Performance of a ZVI‐UASB reactor for azo dye wastewater treatment

BACKGROUND: Zero valent iron (ZVI) is expected to be helpful for creating an enhanced anaerobic environment that might improve the performance of the anaerobic process. Based on this idea, a ZVI packed upflow anaerobic sludge blanket reactor (ZVI‐UASB) was developed to enhance azo dye wastewater treatment. RESULTS: The ZVI‐UASB reactor was less influenced by a decrease in the operational temperature from 35 °C to 25 °C than a reference UASB reactor that did not contain ZVI. In addition, chemical oxygen demand (COD) and color removal efficiencies of the ZVI‐UASB reactor at an HRT of 12 h exceeded those of the reference reactor at an HRT of 24 h. The hydraulic circulation in the ZVI bed enhanced the function of ZVI so that it improved the COD and color removal efficiencies. Moreover, fluorescence in situ hybridization experiments revealed that the abundance of Archaea in the sludge of the ZVI bed was significantly higher than that at the reactor bottom, which made the reactor capable of greater COD removal under low temperature and short HRT conditions. CONCLUSION: This ZVI‐UASB reactor could adapt well to changes in the operational conditions during wastewater treatment. Copyright © 2010 Society of Chemical Industry     

Anaerobic and aerobic treatment of a simulated textile effluent

A simulated textile effluent (STE) was generated for use in laboratory biotreatment studies; this effluent contained one reactive azo dye, PROCION Red H‐E7B (1.5 g dm⁻³); sizing agent, Tissalys 150 (1.9 g dm⁻³); sodium chloride (1.5 g dm⁻³) and acetic acid (0.53 g dm⁻³) together with nutrients and trace elements, giving a mean COD of 3480 mg dm⁻³. An inclined tubular anaerobic digester (ITD) was operated for 9 months on the STE and a UASB reactor for 3 months. For a 57 day period anaerobic effluent from two reactors, a UASB and an ITD, was mixed and treated in an aerobic stage. In days 77–247 68% of the true colour of PROCION Red H‐E7B was removed by anaerobic treatment with no colour removal aerobically and up to 37% COD was removed anaerobically, with a corresponding BOD removal of 71%. For combined anaerobic and aerobic treatment a mean COD removal of 57% and BOD removal of 86% was achieved. Operation of the ITD at a 2.8 day HRT (volumetric loading rate (B _v) 1.24 g COD dm⁻³day⁻¹) and the UASB at a 2 day HRT (B _v 1.74 g COD dm⁻³day⁻¹) gave comparable COD removals but the UASB gave better true colour removal. Effluent from the combined process operating on this simulated waste still contained an average 1500 mg COD dm⁻³, and further treatment would be required to meet consent standards. © 1999 Society of Chemical Industry     

Anaerobic-aerobic processes for the treatment of textile dyeing wastewater containing three commercial reactive azo dyes: Effect of number of stages and bioreactor type

In this study, the effect of number of stages and bioreactor type on the removal performance of a sequential anaerobic-aerobic process employing activated sludge for the treatment of a simulated textile dyeing wastewater containing three commercial reactive azo dyes was considered. Two stage processes performed better than one stage ones, both in terms of overall organic and color removal, as well as the higher contribution of anaerobic stage to the overall removal performance, thereby making them a more energy efficient option. The employment of a moving bed sequencing batch biofilm reactor, which uses both suspended and attached biomass, for the implementation of the anaerobic stage of the process, was compared with a sequencing batch reactor that only employs suspended biomass. The results showed that, although there was no meaningful difference in biomass concentration between the two bioreactors, the latter reactor had better performance in terms of chemical oxygen demand (COD) removal efficiency and rate and color removal rate. Further exploratory tests revealed a difference between the roles of suspended and attached bacterial populations, with the former yielding better color removal whilst the latter had better COD removal performance. The sequential anaerobic-aerobic process, employing an aerobic membrane bioreactor in the aerobic stage resulted in COD and color removal of 77.1±7.9% and 79.9±1.5%, respectively. The incomplete COD and color removal was attributed to the presence of soluble microbial products in the effluent and the autoxidation of dye reduction metabolites, respectively. Also, aerobic partial mineralization of the dye reduction metabolites, was experimentally observed.     

Advanced treatment of textile dyeing wastewater through the combination of moving bed biofilm reactors and ozonation

A four-stage lab-scale treatment system [anaerobic moving bed biofilm reactor (MBBR)-aerobic MBBR-ozonation-aerobic MBBR in series] was investigated to treat textile dyeing wastewater. The MBBRs were operated in a continuous horizontal flow mode. To determine the optimum operating conditions, the effect of hydraulic retention time (HRT) and ozonation time on pollutant removal were analysed by continuous and batch experiments. The optimum operating conditions were found to be 14 h HRT for both anaerobic and no. 1 aerobic MBBRs, 14 min ozonation time and 10 h HRT for no. 2 aerobic MBBR. The average influent concentrations of chemical oxygen demand (COD), suspended solids (SS), ammonia and colour were 824 mg/L, 691 mg/L, 40 mg/L and 165°, respectively. Under these conditions, the average effluent concentrations of COD, SS, ammonia and colour were 47 mg/L, 15.2 mg/L, 5.9 mg/L and 6.1°, respectively, corresponding to total removal efficiencies of 94.3%, 97.8%, 85.3% and 96.3%, respectively. The final effluent could meet the reuse requirements of textile industry. The anaerobic MBBR process improved the biodegradability of the raw wastewater, while the two aerobic MBBRs played an important role in removing COD and ammonia. The ozonation process enhanced the biodegradability of no. 1 aerobic MBBR effluent, and finally, deep treatment was completed in no. 2 aerobic MBBR. The combined process showed a promising potential for treatment of high-strength dyeing wastewater.     

上流式厌氧污泥床反应器处理凉果废水性能研究

采用上流式厌氧污泥床反应器(UASB)法处理凉果废水,考察废水厌氧处理过程中COD、浊度、脱色率、pH、电导率、悬浮物去除率的变化规律。结果表明:随着厌氧时间的增加,UASB反应器对废水的处理效果不断提高。在最适宜的厌氧时间条件下,废水的COD去除率达62.0%、浊度去除率达41.1%、吸光度及脱色率分别为0.498及48.4%、pH为5.4、悬浮物去除率达30.3%。故,UASB法可作为凉果废水的预处理方式,以降低后续废水的好氧处理难度。     

偶氮染料废水的厌氧好氧处理工程实例

介绍了以吸附过滤、上流式厌氧污泥床（UASB）生物接触氧化法相结合的工艺处理偶氮染料废不的工程实例及有关的参数。废水经过中和沉淀、吸附可去除29．7％的COD,再经UASB处理,可去除58．9％的COD,厌氧处理系统内形成颗粒污泥,厌氧出水经生物接触氧化法,可去除80．7％的COD,二沉池出水COD降至150mg/L以下,达到国家污水综合排放一级标准。     

Comparison of COD, nitrogen and phosphorus removal between anaerobic/anoxic/aerobic and anoxic/aerobic fixed biofilm reactor using SAC (Synthetic Activated Ceramic) media

In order to remove nitrogen and phosphorus simultaneously and to develop a compact process for retrofitting a conventional activated sludge system, a new fixed-biofilm reactor was designed and tested employing an operation strategy with three and two reaction phases : anaerobic/anoxic/aerobic (Run-1) and anoxic/aerobic (Run-2). Four kinds of HRT (4, 6, 8 and 10 h) were varied to investigate the effect of nitrification and denitrification in each reactor. The results of the experiments are summarized as follows. All removal rates of COD, T-N and T-P in the water treated in Run-1 were higher than those of Run-2. The average values of COD, T-N and T-P in the treated water were reduced to 5.0 mg/L, 5.6 mg/L and 3.1 mg/L in case of Run-1. The COD and T-N removal efficiencies of Run-1 were higher than that of Run-2, but the difference between Run 1 and Run 2 was almost negligible. More than 60 % T-P removal efficiency could be achieved when the HRT was above 8 hour, but the efficiency was sharply decreased to 36% as the HRT was decreased to 4 hour in case of Run-1. Although the removal efficiency of T-P in Run-2 decreased by 56 % compared with that of Run-1, the fixed biofilm reactor using SAC media reduced the volume of reactor, and high-level COD and T-N removal from domestic wastewater was performed ; stable effluent quality was thereby achieved. The performance of Run 2 with no anaerobic reactor was mostly similar to that of Run 1 with an anaerobic reactor, except for T-P removal. Hence, according to these results, anoxic and aerobic processes using SAC media could be possible for removing organics and nutrients from municipal wastewater, in case phosphorus removal is not considered for municipal wastewater with low concentration of phosphorus.     

UASB处理纤维素乙醇废水的启动运行研究

以厌氧UASB反应器处理纤维乙醇废水为研究对象,探讨分析了UASB的启动和稳定运行过程。结果表明,采用城市污水处理厂的厌氧消化污泥作为接种污泥,在COD有效容积负荷为0.33~1.11 kgCOD/(m3·d)的条件下,UASB反应器成功启动,COD的去除率达到70%以上。启动初期,出水pH会明显高于进水,污泥呈先减少后增加的趋势,当增加进水SO42-浓度到7 250 mg/L,COD/SO42-比值2.7∶1时,会导致纤维素乙醇废水UASB处理系统的崩溃。UASB反应器运行稳定后,污泥浓度增至30~40 g/L,MLVSS/MLSS比值也达到90%左右,在HRT为14~41 h,回流比3∶1~13∶1,有效容积负荷3.45~14.67 kg COD/(m3·d)的条件下,对纤维乙醇生产废水均能保持90%以上的COD去除率,出水COD小于1 000 mg/L。     

上流式厌氧污泥床(UASB)处理冬瓜食品加工废水的试验

采用常温上流式厌氧污泥床(UASB)反应器降解冬瓜加工废水,研究了厌氧颗粒污泥处理冬瓜食品加工废水的处理效果。试验结果表明,当水力停留时间(HRT)为24 h,冬瓜废水进水COD_(Cr)浓度约为10 000mg/L时,相应的容积负荷为10.0 gCOD/(L·d),COD去除率可达97%以上。当容积负荷约为6.0 gCOD/(L·d)时,出水COD_(Cr)可达100 mg/L以下,达到《污水综合排放标准》(GB 8978-1996)一级排放标准的要求。     

生物膜法A~2/O~2焦化废水处理系统缺氧反应器工艺特性

以焦化厂废水处理系统气浮设备出水为试验废水水源,在中试规模上研究了生物膜法A2/O2(厌氧/缺氧/好氧/好氧)系统中缺氧反应器的工艺特性和效果。缺氧反应器为以陶粒作填料的上流式滤池。研究结果表明,缺氧反硝化对去除焦化废水中COD有重要作用。反硝化菌可利用一些好氧微生物和厌氧微生物都难以降解的焦化废水中的有机物作碳源,反硝化反应器可去除进水中40%的COD。缺氧反硝化反应器进水碳氮质量比在5以上就可基本满足焦化废水反硝化对碳源的需求。稳定运行状况下的NO3--N容积负荷不大于0.24 kg/(m3.d)。缺氧反应器的水力停留时间不小于24 h。系统进水COD、NH3-N的质量浓度分别在1 000～2 200、200～400 mg/L范围内,对系统进水不进行稀释的条件下,水解酸化反应器HRT为20 h,缺氧反应器HRT为24 h,一级好氧反应器和二级好氧反应器HRT均为48 h,二级好氧反应器硝化液回流比为3时,生物膜法A2/O2系统处理出水的COD和NH3-N可以同时达到《污水综合排放标准》(GB8978-1996)中的一级排放标准。     

生物膜法A^2／O^2焦化废水处理系统缺氧反应器工艺特性

以焦化厂废水处理系统气浮设备出水为试验废水水源,在中试规模上研究了生物膜法A^2／O^2（厌氧／缺氧／好氧／好氧）系统中缺氧反应器的工艺特性和效果。缺氧反应器为以陶粒作填料的上流式滤池。,研究结果表明,缺氧反硝化对去除焦化废水中COD有重要作用,．反硝化菌可利用一些好氧微生物和厌氧微生物都难以降解的焦化废水中的有机物作碳源,反硝化反应器可去除进水中40％的COD。缺氧反硝化反应器进水碳氮质量比在5以上就可基本满足焦化废水反硝化对碳源的需求．．稳定运行状况下的NO3^- -N客积负荷不大于0．24kg／（m^3·d）．缺氧反应器的水力停留时间不小于24h。系统进水COD、NH3-N的质量浓度分别在1000～2200、200～400mg／L范围内,对系统进水不进行稀释的条件下．水解酸化反应器HRT为20h．缺氧反应器HRT为24h．一级好氧反应器和二级好氧反应器HRT均为48h．二级好氧反应器硝化液回流比为3时．生物膜法A^2／O^2系统处理出水的COD和NH3-N可以同时达到《污水综合排放标准》（GB8978—1996）中的一级排放标准。     

两种UASB+好氧组合工艺处理生活污水试验研究

对UASB与跌水曝气和曝气生物滤池种组合工艺对生活污水的处理效果进行研究,并对跌水曝气和曝气生物滤池作为厌氧后处理的可行性作进一步的探讨.研究表明,UASB反应器在厌氧出水后加后续的好氧处理装置如跌水曝气和曝气生物滤池,能有效去除生活污水中的COD,与只用UASB反应器相比去除率分别提高了28.4%和44.1%,总平均...     

Application of A2O moving-bed biofilm reactors for textile dyeing wastewater treatment

A three-stage pilot-scale moving-bed biofilm reactor (MBBRs, anaerobic-anaerobic-aerobic in series) was investigated to treat textile dyeing wastewater. Each reactor was filled with 20% (v/v) of polyurethane-activated carbon (PU-AC) carrier for biological treatment. To determine the optimum operating conditions of MBBRs, the effect of PUAC carrier, its packing percentage (v/v%) and pH control on COD removal were analyzed by batch experiments. The MBBRs were inoculated with activated sludge obtained from a local dyeing wastewater treatment plant. The MBBR process removed 86% of COD and 50% of color (influent COD=608 mg/L and color=553 PtCo unit) using relatively low MLSS concentration (average 3,000 mg/L in biomass attached to PU-AC carrier) and hydraulic retention time (HRT=44 hr). The MBBR process showed a promising potential for dyeing wastewater treatment.     

制糖废水连续流厌氧发酵制氢系统的运行特性

采用连续流搅拌槽式反应器(CSTR)作为反应装置,探讨了制糖废水厌氧发酵法生物制氢的可行性与运行特征。研究表明,在污泥接种量(以挥发性悬浮固体计)为17.74 g/L,温度为(35±1)℃,水力停留时间(HRT)为6 h,通过调节有机负荷,在12 d左右就可以快速实现生物制氢反应器中微生物的主要代谢类型为乙醇型发酵;而且此时的CSTR产氢发酵系统对负荷冲击表现出了良好的调节能力,在有机负荷(以化学需氧量COD计)从8 kg/(m3.d)提高到24 kg/(m3.d)时,反应系统可在9 d内重新达到稳定运行状态,其COD去除率和产气量由8%和3 L/d提高到20%和12 L/d,发酵气中氢气体积分数为67%。     

Treatment of a combined dairy and domestic wastewater in an up-flow anaerobic sludge blanket (UASB) reactor followed by activated sludge (AS system)

The feasibility of using an up-flow anaerobic sludge blanket (UASB) reactor followed by activated sludge (AS system) for the treatment of wastewater discharged from dairy factory was explored. The UASB reactor was operated at a hydraulic retention time (HRT) of 24 h and organic loading rates (OLRs) ranging from 1.9 to 4.4 kgCOD/m³.d. The average total chemical oxygen demand (COD_total) and total biological oxygen demand (BOD_5total) concentrations of the UASB reactor effluent were 1385 and 576 mg/l, corresponding to percentage removal of 69% and 79%, respectively. Total suspended solids (TSS) and volatile suspended solids (VSS) removal averaged above 72% and 75%, respectively. Residual phosphorous and oil and grease concentrations of the UASB reactor effluent were 8.2 and 44 mg/l, corresponding to percentage removal values of 63% and 83%, respectively. This good performance could be attributed to the relatively long sludge residence time (SRT = 76 d) imposed to the reactor. Total and faecal coliform counts were reduced in the treated effluent by a value of 1.07 and 0.9 log₁₀, respectively. The net sludge yield coefficient was found to be 0.2 g VSS per g COD_total removed per day, corresponding to 20% of the total influent COD imposed to the UASB reactor. The volatile solids / total solids (VS/TS) ratio of 0.66 of excess sludge revealed its good quality. Preliminary batch experiments of the AS system treating UASB reactor effluent indicated first-order removal kinetics between total organic carbon (TOC) and contact time. The TOC removal reached 80%, resulting in only 47 mg/l in the final effluent at a HRT of 2.0 h. Accordingly, the AS system was operated at a HRT of 2.0 h. The system achieved a substantial reduction of COD_total, BOD_{5 total}, TSS and oil and grease resulting effluent quality with residual values of only 35.0, 7.0, 14.0 and 2.8 mg/l, respectively. The geometric mean of total and faecal coliform counts was reduced by a value of 1.28 and 1.64 log₁₀, respectively. Based on these results, it is recommended to use of an integrated system consisting of a UASB reactor followed by the AS system for the treatment of a combined dairy and domestic wastewater to produce a good effluent quality complying with the standards for discharge into agricultural drains.     

不同温度条件下厌氧处理食品废水的试验研究

本试验采用UASB厌氧反应器对某工业园区食品加工废水进行处理。比较了在中温(37±2℃)和模拟原水水温(26～30℃)的条件下,不同负荷对COD去除率的影响。实验结果显示,当水力停留时间为8 h/d时,厌氧反应器容积负荷为6 kgCOD/(m3.d),在模拟原水水温条件下,COD去除率可达到75%左右;在中温条件下,COD去除率可达到80%左右,均有较好的效果;相对于中温而言,原水水温厌氧在工程应用上节省了投资,该实验结果可为该类食品废水厌氧生物处理提供设计运行依据。     

生物膜法厌氧-好氧处理腈纶废水的中试研究

采用生物膜法厌氧-好氧处理腈纶废水,试验研究了不同工况条件下,工艺对腈纶废水的处理效果。试验结果表明,当厌氧水力停留时间(HRT)控制在30 h时,COD与BOD5的去除率分别为23.22%、37.57%,BOD5/COD降低17.96%。当好氧的HRT控制在24 h、气水体积比为40:1时,COD去除率58.92%。当工艺总HRT控制在54 h时,COD去除率达60%以上,BOD5去除率达95%以上,特征污染物二甲基乙酰胺(DMAC)和丙烯腈(AN)的去除率接近100%,系统运行稳定可靠。针对此腈纶废水建议厌氧HRT控制在30 h,好氧HRT控制在24 h,气水体积比控制在40:1。     

两级UASB反应器处理制药废水的试验研究

在中温(37±2℃)条件下,采用有效容积为3 L的UASB厌氧反应器处理含高浓硫酸盐的制药废水,采用两级厌氧处理,一级主要脱除SO42-,二级主要去除COD,经过3个月的驯化,水力停留时间为24 h,一级厌氧在COD/SO42-=2.5～3条件下,COD容积负荷可达到9.5 kgCOD/(m3·d),SO42-容积负荷可达到3.6 kgCOD/(m3·d),COD去除率约20%,SO42-去除去除率能达到65%,出水COD/SO42-比值约为7～8;二级厌氧COD容积负荷可达到7.5 kgCOD/(m3·d),COD去除率能达到75%;系统COD总去除率可达到80%,SO42-总去除率可达到65%以上;本试验研究为利用UASB厌氧反应器处理制药废水提供参考依据。     

A study of A2/O process in El-Berka WWTP by replacing the anaerobic selector with UASB and adopting a hybrid system in the oxic zone

ABSTRACT

A multistage system comprising an upflow anaerobic sludge blanket (UASB) followed by anoxic unit and then oxic activated sludge (AS) with biofilm is studied in El-Berka WWTP, Egypt. Different organic loading wastewaters of chemical oxygen demand (COD) less than 500 mg/L till 3000 mg/L are tested during the study. The hydraulic retention time (HRT) varies for each loading from 7.5 to 10 to 15 h. The UASB reactor accomplishes the removal efficiency of 50%–70% of influent COD. The overall system performs the removal efficiency of 95% of influent COD and NH₄-N. Also, the results are verified by a modified mathematical model.     

木质填料床A/O系统处理低C/N比养猪废水的效能与脱氮机制

针对干清粪式养猪废水 浓度高和低C/N比的特点构建了四格室木质填料床A/O处理系统,通过调控运行探讨其除氮效能和机制。结果表明,在HRT 18.7 h、32℃、硝化液回流比200%、好氧区DO 1.5 mg·L^-1等条件下,即便进水 高达307.7 mg·L^-1,COD/TN平均为0.47,系统对COD、 和TN的去除率仍能维持在66.5%、93.6%和89.0%左右,TN去除负荷达到0.22 kg·m^-3·d^-1以上。系统对COD和TN的去除表现出一定的空间分区特征,其中前三厌氧格室是去除COD主要功能区,末端好氧格室是脱氮功能区。系统的脱氮机制以短程硝化反硝化为主,枯木填料的腐解为反硝化提供了必要的碳源。