Advanced Materials Research Vols. 518-523

Abstract: Fenton-like reaction technologies are attracting considerable attention due to the high oxidizing ability, especially in the treatment of refractory chemical contaminants. However, some disadvantages in traditional Fenton reagents limited its wide application. In this study, pyrite, a natural iron bearing mineral, was used as a new kind of Fenton-like catalyst in the treatment of textile wastewater. The catalytic activity of pyrite and the parameters influencing the removal of Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD5), such as pyrite dosage, H2O2 concentration, pH, and suspended solids (SS) had been systematically examined. Results showed that pyrite exhibited a high catalytic reactivity over a wide pH value range. At the optimal conditions, a COD removal rate of 70% and an increase in the mass ratio of BOD5/COD (B/C) from 0.25 to 0.56 were achieved in the presence of 9.7 mM H2O2 and 10 g/L pyrite at initial solution pH value of 9.0. And what’s more, a rapid decrease in solution pH and a high level of iron were observed when pyrite was added to the wastewater, probably due to the oxidative dissolution of pyrite. Consequently, Apart from the heterogeneous process, it was found that a homogeneous interaction between ferrous iron and H2O2 in a classical Haber-Weiss mechanism was also occurred. The wonderful reactivity of pyrite makes it be used as catalyst for the oxidative technology to treat the original wastewater without the need to pre-adjust the solution pH.

Abstract: Electrostatic precipitator is a kind of important dust collecting equipment. The rapping acceleration is the standard of electrostatic precipitator design and manufacturing. The aim of the work reported in this paper was find a new method for solving the rapping acceleration. Based on the numerical analytical method and the dynamic display algorithm, this paper is to build a new method for solving the rapping acceleration of electrostatic precipitator by using finite element method. By comparing the results of finite element method and the model test data and analyzing calculation results, this method is proved to be correct and effective. Using this method in the analyzing of practical equipment, the result basically tallies with the actual result. The finite element method can be used conveniently in different plate profiles, different ways of hanging, striking hammers and different methods of rapping. So the finite element method has an important practical significance in the analyzing of existing plate and the researching of new plate.

Abstract: Domestic sewage was treated by adopting flocculation, anaerobic and microaerobic combined process under normal temperature. The result demonstrates: total hydraulic retention time is 5.5h (chemical flocculation 1.0h, UASB reactor 2.0h and MUSB reactor 2.5h). UASB reactor can achieve anaerobic sludge granulation under normal temperature and is fairly feasible for low concentration domestic sewage treatment. Compared with single stage UASB reactor, hydraulic retention time of flocculation-UASB combined technique reduces from 4h to 2h. COD removal rate rises from 45% to 50%-60% and suspended COD is mainly removed. DO of microaerobic MUSB technique after anaerobic treatment is 0.2mg/L-0.5mg/L with air and water ratio of 1:1. Effluent quality is stable, in accordance with first standard of Synthetical Draining Standard of Sewage, GB8978—1996.

Abstract: Based on the eco-hydrogeological survey, sampling analysis and combined with groundwater flow systems theory, studied a gully gangue yards of Daliuta mine area on groundwater environmental effect. The results showed that pile of coal waste change the original characteristics of groundwater flow systems, the bottom of gangue heap long term immersion in groundwater, the toxic and hazardous substances unleashing, and with the groundwater runoff to the downstream spread. Combined with the eco-hydrogeology and hydrogeochemistry method, using the Loess carry out the gangue vegetation restoration and groundwater pollution remediation: by cover about 0.3m thickness loess at the top of the gangue yards, and planting Alfalfa, Artemisia ordosica, in order to restoration vegetation of the upper part of sites; In the downstream of gangue yards construct the loess permeable reactive barrier, using the loess adsorb the pollutants in the gangue leachate and purify the groundwater. Through the treatment approaches, gangue yards ecological and groundwater environment has been greatly improved.

Abstract: By the static experiment, we studied the electrochemical oxidation process of simulated hydroquinone wastewater (concentration for 300mg•L-1) in the three-dimensional cell. Experimental inspected how various factors of the packing quality ratio, electrolysis voltage, supporting electrolyte concentration, and the initial pH value influence the effect of the removal of hydroquinone and CODCr. The results of the experiment clearly indicated with the increase of voltage applied the removal rate of hydroquinone and CODCr increased first and then decreased, finally and increased again. In the weak alkali conditions (pH=8.5), the removal rate of hydroquinone and CODCr is the highest, Electrolyte concentration and packing quality ratio to the effect of hydroquinone by electrochemical degradation is the larger. The results of the single factor analysis show that the most suitable processing conditions of simulated hydroquinone wastewater by bipolar electrocatalysis oxidation are the Na2SO4 concentration of 0.03mol•L-1, the electrolytic voltage of 6V, the initial pH value of 8.5, the packing quality ratio of 1:2. With this condition processing 3h, the removal rate of hydroquinone and CODCr reached 83.96% and 39.9%, respectively.

Abstract: Compacted clay is commonly used as an essential material for reducing the permeability in landfill sites. However, compacted clay has defect with shrinkage and desiccation cracking during cyclic drying and wetting, which may increase hydraulic conductivity of compacted clay. It’s necessary to modify clay, and make it have anti-cracking performance. The main objective of the study is to determine the content of fly ash on clay. Laboratory tests were done to determine optimum moisture content, hydraulic conductivity, volume shrinkage on different content fly ash modified clay. It was determined that a certain proportion of fly ash can improve the permeability of clay, and reduce the cracking clay.

Abstract: An innovative biological wastewater treatment system for the removal of organic carbon, sulfur and nitrogen was developed based on biological phase-separation principle. This system consists of three reactors integrated together i.e. sulfate reduction and organic matter removal (SR-CR), autotrophic and heterotrophic denitrifying sulfide removal (A&H-DSR) and nitrification (AN) reactors. In this system, the operational parameters for successful bio-phase separation are sulfate and organic loading rate, hydraulic retention time (HRT), COD/SO₄^2- ratio and pH for the SR-CR reactor, and sulfide and nitrate loading rate, HRT, pH, S ^2- /NO₃^- ratio and COD/NO₃^- for the A&H-DSR reactor. The results from a laboratory scale system demonstrated that for the SR-CR reactor, the optimal operating conditions were HRT≥24 h; sulfate and organic loading rate ≤7.5 kg SO₄^2- /m³•d and ≤10 kgCOD/m³•d; COD/SO₄^2- ≥2; and pH ≥6.5. For A&H-DSR process, the optimal conditions are sulfide loading rate ≤6.0kg S ^2- /m³•d; nitrate loading rate ≤3.5 kg NO₃^-/m³•d; S ^2- /NO₃^-≥1; COD/NO₃^- ≥1.25:1; and pH≥7.5. Under such conditions, high sulfate, ammonia and organic matter removal of 99%, 90% and 99% were achieved, respectively. In this case, the elemental sulfur (S⁰) reclamation efficiency reached 6.0 kg S⁰/m³•d, around 20 times higher than the maximum level as referred in the literatures. DGGE profiling indicated that the predominant functional organisms of Clostridiaceae sp., Desulfomicrobium sp., Methanosaeta sp. dominated in the SR-CR reactor, and Sulfurovum sp., Pseudomonas aeruginosa and Denitratisoma sp. in the A&H-DSR reactor. These species played essential role in metabolic functions in each bio-phase.

Abstract: 14 species of fungi were isolated by the dilution flat method. The laccase activity of numberD2 was the highest (216.45IU) in liquid culture after 15d, it was highest inoculated numberD2, numberD51 and number5 in oil degradation test after 30d of incubation, 48.41IU,5IU and 0.7IU, respectively. The oil degradation rate increased with the time of incubation in COM medium. The rate inoculated numberD52 was the most (64.26%), and was Significantly higher than CK(18.98%). The rate inoculated number3 was the least, and was only 1.40% higher than CK. The Analysis GC-MS results showed that different strains were able to degrade the specific oil components. For the particularity of the strains, it was possible to increase the oil degradation rate with the combination of the strains.

Abstract: The kinetic model of organic removal in single biological aerated filter for domestic waste water treatment was established, and kinetic parameter was calibrated under certain hydraulic loadings. The results showed that organic removal efficiency was affected by the concentration of the influent COD, hydraulic loadings and the height of filter media when the reactor size was unchangeable. It is found that the model was accurate in predicting the effluent quality by the experiment and it could afford new reference evident to optimize the treatment processes.

Abstract: A leaching experiment was carried out over a period of 90 days to determine the manganese (Mn) and iron (Fe) leaching characteristics from artificial soils composed of sewage sludge and fly ash. The leachates of artificial soils were collected every 15 days and the concentration of manganese and iron in leachates of the artificial soil was measured. Results showed that the concentration of Fe and Mn in leachates of artificial soils got to a stable level by the end of the experiment. Moreover, plant Robina pseudoacacia and Amorpha fruticosa had different effect on the leachate Fe and Mn concentration. Robina pseudoacacia resulted in higher leachate Fe concentration, while Amorpha fruticosa resulted in higher Mn concentration. However, the leachate Fe and Mn concentrations from artificial soils was high, and it will also be transported to the surface and ground water. Therefore, some measures should be taken to reduce the concentration of heavy metals in the leachates before these artificial soils being applied on the ecological rehabilitation in mine spoil areas.