聚丙烯二氧化钛负载膜固定化活性污泥对污水处理的研究

利用聚丙烯二氧化钛负载膜为载体,吸附固定活性污泥微生物,处理有机废水,考察了聚丙烯膜的组成、吸咐固定时间以及聚丙烯二氧化钛活性污泥负载膜对污水有机物的降解。由全有机碳分析仪对降解过程的有机物进行检测;结果表明;活性污泥负载膜处理废水8小时后,废水中的有机物含量下降达50％-60％,对所处理的废水的降解效果明显。     

有机废水生物处理工程进展

含生物可降解有机物废水(以下简称废水)的好氧和厌氧活性污泥处理法已有长久的历史。然而这类大型装置的设计和操作控制过去多凭经验,因而只不过是复制和抄袭,效率不佳, 60年代前后,化学工程学及生化工程学的发展为废水生物处理工程学奠立了基础、从那以来,废水处理的实验研究逐步建立在工程学的基础上,取得了很快的进展。     

活性污泥中好气性异养细菌的初步研究

用活性污泥处理工业废水和生活污水是目前应用很广泛的一种生物处理法。此法近年来在我国已逐渐推广应用和发展,但对在处理过程中起主导作用的细菌却缺乏系统的研究。我们于1972年5月到12月对武汉印染厂废水处理场活性污泥中的微生物进行了一些观察,初步研究了好气性异养细菌的优势种类和数量,进行了一些菌株去除有机物能力的试验,希望通过这项工作取得生物处理中细菌学的资料,为进一步研究生物处理的原理和解决生产实践问题提供理论基础。       

谈废水的生物处理

废水是环境污染“三废”之一 ,利用微生物的代谢作用可除去废水中的有机污染物 ,其方法简单、科学 ,常分为需氧生物处理法和厌氧生物处理法两种 ,现对其机制简述如下 :1　需氧生物处理废水生活污水中的典型有机物是碳水化合物、合成洗涤剂、脂肪、蛋白质及其分解产物如尿素、甘氨酸、脂肪酸等。这些有机物可按生物体系中所含元素量的多寡顺序表示为 C H O N S。在废水需氧生物处理中全部反应可用以下两式表示 :微生物细胞 + COHNS+ O2 →较多的细胞 + CO2 + H2 O+ NH3硝化细菌 + NH3 + O2经过 NO2NO-3 + H2 O+较多的硝化细菌生物…     

环保帮手凤眼莲

凤眼莲的生物量大,其发达的根系悬浮于上层水中,与废水接触面积较大,能大量吸附水体中悬浮固体和各种有机物。从而招至大量的以这些有机物为食的微型动物和微生物。据观测发现,在缫丝废水中凤眼莲根系上有微型动物26种。比无凤眼莲的同样污水中多15种,其中优势种类如波豆虫等,是一般活性污泥中的常见种类。     

微生物技术在医疗废水处理中的应用

医院污水含有多种病菌、病毒及寄生虫,其直接危害和潜在危害都是显而易见的,因此,进行医疗废水治理,已成为当务之急。微生物处理主要是通过采用活性污泥法、生物接触氧化法、膜生物反应器、曝气生物滤池法等对污水进行处理,从而有效去除水中的有机物,破坏病原微生物赖以生存的物质基础和保障消毒效果。不同的处理工艺各有优缺,适合于不同规模的医院。     

活性污泥厌气消化的研究

工业废水不经处理任意排放,会严重污染环境,给人类带来危害。目前已广泛采用生化法处理各类废水,在处理过程中将产生大量的活性污泥。活性污泥主要是由尚未被微生物分解的残余有机物、有毒物、无机盐类、重金属离子和大量微生物     

圆红冬孢酵母利用生物乙醇废水-木薯粉水解液发酵产油

【目的】获得能够高效降解生物乙醇废水化学需氧量(COD)的圆红冬孢酵母菌株,评估废水初始COD浓度对驯化菌株生长的影响,将木薯粉生产微生物油脂和高浓度有机废水降解过程整合,以生物乙醇废水为水源制备生物乙醇废水-木薯粉水解液培养基,明确产油效率高、生物乙醇废水COD降解率高的初始还原糖浓度。【方法】采用在高浓度的生物乙醇废水中进行多次驯化的方法,获得能够适应废水环境的圆红冬孢酵母菌株;采用双酶水解法对加入乙醇废水中的木薯粉进行水解;采用重量法监测生物量浓度变化,采用酸热法提取油脂,重铬酸钾法监测COD,DNS法测定废水还原糖浓度,凯氏定氮法测定总氮,钼酸铵比色法测定总磷。【结果】通过驯化筛选得到一株能耐受高浓度生物乙醇废水的优势菌株Rhodosporidium toruloides D5。以未稀释的废水为培养基,驯化菌株的最终生物量浓度和COD降解率分别为3.8 g/L和75.0%。采用生物乙醇废水-木薯粉水解液发酵时,控制初始还原糖浓度低于30 g/L时,生物量浓度和油脂浓度随初始还原糖浓度的升高而升高,均在120 h时达到最高COD降解率,初始还原糖浓度对达到的最大COD降解率无明显影响,废水N、P去除率分别达到99%和92%以上。【结论】在未经稀释的高浓度生物乙醇废水中可获得较高的生物量浓度;采用高浓度生物乙醇废水-木薯粉水解液培养基发酵产油,初始还原糖浓度为30 g/L,可在保证高油脂产量的同时,实现废水COD的高效降解,有效回收利用废水中残余的N、P源,从而降低微生物油脂生产和废水处理成本,研究结果可为开发廉价微生物油脂生产技术提供有用的参考。     

膜生物反应器的研究进展

膜生物反应器是近年来发展的废水处理新技术,具有活性污泥浓度高、污泥龄长、占地面积小、投资省的特点。利用膜生物反应器进行污水处理不仅可以大大节约水资源,还可以大大节约能源,节省设备和运行费用,已成为二十一世纪研究热点。膜生物反应器是通过高效膜分离技术与活性污泥相结合,增大污泥中的特效菌来加快生化反应速率,提高废水处理效果。目前处理对象已从生活污水扩展到高浓度的有机废水和难降解的工业废水。本文综述了膜生物反应器在废水中的应用研究情况,并分析比较了各种膜材质的特点、适用范围以及膜的污染因素和清洗方法,展望了膜生物反应器的应用前景及进一步研究方向。     

基于细胞自动机的实体肿瘤生长动态建模

基于细胞自动机方法,建立了一种简单的实体肿瘤免疫性系统模型,用来模拟实体肿瘤生长过程中的情况．我们基于二维随机、离散细胞自动机计算方法,在生物细胞水平上,建立了一种肿瘤免疫性系统生长模型．该模型考虑了免疫反应的宏观性质,描绘了癌细胞和机体免疫系统之间的细胞相互作用,表现了围绕在肿瘤机体周围,免疫系统细胞的免疫作用发展情况．我们研究了常规细胞自动机模型,设计出实体肿瘤模型随机演化生长规则．最终,构建离散细胞自动机肿瘤免疫性系统模型,并做了相应的数值仿真试验．通过对仿真模型不同参数的调整,最终的仿真结果表明,该模型能反映肿瘤免疫性系统基本的相关性质．     

Simulation of wastewater treatment by aerobic granules in a sequencing batch reactor based on cellular automata

In the present paper, aerobic granules were developed in a sequencing batch reactor (SBR) using synthetic wastewater, and 81 % of granular rate was obtained after 15-day cultivation. Aerobic granules have a 96 % BOD removal to the wastewater, and the reactor harbors a mount of biomass including bacteria, fungi and protozoa. In view of the complexity of kinetic behaviors of sludge and biological mechanisms of the granular SBR, a cellular automata model was established to simulate the process of wastewater treatment. The results indicate that the model not only visualized the complex adsorption and degradation process of aerobic granules, but also well described the BOD removal of wastewater and microbial growth in the reactor. Thus, CA model is suitable for simulation of synthetic wastewater treatment. This is the first report about dynamical and visual simulation of treatment process of synthetic wastewater in a granular SBR.     

Modeling of activated sludge wastewater treatment processes

The performance of an activated sludge wastewater treatment process consisting of an aeration tank and a secondary settler has been studied. A tanks-in-series model with backflow was used for mathematical modeling of the activated sludge wastewater treatment process. Non-linear algebraic equations obtained from the material balances of MLSS (mixed liquor suspended solids or activated sludge), BOD (biological oxygen demand) and DO (dissolved oxygen) for the aeration tank and the settler and from the behavior of the settler were solved simultaneously using the modified Newton-Raphson technique. The concentration profiles of MLSS, BOD and DO in the aeration tank were obtained. The simulation results were examined from the viewpoints of mixing in the aeration tank and flow in the secondary settling tank. The relationships between the overall performance of the activated sludge process and the operating and design parameters such as hydraulic residence time, influent BOD, recycle ratio and waste sludge ratio were obtained.     

A non-structured pseudo-homogeneous model for the activated sludge process

The conventional activated sludge process has been in use for many years for treating wastewater. In this paper a non-structured pseudo-homogeneous model was developed to describe the process. Volume changes as well as the external resistance between the forming flocs and substrate were considered in the model. The kinetic model together with the values of parameters were obtained from the literature. A retention time of 12 hr was found to give over 95% removal of the substrate from the wastewater. Floc diameter, retention time, fraction of biomass recycled, substrate and biomass feed concentration were found to be important factors in the overall efficiency of the treatment process.     

Characterization and biological treatment of ceramic industry wastewater

Ceramic industry wastewaters not only contain high suspended and total solids but also significant amounts of dissolved organics resulting in high BOD or COD loads. Suspended solids can be removed from the wastewater by chemical precipitation. However, dissolved BOD/COD compounds can only be removed by biological or chemical oxidation. Effluent wastewater from chemical sedimentation stage of EGE CERAMIC industry was characterized and subjected to biological treatment in a laboratory scale activated sludge unit. Experiments were conducted at different hydraulic and solids retention times. The best results were obtained with Š_c=20 h of hydraulic and Š_c=20 days of solids retention times (sludge age) resulting in effluent COD concentration of 40 mg/l from a feed wastewater of 720 mg/l COD content. The suspended solids content of the activated sludge effluent was approximately 52 mg/l.     

Short-term batch studies on biological removal of chromium from synthetic wastewater using activated sludge biomass

Biological treatment of Cr(VI)-containing wastewater has drawn much attention recently as a method to treat environmental Cr(VI) contamination. The activated sludge method, due to its convenient operation and easy-to-scale-up, has been widely applied to treat municipal wastewater and some industrial wastewaters. In order to develop a suitable technique using activated sludge as the biomass to continuously remove Cr(VI) from wastewater, this paper investigated in short-term batch experiments the environmental elements affecting chromium biological removal from synthetic wastewater. The dissolved oxygen (DO), Cr(VI) initial concentration, biomass density, temperature, glucose content in the influent and contact time were observed to strongly influence chromium removal. It was found that the chromium removal efficiency decreased with the increase of DO and Cr(VI) initial concentration as well as glucose content in the feed, but increases in temperature and contact time improved the chromium removal efficiency. Although raising biomass concentration resulted in an increased chromium removal efficiency under both anaerobic and aerobic conditions, its influence on specific chromium removal was not significant.     

Assessment of characteristics and biological treatment technologies of Jordanian wastewater

Demand for wastewater treatment facilities will increase as Jordan's population grows. In addition, currently available systems of treatment desperately need upgrades in capacity or supplementary systems; especially in the Amman-Zarqa region. Overall; based on the current wastewater flow rates; approximately 85% of the collected sewerage is treated in stabilization ponds, 10% in trickling filters, and 5% in activated sludge systems. This study was carried out to analyze and identify the properties of Jordanian wastewater; compare it to the common characteristics internationally known; and couple that with a proposal of an appropriate treatment technology. Five treatment plants were selected to achieve the objectives of this study; the flow rate of which constitutes approximately 80% of the total treated wastewater in Jordan, based on the design capacity. The study concluded that the wastewater generated in Jordan is classified as strong in terms of total dissolved solids content, total suspended solids content, and chemical and biochemical oxygen demands (COD and BOD). The efficiency of the selected technologies in removing dissolved solids from wastewater was low while it was reasonably high in terms of suspended solids removal. The technology achieving highest percent removals of BOD and solids was that of activated sludge and its modifications. Based on the factors considered in evaluating and selecting unit operations and processes, the activated sludge and its modifications are probably the process technology that should be used in treating Jordanian domestic wastewaters.     

Study of Biological Activity and Process Stability in Submerged Membrane Bioreactors

Synthetic wastewater was treated in a bench scale submerged membrane bioreactor (SMBR). A long‐term experiment was conducted by varying the sludge residence time (SRT) (10–500 d) and BOD loading (1.3–0.25 kg/m³·d). The biological activity was observed in terms of the oxygen utilization rate (OUR) and adenosine triphosphate (ATP) profile; the process stability was analyzed based on the extent of organic degradation and suction pressure. The microbial population in the SMBR was dependent on the SRT and BOD loading, and its biological activity was increased with an increase in the SRT or BOD loading. At a low feed to microorganism (F/M) ratio (0.06 kg BOD/kg MLSS·d), the sludge production of the reactor was reduced to 0.04 kg MLSS/kg BOD, which is much less than in the conventional activated sludge process (0.4–0.6 kg MLSS/kg BOD). The F/M ratio influenced the biological activity (via ATP and the OUR) significantly at a short SRT (≤90 d). However, the effect of the F/M ratio ceased at a low F/M ratio (≤ 0.07 kg BOD/kg MLSS·d). The accumulation of organics in the SMBR was accompanied with an increase in the supernatant TOC, which caused a high suction pressure and an abrupt change in the operating conditions to process instability. However, the process stability of the SMBR increased with an increase in the SRT and a decrease in the BOD loading along with a concomitant decrease in the biological activity and sludge production.     

Protozoan and metazoan communities treating a simulated petrochemical industry wastewater in a rotating disc biological reactor

The microfauna of adhered biofilms treating a simulated petrochemical plant wastewater was investigated in relation to the organic loading and the toxicity. Experiments in a six-compartment laboratory rotating biological reactor were performed at organic loadings of 0.99, 1.38 and 1.97g/l.day. The concentration of organic compounds in the artificial wastewater (phenol, acetophenone and styrene), toxicity of the wastewater, number of representative types of microfauna, their biomass and species diversity were monitored along the reactor. During this study 25 species were identified and attributed to seven classes of the three types Sarcomastigophora, Ciliophora and Nemathelminthes. Eight species from 18 ciliates have been reported in the literature as being commonly found inhabitants of aerobic wastewater treatment plants. An inverse relationship between the number of microfauna representatives and the organic loading was found. The presence of the most common species was related to the reactor operating conditions. A correlation between the toxicity of the wastewater measured by the Paramecium express-test and the distribution and abundance of microfauna was established. This express-test made it possible to predict the biological quality of the biofilm of activated sludge. Therefore, it is recommended as one of the control parameters to monitor systems of biological wastewater treatment.     

Biodegradation of wastewater pollutants by activated sludge encapsulated inside calcium-alginate beads in a tubular packed bed reactor

The wastewater treatment plants produce large quantities of biomass (sludge) that require about one-third of the total inversion and operation plant costs for their treatment. By the microorganisms immobilization it is possible to handle high cell concentration in the reactor, increasing its efficiency, reducing the loss of biomass and the wash out is avoided. Moreover, there is no cell growth then the sludge production is reduced. In this study, the COD removal and VSS variation were modeled in a tubular reactor with activated sludge immobilized in Ca-alginate. Moreover, two aspects that are commonly not considered in the performance of the actual reactors of this kind were introduced; the performance in non-steady state and the dispersion effect. The model was calibrated with an actual wastewater taken out from a Mexican wastewater treatment plant. The results of the performance of the tubular bioreactor at different scenarios (i.e., different residence time and VSS in the reactor) are presented. With longer residence times and higher VSS concentration in the Ca-alginate beads in the tubular bioreactor it is possible to increase the time operation of the bioreactor and to treat higher volumes of wastewater. During the process, the sludge generation was drastically reduced and it is possible to remove nitrogen form the wastewater making this process more attractive.     

Immobilised activated sludge based biosensor for biochemical oxygen demand measurement

A biochemical oxygen demand (BOD) sensor, based on an immobilised mixed culture of microorganisms in combination with a dissolved oxygen electrode, has been developed for the purpose of on-line monitoring of the biological treatment process for waste and wastewater. The sensor was designed for easy replacement of the biomembrane, thereby making it suitable for short-term use. The drawbacks of activated sludge based sensor, such as short sensor lifetime, were thereby circumvented. The sensor BOD measurements were carried out in the kinetic mode using a flow injection system, resulting in 25 s for one measurement followed by 4–8 min recovery time. Based on the results of normalised sensor responses, the OECD synthetic wastewater was considered to be a more suitable calibration solution in comparison with the GGA solution. Good agreement was achieved between the results of the sensor BOD measurement and those obtained from BOD₅ analysis of a wastewater sample from a food-processing factory. Reproducibility of responses using one sensor was below ±5.6% standard deviation. Reproducibility of responses using different sensors was within acceptable bias limits, viz. ±15% standard deviation.