两种新型好氧滤池的试验研究

本文介绍了两种广泛用于化学工业污水及其它有机污水处理的新型好氧滤池,一种是采用水射器充氧的生物滤池,另一种是采用溶气泵充氧的生物滤池.通过试验研究得出结论,两种新型好氧滤池的效率均高于采用单孔膜曝气的传统好氧滤池.     

三种白酒废水好氧处理工艺的对比

比较了生物接触氧化法、SBR(或CASS)和曝气生物滤池(BIOFOR)这三种白酒废水好氧处理工艺的优缺点.相比而言,曝气生物滤池(BIOFOR)工艺是白酒废水处理的优选工艺,其具有一次性投资少,运行费用低,处理效果好,运行稳定、维护方便等优点,但BIOFOR工艺要求进水水质在700mg/L以下,因此,应与生物接触氧化法结合使用,采用生物接触氧化法+BIOFOR滤池工艺作为白酒废水的好氧处理工艺.     

啤酒工业废水处理中的泡沫问题

啤酒工业废水的特点是含有高浓度的有机物和一定浓度的悬浮固体。其 BOD_5/COD 值在0.67-0.8左右,可生化性很强(一般认为该值大于0.3即为可生化的)。因此,啤酒厂常用生物处理法来降低其中的有机物含量。活性污泥法和生物膜法是利用好氧微生物处理污水的生物处理方法。活性污泥法的 A-O 系统(缺氧—好氧法)和生物膜法的淹没式生物滤池(生物接触氧化法)是目前啤酒厂常采用的两种具有代     

悬浮生物滤池A/O工艺处理印染废水

通过采用悬浮生物滤池A/O(厌氧/好氧,Anoxic/Oxic)工艺处理模拟和实际印染废水,研究了在不同染料种类及浓度条件下,该工艺对两种废水的处理效果.研究结果表明,该工艺对实际废水的脱色率在80%以0上,COD去除率在85%以上,是处理印染废水的有效方法之一.     

厌氧技术处理肉类加工企业废水效果好

随着经济体制改革的深入,农村商品生产蓬勃发展。要求食品工业充分利用农产品资源,满足城乡人民生活水平日益提高的需要,扩大出口,增加外汇。现食品加工行业纷纷进行规模不一的技术改造。尤其是环境保护方面已提到相当重要地位,此技术改造中牵涉到必须进行的污水治理工程。在此推荐一种近来已发展为较为成熟,既有社会效益,又有经济效益的工艺方式。下面概略介绍一下处理技术。一、两种工艺的技术经济比较提起污水处理工程,人们容易联想起体积庞大的曝气池、生物滤池。这些方法属好氧生物处理的范围,即在污水处理中要为微生物的生长提供氧气。这些好氧处理法由于     

预充氧时Lager和Ale酵母的氧需求

适量的氧供给对酵母增殖及其发酵性能是很重要的，因为氧是合成甾醇和不饱和脂肪酸的关键。替代麦汁充氧的是预充氧技术，也就是在发酵前将酵母细胞直接处于氧环境的处理方法。本文介绍的是两种lager和六株ale酵母菌株预充氧反应的研究结果，酵母细胞的预充氧在一个膜环路反应器中进行。尽管每株菌株的反应不同，但获得的数据是成功的，不同菌株的甾醇和不饱和脂肪酸的累积变化显著。预充氧期间，检测的甾醇浓度可增加1．5～4倍，不饱和脂肪酸的浓度可增加1．5～6倍。其中七株预充氧的酵母发酵性能良好，一株ale酵母的预充氧未能使其发酵条件最优化。同未经充氧处理的酵母细胞相比，预充氧酵母发酵的酯类和高级醇明显较高。该实验结果表明，预充氧技术替代麦汁充氧是相当有希望和值得进一步实验的。     

曝气生物滤池(BAF)研究进展

曝气生物滤池(Biological Aerated Filter,简称BAF)由于处理能力强、抗冲击负荷和生物降解过程独特而受到青睐。介绍了曝气生物滤池的特点、结构形式和应用情况,综述了曝气生物滤池研究在有机物和SS去除、硝化反硝化、除磷、生物膜处理机理以及反应动力学等方面的最新进展,指出曝气生物滤池是符合我国国情的新型固定模生物处理技术,应加大研究力度,迅速使之国产化并投入使用。     

食品工厂污水处理新方法

食品工厂尤其是罐头食品厂在生产过程中会产生大量含有机污染物的废水。过去一般均采用活性污泥法处理，曝气池占地面积大，污水处理效率低。本文介绍一种生物过滤法，采用人工合成的轻质滤料，利用空气震荡方式设计一种高负荷生物滤池即biosmedi滤池，在上海梅林三得利等食品工厂污水处理中试验运行了一年多时间，取得了较好的效果。     

啤酒生产废水处理工艺的对比分析

详细分析了啤酒生产废水的来源、特点,对啤酒生产废水处理中相对成熟的几种厌氧+好氧处理工艺进行了阐述,包括UASB+生物接触氧化,EGSB+生物接触氧化,厌氧水解酸化+三相好氧生物流化床三种工艺.用实例对三种厌氧+好氧工艺的处理效果加以分析,推荐了两种技术成熟,处理效果稳定的啤酒生产废水处理工艺.     

啤酒废水溶解氧测定之滴定法

啤酒废水属于高浓度有机废水,国内现阶段一般都采用厌氧与好氧相结合的处理方法处理。在好氧处理阶段,充氧量是否充足或过量,决定着好氧微生物的生存环境,直接影响污染物的去除率,因此保证足够的氧气量非常必要。现在一些企业都使用快速溶氧检测仪来测定溶氧,此方法时间久了测定结果不是很稳定,现将传统的滴定方法推荐给大家,建议对比一下,可以作以参考。     

熔喷非织造布高精度过滤膜的开发

按高精度过滤膜的品质要求,选择丙纶为原料,经熔喷法及热轧加工开发成寿命长、通量高、成本低的过滤材料。简介熔喷非织造布过滤膜基布的生产和热轧加工的工艺参数的确定,并分析了各参数对滤料质量的影响。     

熔喷非织造布过滤性能的研究

分析了影响熔喷非织造布过滤性能的主要工艺参数。神经网络方法可以用于预测非织造布生产工艺和过滤性能的关系。     

抗菌空气过滤材料的制备及其性能研究

利用nano-Ag/nano-TiO2对丙纶熔喷非织造材料进行抗菌功能改性,通过改变等离子体处理时间、nano-Ag/nano-TiO2配比、改性处理时间、改性温度等工艺参数,成功制备出具有抗菌功能的熔喷非织造空气过滤材料,并进行了相关性能测试。结果表明:nano-Ag/nano-TiO2改性的最佳工艺为nano-Ag/nano-TiO2配比36:1,反应温度30℃,改性时间10 min。Nano-Ag/nano-TiO2成功附着在材料表面,且未破坏材料原有纤维结构,过滤性能没有发生大的变化,与未改性的材料一样具有较好的过滤性能。PP熔喷非织造材料经nano-Ag/nano-TiO2改性后,具有明显的抗菌杀菌功能,且有较好的抗菌持久性。     

长效液体乳聚乙烯吹塑薄膜阻隔性能研究

通过对包装用聚乙烯吹塑薄膜的水蒸气透过量、氧气透过量进行研究,在满足液体牛奶保鲜期要求前提下,能够最大限度地降低对聚乙烯吹塑薄膜的阻透性要求,从而降低液体牛奶产品的包装成本。     

Regulation of alcoholic fermentation in batch and chemostat cultures of Kluyveromyces lactis CBS 2359

Kluyveromyces lactis is an important industrial yeast, as well as a popular laboratory model. There is currently no consensus in the literature on the physiology of this yeast, in particular with respect to aerobic alcoholic fermentation (‘Crabtree effect’). This study deals with regulation of alcoholic fermentation in K. lactis CBS 2359, a proposed reference strain for molecular studies. In aerobic, glucose-limited chemostat cultures (D=0·05–0·40 h⁻¹) growth was entirely respiratory, without significant accumulation of ethanol or other metabolites. Alcoholic fermentation occurred in glucose-grown shake-flask cultures, but was absent during batch cultivation on glucose in fermenters under strictly aerobic conditions. This indicated that ethanol formation in the shake-flask cultures resulted from oxygen limitation. Indeed, when the oxygen feed to steady-state chemostat cultures (D=0·10 h⁻¹) was lowered, a mixed respirofermentative metabolism only occurred at very low dissolved oxygen concentrations (less than 1% of air saturation). The onset of respirofermentative metabolism as a result of oxygen limitation was accompanied by an increase of the levels of pyruvate decarboxylase and alcohol dehydrogenase. When aerobic, glucose-limited chemostat cultures (D=0·10 h⁻¹) were pulsed with excess glucose, ethanol production did not occur during the first 40 min after the pulse. However, a slow aerobic ethanol formation was invariably observed after this period. Since alcoholic fermentation did not occur in aerobic batch cultures this is probably a transient response, caused by an imbalanced adjustment of enzyme levels during the transition from steady-state growth at μ=0·10 h⁻¹ to growth at μ_max. It is concluded that in K. lactis, as in other Crabtree-negative yeasts, the primary environmental trigger for occurrence of alcoholic fermentation is oxygen limitation. © 1998 John Wiley & Sons, Ltd.     

浅谈丙纶熔喷非织造布在过滤领域的应用

由于独特的生产工艺赋予丙纶熔喷非织造布的基本属性 ,使其成为空气过滤和液体过滤中性能较好的超细过滤材料 ,用于烛形滤器和滤袋达到微滤效率 ,可过滤掉 0 .2 μm～ 10 μm以上的微粒。     

神经网络用于熔喷非织造布过滤性能的研究

建立神经网络 ,用熔喷非织造布生产工艺参数和过滤性能指标对其进行训练 ,得到反映熔喷非织造布生产工艺参数与过滤性能因果关系的神经网络模型 ,进而实现由已知工艺参数来预测熔喷非织造布的过滤性能。针对BP算法的收敛速度慢和局部极值的缺点 ,提出了两种改进方法。     

溶液喷射纺纳米纤维制备技术及其应用进展

为进一步推广溶液喷射纺丝技术,并为该技术的研究提供理论与实践参考,综述了国内外溶液喷射纺丝技术的制备机制、基础研究及其纳米纤维应用等方面的研究进展。主要从机制、工艺研究等角度将溶液喷射纺丝技术与熔喷、静电纺丝技术进行对比,溶液纺丝技术具有原料适用性广、生产效率高等特点;从纤维形貌、结构控制等方面,阐述了通过溶液喷射纺丝新工艺开发加工制备具有特殊形态结构的纳米纤维。介绍了溶液喷射纺纳米纤维在医用、过滤、电极、隔膜等材料领域的应用,并对溶液喷射纺丝技术当前发展的不足及未来发展前景进行了总结与展望。     

The impact of oxygen availability on stress survival and radical formation of Bacillus cereus

Both the growth and stress survival of two model Bacillus cereus strains, ATCC 14579 and ATCC 10987, were tested in three different conditions varying in oxygen availability, i.e., aerobic, microaerobic and anaerobic conditions. Both B. cereus strains displayed highest growth rates and yields under aerobic conditions, whereas the microaerobic and anaerobic cultures showed similar reduced growth performances. The cells grown and exposed microaerobically and anaerobically were more resistant to heat and acid than cells that were cultured and exposed aerobically. On the other hand, the anaerobically grown cells were more sensitive to hydrogen peroxide compared to the (micro)aerobically grown cells. The increased heat- and acid-induced inactivation in aerobic conditions appeared to be associated with intracellular accumulation of excess hydroxyl and/or peroxynitrite radicals, as determined by flow cytometry in combination with the fluorescent reporter dye 3′-(p-hydroxyphenyl) fluorescein. This suggests that radical formation may contribute to inactivation of bacteria in the presence of oxygen, such as in aerobic and microaerobic conditions. No evidence was found for radical formation upon exposure to salt and hydrogen peroxide. The increased resistance to heat and acid in microaerobic and anaerobic conditions shows that oxygen availability should be taken into account when behavior of bacteria, such as B. cereus, in food industry related conditions is investigated, because oxygen availability may affect the efficiency of food preservation conditions.     

Characterization of a marine origin aerobic nitrifying-denitrifying bacterium

The bacterial strain F6 was isolated from a biological aerated filter that is used for purifying recirculating water in a marine aquaculture system and was identified as Marinobacter sp. based on the analysis of its 16S rRNA gene sequence. Strain F6 showed efficient aerobic denitrifying ability. One hundred percent of nitrates and 73.10% of nitrites were removed, and the total nitrogen (TN) removal rates reached 50.08% and 33.03% under a high nitrate and nitrite concentration in the medium, respectively. N(2)O and (15)N(2), as revealed by GC-MS and GC-IRMS, were the products of aerobic denitrification. Factors affecting the growth and aerobic denitrifying performance of strain F6 were investigated. The results showed that the optimum aerobic denitrification conditions for strain F6 were the presence of sodium succinate as a carbon source, a C/N ratio of 15, salinity ranging from 32-35?g/L of NaCl, incubation temperature of 30°C, an initial pH of 7.5, and rotation speed of 150?rpm [dissolved oxygen (DO) 6.75?mg/L]. In addition, strain F6 was confirmed to be a heterotrophic nitrifier through its NO(2)(-) generation and 25.96% TN removal when NH(4)(+) was used as the sole N source. Therefore, strain F6, the first reported member of genus Marinobacter with aerobic heterotrophic nitrifying-denitrifying ability, is an excellent candidate for facilitating simultaneous nitrification and denitrification (SND) in industry and aquaculture wastewater.