 g L^(-1) and peaks up to 2.3±0.2 g L^(-1).A sulfate reduction rate of 20.6±0.9 g L^(-1)d^(-1) was achieved,with maxima up to 27.2 g L^(-1)d^(-1),which is among the highest reported considering a literature review of 39 studies.The rates reported here are 6e8 times higher than those reported for other reactors without active sulfide removal and the only reported for expanded bed sulfate-reducing bioreactors using H2.By increasing the influent sulfate concentration and maintaining high sulfide concentrations,sulfate reducers were promoted while fermenters and methanogens were suppressed.Industrial wastewater containing 4.4 g L^(-1) sulfate,0.036 g L^(-1) nitrate and various metals(As,Fe,Tl,Zn,Ni,Sb,Co and Cd)was successfully treated with all metal(loid)s,nitrates and sulfates removed below discharge limits.

Kinetics of municipal sewage degradation in EGSB and UASB reactors at 10 ℃

Kinetics of municipal sewage degradation in Expanded Granular Sludge Bed(EGSB)and Up-flow Anaerobic Sludge Blanket(UASB)reactors at 10℃ were investigated via continuous experimental equipments.The results indicated that the whole reaction process can be simulated by the first-order dynamic equation model.Dynamic parameters such as k,Vmax and Ks of UASB in hydrolysis acidification stage were 1.08 d-1,2.8 d-1 and 372 mg/L comparing to those of 1.18 d-1,3.5 d-1 and 112 mg/L in the methanogenesis stage respectively.The EGSB’s k,Vmax and Ks were 2.91 d-1,14.3 d-1 and 470 mg/L in the hydrolysis acidification stage comparing to those of 1.68 d-1,6.6 d-1 and 103 mg/L in the methanogenesis stage respectively.Comparison of k values of the two stages in UASB and EGSB indicates that hydrolysis acidification stage is the controlling step for the whole reaction process of UASB,while methanogenesis stage is the controlling step in EGSB.Compared with UASB,municipal sewage treatment by EGSB at 10 ℃ can reach the same effluent requirement with lower retention time due to its effluent recirculation.

Quick start-up of EGSB reactor treating fresh leachate of municipal solid waste

An expanded granular sludge bed （EGSB） reactor inoculated with anaerobic granular sludge was started up with its COD removal performance, self-balancing of pH, biogas production rate and characteristics of the granular sludge during the start-up period being investigated. The results indicated that the EGSB reactor can be started up successfully in 27 d by increasing the organic loading rate rapidly. The removal efficiency of COD was maintained above 93% with influent COD concentration of 25 000 mg/L and OLR of 37.94 kgCOD/（m 3 ·d）. The EGSB reactor with good pH self-balancing could be fed with fresh leachate of low pH value （4 5）. The biogas production rate was closely related with OLR and COD reduction. Every gram of COD fed （consumed） to the reactor produced 0.34 L STP （0.36 L STP ） biogas with 0.21 L STP （0.23 L STP ） methane. Thus, 65% 70% of the produced biogas was methane. Sixty one percentage of COD fed to the reactor was converted to methane, another 33% was converted to biomass by metabolism, and the other 6% was left in the liquid phase. The specific methanogenic activity （SMA） of the granular sludge had increased by 92% after 27 d dynamic incubation. The granular sludge in the reactor had good settlement performance with majority diameter of 1 2 mm.

不同温度下厌氧氨氧化处理含挥发酚和石油类废水运行条件优化试验研究

目前,在工业化进程中有大量的挥发酚和石油类有机物排入水体,严重制约着生物脱氮工艺的发展。而厌氧氨氧化是比传统除氮更节约成本且污染程度低的新型生物脱氮工艺。因此,研究采用厌氧氨氧化工艺处理含挥发酚和石油类的废水,主要对系统的内回流比、水利停留时间(HRT)进行优化,同时考察二者在不同温度下对系统脱氮性能的影响。最终,得出最优运行条件。结果显示,内回流比150%、HRT=8 h,且运行温度为35℃时,厌氧氨氧化系统脱氮效果最佳,对氨氮、亚硝态氮去除率分别高达84.13%和97.79%;系统脱氮速率为0.59170 kgN/(m^(3)·d);厌氧氨氧化反应贡献率为98.3%。

EGSB+两级BioDopp工艺在酿酒废水处理中的应用

采用膨胀颗粒污泥床(EGSB)+两级BioDopp工艺应用于西南某酿酒厂高CODCr酿酒废水处理。通过检测启动过程中挥发性脂肪酸(VFA)以及碱度(ALK)的浓度变化,发现VFA质量浓度保持在250 mg/L左右,同时反应器内ALK浓度较高,说明ESBG能实现对酿酒废水的稳定处理。经过一段时间对酿酒废水的稳定处理,其中EGSB进水CODCr均值在50 000 mg/L,氨氮均值为1 000 mg/L,总氮均值为3 000 mg/L,污染物去除率均超过90%。一级BioDopp生化池CODCr去除率均值达到93.5%,氨氮去除率均值达到88.9%,总氮去除率均值达到83.5%,总磷去除率均值为55.0%。二级BioDopp生化池出水CODCr、氨氮、总氮和总磷均值分别为37.8、2.9、11.3 mg/L和0.30 mg/L,满足《城镇污水处理厂污染物排放标准》(GB 18918-2002)一级A标准。通过计算发现EGSB+两级BioDopp工艺吨水处理成本约为1.76元/(m^(3)·d),低于“升流式式厌氧污泥床(UASB)+AAO”“中和混凝沉淀-内循环(IC)厌氧反应器-接触氧化-曝气生物滤池”以及“UASB+序批式活性污泥法(SBR)”等工艺运行成本,能实现低成本、高处理率的效果。

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%.

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。

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.

常温下EGSB处理低浓度城市污水的初步研究

通过间歇试验和中试研究,初步探讨了悬浮物、温度和溶解氧对膨胀颗粒污泥床(EGSB)在常温下处理低浓度城市污水的影响。中试结果表明,城市污水中的悬浮物在EGSB中能够得到有效去除,不会在系统中沉积而影响运行效果;EGSB的出水可回流且城市污水的COD浓度低,缓解了温度对系统的影响,EGSB对CODtotal的去除率可保持在70%左右;颗粒污泥的外层兼性菌消耗了溶解氧,保护了产甲烷菌,减轻了溶解氧对颗粒污泥降解城市污水的抑制作用。初步研究结果表明,悬浮物、温度和溶解氧对EGSB在常温下处理低浓度城市污水不会产生不利影响。

低COD浓度废水启动EGSB反应器

以厌氧活性污泥和好氧活性污泥接种于2个膨胀颗粒污泥床（EGSB）反应器中，进水流量为10mL／min，回流量为180mL／min，进水COD浓度在180mg／L左右，有机负荷率（OLR）为1．728kgCOD／m^3·d左右，污泥负荷率（SLR）为0．19kgCOD／kgMLSS·d左右，出水COD浓度维持在40mg／L左右，COD去除率达80％以上。控制温度在32～35℃，pH在6．8～7．2，反应器内氧化还原电位在-340mV以下，水力停留时间（HRT）4．2h，上升流速4．86m／h以及加入80mg／L絮凝剂（硫酸铝钾），缩短了启动时间，促进了颗粒污泥的形成。分别经过60d和120d运行，反应器启动成功。结果表明，上升流速、絮凝剂和污泥类型对颗粒污泥的形成有影响；接种好氧活性污泥在低浓度COD下，合理控制负荷速率能成功启动EGSB反应器。

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。