Enhancing completely autotrophic nitrogen removal over nitrite by trace NO2 addition to an AUSB reactor

BACKGROUND: Completely autotrophic nitrogen removal over nitrite (CANON) could decrease energy consumption and CO₂ release compared with conventional nitration–denitrification. Trace NO₂ addition could enhance the activities of aerobic and anaerobic ammonium oxidation. RESULTS: An aerated upflow sludge bed (AUSB) reactor inoculated simultaneously with aerobic and anaerobic ammonium oxidizing sludge was operated to cultivate granular sludge capable of carrying out CANON. The results showed that the efficiency and rate of total nitrogen (TN) removal reached 61% and 0.114 kgN, respectively (m^?3 day^?1) for DO = 0.5–0.6 mg L^?1. Batch tests indicated that trace NO₂ addition could increase the CANON activity of sludge. The TN removal rate and efficiency of the reactor was increased to 0.234 kgN m^?3 day^?1 and 63%, respectively, when the reactor was aerated with air containing 2.7–3.3 mmol m^?3 NO₂ and DO was at 0.5–0.8 mg L^?1. CONCLUSIONS: Trace NO₂ addition provides an alternative to increase the capacity of a CANON system at low DO concentration. Copyright © 2009 Society of Chemical Industry     

后置石英砂滤池强化UBAF生物过滤效果的试验研究

因气水同向流,在升流式曝气生物滤池(UBAF)运行中,滤料表面脱落的生物膜易随出水流出,影响出水水质。利用后置石英砂滤池的截滤能力,可有效截留UBAF出水中夹带的细小悬浮物和微型生物,提升出水水质。试验表明,后置石英砂滤池可使UBAF工艺对污水中COD、NH3-N、SS、色度等污染指标的去除率均有提高。     

某高浓度生物食品添加剂废水处理工艺设计与运行

根据某生物技术公司生产废水有机物浓度高的实际特点,设计采用分质预处理后再综合处理工艺。进水水量500 m3/d,废水主要为生产食品添加剂产生的有机废水,其中部分废水含有较高CODCr。经过多年实际运行检验,该处理工艺对食品添加剂废水处理具有处理效果良好,运行稳定,管理简便等优点。     

Start-up of an UASB reactor treating potato-starch wastewater using an alkalimetric follow-up procedure

Monitoring of volatile fatty acids (VFA) by gas chromatography or hydrogen with specific electrodes is used for the determination of instability in anaerobic reactors. However, such methods are not normally applied in full-scale reactors due to the need for expensive equipment. A two end-point alkalimetric method has been proposed in the literature for the follow-up and control of anaerobic digesters. This paper deals with results of the start-up and operation of a laboratory UASB (Upflow Anaerobic Sludge Blanket) reactor (5.61) treating potato-starch wastewater, where such an alkalimetric method was simultaneously used and compared with gas-chromatography VFA monitoring.     

Producing hydrogen from the fermentation of cheese whey and glycerol as cosubstrates in an anaerobic fluidized bed reactor

This study aimed to evaluate the effect of the organic loading rate (OLR) (60, 90, and 120 g Chemical Oxygen Demand (COD). L^?1. d^?1) on hydrogen production from cheese whey and glycerol fermentation as cosubstrates (50% cheese whey and 50% glycerol on a COD basis) in a thermophilic fluidized bed reactor (55 °C). The increase in the OLR to 90 gCOD.L^?1. d^?1 favored the hydrogen production rate (HPR) (3.9 L H₂. L^?1. d^?1) and hydrogen yield (HY) (1.7 mmol H₂. gCOD^?1_app) concomitant with the production of butyric and acetic acids. Employing 16S rRNA gene sequencing, the highest hydrogen production was related to the detection of Thermoanaerobacterium (34.9%), Pseudomonas (14.5%), and Clostridium (4.7%). Conversely, at 120 gCOD.L^?1. d^?1, HPR and HY decreased to 2.5 L H₂. L^?1. d^?1 and 0.8 mmol H₂. gCOD^?1_app, respectively, due to lactic acid production that was related to the genera Thermoanaerobacterium (50.91%) and Tumebacillus (23.56%). Cofermentation favored hydrogen production at higher OLRs than cheese whey single fermentation.     

斜窄流分级技术在磷矿磨矿回路中的应用研究

在采用斜窄流分级技术进行磷矿开路磨矿产品料浆分级中试,且取得良好技术指标的基础上,在新建磷矿闭路磨矿分级回路作业中首次设计采用了100 m2斜窄流分级箱.生产考查结果表明,分级设备运行稳定,分级效率高达61.79％.设备优良的分级性能,提高了磨矿系统处理能力,改善了磨矿产品粒度特性,产品粒度较好地满足了后续工序技术要求,系统取得了满意的技术经济指标.     

Hydrodynamics of upflow anaerobic sludge blanket reactors

The hydrodynamic characteristics of upflow anaerobic sludge blanket (UASB) reactors were investigated in this study. A UASB reactor was visualized as being set‐up of a number of continuously stirred tank reactors (CSTRs) in series. An increasing‐sized CSTRs (ISC) model was developed to describe the hydrodynamics of such a bioreactor. The gradually increasing tank size in the ISC model implies that the dispersion coefficient decreased along the axial of the UASB reactor and that its hydrodynamic behavior was basically dispersion‐controlled. Experimental results from both laboratory‐scale H₂‐producing and full‐scale CH₄‐producing UASB reactors were used to validate this model. Simulation results demonstrate that the ISC model was better than the other models in describing the hydrodynamics of the UASB reactors. Moreover, a three‐dimensional computational fluid dynamics (CFD) simulation was performed with an Eulerian‐Eulerian three‐phase‐fluid approach to visualize the phase holdup and to explore the flow patterns in UASB reactors. The results from the CFD simulation were comparable with those of the ISC model predictions in terms of the flow patterns and dead zone fractions. The simulation results about the flow field further confirm the discontinuity in the mixing behaviors throughout a UASB reactor. © 2008 American Institute of Chemical Engineers AIChE J, 2009     

Influence of Reactor Configuration on the Selective Oxidation of Glycerol over Au/TiO2

The oxidation of glycerol by molecular oxygen in the aqueous phase over Au/TiO₂ was investigated in both a batch reactor and a continuous upflow fixed bed reactor. The effects of catalyst particle size, gas flow rate, liquid flow rate, reaction temperature, dioxygen pressure, and solution pH were examined in the fixed bed system. The unique hydrodynamics of the fixed bed system allowed for secondary oxidation products such as tartronic acid and oxalic acid to form in substantial amounts, which contrasts the product distribution observed in a batch system. These results suggest that reactor configuration can play an important role in the observed product selectivity from oxidation reactions over highly active gold catalysts.     

利用UASB反应器处理人工废水的动力学研究

利用自制上流式厌氧污泥床反应器研究了以石英砂为惰性粒子的颗粒污泥降解人工合成废水产生甲烷气体的产气动力学，得出可与实际试验数值较好吻合的动力学方程。     

抗生素废水生物处理的试验研究

为找出抗生素废水适合的生物处理方法,研究了水解酸化-厌氧-好氧组合工艺处理高浓度抗生素废水的试验.结果表明:采用相同体积(62 L)的升流厌氧污泥床和厌氧复合床(UBF)处理水解酸化后的抗生素废水,当COD容积负荷为6.0 kg/(m3.d)时,厌氧复合床对SS、COD、BOD5的去除率分别为75.6%、91.7%、96.1%;出水采用相同体积(64 L)的生物接触氧化反应器和周期循环活性污泥系统(CASS)进行处理,当COD容积负荷为1.6 kg/(m3.d)时,周期循环活性污泥系统对SS、COD、BOD5的去除率分别为91.6%、88.7%9、5.4%.结果表明UBF和CASS系统是抗生素废水处理中先进高效的生物反应器.