Applied Mechanics and Materials Vols. 295-298

Abstract: The treatment efficiency of domestic sewage by the SBR filled with humus soil was investigated and compared with that by the conventional SBR. The results show that the removal rates of organic matters, NH4+-N and TP by the SBR filled with humus soil reach 85%, 83% and 72% respectively. Compared with the conventional SBR, the degradation rate of organic matters is improved, and the addition of humus soil contributes to occurrence of SND, thus the removal rate of NH4+-N is increased. The addition of humus soil shortens the oxidation time of organic matters and the nitrification time of NH4+-N, which can improve the treatment efficiency and reduce the operation cost.

Abstract: With the increasing incidence of accidental oil spills, there is now a growing worldwide concern about the urgent need to purify oil-polluted sea water and conserve the marine ecosystem. Carbonized rice hull (CRH) prepared in the open air has been studied as adsorbent for purification of oil-polluted sea water. The adsorption effects of CRH and CRH absorption bag were both investigated. The results showed that under the dosage of 20 g/L and initial oil concentration of 746, 520 and 380 μg/L, the obtained oil removal efficiencies were 59.0%，78.8% and 67.1%, respectively. The adsorption bag counterpart indicated that under the initial oil concentration of 546 μg/L, an equilibrium state was reached for all the three kinds of package bags. The obtained adsorption amounts were 21.7, 25.5, 22.8 μg/g and the corresponding removal efficiencies were 59.7%, 70.0% and 62.6%, respectively.

Abstract: Using electrochemical oxidation method treats the acid red 3R simulation wastewater, investigates the influence of current density, electrolyte concentration, pH-value and aeration and their interaction on the removal rate of chroma. Through the design of Box-Benhnken Design(BBD) and the response surface analysis, the influence sequence of all variables is current density > aeration > electrolyte concentration > pH-value, the influence sequence of all interaction is electrolyte concentration-aeration > current density-aeration ,electrolyte concentration-pH value > current density-pH value > pH value-aeration > current density-electrolyte concentration. Ultimately, the optimal value is 98.4915% under the condition of current density of 6.51mA/cm2,electrolyte concentration of 0.04mol/L,pH-value of 4.17 and aeration of 0.24m3/h.

Abstract: This research has discussed the biofilm formation on the treatment of pharmaceutical wastewater in BAF. The removal rate of COD and NH3-N and law of the performance on the temperature and height of fillers are studied here. The results show that the BAF can still maintain a higher COD removal rate in the 13°C-25°C, the average removal rate reaches 86.9%. The denitrification is impacted by low temperature that the average removal rate of 74.7%. Experiment shows that, from 0cm to 65cm part, the removal rate of COD reachs 86.3%. The good performance of NH3-N removal rate mainly concentrates in the height of 35cm ~ 95cm.

Abstract: The composition of acidizing waste fluid is complicated, its chromaticity is high, the demand of chemical oxygen (CODCr) is high and hard to be degraded by biochemical treatment. That is why it causes serious pollution to the environments. The four process--neutralization/iron chipping micro-electrolysis/oxidation/coagulation were used to treat acidizing waste fluid. A new method of treating acidizing waste fluid with the neutralization/iron chipping micro-electrolysis/oxidation/coagulation was put forward. The optimal conditions of the treatment of single reaction are given. The experimental results showed that if neutralization/iron chipping micro-electrolysis/oxidation/coagulation are used, the removal rate of chromaticity is 100%, the removal rate of CODCr is more than 96%, CODCr could be reduced to less than 150mg/L, and the treated wastewater can come to the second discharge standard allowing to be discharged. The analysis result shows that lixivium from solidified sludge cake of per unit operation comply with the second kind of general industrial sold of state standard for pollution control on the storage and disposal site for general industrial sold,GB18599-2001.

Abstract: The coagulation/iron chipping micro-electrolysis process was used to treat drilling wastewater .A new method of the depth removal of CODCr in wastewater from petroleum drilling was put forward. The effects on the reaction were investigated by single factor tests. The optimal conditions of the treatment are given as follows: weight ratio of iron chipping to reactive carbon 0.5, pH1.0, reaction time 2 hours, normal atmospheric temperature, after reacting the pH in solution being adjusted to be 11 by lime milk. The experimental results showed that following chemical coagulation/micro-electrolysis process, the removal rate of chromaticity is 100%, CODCr could be reduced to less than 150mg/L and the treated wastewater can come to the first and the second discharge standard of state comprehensive discharge criteria GB8978-1996. The analytic result shows that lixivium from solidified sludge cake of per unit operation comply with the second kind of general industrial sold of state standard for pollution control on the storage and disposal site for general industrial sold,GB18599-2001.

Abstract: Bacillus thuringiensis (Bt) and purple nonsulfuer photosynthetic bacteria (PSB) are effective in the degradation of nutrients in fishmeal wastewater (FW) in the present study. The Bt was first cultivated in formulation FW, and then FW treated by Bt was further treated by PSB isolates. The Bt spore count reaches up to 3.15x109cell/ml and its sporulation rate achieves 99% after incubation for 72 h at 28±2°C. Under aerobic with light condition with a PSB inoculum: FW ratio of 1:3, the proliferated PSB cells weighs 13.5 g/ l after being incubated for 72 h at 28±2°C. The treatments of FW with Bt followed by PSB significantly reduces the chemical oxygen demand, total protein, total nitrogen, total phosphorus, and salinity. Their total removal rates are 91.1%, 78.8%, 89.6%, 76.3% and 21.0%, respectively. The ammonia nitrogen increases by 46.3% .The rapid nutrient removal and cell proliferation may make Bt and PSB applicable in treating FW to reduce environmental pollution and produce valuable bacteria.

Abstract: Magnetic flocculation technology was investigated for the removal of copper and zinc ions from simulated tin smelting wastewater, and the effects of magnetic powder dosage, flocculant dosage, and pH on the removal of copper and zinc ions were estimated. The results show that the effluent quality is poor with magnetic powder, PAC and PAM separately dosed, but when magnetic powder is combined with PAC or PAM, the excellent effluent quality is obtained with the removal rate of the copper and zinc ions of more than 90% and 70% respectively. In addition, under the condition of magnetic powder dosage of 30g/L and PAC dosage of 60mg/L, pH show more significant effect on zinc ions than copper ions with pH increased from 5 to 10, and the removal rate of zinc ions increase by about 24%, while the removal rate of copper ions only increase by about 2.5%. Compared with the system with single metal ion, the coexistent ion system has excellent heavy metal removal efficiency, namely the copper ions removal rate increase by 3.42%, and the zinc ions removal rate increase by 0.46%. Moreover, magnetic flocculation technology presents the characteristics of shorter time of flocculation and sedimentation, smaller volume of the flocs and faster separation velocity.

Abstract: By- products are widespread in the crystallization of magnesium ammonia phosphate (MAP) as the differences in reactive conditions which effects the forms and habits of crystals. The study focused on the supernatant from septic tank in order to achieve in-situ treatment. Based on the effluent, the optimization research of initial phosphate concentration and pH was investigated by using single factor analysis. The crystal products with different reaction condition were also characteristiced through the XRD analysis. The experimental results showed that the optimum reactants molar ratio of n(NH4+):n(Mg2+):n(PO43-) were 90:25:1, 4:1.6:1 and 3:1.4:1 when pH value was 9.5 with initial phosphate concentration 8mg/L, 50mg/L and 100mg/L, respectively. It was also observed that the phosphate removal rate increased with increasing the initial phosphate concentration or pH value. As the aging time increased, the removal rate was in parabolic curve with 30 minute at the highest point. The XRD analysis revealed that the best MAP crystal could be produced with initial phosphate concentration 50mg/L and pH 9.0.

Abstract: With the rapid development in industrialization and urbanization, various air pollutants are emitted into atmospheric environment. NO, SO₂, Hg⁰ are the most important pollutant in the flue gas. The application of non-thermal plasma (NTP) technology in the removal of NO, SO₂, Hg⁰ was reviewed respectively. Environmental applications have mainly involved plus corona discharge (PCD) and dielectric barrier discharge (DBD) system. In the future, the application of plasma technology in the flue gas could be focused on multiple pollutants synergistic mechanism.