Treatment of palm oil mill effluent by upflow anaerobic filtration

An upflow anaerobic filter (23 dm³ working volume) was used for the treatment of palm oil mill effluent. The filter was continuously operated for 215 days with organic loads ranging from 1·2 to 11·4 kg of chemical oxygen demand per cubic metre per day and hydraulic retention times from 15 to 6 days. The overall substrate removal efficiency was very high, up to 90% and the filter effluent contained almost no suspended solids. For all runs, the operation of the filter exhibited good stability for acidity and alkalinity, indicating that the use of buffer solutions would not be required. The methane concentration in the biogas, whose production varied from 20 to 165 dm³ per day, was about 60%. Daily gas production varied in the range 0·69–0·79 dm³ per gram of chemical oxygen demand removed.     

SIMULATION OF A THREE PHASE REACTOR FOR THE SOLVENT METHANOL PROCESS

Single pass conversions in conventional vapor phase methanol synthesis are low, necessitating recycle of large quantities of unconverted reactants. In the Solvent Methanol Process (SMP), the use of an inert and highly selective solvent in the synthesis loop enables the removal of methanol as soon as it is formed and helps overcome equilibrium limitations that exist in the vapor phase process. An industrial scale, packed bed, adiabatic reactor with cocurrent upflow of synthesis gas and solvent has been simulated for the SMP. The simulation shows that very high single pass conversions of CO and H₂ are attainable such that recycle can be eliminated. Reaction rates are however lower than vapor phase rates due to pore diffusion limitations.     

Mixing characteristics and performance of the anaerobic upflow blanket filter (UBF) reactor

Mixing characteristics (using a radioactive tracer) and reactor performance of the upflow blanket filter (UBF) reactor operated at different loading rates (up to 32 kg chemical oxygen demand (COD) m^?3 day^?1) were compared. The results indicated that mixing profiles of the reactor operated with effluent recirculation and without biomass were of the perfectly mixed type. Operation without recirculation resulted in about 18% dead space. The filter made of plastic rings and located in the top third of the reactor had no negative effect on reactor mixing. Operation at loading rates of up to 25 kg COD m^?3 day^?1 permitted a soluble COD removal rate of 95% with a methane production rate of 5.9 m³ m^?3 day^?1. At higher loading rates, the efficiency of COD reduction decreased with a decrease of the specific acetoclastic activity to 0.5 kg acetate removed per kg volatile suspended solids (VSS) day^?1. At all loading rates studied it was observed that the performance was not related to the mixing characteristics, which had remained of the perfectly mixed type with an occasional small dead space (below 10%). The good mixing characteristics of the UBF reactor coupled with the high biomass content and the effective action of the filter make this reactor one of the most promising designs for the treatment of soluble wastes.     

Effect of inlet mass loading,water and total bacteria count on methanol elimination using upward flow and downward flow biofilters

An upward flow biofilter and a downward flow biofilter using compost for removing methanol from air were investigated to compare the biofilter performance and to realize the advantages of using downward flow biofilters for accessibility to water make‐up. Both the upward flow and downward flow columns showed similar performance in terms of elimination capacity (EC) versus inlet mass loading (IC). The maximum elimination capacity (EC) from these two biofilters was approximately 101 g m⁻³ h⁻¹ with an optimum methanol loading rate at inlet (IC) of 169 g m⁻³ h⁻¹ (7.5 g m⁻³ of methanol with superficial velocity of 7.6 m h⁻¹). The effect of water movement within the bed on elimination capacity was monitored. In addition, it was found that when the water content in the compost was below 35% by weight, microbial activity was impaired. Once the compost media had dried, it became hydrophobic and could be rewetted only with great difficulty. Total bacteria count was performed on compost samples during the entire operation. The relationship between elimination capacity and total bacteria count was reported. Similar trends were shown by the variations of elimination capacity and total bacteria count with methanol loading: both initially increase, go through a plateau, then decrease with loading. © 2000 Society of Chemical Industry     

UASB+AF-接触氧化联合工艺处理餐饮废水的试验

本研究针对我国餐饮废水污染源分散、污染严重、处理效果差，采用UASB AF-接触氧化联合工艺对餐饮废水进行处理，当联合工艺的总水力停留时间为8h，工艺对餐饮废水处理效果良好，CODCr、NH3-N、TP、SS的去除率分别为91．77％-98．20％、88．02％～96．00％、56．32％-92．14％、85．00％-90．91％，出水中CODCr、NH3-N、SS达到文献[1]中的一级标准．     

UASB反应器的启动及黑索今废水处理研究

文章研究了牛粪为接种物的UASB反应器的启动及这一阶段黑索今废水处理效果，研究结果表明：①牛粪可用作UASB反应器的接种物②采用UASB为主要工艺流程的处理系统处理黑索今废水，经处理后的出水符合污水综合排放标准；在厌氧阶段，黑索今的平均去除率可达88％。     

HRT对丙酸去除效能的影响及丙酸氧化菌群的响应

为探究水力停留时间(HRT)对丙酸去除效能的影响及丙酸氧化菌群的响应,以丙酸为底物,升流式厌氧污泥床(UASB)的运行为基础,研究HRT缩短对UASB系统丙酸去除的影响,并通过聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)指纹分析技术,分析丙酸氧化菌群随HRT缩短的演替规律.结果表明,在保持进水COD 2 000 mg·L-1不变,HRT由10 h经由8、6h缩短至4h的过程中,每次HRT的缩短都会造成UASB系统中丙酸的短期积累.但经过一段时间的连续运行之后,UASB均能重新达到稳定运行状态,并保持较高的丙酸去除率.在此过程中,UASB中厌氧活性污泥的比CODpro去除率由HRT 10 h时的1.2 kg/(kg·d)逐渐提高到4h时的1.7 kg/(kg· d).HRT的缩短使UASB系统中丙酸氧化菌群发生了明显的演替,以条带2～4为代表的丙酸氧化菌(Syntrophobacter fumaroxidans)随着HRT的缩短逐渐被强化,而条带5(S.sulfatireducens)逐渐减弱.丙酸氧化菌Pelotomaculum propionicicum(条带1和6)在整个运行过程中优势度保持相对稳定.HRT的缩短刺激了具有较高动力学特性的条带2～4(S.furnaroxidans)快速增殖,使其在活性污泥中的优势度不断提高,而该菌的强化使得UASB系统能够在有机负荷高达18 kg/(m3·d)条件下仍保持了94.1％的丙酸去除率.     

内循环UASB-好氧接触氧化法处理高浓度丙烯酸及酯废水

高浓度丙烯酸及酯废水成分复杂,毒性高,处理难度较大.利用内循环UASB-好氧接触氧化工艺对高浓度丙烯酸及酯废水进行处理.在进水COD约为10 000 mg/L的条件下,UASB反应器出水挥发性脂肪酸质量浓度均处于200 mg/L以下,pH维持在7.0左右,COD去除率为70％～80％,说明UASB反应器运行良好;好氧接触氧化出水COD达到500 mg/L以下,COD去除率达到92％～96％,且运行稳定.     

纤维素乙醇废水处理研究与工程应用

采用铁炭微电解-Fenton+UASB+MBR组合工艺处理纤维素乙醇废水,并对工程设计运行参数和污染物去除机理进行了探索。结果表明:在微电解反应5 h,UASB停留时间36 h,MBR停留时间25 h条件下处理纤维素乙醇废水,经絮凝脱色后出水COD、氨氮等指标均达到《发酵酒精和白酒工业水污染物排放标准》(GB 27631—2011)中的规定,且运行效果稳定,费用较低。     

UBF-SBR工艺处理啤酒废水的工程应用

UBF－SBR工艺处理啤酒工业废水工程应用表明，当UBF的水力停留时间为10h时，UBF的进水和出水CODCr,BOD5,SS分别为1022mg/L,543mg/L,383mg/L和290mg/L,128mg/L,273mg/L；UBF出水采用SBR进行处理，当SBR的运行周期为12h时，SBR出水的CODCr，BOD5，SS分别为67mg/L,12mg/L,96mg/L，出水水质稳定达到国家啤酒工业废水排放标准。本工艺技术具有投资省，电耗和运行费用低，启动速度快，运行稳定可靠，占地面积小，污泥排放量少，管理方便等明显特点。