聚糖菌的代谢机制及生物学特性研究进展

强化生物除磷(EBPR)是一种经济、高效、可持续的除磷工艺之一,然而聚糖菌(GAO)的过量生长将导致EBPR系统恶化甚至完全失效.介绍了GAO的厌氧/好氧代谢机制,重点总结了两种GAO(Competibacter和类Defluviicoccus vanus细菌)的生物学特性,分析了碳源、pH、温度等影响GAO生长的关键因素,并对今后的研究进行了展望.     

Fenton试剂氧化苯酚过程中Fe（Ⅱ）浓度的变化

考察了Fenton试剂氧化降解苯酚过程中Fe(Ⅱ)浓度的变化,并通过实验探讨了其变化的原因.实验结果表明,在Fenton反应发生的第1 rain内,Fe(Ⅱ)浓度可降低到初始浓度的60%左右,随着反应的继续Fe(Ⅱ)浓度在大约20min降低到最小值,然后开始增大,说明了Fe(Ⅲ)还原作用的存在;Fenton试剂氧化降解苯酚的中间产物包括对苯二酚、邻苯二酚、间苯二酚和苯醌等,其中前三者能对Fe(Ⅲ)有效还原,是Fenton试剂氧化降解苯酚过程中Fe(Ⅲ)还原的主要途径之一.     

锌精炼铅塔燃烧系统烟气温度模糊控制研究

针对锌精馏铅塔动态过程中的非线性、非最小相位特征、不稳定性、时滞和负荷干扰,基于模糊控制策略下给出了锌精馏铅塔燃烧系统新的控制方法.运用模糊控制系统对锌精馏铅塔的烟气温度进行仿真研究和实时控制结果表明,该研究所设计的模糊控制器能够克服许多干扰因素,产生了良好的控制效果.     

Co3O4/介孔分子筛催化剂对苯催化完全氧化的研究

分别以介孔分子筛MCM-41、MCM-48、SBA-15为载体,采用等体积浸渍法制备了氧化钴/介孔分子筛催化剂,利用N₂吸附、X射线衍射、程序升温还原等技术对催化剂进行了表征,考察了Co₃O₄的负载量及载体的孔结构对催化剂完全催化氧化苯的性能的影响。结果表明,Co₃O₄的负载量为20%时,催化剂的催化活性最好;载体的孔径和催化剂的可还原性能是影响催化活性的主要因素,催化剂活性顺序为Co₃O₄ /SBA-15> Co₃O₄ /MCM41> Co₃O₄ /MCM-48。     

耐热乳杆菌的分离及在食物垃圾乳酸发酵中的应用

食物垃圾在我国城市生活垃圾中占有较大比重.发酵食物垃圾生产乳酸是实现其资源化的有效方法.从厌氧发酵的食物垃圾中分离到一株耐热乳酸菌TY50,根据形态、生理生化特征和16S rDNA序列,确定该菌株属于乳杆菌属的干酪乳杆菌组群(Lactobacillus casei group),其最高生长温度为52℃.TY50发酵食物垃圾生产乳酸的最佳同液比为1:12,最适温度为45 ℃.在pH 5.5～6.0条件下,发酵食物垃圾产生36.29 g/L的乳酸,乳酸体积产牢和转化率(乳峻/垃圾干重)分别达到1.01 g/(L·h)和0.44.     

由粉煤灰合成单一的沸石及其对Cr(Ⅵ)的吸附研究

以粉煤厌为原料采用两步法合成了2种单一沸石矿物种的NaA和NaX型沸石,并对产物的结构和性能进行了详细表征.2种沸石产物的吸附性能比较结果表明,NaA型沸石优于NaX型沸石.在静态吸附条件下,研究了NaA型沸石吸附水溶液中Cr(Ⅵ)的相关参数(溶液pH值、吸附温度和吸附时间),并用Langmuir和Freundlich等温吸附线对吸附结果进行拟和.结果表明:Cr(Ⅵ)的吸附行为符合Langmuir方程;饱和吸附量为47.78 mg/g.NaA型沸石对Cr(Ⅵ)的吸附是物理和化学吸附两种行为共同作用的结果.     

Low cost measurements of nitrogen and sulphur dry deposition velocities at a semi-alpine site: gradient measurements and a comparison with deposition model estimates

The conditional time averaged gradient method was used to measure air-surface exchange of nitrogen and sulphur compounds at a semi-alpine site in Southern Norway. Dry deposition velocities were then obtained from the bi-weekly concentration gradient measurements. Annual deposition velocities were found to be 1.4, 11.8 and 4.0 mm s(-1) for NH3, HNO3 and SO2, respectively, if all data were included, and to be 10.8, 11.8 and 13.0 mm s(-1), respectively, if only positive values were included. Measured deposition velocities were compared to two sets of values estimated from a big-leaf dry deposition module applying to two different land types (short grass and forbs, and tundra), driven by measured micrometeorological parameters. The deposition module gives reasonable values for this site throughout the year, but does not reproduce the large variability as shown in the measured data. No apparent seasonal variations were found from either measurements or module estimates due to the very low productivity of the studied area.     

Anaerobic degradation behavior of nonylphenol polyethoxylates in sludge

Anaerobic biodegradation behavior of nonylphenol polyethoxylates (NPEOs) was investigated. Results showed that terminal electron acceptors, organic matters, initial concentration, and temperature had great influence on the anaerobic biodegradation of NPEOs. Anaerobic biodegradation of NPEOs could be enhanced by adding sulfate or nitrate while this process could be inhibited by adding organic matters. The maximum removal rate increased 1.24 microM d(-1) for each ten micromoles increase in initial concentration. The decrease in temperature caused a sharp decrease in the removal efficiency of NPEOs. The temperature coefficient (PHI) for the anaerobic biodegradation of NPEOs was 0.01 degrees C(-1). Nonylphenol (NP), the typical intermediate of NPEOs, could inhibit the anaerobic biodegradation of NPEOs only at high concentration. However, these environmental factors had no effect on the anaerobic biodegradation pathway of NPEOs. The accumulation of NP and short-chain NPEOs during NPEO biodegradation led to a significant increase in the estrogenic activity during the biodegradation period.     

Effect of two major N-nitroso hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) metabolites on earthworm reproductive success

Soil and topical tests were employed to investigate the effect of two N-nitroso metabolites of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) on earthworm reproduction. The lowest observed effect concentration (LOEC) for cocoon production and hatching was 50mg/kg for both hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX) in soil. MNX and TNX also significantly affected cocoon hatching in soil (p<0.001) and in topical tests (p=0.001). The LOECs for cocoon hatching were 1 and 10mg/kg for MNX and TNX in soil, respectively, and 10mg/L in the topical test. Greater than 100mg/kg MNX and TNX completely inhibited cocoon hatching. In soil, the EC20 values for MNX were 8.7 and 8.8mg/kg for cocoon and juvenile production, respectively, compared to 9.2 and 9.1mg/kg for TNX, respectively. The EC20 values for the total number of cocoon hatchlings were 3.1 and 4.7mg/kg for MNX and TNX, respectively, in soil and 4.5 and 3.1mg/L in the topical test. Both MNX and TNX inhibited cocoon production and hatching, suggesting that they may have a negative affect on soil ecosystems at contaminated sites.     

Design of a novel non-equilibrium plasma-based water treatment reactor

A novel non-equilibrium plasma-based water treatment reactor consisting of high voltage multi-needle electrode submerged in aqueous phase and reticulated ground electrode suspended in gas phase above water was developed and applied to treat low concentrations of methyl orange (MO). The electrode configuration was optimized. Higher number and more uniform distribution of streamers were produced in gas phase when parallel five-needle configuration with needle spacing of 10mm for high voltage electrode, macroporous ground electrode with mesh size of 0.42mm, and electrode gap of 17mm were adopted. This case corresponds to the largest amount of hydrogen peroxide and ozone produced in aqueous phase and gas phase, respectively, and air flow rate presents an economical value. The injection of wastewater above ground electrode for pretreatment and the design of fixed mesh barriers further increase the amount of ozone dissolved in aqueous solution. The conversion of MO presents a positive correlation with input voltage and the increase of pulse repetition rate is conducive for the conversion. In addition, the effect of initial solution concentration and treating volume on the conversion, energy yield and COD removal was evaluated.