Performance evaluation of a modified step-feed anaerobic/anoxic/oxic process for organic and nutrient removal

A pilot scale modified step-feed process was improved to increase nutrient(N and P)and organic removal operations from municipal wastewater.It combined the step-feed process and a method named "University of Cape Town(UCT)".The effect of nutrient ratios and inflow distribution ratios were studied.The highest uptake efficiency of 95% for chemical oxygen demand(COD)has been achieved at the inflow distribution ratio of 40/35/25.However,maximum removal efficiency obtained for total nitrogen(TN)and phosphorus at 93% and 78%,respectively.The average mixed liquor suspended solids(MLSS)was 5500 mg·L~(-1).In addition,convenient values for dissolved oxygen(DO)concentration,and p H were obtained throughout different stages.The proposed system was identified to be an appropriate enhanced biological nutrient removal process for wastewater treatment plants owing to relatively high nutrient removal,sturdy sludge settle ability and COD removal.     

剩余活性污泥碱性发酵液用于厌氧交替好氧-缺氧序批式反应器生物除磷脱氮的碳源的研究(英文)

Activated sludge process has been widely used to remove phosphorus and nitrogen from wastewater. However, the nitrogen and phosphorus removal is sometimes unsatisfactory due to the low influent COD. Another problem with the activated sludge process is that large amount of waste activated sludge is produced, which needs further treatment. In this study, the waste activated sludge alkaline fermentation liquid was used as the main carbon source for phosphorus and nitrogen removal under anaerobic followed by alternating aerobic-anoxic conditions, and the results were compared with those using acetic acid as the carbon source. The use of alkaline fermentation liquid not only affected the transformations of phosphorus, nitrogen, intracellular polyhydroxyalkanoates and glycogen, but also led to higher removal efficiencies for phosphorus and nitrogen compared with acetic acid. It was observed that ammonium was completely removed with either alkaline fermentation liquid or acetic acid as the carbon source. However, the former resulted in higher removal efficiencies for phosphorus (95%) and nitrogen (82%), while the latter showed lower ones (87% and 74%, respectively). The presence of a large amount of propionic acid in the alkaline fermentation liquid was one possible reason for its higher phosphorus removal efficiency. Exogenous instead of endogenous denitrification was the main pathway for nitrogen removal with the alkaline fermentation liquid as the carbon source, which was responsible for its higher nitrogen removal efficiency. It seems that the alkaline fermentation liquid can replace acetic acid as the carbon source for phosphorus and nitrogen removal in anaerobic followed by alternating aerobic-anoxic sequencing batch reactor.     

活性污泥法脱氮除磷工艺的优化设计

利用活性污泥2D模型对城市污水厂脱氮除磷工艺进行优化设计,构建A²/O工艺的仿真模型,通过模型校正对工艺参数进行优化,并将优化设计与传统设计法和试算法进行比较。结果表明,优化模型得出的模拟结果与实验测定值基本相吻合。优化设计法得出的污水厂基建费用和运行成本与其他两种方法相比,都有了很大的降低,虽然出水水质略有下降,但仍满足国家排放一级B标准。活性污泥2D模型可以对污水厂进行优化设计和控制。在满足出水水质前提下,降低污水厂的费用,并对以后的工艺设计提供理论指导。     

针铁矿促进剩余污泥厌氧消化中的脱氮除碳

剩余污泥厌氧消化因其较低的能源转化率使其发展有所受限,且污泥中高浓度有机质也会影响脱氮效果。理论上,在含铁(Ⅲ)（氢）氧化物的厌氧消化系统中,微生物能通过异化铁还原去除有机物和氨氮（Feammox）,但两者同步去除还有待验证。因此本研究通过向污泥厌氧消化系统中添加针铁矿,探究铁(Ⅲ)（氢）氧化物对同步脱氮除碳的影响。结果显示,随着针铁矿添加量的增加,反应器中有机物浓度逐渐减少。当添加50mmol/L针铁矿时,甲烷累积产量达到695.1mL,相较于没有添加针铁矿的厌氧系统提升了30.3%;TS/VS去除率也提升了21.1%/33.8%,说明针铁矿可有效促进污泥减量化。添加针铁矿的反应器中总氮去除率也有一定提升,当针铁矿添加50mmol/L时,去除率达到21.0%。以上结果表明,添加针铁矿可以在污泥厌氧消化中起到同时脱氮除碳的效果。     

污泥回流比对A2/O工艺脱氮除磷效果的影响

污泥回流比作为活性污泥法设计与运行的参数已显示出比其它参数更加重要.试验以实际生活污水、生产废水为对象,考察污泥回流比对系统有机污染物去除效果的影响以及污泥特性的变化.试验结果表明:污泥回流比为80％时系统总体脱氮除磷效果最好,CODCr、NH3-N、TN、TP的去除率分别为92％、98％、81％、94％.在此条件下,...     

Evolution of the activated sludge process: the first 50 years

The paper presents a critical overview of the first 50 years in the evolution of the activated sludge process. Recognition of the role of aeration and microbial activity in the purification of sewage in the early studies established the basis for the accidental discovery of the process, which was immediately adapted into practice. The problems encountered during operation started a period of empirical expansion with many process modifications. As scientific support lagged behind practice, efforts were then directed towards exploring and understanding the fundamentals of the system related to substrate removal mechanisms, microbiology, process kinetics and stoichiometry, nitrogen transformations and, then, translating accumulated information into design. Extensive research generated remarkable findings which should be regarded as major milestones for future progress in many areas such as fractionation of substrate and biomass, particle size distribution, and substrate storage. A rational foundation of the activated sludge process for the removal of organic carbon could then be established based on mass balance. This approach also defined essential parameters that could relate microbial reactions involved with plant design and operation. Scientific ideas and discoveries have also enabled conceptual development of many emerging technologies such as the sequencing batch reactor, enhanced biological phosphorus removal, the oxic‐settling anaerobic process, and the super‐fast membrane bioreactor. © 2014 Society of Chemical Industry     

改良型A~2/O工艺对低碳源城市污水的脱氮除磷效果

以城市污水为原水,考察了一种分点进水的改良型A2/O工艺的脱氮除磷效果。试验结果表明,原水按照6∶4的体积比分别进入厌氧池和缺氧池后,增加了缺氧池的碳源浓度,提高了该系统的脱氮效果。当进水中碳氮质量比平均为6.84、硝化液回流比为200%,CODCr、TN、NH3-N和TP的平均质量浓度分别为237.02、36.39、22.99和4.98mg/L时,出水CODCr、TN、NH3-N和TP的平均质量浓度分别为34.29、10.70、0.18和0.46mg/L,去除率分别为85.53%、70.60%、99.22%和90.76%。