Advanced Materials Research Vols. 955-959

Abstract: The principle and mechanism of triphenylarsine (TPA) accumulation of arsenic hyper-accumulator-Pteris vittata L was investigated to remediate soil contaminated by abandoned arsenical chemical weapons in somewhere in Jilin Province, by means of soil and water culture in the greenhouse. Through analysis of changes in concentrations of total arsenic and TPA in Pteris vittata L. and in inorganic arsenic concentration of water culture solution, observation of apparent characteristics and determination of organic arsenic forms in Pteris vittata L., results show that Pteris vittata L. could accumulate TPA in soil when the concentration of TPA in soil is less than 150 mg/kg, and the concentration of arsenic in Pteris vittata L. increase initially and then decrease with TPA concentration increasing. When Pteris vittata L. had grown 3 months, the TPA concentration reaches its maximum, i.e. 316.85mg/kg (dry), while, the bioconcentration factor (BCF) decreases gradually. Although Pteris vittata L. still could accumulate TPA after TPA concentration reached more than 150 mg/kg, arsenic concentration in Pteris vittata L. significantly reduce due to stress effect of TPA.

Abstract: Arsenic contaminated soil is a serious worldwide problem nowadays, and soil washing technique is one of hottest topics in the area of remediating arsenic contaminated soils, while treatment of the washing effluent is still an urgent problem. In this study, in order to select the best washing extractants for arsenic contaminated soil of the Xiangxi Autonomous Prefecture, nine kinds of extractants (citric acid, oxalic acid, malic acid, tartaric acid, H₃PO₄, KH₂PO₄, KOH, NH₄Ac and ultra-pure water) were studied. Innovatively, a new material (calcined Mn-Fe Layered double hydroxide) was firstly introduced and fully applied to the adsorption of arsenic washing effluents. Results showed citric acid, oxalic acid and KH₂PO₄ were the optimal extractants for arsenic contaminated soil, considering the extraction rate and environmental perspective. When the concentrations were 200, 300, 300 mmol/ L , solution soil ratios were 10, 10, 20 mL/g , extraction times were 12,12,12 h, the citric acid, oxalic acid and KH₂PO₄, respectively, achieved the maximum extraction rate of 39%, 65% and 29%. Calcined Mn-Fe LDH used in this work was characterized by SEM and FT-IR, indicating the unique structure and high phase purity of the synthetic samples. For the 28mg/L arsenic effluent washing by citric acid, calcined Mn-Fe LDH showed the most effective capacity as adsorbent under neutral or weak base condition as well as 2 h absorption time.

Abstract: Using municipal sewage treatment plant sludge as the inoculation sludge, anaerobic ammonia oxidation experiment started in a UASB reactor with an effective volume of 3.5L. The experiment lasted 116d, experimental medium term, the system NH₄⁺-N, NO₂^--N removal rates were above 50%. Changing influent load will cause a greater impact on the reactor, resulting in fluctuations of NH₄⁺-N and NO₂^--N removal rate. Late, NO₂^--N / NH₄⁺-N values ​​remain at around 1. The sludge in the reactor changed from gray-brown to pink. The system is more stable for removing NH₄⁺-N and NO₂^--N.

Abstract: Using the phosphogypsum as adsorbent prepared from microwave modified for the removal of lead ions from aqueous solution has been investigated under optimized conditions in this study. Influences of parameters like adsorbent dose 0.5-1.5g/100mL, initial concentration of ions 20–60 mg/L , pH 5.0–7.0 and temperature 20–30°C on Pb ions adsorption were also examined, using Box-Behnken design matrix. Very high regression coefficient between the variables and the response indicates excellent evaluation of experimental data by second order polynomial regression model. The response surface method indicated that adsorbent dose 1.0g/100mL, initial concentration of ions 40mg/L , pH 7.0 and temperature 20°C were optimal for adsorption of Pb ions .

Abstract: The effect of the addition of lactate on the startup of the anaerobic treatment of pharmaceutical wastewater using expanded granular sludge bed (EGSB) was investigated. Two EGSB reactors in the same size were employed. The influent of the reactor was pharmaceutical wastewater (PW), while the influent of the other reactor was the mixed water (MW) of the pharmaceutical wastewater and lactate. When the volumetric loading was 2 kg COD m^-3d^-1 and 0.4 kg SO₄^2- m^-3d^-1, the removal efficient was 91% and 90.5%, higher than the influent without lactate. The addition of lactate could improve the removal of COD and sulfate during the startup time.

Abstract: This article takes one of the mine in Caidian as an example, it analyzes the mine’s environmental geological problems and hazards, brings out the measures of recovery and management with the development and utilization, summarizes the environmental benefits of the management project. The project is a demonstration of the mine geological environment management in Wuhan. What’s more, it gives reference to similar mines’ geological environment protection and recovery management.

Abstract: Transverse and longitudinal velocity profiles on the xoy plane at z=0 and 5cm of side discharge jet under the action of crossflow and wave, velocity vectors on the xoy plane at z=0 and 5cm of side discharge jet under the action of wave and crossflow were measured by Micro ADV in this paper, respectively. Effects of wave and crossflow on velocity profiles and velocity vectors of side discharge jet were analyzed. The preliminary experimental results showed that transverse velocity profiles of side discharge jet centerline was less affected by crossflow and wave, however, effects on transverse and longitudinal velocities over the jet centerline were significant. Also, velocity vectors over of side discharge jet centerline were remarkably affected by wave and crossflow though velocity vectors on the jet centerline was less affected.

Abstract: The phytoremediation of jointly contaminated farmland soil with Cd and PAHs was studied in the long-term and representative wastewater irrigation area in Northeast China. Black nightshades (Solanum nigrum L), proved to be a Cd-hyperaccumulator was taken to remove the Cd contaminant from soil during one growing seasons in field test and thirteen lawn grasses and pasture grasses were taken to remediate the PAHs in pot experiments. Results showed that the residual concentrations Cd and PAHs were 1.94~3.69 mg/kg (dry weight) and 1.69~2.71 mg/kg (dry weight), respectively, still much higher than the Soil Quality Standard after the stop of wastewater irrigation for more than 20 years. The black nightshades could tolerate and grow well in the jointly contaminated farmland, with the distribution sequence of Cd in the order of leaf> stem> fruit> root, and the removal rate in the high-density black nightshade treatment was 1.40 percent in one growing season, higher than that in the moderate-density treatment and low-density treatment. Alfalfa, rye grass, Balin, tall fescue and white clover were more efficient than others of the tested thirteen grasses for the remediation of PAH-contaminated soil.

Abstract: Constructed wetland is a new type of water treatment technology which has been in great price for its characteristic including low cost, simplicity of operator and landscape value. Climatic environment and temperature has a strong influence to the wetlands which restricts the application of constructed wetlands in the northern cold areas. This paper elaborated the technical progress of constructed wetlands, analyzed the problems in the operational process of constructed wetlands located in low-temperate areas in winter, offered some solving measures which could make sure the wetlands running steadily including interior structure optimization and external insulation.

Abstract: Sewage treatment plant reconstruction project in cold area of China (the scale of processing is 20×10⁴m³/d). The project have adopted advanced MBR process for both lacking space and improving effluent quality requirements .After secondary treatment, sewage flow through invasive hollow fiber membrane module to dewater, and then discharged the water after chlorination. Relatively, designed effluent quality is stable and achieve the primary standard of " comprehensively discharged standard of sewage in Liaoning province" (DB21/1627-2008). This paper introduced the technological process and main structure design parameters, the maintenance of membrane module as well as economic and environmental benefits analysis and so on of the sewage treatment plant.