Analysis of uranium removal capacity of anaerobic granular sludge bacterial communities under different initial pH conditions

Environmental Science and Pollution Research - The bacterial community of an anaerobic granular sludge associated with uranium depletion was investigated following its exposure to uranium under...     

Analysis of the influence of passenger vehicles front-end design on pedestrian lower extremity injuries by means of the LLMS model

Objective: This work aims at investigating the influence of some front-end design parameters of a passenger vehicle on the behavior and damage occurring in the human lower limbs when impacted in an accident.

Methods: The analysis is carried out by means of finite element analysis using a generic car model for the vehicle and the lower limbs model for safety (LLMS) for the purpose of pedestrian safety. Considering the pedestrian standardized impact procedure (as in the 2003/12/EC Directive), a parametric analysis, through a design of experiments plan, was performed. Various material properties, bumper thickness, position of the higher and lower bumper beams, and position of pedestrian, were made variable in order to identify how they influence the injury occurrence. The injury prediction was evaluated from the knee lateral flexion, ligament elongation, and state of stress in the bone structure.

Results: The results highlighted that the offset between the higher and lower bumper beams is the most influential parameter affecting the knee ligament response. The influence is smaller or absent considering the other responses and the other considered parameters. The stiffness characteristics of the bumper are, instead, more notable on the tibia. Even if an optimal value of the variables could not be identified trends were detected, with the potential of indicating strategies for improvement.

Conclusions: The behavior of a vehicle front end in the impact against a pedestrian can be improved optimizing its design. The work indicates potential strategies for improvement. In this work, each parameter was changed independently one at a time; in future works, the interaction between the design parameters could be also investigated. Moreover, a similar parametric analysis can be carried out using a standard mechanical legform model in order to understand potential diversities or correlations between standard tools and human models.     

流域水环境污染物总量控制技术及运用分析

本文首先阐述了TMDL在污染物总量控制中的应用,然后结合特点和存在的不足之处,对我国总量控制技术的实施现状进行了剖析,最后明确提出了水环境污染物总量控制技术实施体系的构建措施,旨在将流域水环境的污染物排放控制在合理范围内,确保良好的控制效果,最大程度地满足环境质量标准。所以现对流域水环境污染物总量控制技术及运用进行详细论述,希望为相关行业人士提供些许帮助。     

Analysis of gas flow behavior in an annular fluidized-bed reactor for polystyrene waste treatment

The characteristics of bubble properties and the chaotic flow behavior of gas were investigated in an annular fluidized bed (0.102 m in inner diameter and 2 m in height) because the behavior of gas flow in such a reactor is one of the important factors governing reactor operation, reactor performance, and the reaction itself. Pressure fluctuations as a state variable for the analysis of gas flow behavior were measured and analyzed. Bubble properties were determined by adopting the cross-correlation function of pressure fluctuations. The resultant chaotic flow behavior of gas was interpreted by means of chaotic parameters such as the Kolmogorov entropy. It was found that the Kolmogorov entropy could be utilized effectively to explain the nonlinear dynamic behavior of gas-solid flow in the annular fluidized bed. The pierced length and rising velocity of bubbles increased with increasing gas velocity, bed temperature, and particle size of the bed material. The bubble frequency increased with increasing gas velocity and bed temperature, while it decreased with increasing particle size of the bed material. Correlations to predict the bubble properties in annular fluidized-bed reactors were suggested.     

鼠李糖脂对剩余污泥中铜和镍的去除

采用批次淋洗的方法研究了鼠李糖脂浓度、pH、淋洗时间、提取次数以及重金属形态对剩余污泥中Cu和Ni去除效果的影响。结果表明,随着鼠李糖脂浓度的增加,2种重金属的去除率增加,且鼠李糖脂在碱性条件下对Cu和Ni的去除效果较好,最高去除率可分别高达80.77%和46.74%;随着振荡时间和提取次数的增加,Cu和Ni的去除率随之增加,并明显高于去离子水的提取;对污泥重金属形态进行分析发现,鼠李糖脂能有效去除酸提取态的Cu和Ni。研究结论可为剩余污泥的资源化而产生重金属安全隐患问题提供解决的参考方案和奠定理论基础。     

旋转填充床中Fenton＋O3氧化降解模拟阿莫西林废水

以旋转填充床（RPB）作为反应装置,研究了Fenton工艺与Fenton＋O3工艺处理模拟阿莫西林废水的效果,考察了FeSO4·7H2O的投加量、温度、旋转床转速、液体流量及pH对C0D去除率的影响。实验表明,Fenton＋O3工艺的COD脱除率及BOD5／COD相对于Fenton工艺分别提升26．7％和140％。该工艺在pH为3、温度为25℃、液体流量30L／h、气体流量2．5L／h、转速800r／min、H2O2的投加量为1mmol／L及Fe2＋投加量为0．4mm01／L的条件下,100mg／L的模拟阿莫西林废水中COD的去除率达到57．9％,BOD5/COD从0增加到0．36,满足后续生化处理要求。     

Characteristics of photocatalytic oxidation of toluene, benzene, and their mixture

The investigation of the photocatalytic oxidation (PCO) of multicomponent volatile organic compounds (VOCs) is very important to the application of PCO technology, because there is seldom a single VOC component in indoor air. In this paper, the characteristics of binary indoor VOCs, toluene and benzene, were experimentally studied using a mass transfer based method that we developed. The concentration ranges for toluene and benzene were 4.48-27.4 mg/m3 and 1.82-4.08 mg/m3, respectively. We found the following: (1) the PCO of each individual contaminant studied obeys the unimolecular form of the Langmuir-Hinshelwood (L-H) rate form; (2) the PCO of the binary contaminants follow the competitive adsorption L-H rate form; (3) the reaction-coefficient for PCO of individual contaminants differs from that in the competitive adsorption L-H rate form; and (4) the component impact factor of A to B, put forward in this paper, is a useful parameter describing the influence of A on the reaction coefficient of B, and it was found that the impact factor of toluene (a chemically active component) on benzene (a chemically stable component) is high, and the impact factor of benzene on toluene is low.     

pH对混合污泥水解酸化的影响

pH对剩余污泥和初沉污泥水解酸化的影响已有报道,但pH对混合污泥水解酸化的影响尚鲜见报道。为此对厌氧环境,(20±1)℃,pH=4～11以及不控制pH条件下混合污泥的水解酸化特征进行了研究。研究发现:对pH调控有利于污泥SCOD的溶出,在较强的碱性条件下污泥溶出的SCOD要大于其他条件下的,特别是pH=10和11条件下污泥溶出的SCOD要远高于其他条件下。碱性环境和酸性环境以及中性环境相比更有利于混合污泥产酸,最佳产酸pH条件为pH=10。在酸性和极端碱性条件下均有利于混合污泥中氨氮和磷的释放。碱性环境利于挥发性悬浮固体(VSS)的去除,但不利于总悬浮固体(TSS)的去除。在不同pH条件下将混合污泥的发酵特征和剩余污泥和初沉污泥发酵特征比较,发现3种污泥水解和产酸均在碱性条件下最好,且在20～22℃的条件下,产酸量均在pH=10的条件下达到最大。     

基于GIS的广西农业暴雨洪涝灾害风险评估

以自然灾害风险评估理论和方法为指导,遥感本底数据、气象数据、基础地理信息数据、社会经济数据为基础数据,构建广西农业暴雨洪涝灾害风险评估指标体系,采用层次分析及加权综合法建立农业暴雨洪涝灾害风险评估模型;借助GIS技术,计算广西农业暴雨洪涝灾害致灾因子危险性、孕灾环境敏感性、承灾体易损性、防灾减灾能力及综合风险指数,并对广西农业暴雨洪涝灾害进行风险区划,采用相关分析法将广西农业暴雨洪涝灾害风险结果与广西历史暴雨洪涝灾情数据进行对比验证,研究结果表明,农业暴雨洪涝风险分布结果与洪涝灾情损失的空间分布基本吻合,南部沿海的风险性最强,西部风险性最小。     

UASB反应器反硝化处理对氨基二苯胺生产废水

采用UASB工艺处理橡胶助剂对氨基二苯胺（RT培司）生产废水。实验结果表明：UASB启动初期（1~16 d）,COD去除率由60.8%降至24.2% ,TOC去除率由75.6%降至37.2%;UASB运行16 ~50 d,COD去除率逐渐提高;运行50 d时COD去除率为69.4%,TOC去除率高达90.0%。在进水COD负荷不超过6 kg/（m³·d）的条件下,UASB对COD的去除率为42.7%~69.4%,TOC去除率为58.0%~90.0%,NO_{3^--N去除率接近100%。本实验最佳进水TOC 与TN 比为2.0,UASB进水pH可调节为4.5左右,反应温度为18~34 ℃时对UASB反硝化处理效果影响不大。UASB对苯系化合物的去除率从高至低顺序为对硝基酚>苯酚>苯胺。}