Applied Mechanics and Materials Vols. 448-453

Abstract: Research was conducted on pilot-scale, two-stage batch-flow constructed wetland systems for domestic wastewater treatment. Synthetic domestic wastewater was treated in a pre-acidification reactor with a hydraulic retention time (HRT) of 3 hours and the average removal rate of chemical oxygen demand (COD) and ammonia-nitrogen (NH₄-N) reached 30% and 13.6%, respectively. The first-stage constructed wetland operated with up-flow and batch feed and drain. One cycle was 12h, including 6h feed and 6h drain. With HRT of 3 days, the effluent COD concentrations fluctuated from 32.5 mg/L to 103.4 mg/L, removal rates varied from 60% to 88%; effluent NH₄-N concentrations were in the range of 4.8 mg/L to 10.8 mg/L, removal rates varied from 50% to 70%. The second-stage constructed wetland operated with down-flow, which one cycle was 24h, including 12h feed and 12h drain. With HRT of 1 day, effluent COD concentrations varied from 15.7 mg/L to 48.7 mg/L, removal averaged 53.2%; effluent NH₄-N concentrations ranged from 0 mg/L to 0.4 mg/L, average removal exceeded 99%. The spatial variation of COD and NH₄-N in the first-stage constructed wetland demonstrated that entrainment of air during draining of constructed wetland could strengthen the removal of COD and NH₄-N. Temperature had no significant effect on COD degradation while obviously affected the removal of NH₄-N.

Abstract: The influences on the performance of wet flue gas desulfurization system in mercury removing after adding mercury removal additive were studied. As a consequence, the mercury removal efficiency can be improved by this kind of additive, that the efficiency of elemental mercury and total mercury is raised along with the amount of additive is increased. And so can the desulfuration efficiency. The oxidation of calcium sulfite in desulfurization is promoted by the mercury removal additive, increase the reduce speed of calcium sulfite concentration.

Abstract: Pesticide pollutions have become increasingly severe. Especially the extensive production and application of chlorpyrifos have resulted in the environmental pollution and ecological damage. The employment of the immobilized microorganism degradation of chlorpyrifos in soil is a kind of effective technology without secondary pollution. The best ratio of immobilized carrier has been determined by comparison among different carriers for chlorpyrifos degradation. Based upon the adoption of Bacillus LLBD4, pH value, temperature and initial concentration of chlorpyrifos were studied in this experiment. The results showed that the combination of 10% of PVC, 1% of activated carbon and 0.5% sodium alginate can be served as the best carrier, furthermore, chlorpyrifos degradation efficiency reached the peak when the pH was set to 7.0, the initial concentration of chlorpyrifos was 100 mg·L^-1 at 30°C, reaching about 83%.

Abstract: Iron-carbon micro-electrolysis was applied in the treatment of the steel wastewater containing chromium,The effects of initial pH, stirring speed, Fe /C (quality), reaction time were investigated by single factor experiments. According to the results of the static experiments, the dynamic test is carried out in a fixed bed reactor composed of iron and carbon,the experimental results show that when the flow rate of less than 40ml/min, the system can be continuously stable operation 6h.

Abstract: Select the e-waste in the PC board as the research object, and through microwave-assisted digestion and flip Preparation leaching solution, respectively, using inductively coupled plasma atomic emission spectrometry (ICP-AES) and gas chromatography - mass spectrometry (GC-MS) analysis of the circuit board test results with HJ/T299 set forth in the various elements and organic matter concentration limits comparison shows that a computer circuit board has a leaching toxicity, is hazardous waste for the computer circuit boards harmless and resource provide a reliable theoretical basis.

Abstract: UV radiation, as an effective method for bacteria inactivation, has been applied popularly on ballast water treatment. However, the inactivation efficiencies of UV radiation greatly depend on the UV intensity which distributed unevenly in water and can be deeply affected by the suspending particles in water. For better understanding of the spatial distribution of UV radiation, a 16W UVC lamp was measured underwater to detect the radiant intensity over horizontal and vertical distance. The distribution tendency of UV radiant intensity was probed behind large amounts of experimental data. In addition, four types of different water including tap water, clean seawater, seawater mixed with suspending substances (SS), and seawater mixed with typical algae, were studied to identity the influence of water environment on UV transmission. The impacting significances were compared among different water quality, to optimize the ballast water treatment methods combining with UV radiation.

Abstract: A novel process of CO₂ sequestration in mixtures of sodium humate (HA-Na) and waste gypsum was proposed. Experiments investigated the CO₂ absorption properties for HA-Na solution. HA-Na solution shows great performance in CO₂ absorption, and the CO₂ absorption amount reaches to 0.96 mol for 3 hours with 100 mL HA-Na solution (0.04 g/mL), at the condition of 15 °C, gas flow rate of 40 mL/h. the CO₂ sequestration mechanism by HA-Na and desulfurization gypsum (DG) was analyzed. CaSO₄ plays a key role in the CO₂ absorption by HA-Na solution. A permanent method of CO₂ sequestration is achieved by the mixtures of HA-Na and waste gypsum.

Abstract: Five different lengths artificial aquatic plants were used to purify wastewater. The artificial aquatic strings of 10cm diameter cylinder were divided into five groups, such as 0cm (A, CK), 50cm (B),100cm (C),150cm (D) and 200cm (E), respectively. The experimental results showed that the best removal efficiency was 78.3% and 73.5% for COD and ammonina nitrogen in the C group, and for the total phosphorus (TP), the best removal efficiency was 61.3% in the B group. Therefore, it is suggested that the best length is 100cm at 22°C to 26°C in the water according to the comprehensive removal efficiency.

Abstract: Most odorous compounds are toxic or hazardous for ecological environment and human health. Compare with the physical or chemical methods, the biological technologies can offer a cost effective and environment friendly alternative to odorous control. The microorganisms in the bioreactor were mainly the bacteria. But the removal efficient (RE) of pollutants by bacteria in the conditions of low moisture content and low pH seemed not so excellent. Recently, fungi were found that they could keep high activity and grew better in this condition than bacteria, and some characteristics of fungi were favor to the pollutions degradation, which showed the great potential to treat the hydrophobic compounds of the odors. Some scholars had paid their attentions in this field and did related researches. This review aimed to summarize the studies about the use of fungi in the odorous treatment and insight into the future research and development (R&D) needs of fungi in odorous control.

Abstract: Erlongshan Reservoir water quality was evaluated for Class Ⅳand Class Ⅴby monitoring continuously indexes and was unable to meet the requirement of central drinking water source due to higher COD_Mn, TN and TP and eutrophic environment. The treatment measure including pollution source control and pollutant reduction was put forward for the sake of water quality improvement.