Advanced Materials Research Vols. 518-523

Abstract: Electrokinetics is a soil remediation technology under development. One of its advantages is that it can realize in suit remediation. A series of bench-scale experiments were carried out and result showed that electrokinetic technology was effective in promoting BDE15 desorption and migration in soil, and its effect depends on the type of electrodynamics. Ion concentration was changed for the electrolysis reaction, and lead to current changed. The current variation tendency was increase first then decrease.Soil pH and temperature was changed as a result of electric field, soil resistance and temperature increases, the cathode temperature up to 40°C.

Abstract: In this paper, we utilized IC reactor to treat straw-washing wastewater of straw pulping and papermaking. The removal rate of COD in normal operation is 28.14%, which is much lower than the value of wake-up stage and acclimation stage; gas production rate in the whole normal operation phase kept a lower level, and the average is 12.36L/h; so straw-washing water is not suitable for advanced anaerobic treatment. While COD removal rate is 28.14%, SCOD removal rate is only 6.96%; added the effluent VFA concentration which is 692~1211mg/L is greatly exceed normal control level, we can know that when treating straw-washing water the biological system was under acidification phase of the anaerobic process. Thus the straw-washing water is suitable for hydrolysis-acidification Process. Granular size of seed sludge was 3~5mm, 100 days later it became 1.5~3mm, and 120 days later it was 1~2.5mm mainly, With the acidification occurring, the mass proportion of the granular sludge to total sludge was reduced, the proportions of 2# and 3# sampling ports are decreasing from 70~85% to 30~50%. Because of lack of adequate nutrition and appropriate loading conditions, straw-washing water can’t support the cultivation and maintenance of granular sludge.

Abstract: The magnetic chitosan microparticles were prepared by microemulsion method and raid removal of Cd(Ⅱ) and Pb(Ⅱ). Batch tests were carried out to investigate the adsorption performance. It was found that adsorption of Pb²⁺ and Cd²⁺ was dependent on pH, and increasing the pH is favorable for heavy metal ions removal. The sorption isotherms of the adsorbent for these metals fitted better with Freundlich model than the Langmuir model, with maximum adsorption capacities of 69.83 mg/g and 18.03 mg/g for Pb²⁺ and Cd²⁺, respectively. The adsorption equilibrium was reached within 15 min. The temperature effects revealed that the adsorption capacity increased significantly with increasing temperature, and the adsorption process was endothermic in nature at 25°C to 75°C.

Abstract: In order to further improve the collection efficiency of ESP especially for high-resistivity dust and perfect electrostatic collection theory, how dust layer effects collection efficiency should be revealed more accurately. Taking dust layer as research object, the paper has theoretically analysed the charge distribution of dust layer based on basic principles of electrostatics and Ohm’s Law in order to deduce the formula of the amount of accumulated charge in dust layer. The formula of electric-field strength formed by accumulated charges in collection space was deduced according to the principle of constant voltage and the potential continuity principle of phase boundary. Then the formulas of calculating the effective collecting electric-field and the effective theory migration velocity of charged particles were obtained. The theoretical criterion of occurring back corona was proposed by theoretical analysis of distribution characteristics of electric-field strength in dust layer. Besides that, the elaboration of non-static electrostatic collection theory has enriched and developed the traditional electrostatic collection theory. The paper has player an important role in the design of structure and the selection of operating parameters of ESP, and in the direction to explore the new ways of improving collection efficiency of high-resistivity dust.

Abstract: In this experimentation an A/O submerged membrane bioreactor was designed to study the treatment of oil-refining wastewater. The result show that the average effluent COD was below 18 mg/L, the removal rate of COD was over 97% and the removal rate was stable; the removal rate of NH4+-N was influenced by PH value, the average effluent NH4+-N was less than 0.97 mg/L and the average removal rate was over 98%; the average effluent oil was below 5mg/L and removal rate was over 96%; effluent phenol was less than 0.12mg/L and the removal rate was nearly 100%.

Abstract: Potassium permanganate composites (PPC) preoxidation/coagulation/ sedimentation/ultrafiltration process was used to treat algae-rich reservoir water. The results of the process optimization tests showed that the optimal dosage of polyaluminium chloride and PPC are respectively 3mg/L and 0.4mg/L. The effect of PPC preoxidation on the coagulation/sedimentation/ultrafiltration process was studied on the pilot device. The combined process can control the effluent turbidity under 0.1NTU. The dosing of 0.4mg/L PPC can increase the removal rate of UV254¬ and algae by 10% and 28% respectively. The synergetic effect between PPC preoxidation and ultrafiltration can enhance the removal of pollutants such as organic matter and algae and control the membrane fouling by decrease the foulant load on the membrane

Abstract: The main objective of this study is to investigate the feasibility of treatment of livestock waste water with biogas slurry by the constructed wetland and provide the operation parameters for a full scale constructed wetland to improve the quality of waste water. The results showed that when the influent flux was 1.5m3/d, the average removal rates of Turbidity, COD, TN, NH4+-N and TP in the horizontal subsurface flow constructed wetland system were 89.57%, 59.21%, 55.09% 55.57% and 53.80% respectively. The wetland system has high treatment effect and run stably in the pretreatment process of livestock waste water with biogas slurry.

Abstract: Treatment of municipal wastewater with biological/chemical process was studied in this paper. Chemical agents-polyaluninum sulfate was selected in this test to determine the effect on phosphorus removal and to assess the effect of coagulants on denitrification and organics removal by using coagulants cooperated with organisms. The result indicated that the removal efficiency of total phosphorus increased by 74.2%, and raised noticeably and meets the first class standard(GB 8978-1996) ,the average removal efficiencies of total nitrogen and organic increased by 0.04% and 8.2%. It was verified that the PAS together with activated sludge have the synergistic effect on nitrogen and phosphorus removal and the organic compound removal.

Abstract: A pellet method was used to treat the radioactive wastewater in the paper. Calcium carbonate powders were used to prepare seeds, sodium carbonate was used as the chemical precipitant and the natural isotope of strontium (88Sr) was used instead of 90Sr. The strontium element was removed by forming compacted crystal particles on the seeds. The impact of temperature on seed preparation and the effect of the process were studied. After 30 cycles of operation, the calcium carbonate powders grew to larger particles and the effluent turbidity and hardness maintained stable. Therefore it was enough for 30 cycles to complete the preparation of the seeds. When the seeds were used to treat the strontium wastewater, the effluent turbidity was initially high and then declined quickly. The average effluent turbidity was 0.51NTU. The mean hardness removal efficiency was 55.24%. The strontium removal rate fluctuated and the average removal efficiency was 97.36%. Ferric chloride coagulation and micro-filtration would enhance the effect of strontium removal. The average removal efficiency could be up to 99%. The formation of pellets enhanced the sedimentation performance of the precipitates formed. The mixture was kept quiescent for 24h after the test was over. The chemical sludge concentration factor was more than 5000.

Abstract: In accordance with the shortcoming of naturally purification processing to liquid propellant dimethyl hydrazine waste water, the paper is putting forward the combined processing technology of naturally purification and artificial wetland. Designed process flow of the combined processing technology, and the naturally purification and artificial wetland dealing with the structure of pond, and to his processing dimethyl hydrazine the effect to imitate waste water has been in progress research. The result indicates: the technology can effective remove dimethyl hydrazine and his degradation product in the waste water, and the back waste water of processing achieves the placing in proper order quota.