废水生物处理技术发展浅谈

废水处理的方法主要有物理法、化学法和生物法。本文综述了近两年来废水的生物处理法的发展,对生物处理法进行叙述和比较,并对今后废水的生物处理发展方向进行分析。     

生物膜同步硝化反硝化脱氮过程中N2O的产生量及机理分析

为了考察生物膜同步硝化反硝化脱氮过程中氧化亚氮(N2O)的释放量,以碳纤维为填料,采用SBR反应器研究了实际生活污水生物膜同步硝化反硝化过程中N2O释放量并对其产生机理进行了分析.在低溶解氧水平(0.2～1.5 mg/L)下系统同步硝化反硝化率维持在79%以上.在4个溶解氧水平0.2、0.4、1.0、1.5 mg/L下,每去除1 g氨氮N2O释放量分别为0.005、0.025、0.021、0.025 g,远低于短程硝化反硝化系统N2O释放量.1个反应周期内,N2O释放量随NH4+-N氧化而增加,NH4+-N氧化结束后,N2O释放量急剧减少.在曝气状态下,N2O释放速率与ρ(COD)呈现了较好的相关性.分析发现,生物膜同步硝化反硝化系统中N2O主要是由异养硝化和好氧反硝化产生.     

Inhibitory Activity of Paenibacillus polymyxa on the Biofilm Formation of Cronobacter spp. on Stainless Steel Surfaces

The objective of this study was to control the survival or biofilm formation of Cronobacter spp. on stainless steel surfaces using Paenibacillus polymyxa. The antibacterial activity of a cell‐free culture supernatant (CFCS) of P. polymyxa against Cronobacter spp. was found to vary with P. polymyxa incubation time. Maximum activity occurred when P. polymyxa was incubated at 25 or 30 °C for 96 h. When the CFCS was introduced to Cronobacter spp. adhered to stainless steel strips at 25 °C for up to 72 h, the CFCS successfully inhibited Cronobacter biofilm formation. Additionally, stainless steel surfaces with a preformed P. polymyxa biofilm were exposed to Cronobacter spp. suspensions in PBS or 0.1% peptone water at 3, 5, or 7 log CFU/mL to facilitate its attachment. The Cronobacter population significantly decreased on this surface, regardless of inoculum level or carrier, when the P. polymyxa biofilm was present. However, the microbial population decreased within 6 h and remained unchanged thereafter when the surface was immersed in an inoculum suspended in 0.1% peptone water at 5 or 7 log CFU/mL. These results indicate that P. polymyxa is able to use a promising candidate competitive‐exclusion microorganism to control Cronobacter spp.     

Electrochemical sensors for biofilm and biocorrosion

The presence of biofilm modifies the electrochemical properties of the interface and the mass transport near the interface. Two biofilm effects are damageable: the reduction of heat and/or mass transfer and the biocorrosion or microbiologically influenced corrosion (MIC). Two kinds of electrochemical sensors were developed: the first kind for the biofilm detection and the second one to evaluate the MIC risk. The biofilm detection is obtained by considering either the potential modification of the interface or the mass transport modification. The mass transport modification is analysed by considering the limiting diffusion current measured on a gold electrode where the biofilm development occurs. The MIC risk is evaluated with a sensor composed of two concentric electrodes in the material under investigation (e.g. carbon steel): a small disk electrode in the centre and a large ring. In a first step, a pit is artificially initiated by applying a current through these electrodes. In a second step, the risk factors of MIC are investigated by analysing the free coupling current circulating between these two short‐circuited electrodes.     

表面处理对炭纤维挂膜性能的影响研究

以SEM,XPS等为手段研究了炭纤维经不同表面处理后表面形貌、表面官能团及其亲水性的变化情况,对比分析了经不同表面处理的炭纤维对固着在污水中的微生物膜的影响.得出以下结论:①在污水生物膜处理工艺中以高强型炭纤维作为载体是可行的;②提高炭纤维的表面亲水性有利于增加微生物的挂膜量;③对炭纤维表面结构影响小的处理方法不会破坏炭纤维的生物相容性,因此挂膜效果相对较好.     

食源性混合菌生物被膜的形成和相互作用机制

在食品加工中,食源性病原菌生物被膜的存在会引发大量食品污染等安全问题。目前,国内外学者深入研究了单一菌生物被膜,然而对混合菌生物被膜的研究较少。本文在现有的研究基础上,归纳总结了食源性混合菌生物被膜的形成规律及混合菌生物膜中菌种间的相互作用,初步探讨了群体感应在混合菌生物膜中的作用,以期为食品领域应对和破解食源性混合菌生物被膜污染问题提供思路。     

适合中小城镇生活污水脱氮除磷工艺的研究

水体富营养化现象已成为人类面临严重的水环境问题之一 ,降低废水中氮和磷含量是防止水体富营养化的主要任务。软性填料淹没式生物膜序批式 (SBR)处理工艺 ,可使COD去除率达90 %以上 ,BOD去除率可达98 %以上 ,氮去除率75 %以上 ,磷的去除率可达90 %左右。是适合中小规模城镇生活污水脱氮除磷行之有效的技术之一。     

序批式生物膜法的脱氮特性研究

对序批式生物膜工艺的脱氮特性进行了探讨，并提出了过量储存-SND脱氮作用机理，即厌氧段脱氮主要靠生物膜对含碳、氮有机物的过量储存作用，而好氧段脱氮则靠生物膜的同步硝化反硝化(SND)作用，反硝化的有机碳源主要为生物膜在厌氧段过量储存的有机物。镜检发现反应器中的优势菌属为假单胞菌属，其次为气单胞菌属、芽孢杆菌属、微球菌属、硝化杆菌属。     

两级生物膜处理合成洗涤剂废水

采用厌氧生物滤池(AF)—好氧生物接触氧化(BCO)联合工艺对合成洗涤剂(LAS)废水进行处理试验。结果表明,AF反应器在HRT=24h、温度(32±2)℃、pH为7～8、营养母液质量浓度5mg/L条件下,BCO反应器在HRT=12h、常温、DO为4～5mg/L条件下,对LAS和COD的去除率分别可达到85%和95%,出水达到国家《污水综合排放标准》(GB8978—1996)规定的一级排放标准。