Degradation of toluene and benzene by Trametes versicolor

In this study, biological degradation of non-polar monoaromatic compounds, benzene and toluene, by one of the white rot fungi, namely Trametes versicolor was analyzed and the biomass formed was determined. The studies were carried out in mediums which contain basic nutrients in certain amounts, toluene and benzene at concentrations of 50, 100, 200, 250 and 350 mg/l, pH at 5, temperature at 28 degrees C and rpm at 150. Within an incubation period of 48 hours, it was observed that, removal was completed in 4 hours when toluene concentration was 50 mg/l and was completed in 36 hours when concentration was 300 mg/l. Biodegradation was completed at the end of 4th hour at benzene concentration of 50 mg/l while it continued for 42 hours at the concentration of 300 mg/l. With the addition of veratryl alcohol (3,4-Dimethoxybenzyl alcohol) to the basic feed medium, the operation of the enzyme system gained speed and biodegradation completed in a shorter time period.     

几种天然矿物去除苯酚效果及日光光解效应评价

本文以四种天然矿物为受试矿物,评价了它们去除苯酚的效果,以及日光光解放应及温度,ＰＨ值,矿物浓度,苯酚初始浓度对去除效果的影响。     

Vinasse biodegradation by Phanerochaete chrysosporium

Vinasse is a colored recalcitrant wastewater of the distillery industry. The aim of this work was to study the use of Phanerochaete chrysosporium for the vinasse degradation under two different growth conditions. Vinasse was treated by P. chrysosporium in a liquid inoculum form, during 32 days at room temperature (approximately 25 degrees C) and at 39 degres C. Chemical oxygen demand (COD), total phenol concentration and color removal were measured and there8 was a decrease in COD, phenolic concentration and color of 47.48%, 54.72% and 45.10% respectively, at room temperature and a decrease in 54.21%, 59.41% and 56.8 1% respectively at 39 degrees C.     

Quantification of polyphenols during retting and characterization of bacteria from the Kadinamkulam Backwaters, Kerala

The retting environment which provides a competitive niche for specialized microbes is speculated to harbour a variety of microbes with high biodegradation potential. In this context, an effort has been made to isolate and identify bacterial species having high tolerance to phenol In vitro. Maximum polyphenol (1.897 mg l(-1)) as observed during the initial period of retting, which decreased as retting proceeded. Based on biochemical characterization, the isolated bacterial strains were identified as Micrococcus sp., Moraxella sp. strain MP1, Moraxella sp. strain MP2 and Moraxella sp. strain MP3, Pseudomonas sp. strain PP1 and Pseudomonas sp. strain PP2, Amphibacillus sp., Brucella sp. strain BP1 and Brucella sp. strain BP2, Aquaspirillum sp., Escherichia coli strain EP1 and Escherichia coli strain EP2, Campylobacter sp., Aeromonas sp., Neisseria sp., Vibrio sp., Erwinia sp. and Mesophilobacter sp. These strains were found to tolerate maximum concentration of phenol viz. 200 to 1000 mg l(-1). Plasmid analysis of phenol resistant bacterial isolates showed that almost all the cultures had at least one plasmid of size > 1Kb. Studies on the protein profile of isolated bacterial cultures showed the presence of proteins with molecular sizes ranging from 10 to 85 KDa with exception of Mesophilobacter and Neisseria having still high molecular weight protein (95 KDa). Bacterial strains isolated from coir-ret-liquor showed tolerance to high phenol concentration.     

Characterization of two metal resistant Bacillus strains isolated from slag disposal site at Burnpur, India

Two strains of Bacillus sp. resistant to arsenate and lead designated as AsSP9 and PbSP6, respectively were isolated from the slag disposal site. They were identified to be related to Bacillus cereus cluster on the basis of 16S rDNA based sequence analysis and phenotypic characteristics. Both were rod-shaped (AsSP9, 2-5 microm and PbSP6, 2-4 microm), aerobic, salt tolerant (2-8% NaCI), endospore forming bacteria with minor differences like the AsSP9 showed sporangial bulging and PbSP6 had positive lipase activity. The temperature range for their growth was 20-40 degrees C and pH range 6.0-9.0 with an optimum temperature of 37 degrees C and pH of 7 for both strains. The principal nitrogen sources forAsSP9 and PbSP6 were DL-Tryptophan and L-Phenylalanine, respectively. The suitable carbon source forAsSP9 was lactose and for PbSP6 sucrose. The heavy metal accumulation efficiency was found to be 0.0047 mg g(-1) of dry mass forAsSP9 and 0.686 mg g(-1) of dry mass for PbSP6.     

Assessment of phenol-degrading ability of Acinetobacter sp. B9 for its application in bioremediation of phenol-contaminated industrial effluents

Successful bioremediation of a phenol-contaminated environment requires application of those microbial strains that have acquired phenol tolerance and phenol-degrading abilities. A newly isolated strain B9 of Acinetobacter sp. was adapted to a high phenol concentration by growing sequentially from low- to high-strength phenol. The acclimatised strain was able to grow and completely degrade up to 14?mM of phenol in 136?h. The degradation rates were found to increase with an increase in the phenol concentration from 2.0 to 7.5?mM. The strain preferred neutral to alkaline pH range for growth and phenol degradation, with the optimum being pH 8.0. The optimum temperature for phenol degradation was found to be in the range of 30–35°C. Transmission electron micrographs showed a disorganised and convoluted cell membrane in the case of phenol-stressed cells, showing a major effect of phenol on the membrane. Enzymatic and gas chromatography-mass spectrometry studies show the presence of an ortho-cleavage pathway for phenol degradation. Efficient phenol degradation was observed even in the presence of pyridine and heavy metals as co-toxicants showing the potential of strain in bioremediation of industrial wastes. Application of strain B9 to real tannery wastewater showed 100% removal of initial 0.5?mM phenol within 48?h of treatment.     

Effect of dilution rate on dynamic and steady-state biofilm characteristics during phenol biodegradation by immobilized Pseudomonas desmolyticum cells in a pulsed plate bioreactor

Continuous pulsed plate bioreactor (PPBR) was used for phenol biodegradation. Pseudomonas desmolyticum cells immobilized on granular activated carbon was used. Dynamic and steady state biofilm characteristics depend on dilution rate (DR). Lower DR favour phenol degradation and uniform, thick biofilm formation. Exo polymeric substance production in biofilm are favoured at lower dilution rates. Pulsed plate bioreactor (PPBR) is a biofilm reactor which has been proven to be very efficient in phenol biodegradation. The present paper reports the studies on the effect of dilution rate on the physical, chemical and morphological characteristics of biofilms formed by the cells of Pseudomonas desmolyticum on granular activated carbon (GAC) in PPBR during biodegradation of phenol. The percentage degradation of phenol decreased from 99% to 73% with an increase in dilution rate from 0.33 h?1 to 0.99 h?1 showing that residence time in the reactor governs the phenol removal efficiency rather than the external mass transfer limitations. Lower dilution rates favor higher production of biomass, extracellular polymeric substances (EPS) as well as the protein, carbohydrate and humic substances content of EPS. Increase in dilution rate leads to decrease in biofilm thickness, biofilm dry density, and attached dry biomass, transforming the biofilm from dense, smooth compact structure to a rough and patchy structure. Thus, the performance of PPBR in terms of dynamic and steady-state biofilm characteristics associated with phenol biodegradation is a strong function of dilution rate. Operation of PPBR at lower dilution rates is recommended for continuous biologic treatment of wastewaters for phenol removal.     

Utilization of nano/micro-size iron recovered from the fine fraction of automobile shredder residue for phenol degradation in water

Phenol removal by n/m Fe in the presence of H₂O₂ was highly effective. Increasing the amounts of n/m Fe and H₂O₂?increased the phenol removal rate. Phenol removal was decreased with an increase in the concentration of phenol. The natural pH (6.9) of the solution was highly effective for phenol removal. The pseudo-first-order kinetics was best fitted for the degradation of phenol. The study investigates the magnetic separation of Fe from automobile shredder residue (ASR) (<0.25 mm) and its application for phenol degradation in water. The magnetically separated Fe was subjected to an ultrasonically assisted acid treatment, and the degradation of phenol in an aqueous solution using nano/micro-size Fe (n/m Fe) was investigated in an effort to evaluate the possibility of utilizing n/m Fe to remove phenol from wastewater. The prepared n/m Fe was analyzed by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The effects of the dosages of n/mFe, pH, concentration of phenol and amount of H₂O₂ on phenol removal were evaluated. The results confirm that the phenol degradation rate was improved with an increase in the dosages of n/mFe and H₂O₂; however, the rate is reduced when the phenol concentration is higher. The degradation of phenol by n/mFe followed the pseudo-first-order kinetics. The value of the reaction rate constant (k) was increased as the amounts of n/m Fe and H₂O₂ increased. Conversely, the value of k was reduced when the concentration of phenol was increased. The probable mechanism behind the degradation of phenol by n/m Fe is the oxidation of phenol through hydroxyl radicals which are produced during the reaction between H₂O₂ and n/m Fe.     

白腐菌Trametes hirsute对六氯苯的降解及其条件优化

在液体体系下,筛选了5株白腐菌,对六氯苯进行了降解研究,并优化了白腐菌Trametes hirsute TH对六氯苯的降解条件.结果表明,不同白腐菌均能降解六氯苯,其中白腐菌Trametes sp.TR对六氯苯降解率最高,达90.21%;而白腐菌T.hirsute TH对六氯苯降解率为87.08%,但生物量最高,达3.33 g/L.通过响应面法优化白腐菌T.hirsute TH降解六氯苯的条件,结果显示,转速、接种量和培养时间是影响六氯苯降解的主要因素.优化后的最佳条件为:转速125 r/min,菌丝接种量8%(V/V),培养时间2 d,温度28 ℃,pH为7.在优化条件下,2 d内白腐菌T.hirsute TH对浓度为10 mg/L的六氯苯降解率和降解量分别可达91.52%和2.288 mg L-1 d-1.图2表7参17     

原生质体电诱导融合构建去除重金属的高效菌

研究了采用原生质体电融合技术构建高效的重金属去除菌;对影响电融合效率的几个参数,以及融合子的生长条件、除铬性能和遗传稳定性等方面进行了考察;确定了进行电融合的最佳条件,并选出 1株最好的融合株R32. 实验结果表明:R32不论是在处理低浓度还是高浓度的铬液时,其去除率和还原率都明显高于 2株亲本菌,处理低浓度含铬废水时,去除率和还原率可达到 100%;处理高浓度含铬废水(200mgL-1 )时,还原率仍可达 50%以上. 经过多次传代后,R32的除铬能力保持稳定. 当投菌量>10gL-1 (湿重)时,其去除率和还原率都在 80%以上. 正交实验结果显示,pH和Cu2 浓度对R32的生长影响都不大,这些特点都有利于R32在实际含铬废水处理中的应用. 图 4表 3参 14     

Removal of Novacron Golden Yellow dye from aqueous solutions by low-cost agricultural waste: Batch and fixed bed study

The present work describes the removal of Novacron Golden Yellow (NGY) dye from aqueous solutions using peanut hulls. The experiments were performed with native, pretreated and immobilised forms of peanut hulls. The effect of various operational parameters (pH, biosorbent dose, initial dye concentration and temperature etc.) was explored during batch study. NGY showed maximum removal at low pH and low biosorbent dose. High initial dye concentration facilitated the biosorption process. Maximum dye removal with native, pretreated and immobilised biomass was found to be 35.7, 36.4 and 15.02 mg/g respectively. The experimental data were subjected to different kinetic and equilibrium models. The kinetic data confirmed the fitness of pseudo-second-order rate law for NGY biosorption. The equilibrium modelling was carried out by Freundlich, Langmuir and Temkin models. The isothermal data of NGY removal were best described by Freundlich adsorption isotherm. Negative values of Free energy change (Δ G⁰) for NGY with native and pretreated biomass depicted the spontaneous nature of biosorption process. In column mode, the effects of bed height, flow rate and initial dye concentrations were optimised. Maximum NGY biosorption (7.28 mg/g) was observed with high bed height, low flow rate and high initial concentration in continuous mode. Bohart–Adams model best fitted to the data obtained from column studies. The results indicated that the peanut hulls could be used effectively for the removal of dyes containing wastewater.     

Effect of dilution rate on dynamic and steady-state biofilm characteristics during phenol biodegradation by immobilized <Emphasis Type="Italic">Pseudomonas desmolyticum</Emphasis> cells in a pulsed plate bioreactor

Pulsed plate bioreactor (PPBR) is a biofilm reactor which has been proven to be very efficient in phenol biodegradation. The present paper reports the studies on the effect of dilution rate on the physical, chemical and morphological characteristics of biofilms formed by the cells of Pseudomonas desmolyticum on granular activated carbon (GAC) in PPBR during biodegradation of phenol. The percentage degradation of phenol decreased from 99% to 73% with an increase in dilution rate from 0.33 h^–1 to 0.99 h^–1 showing that residence time in the reactor governs the phenol removal efficiency rather than the external mass transfer limitations. Lower dilution rates favor higher production of biomass, extracellular polymeric substances (EPS) as well as the protein, carbohydrate and humic substances content of EPS. Increase in dilution rate leads to decrease in biofilm thickness, biofilm dry density, and attached dry biomass, transforming the biofilm from dense, smooth compact structure to a rough and patchy structure. Thus, the performance of PPBR in terms of dynamic and steady-state biofilm characteristics associated with phenol biodegradation is a strong function of dilution rate. Operation of PPBR at lower dilution rates is recommended for continuous biological treatment of wastewaters for phenol removal.

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活性炭负载TiO2催化臭氧氧化去除水中酚的研究

本文采用活性炭负载TiO2作催化剂对臭氧氧化去除含酚废水进行了研究．研究了不同的酚初始浓度、pH值及臭氧浓度对苯酚去除率的影响，获得了反应动力学常数．实验结果表明：苯酚初始浓度越小，去除率越高．在本实验条件下，向150mL苯酚溶液中通入浓度为3．48mg/L、流量为0．05m^3／h的臭氧化空气反应30min去除率即可达到99％以上。     

低温下曝气生物滤池预处理污染河水的试验研究

采用两段曝气生物滤床串联工艺预处理入滇新运粮河河水,研究了其在冬天低温条件下对有机物和氨氮的去除效果,并考察了pH值的变化。结果表明,在进水流量为2.4 m3.d-1、水温为13-16℃、原水ρ（CODCr）为66.46-107.82 mg·L-1、ρ（氨氮）为22.15-30.68 mg·L-1的水质特征条件下,系统对CODCr和氨氮的去除率分别为36.08%-50.37%和76.98%-93.56%。其中,碳氧化段以去除有机物为主,硝化段以去除氨氮为主;系统中硝酸氮质量浓度明显升高,无亚硝氮的积累;装置对总氮的平均去除率为19.56%,可以认为总氮的去除是同步硝化反硝化的结果。系统中pH值有所变化但维持在7-8之间,其中碳氧化段pH值升高,硝化段pH值下降。系统对有机物和氨氮良好的去除效果为后续进一步的生物处理提供了条件。     

有机凹凸棒粘土吸附水中苯酚的试验

凹凸棒粘土经溴化十六烷基三甲胺（ＣＴＭＡＢ）改性后,对水中酚具有较强的吸附能力,苯酚浓度为１００ｍｇ／Ｌ时,加入量为４％,ｐＨ为８．０时,去除率达到８８．５％,且有机凹土经再生后可反复使用。吸附平衡浓度与吸附量关系符合Ｆｒｅｕｎｄｌｉｃｈ吸附等温式。     

Biodegradation of 2-methylisoborneol by bacteria enriched from biological activated carbon

One of the most common taste and odour compounds (TOCs) in drinking water is 2-methylisoborneol (2-MIB) which cannot be readily removed by conventional water treatments. Four bacterial strains for degrading 2-MIB were isolated from the surface of a biological activated carbon filter, and were characterized as Micrococcus spp., Flavobacterium spp., Brevibacterium spp. and Pseudomonas spp. based on 16S rRNA analysis. The removal efficiencies of 2-MIB with initial concentrations of 515 ng·L^-1 were 98.4%, 96.3%, 95.0%, and 92.8% for Micrococcus spp., Flavobacterium spp., Brevibacterium spp. and Pseudomonas spp., respectively. These removal efficiencies were slightly higher than those with initial concentration at 4.2 mg·L^-1 (86.1%, 84.4%, 86.7% and 86.0%, respectively). The kinetic model showed that biodegradation of 2-MIB at an initial dose of 4.2 mg·L^-1 was a pseudo-first-order reaction, with rate constants of 0.287, 0.277, 0.281, and 0.294 d^-1, respectively. These degraders decomposed 2-MIB to form 2-methylenebornane and 2-methyl-2-bornane as the products.     

人居生活废弃物生物黑炭对水溶液中Cd2+的吸附研究

以人居生活废弃物生物黑炭为材料,探讨生物黑炭对Cd2+的吸附动力学及热力学特性,通过平衡吸附法研究吸附时间、Cd2+初始质量浓度、吸附剂投加量、溶液pH值以及黑炭粒径对Cd2+吸附率的影响.结果表明,吸附时间为2h时基本达到吸附平衡,准二级动力学方程能很好地描述生物黑炭对Cd2+的吸附过程.Langmuir模型能较好地描述生物黑炭对Cd2+的等温吸附过程,根据该模型模拟得到25℃条件下Cd2+最大吸附量为6.22mg·g-1.Cd2+去除率随生物黑炭投加量的增加而增大;生物黑炭对Cd2+吸附量随其粒径减小而增大;溶液初始pH值为4.0～7.5时,pH值变化对Cd2+吸附量的影响不显著.采用人居生活废弃物生物黑炭去除水溶液中Cd2+时,控制溶液Cd2+初始质量浓度30mg·L-1,粒径小于0.25 mm,投加水平8g·L-1,反应温度25℃,反应时间1～2h,Cd2+去除率可达80％.人居生活废弃物生物黑炭可以作为去除污染水体中Cd2+的吸附剂.     

Performance of an ANAMMOX reactor treating wastewater generated by antibiotic and starch production processes

A pilot-scale anaerobic ammonia oxidation (ANAMMOX) reactor was used to treat mixed wastewater resulting from a chlortetracycline and starch production process. The results, collected over the course of 272 days, show that the ratio of influent ammonium to nitrite, pH, and temperature can all affect the efficiency of nitrogen removal. The ratio of influent ammonium to nitrite was maintained at about 1:1 at a concentration below 200 mg·L^-1 for both influent ammonium and nitrite. The total nitrogen (TN) loading rate was 0.15–0.30 kgN·m^-3·d^-1, pH remained at 7.8–8.5, and temperature was recorded at 33±1°C. The rate of removal of ammonia, nitrite, and TN were over 90%, 90%, and 80%, and the effluent ammonium, nitrite and TN concentrations were below 50, 30, and 100 mg·L^-1.     

硫酸盐还原菌对酸性废水中重金属的生物沉淀作用研究

在小型连续搅拌槽式反应器（CSTR）中,研究了持续低pH条件下,硫酸盐还原菌的生物沉淀作用对人工配制酸性重金属废水的处理效果。试验设置反应器进水pH值依次为4-3,3．5和2．6三个处理,进水中Cu^2＋、Zn^2＋和Cr^3＋含量分别为65、36和10mg·L^-1,SO4^2-含量约为6200mg·L^-1,接种物为经耐酸驯化的混合硫酸盐还原菌,试验时控制水力停留时间为36h,通过定期测定反应器出水pH、氧化还原电位（ORP）、碱度、SO4^2、S^2-以及重金属含量变化等指标来考察废水生物沉淀的处理效果。研究结果表明：对于进水pH值为2．6～4.3的酸性重金属废水,硫酸盐还原菌的生物沉淀作用均有较好的处理效果。处理后,反应器出水pH值大幅升至6．5～8．0,碱度由起始的300～2000mg·L^-1增至7500-4600mg·L^-1,废水中S041-还原率达72％～80％,Cu^2＋和Zn^2＋的去除（沉淀）率达99．9％,Cr^3＋去除率达99．1％。此外,随着进水pH值由413降至2．6,反应器出水pH和碱度均呈现逐步下降的趋势,而S04}的生物还原和重金属的去除效果变化不大。从反应器运行稳定性考虑,控制酸性重金属废水的进水pH值为3．5较适宜今后的实际应用。     

Studies on influence of natural biowastes on cellulase production by Aspergillus niger

The objective of this study was to determine the influence of natural biowaste substrates such as banana peel powder and coir powder at varying environmental parameters of pH (4-9) and temperature (20-50 degrees C) on the cellulase enzyme production by Aspergillus niger. The cellulase enzyme production was analyzed by measuring the amount of glucose liberated in IU ml(-1) by using the dinitrosalicylic acid assay method. The substrates were pretreated with 1% NaOH (alkaline treatment) and autoclaved. The maximum activity of the enzyme was assayed at varying pH with temperatures being constant and varying temperatures with pH being constant. The highest activity of the enzyme at varying pH was recorded at pH 6 for banana peel powder (0.068 +/- 0.002 IU ml) and coir powder (0.049 +/- 0.002 IU ml(-1)) and the maximum activity of the enzyme at varying temperature was recorded at 35 degrees C for both banana peel powder (0.072 +/- 0.001 IU ml(-1)) and coir powder (0.046 +/- 0.003 IU ml(-1)). At varying temperatures and pH the high level of enzyme production was obtained at 35 degrees C and pH 6 by using both the substrates, respectively. However among the two substrates used for the production of cellulases by Aspergillus niger banana peel powder showed maximum enzymatic activity than coir powder as substrate.