Simulation analysis of environmental risk accident and management of high-sulfur gas field development in complex terrain

Environmental risk of high sulfur gas field exploitation has become one of the hot spots of environmental management studies. Severe gas H₂S blowout accidents in recent years have shown that poor understanding and estimates of the poisonous gas movement could lead to dangerous evacuation delays. It is important to evaluate the real concentration of H₂S, especially in complex terrain. Traditional experiential models are not valid in the case of rough terrain, especially in low-lying areas where the gas accumulates. This study, using high sulfur content gas field of Sichuan “Pu Guang gas field” as study object and adopting objective diagnosis of wind field of land following coordinate three dimensions, applied Lagrangian Puff Model and breaking up technique of puffs to simulate the H₂S diffusion condition of blowout accidents produced in the high sulfur content gas field of complex terrain area. The results showed that the H₂S distribution did not occur mainly in low wind direction, and due to the obstruction of the mountain’s body, it accumulated in front of mountain on produced turn over, flowed around submitted jumping type distribution. The mountain waist near the hilltop and low hollow river valley site rapture points simulating contrast showed that the higher the rapture point, the better the diffusing condition of pollutant, the distribution of risk sensitive point decided piping rupture environmental risk size combining the H₂S diffusion result and residential area dispersing in the study area, synthetic judge located in the high rapture point environmental risk was smaller than the low hollow point, thus it was suggested to carryout laying of lining build of equal high line of higher terrain. According to simulation results, the environmental risk management measures aimed at putting down adverse effects were worked out.     

Experimental study on the control of black smoke pollution from the ceramic kilns based on the mechanism of the surfactant and coagulant

Aiming at the characteristics of carbon black, a new method of controlling the black smoke from the industrial coal-burning ceramic kilns by wetting was brought forward. The carbon black in the flue of coal-burning ceramic kiln was collected for the experiments, and its physical and chemical properties were studied in detail. In order to change the sedimentation and wettability state of the carbon black, the complex solution of the coagulant and surfactant was applied. After a series of orthogonal experiments, the complex solutions with better effects were chosen. Then, the sedimentation percentage of carbon black treated by the selected complex solutions was measured. The optimized complex solutions included Na₂SO₄ (100 mmol/L), sodium dodecyl benzenesulfonate (SDBS) (1.2 mmol/L) and polyacrylamide (PAM) (40 mg/L). After carbon black was absorbed, the complex solutions were clear and colorless. The complex solutions can be recycled, and the sedimentation percentage of carbon black is 94%.     

化工过程废物最小化方法的研究进展

系统化的废物最小化方法对于环境友好且具有竞争力的化工过程的研发、综合、设计和改造具有非常重要的指导作用。简介了废物最小化的一般原则;综述了目前国内外各类系统的废物最小化方法,包括定性类方法如分层决策法、环境优化技术法、结构化法及3Es法等,定量类方法如各种数学优化法、夹点分析法、废物削减算法以及人工智能法及组合式方法;展望了该领域的研究发展趋势。     

生物过滤氧化反应器处理焦化废水

针对钢铁厂焦化车间采用普通活性污泥工艺处理焦化废水 ,出水水质经常超标 ,且对冲击负荷适应力差的情况 ,使用生物过滤氧化反应器 (BIOFOR)工艺对废水进一步进行处理 ,运行结果表明 ,BIOFOR表现出良好的抗冲击负荷能力 ,对CODCr、NH3 N、SS、油类、酚、氰化物等主要污染物的去除率都分别为 6 4 7%、79 8%、76 6 %、5 2 1%、95 4 %、6 1 4 % ,出水水质高于GB8978 1996第二类污染物二级排放标准。     

染料脱色菌的筛选及对活性艳红X-3B的脱色研究

从广州某印染厂生化处理池的活性污泥中筛选到三株对活性艳红X-3B具有高效脱色作用的真菌,其中菌株HMX-3的脱色能力最强。考察了培养时间、温度、培养方式、pH值以及染料浓度对HMX-3脱色能力的影响。结果表明,菌株HMX-3对150mg/L X-3B的24h脱色率达65.8%,经60h可使其完全脱色;HMX-3对活性艳红X-3B脱色的最适温度为25℃~35℃,最佳pH值为6~8,且振荡培养较静置培养条件下的脱色率高;随染料浓度的增加,脱色率降低,但对于400mg/L的X-3B在72h时的脱色率可达86.7%。     

Optimization of process parameters of extraction of lotaustralin from the roots of Rhodiola rosea L using supercritical CO2 plus modifier

Lotaustralin from the root of Rhodiola rosea L was extracted using supercritical carbon dioxide with methanol as modifier. Response surface methodology using Box–Behnken experimental design was utilized to explore parameters for supercritical carbon dioxide extraction. The effects of various values of temperatures (50–70 °C), pressures (200--400 bar), and percentages of methanol modifier (80%–100%) on the extraction yields of lotaustralin were evaluated. Extract identification was performed using high-performance liquid chromatography. The experimental data obtained were fitted to second-order polynomial equations and assessed using analysis of variance. The highest yields predicted from the experiments were 2.05 g kg^?1 lotaustralin at the optimal values, i.e. temperature 65 °C, pressure 316 bar, 88% methanol modifier at a flow rate of 0.4 mL min^?1, and dynamic extraction time 90 min.     

Remediation of soil and groundwater contaminated with organic chemicals using stabilized nanoparticles: Lessons from the past two decades

▪ Overviewed evolution and environmental applications of stabilized nanoparticles. ▪ Reviewed theories on particle stabilization for enhanced reactivity/deliverability. ▪ Examined various in situ remediation technologies based on stabilized nanoparticles. ▪ Summarized knowledge on transport of stabilized nanoparticles in porous media. ▪ Identified key knowledge gaps and future research needs on stabilized nanoparticles. Due to improved soil deliverability and high reactivity, stabilized nanoparticles have been studied for nearly two decades for in situ remediation of soil and groundwater contaminated with organic pollutants. While large amounts of bench- and field-scale experimental data have demonstrated the potential of the innovative technology, extensive research results have also unveiled various merits and constraints associated different soil characteristics, types of nanoparticles and particle stabilization techniques. Overall, this work aims to critically overview the fundamental principles on particle stabilization, and the evolution and some recent developments of stabilized nanoparticles for degradation of organic contaminants in soil and groundwater. The specific objectives are to: 1) overview fundamental mechanisms in nanoparticle stabilization; 2) summarize key applications of stabilized nanoparticles for in situ remediation of soil and groundwater contaminated by legacy and emerging organic chemicals; 3) update the latest knowledge on the transport and fate of stabilized nanoparticles; 4) examine the merits and constraints of stabilized nanoparticles in environmental remediation applications; and 5) identify the knowledge gaps and future research needs pertaining to stabilized nanoparticles for remediation of contaminated soil and groundwater. Per instructions of this invited special issue, this review is focused on contributions from our group (one of the pioneers in the subject field), which, however, is supplemented by important relevant works by others. The knowledge gained is expected to further advance the science and technology in the environmental applications of stabilized nanoparticles.     

Acceleration of the particulate organic matter hydrolysis by start-up stage recovery and its original microbial mechanism

• Carbon availability was partially solved by POM recovery and fermentation. • 12% carbon sources were regenerated by fermentation of the entrapped 35% TCOD. • The unique microbial communities facilitated the efficient hydrolysis of the POM. • Considerable economic benefits in aeration power and ECS dosage were anticipated. To address the availability of carbon sources for denitrification, the accelerated hydrolysis of the most abundant but low-availability fraction of particulate organic matter (POM) was investigated. Mesh sieves with different pore sizes were used as primary pretreatment at the start-up-stage of the biological process to separate some POM from the liquid system. The changes in soluble carbohydrates and proteins were monitored to investigate the hydrolysis performance of the sieved POM, with waste activated sludge (WAS) as the control test. The results showed that an average of 35% POM could be entrapped before filtrate mat development. In addition, benefiting from the high polysaccharides concentration, as well as the high availability due to the relatively loose physical structure, a 23% hydrolysis efficiency of POM was obtained, in contrast to that of WAS (3.4%), with a hydrolysis constant of 0.39 h⁻¹. The prominent performance was also attributed to the unique microbial communities having been domesticated at a lower temperature, especially the cellulose-degrading bacteria Paraclostridium and psychrophile Psychrobacter, making up 6.94% and 2.56%, respectively. Furthermore, the potential benefits and application of improved POM hydrolysis by start-up stage recovery via mesh sieves combined with anaerobic fermentation were evaluated, including selective POM entrapment, alleviation of blockage and wear, and a reduction in aeration energy. By the proposed strategy, carbon availability for biological nutrient removal (BNR) processes is anticipated to be improved more economically than that can be achieved by primary clarifier elimination.