Pseudomonas sp. ZXY-1, a newly isolated and highly efficient atrazine-degrading bacterium, and optimization of biodegradation using response surface methodology

Atrazine, a widely used herbicide, is increasing the agricultural production effectively, while also causing great environmental concern. Efficient atrazine-degrading bacterium is necessary to removal atrazine rapidly to keep a safe environment. In the present study, a new atrazine-degrading strain ZXY-1, identified as Pseudomonas, was isolated. This new isolated strain has a strong ability to biodegrade atrazine with a high efficiency of 9.09 mg/L/hr.Temperature, p H, inoculum size and initial atrazine concentration were examined to further optimize the degradation of atrazine, and the synthetic effect of these factors were investigated by the response surface methodology. With a high quadratic polynomial mathematical model(R~2= 0.9821) being obtained, the highest biodegradation efficiency of 19.03 mg/L/hr was reached compared to previous reports under the optimal conditions(30.71°C, pH 7.14, 4.23%(V/V) inoculum size and 157.1 mg/L initial atrazine concentration).Overall, this study provided an efficient bacterium and approach that could be potentially useful for the bioremediation of wastewater containing atrazine.     

新型重金属絮凝剂巯基乙酰化羟甲基聚丙烯酰胺的优化制备

为提高含铜废水的处理效果及简化处理流程,以聚丙烯酰胺(PAM)、甲醛、氢氧化钠、巯基乙酸(TGA)为原料,先经羟甲基化反应制备中间产物羟甲基聚丙烯酰胺(MPAM),再通过酰胺化反应将巯基接枝到MPAM分子链上,制备出新型重金属絮凝剂巯基乙酰化羟甲基聚丙烯酰胺(MAMPAM).以水样中Cu(Ⅱ)的去除率为考察目标,采用Plackett-Burman实验、最陡爬坡实验和响应面法中CCD实验优化MAMPAM的制备条件.结果表明,MAMPAM最优制备条件为:MPAM浓度0.31%、MPAM与TGA物质的量比为1∶3.2、反应介质p H值为4.76、反应温度为25℃、反应时间为2 h,在此条件下制备的MAMPAM对Cu(Ⅱ)的去除率为95.30%,与模型的理论预测值94.47%接近,相对偏差仅为0.83%,模型合理可靠.红外分析表明MPAM分子链上成功接上了巯基.MAMPAM对不同初始浓度的含Cu(Ⅱ)水样具有很好的去除效果,Cu(Ⅱ)去除率均能达到90%以上.MAMPAM有望成为一种有效的含铜废水处理剂,具有一定的应用前景.     

后处理设施给水系统可靠性的GO法研究

后处理设施给水系统是后处理设施重要的公用系统,对后处理设施的稳定、安全运行至关重要.给水系统的可靠性需要深入分析,应用GO法进行了研究.获得了给水系统的平均故障概率、最小割集、重要度等可靠性指标.结果表明,给水系统的可靠性比较高,符合单一故障准则,二阶最小割集对系统故障的贡献最大,应该采取措施予以消除.进一步深入对比分析GO法与故障树法,结果显示,对于给水系统的可靠性分析,GO法有建模容易且图形简洁的优点.     

菌株Pseudomonas sp. JF122降解苯酚同时还原Cr(VI)的条件优化及生长特性研究

采用富集培养法,从钢铁厂附近河流污泥中分离筛选到1株能同时降解苯酚与还原Cr(VI)的菌株JF122.在600 mg·L^-1苯酚与1.2 mg·L^-1 Cr(VI) 的条件下,采用单因素实验考察了温度、初始pH、该菌接种量等因素对其同时降解苯酚与还原Cr(VI)的影响,并通过正交试验L₉(3³)获得适宜的苯酚降解与Cr(VI)还原条件.结果表明,菌株JF122降解苯酚与还原Cr(VI)的适宜条件为:30 ℃、初始pH=6和接种量1%,此条件下,菌株JF122在56 h内能够降解600 mg·L^-1苯酚同时还原1.2 mg·L^-1 Cr(VI).应用响应曲面法建立了菌株JF122的生长与温度、初始pH、接种量等因素间关系的数学模型,并对其生长条件进行了优化.结果表明,菌株JF122最优生长条件与其降解苯酚并同时还原Cr(VI)的最优条件具有一致性.     

Modeling assessment for ammonium nitrogen recovery from wastewater by chemical precipitation

Chemical precipitation to form magnesium ammonium phosphate (MAP) is an effective technology for recovering ammonium nitrogen (NH4 +-N). In the present research, we investigated the thermodynamic modeling of the PHREEQC program for NH4 +-N recovery to evaluate the effect of reaction factors on MAP precipitation. The case study of NH4 +-N recovery from coking wastewater was conducted to provide a comparison. Response surface methodology (RSM) was applied to assist in understanding the relative significance of reaction factors and the interactive effects of solution conditions. Thermodynamic modeling indicated that the saturation index (SI) of MAP followed a polynomial function of pH. The SI of MAP increased logarithmically with the Mg2+/NH4 + molar ratio (Mg/N) and the initial NH4 +-N concentration (CN), respectively, while it decreased with an increase in Ca2+/NH4 + and CO3 2??/NH4 + molar ratios (Ca/N and CO3 2??/N), respectively. The trends for NH4 +-N removal at different pH and Mg/N levels were similar to the thermodynamic modeling predictions. The RSM analysis indicated that the factors including pH, Mg/N, CN, Ca/N, (Mg/N) (CO3 2??/N), (pH)2, (Mg/N)2, and (CN)2 were significant. Response surface plots were useful for understanding the interaction effects on NH4 +-N recovery.     

中心组合设计优化S-Cr-TiO2催化剂光降解工艺条件

在确定的温度和光照条件下,采用中心组合设计法研究了固相反应法合成的硫与铬共掺杂二氧化钛(S-Cr-TiO2)光催化剂与水溶苯胺蓝(ANB)可见光降解过程中的三个作用因子:催化剂的浓度、水溶苯胺蓝水溶液的pH值及其初始浓度之间的相互作用关系,得到了影响因子与降解速率之间的回归方程及因素之间相互作用的响应面图.结果表明,S...     

Bitter coil design methodology for electromagnetic pulse metal processing techniques

Electromagnetic pulse metal processing techniques (EPMPT) such as welding, forming and cutting have proven to be an effective solution to specific manufacturing problems. A high pulse magnetic field coil is a critical part of these technologies and its design is a challenging task. This paper describes a Bitter coil design using a newly developed methodology for a simplified analytical calculation of the coil and complementary finite element models (FE) of different complexity. Based on the methodology a Belgian Welding Institute (BWI) Bitter coil has been designed and tested by means of short circuit experiments, impedance and B-field measurements. A good agreement between the calculated and the experimental design parameters was found.     

Myrothecium verrucaria NF-08产漆酶条件的响应面法优化及粗酶染料脱色研究

以半知菌属疣孢漆斑菌Myrothecium verrucaria NF-08为供试菌,采用响应面方法优化菌株产漆酶条件,并以其漆酶粗酶进行3种结构类型6种染料的脱色试验,考察了粗酶浓度、温度和p H值对脱色率的影响.两水平析因设计、中心组合设计和验证试验结果表明:葡萄糖浓度为15.4 g·L~(-1)、蛋白胨浓度为43.3 g·L~(-1)和培养基初始p H值为6.68时,漆酶活性达到最大值(25.58±1.60)U·m L~(-1),是单因素试验(16.82 U·m L~(-1))的1.52倍,提高了52.1%.以上述发酵条件获得的M.verrucaria NF-08漆酶粗酶对3种结构类型染料均有脱色效果,排序为偶氮类优于芳甲烷类优于蒽醌类.脱色率随粗酶浓度增大(2~8 U·m L~(-1))、反应温度升高(15~35℃)而上升,随p H值上升(4~10)而下降.粗酶浓度为5 U·m L~(-1),反应温度为25℃,p H值为4时,偶氮类染料铬黑T和芳甲烷类染料碱性品红即可几乎完全脱色,脱色率分别为99.2%和94.6%.     

Systematic review on the implementation methodologies of inherent safety in chemical process

The accomplishments of inherent safety in the field of loss prevention thus far are impressive due to its scientific philosophy: reducing risks at source rather than adding engineered and procedural protections. Generally, the implementation of inherent safety can be done through a cohesive set of fourteen principles elucidated by Kletz and Amyotte. This work, guided by the fourteen principles, presents a systematic review on the implementation methodologies of inherent safety. Firstly, PRISMA procedure was adopted to select eligible literatures according to inclusive and exclusive criteria. After obtaining the selected literatures, the preference, level of application, and gaps in using these principles were critically analyzed. Of the fourteen principles, intensification, substitution, attenuation, simplification, limitation of effects, and avoidance of knock-on effects are preferable to implementing inherent safety in chemical process. Although the remaining principles are also potentially useful, they are not commonly used due to their costs and complexities of implementation. Overall, this work presents a complete spectrum to look across the implementation methodologies of inherent safety and concludes with some holistic and inclusive approaches as future research recommendations.     

响应面法优化预氧化强化混凝处理铁锰地下水

以KMnO_4为氧化剂,Al_2(SO_4)_3·18H_2O为混凝剂,含铁锰离子地下水为模拟用水,考察预氧化强化混凝法的效果。利用响应面设计试验,分析氧化剂投加量、混凝剂投加量和pH值对铁锰去除的交互作用。模型优化结果显示,在氧化剂投加量4.16 mg/L,混凝剂投加量263.68 mg/L,pH值为7.54的最佳工艺参数下,铁锰去除率分别可达98.22%和97.49%。