Applied Mechanics and Materials Vols. 178-181

Abstract: Polyferric sulfate (PFS) is classified two kinds by prepared approaches: (1) alkalization preparation of polyferric sulfate (APFS), (2) oxidation preparation of polyferric sulfate (OPFS). Different properties were discussed about OPFS and APFS, such as basicity (OH/Fe³⁺), zeta(ζ)-potential, pH. It is concluded that APFS and OPFS with same basicity have different structural feature although they have same compounds and bonds. By comparison with APFS, OPFS and ferric sulfate, OPFS has good charge neutralization capability and exhibits good coagulation performance in turbidity removal for synthetic wastewater. APFS have higher interparticle bridging capability for paper wastewater.

Abstract: The removal efficiency of dibutyl phthalate (DBP) and its environmental hormone treated by biofilm reactor has been investigated. Besides, the the kinetic model of the degradation of DBP and its degradation products in the reactor have been discussed. The results indicate that the biofilm reactor had a positive effect on the removal of DBP and was able to significantly reduce the environmental hormone in DBP influent. The activity of β-galactosidase dropped from 13.55 millers to 3.3 millers and the removal efficiency of DBP reached 98.5% at water temperature 20°C and HRT (Hydraulic Retention Time) of 4 hours. The metabolic intermediate of DBP in the reactor mainly consisted of dibutyl phthalate and phthalic acid. The kinetic models of the degradation of DBP can be expressed by Lawrence-McCarty equation.

Abstract: By using grafting reaction, starch-g-poly (acrylic acid) (starch-g-PAA) hydrogel was prepared and used to adsorb methylene blue (MB). Adsorption isotherm and kinetic of the sorption process were studied. Meanwhile, various thermodynamic parameters were calculated. The absorption experimental results demonstrate that the prepared starch-g-PAA is an effective adsorbent for removal of MB from aqueous solution. The adsorption of MB by starch-g-PAA is Freundlich type. Furthermore, the adsorption kinetics analyze demonstrates that the adsorption process follows the pseudo-second-order model, and the adsorption is a multi-step process. Moreover, the calculated thermodynamic parameters indicate the spontaneous and endothermic nature of the adsorption process. The values of adsorption activation energy demonstrate that the adsorption is mainly diffusion-controlled process.

Abstract: Two continuously stirred tank reactors (CSTR) were used to investigate the effect of L-cysteine on continuous dark fermentative hydrogen production system. L-cysteine was added into one of the reactors at 0.1 g/L continuously, the other reactor was without L-cysteine addition. Liquid end products, oxidation-reduction potential (ORP), pH, biomass and hydrogen production rate (HPR) were examined during the operation. The lag time of ethanol generation in the L-cysteine added reactor was shortened to 21 days compared to 25 days in the blank. The HPR increased from 2.73 L/d in the reactor without L-cysteine addition to 2.82 L/d in the added one. The volatile suspended solids (VSS) in the reactor with L-cyateine was 10.1 g/L by the end of the operation compared to 9.2 g/L in the other. Addition of L-cysteine into the hydrogen production system accelerates the formation of ethanol-type fermentation and enhances the hydrogen production by creating an optimal low ORP environment, and by increasing the biomass growth simultaneously.

Abstract: The migration characteristics of iron ions in laterite in water can reflected by change characteristics of iron ion concentration in water solution. Its migration ability depends on itself features of laterite and the effect of external environment. The results show that, the migration ability of iron ion in laterite were weakened with increasing of compaction energy and extending of immersion times, were strengthed with increasing of moisture content and temperature. The effect of compaction energy is least, the effect of temperature is maximum, the effect of moisture content is between them. Its migration process is that iron ion of adsorption in laterite particles surface were dissolved and migrated into process of the water solution. Its migration mechanism can explained from water environmental balance and temperature balance and ion concentration balance. The results changed the migration characteristics of iron ion in laterite at different influencing factors.

Abstract: Diversion wall can improve bend flow patterns in an oxidation ditch. In this paper, a non-equal thickness diversion wall was proposed, and studied by numerical simulation method. The simulated velocity field of the new shape of oxidation ditch diversion wall was compared with that of the common shape diversion wall under the same boundary conditions, which shows that the new shape can better improve the bend flow patterns in an oxidation ditch, and reduce the size of the backflow area and increase the high-velocity region in the channel.

Abstract: The carbinol in wastewater from inhalation and direct contact present more risk to human health, as well as cause hazard to ecological environment through waste water emission directly and soil infiltration. In this paper, health risk assessment of wastewater with carbinol in gas field is performed using mathematical models of non-carcinogenic health risk assessment. The results show that the non-carcinogenic health risks caused by wastewater with carbinol are in the range of 6.33×10-5 to 9.20×10-5, which are much higher than the acceptable risk level 7.00×10-5. Through the calculation of the threshold of the carbinol concentration in the wastewater, the carbinol concentration in the wastewater is less than 24500mg/L, not on human body risks. However, the carbinol concentration in the wastewater is much than 24500mg/L, it is a health risk to human body, which provides the scientific basis for the prevention and mitigation of wastewater with carbinol health risks.

Abstract: In this paper, the flow structure of the oxidation ditch was studied using numerical simulation method and different submerged depth of aeration impellers. The computed velocity fields were analyzed, which shows that under the same conditions, and by using the optimal submerged depth the average velocity of the flow in oxidation ditch is increased and the velocity near-bottom has increased significantly. The results of comparisons show that the velocity distribution is more uniform along the depth direction, and that the flow velocity distribution structure can prevent sludge from settling in the oxidation ditch processing system at the submergence ratio called the optimal submergence ratio, which helps to improve the efficiency of oxidation ditch sewage treatment system.

Abstract: The adsorption performance of Menthylene blue from aqueous solution by furfural residue was studied. The results show that the adsorption of Menthylene blue on furfural residue reached equilibration by 60 minutes. The removal efficiency of Menthylene blue in aqueous solution on furfural residue of Menthylene blue achieved the 95.38% in 50mL 200mg.L-1 Menthylene blue aqueous solution with adding 4g/L furfural residue. The temperature had an effect on the removing of the Menthylene blue on furfural residue, and the adsorption of furfural residue to menthylene blue was decalescence reaction. The relationship between adsorbing capacity (qe) and equilibrium mass concentration (ρe) is in accordance with the isothermal adsorption equations of Freundlich and Langmuir.

Abstract: The random discharge status of acid wastewater in laboratory is a potential hazard to the municipal drainage system, wastewater treatment system and water resources. In this paper, an in-situ acid wastewater treatment equipment for laboratory is suggested. It is composed of an acid wastewater tank, an alkali wastewater tank, a neutralization tank, a washing gas box, pipes and other accessories. It can make the best use of the alkali wastewater produced in the laboratory to deal with the acid wastewater on site. The neutralization reaction takes place in the neutralization tank, and the solution reacted couldn’t be discharged into the indoor drainage pipeline until its pH qualifies the standard. Through the sludge discharge pipe, the deposits can be collected individually, and then be hurtlessly treated and reused. Meanwhile, through the washing gas box the waste gas is decontaminated and discharged into atmosphere. So it can not only reduce the environmental pollution but also lower the treatment cost which corresponds with the idea of green laboratory. This equipment has the economical, practical, and workable property. Not only that, through a reasonable transformation, it is also suitable for other kinds of wastewater, so it has a certain technical populization value.