Papers by Author: Jie Ding

Abstract: The internal flow field of EGSB (Expanded Granular Sludge Bed) reactor was investigated by using CFD simulation. A three-dimensional Eulerian–Eulerian two phase (sewage-granular sludge) fluid model was applied to investigate the impact of water distribution system on the internal flow field by considering the ratio α of hole area to reactor area. Results showed that the flow state of sludge granules changed periodically when the sludge bed reached a stabilization stage, and every cycle included two periods (U period and D period), where U stands for up-flow of the granular sludge and D represents down-flow. Keeping the upward-flow velocity of reactor at 3 m/h and reducing ratio α from 1.44% to 0.25%, the flow state of the two periods changed differently and was closely related to the height of reactor. Besides, the ratio α could affect the homogeneity of sludge granules, which could further influence the performance of the reactor. In addition, a validation experiment was conducted to verify the practical applicability of the fluid model, a good relationship between simulation and experiment was discovered, which further confirmed that the ratio α of water distribution system has significant impact on the internal flow field of EGSB.

Abstract: In this paper, poly aluminium chloride (PAC) was used to remove phenol and aniline from the aqueous phase .The adsorption properties of this process was investigated by zeta potential measurement, infrared spectroscopy and the analysis of pollutants structure and adsorption kinetic. The results described that not only electrostatic attraction but hydrogen adsorption were the main mechanism of both the phenol adsorption and the aniline adsorption. The pseudo second-order kinetic equation could best describe these two adsorption kinetics. The calculated activated energy of adsorption processes of phenol and aniline were 47.2KJ/mol and 44KJ/mol, respectively, which indicated that the adsorption process was chemisorption. Friedrich model was fitter to describe the adsorption isotherm of these two adsorption processes.

Abstract: The reactor was started up under the neutral condition. The pH value in the reactor was gradually lowered down. At pH 7.0, the average COD removal efficiency the biogas yield and the methane content of the UASB reactor were steady at 93% above, 25L·d^-1 and 54%, respectively. During the period of the pH value lowered from 7.0 to 5.5, the average of the COD removal efficiency, the biogas yield and the methane content of the UASB reactor were 83.1%, 19.6L/d and 47.7%, respectively. At pH 5.5, the operating condition of UASB reactor began to recover from the 76^th day, and on the 84^th day, the COD removal efficiency, biogas yield and the methane content recovered to 80.5%, 17.1L/d and 47.9%, respectively.

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: Anaerobic hydrogen production in a continuous two-stage fermentation system was studied. Two continuously stirred tank reactors (CSTR) were employed to evaluate performances of the system. The first stage was fed with molasses wastewater, and the effluent discharged from the first stage was subsequently fed into the second stage. The hydrogen production rate (HPR) in the second stage achieved a remarkable increase from 1.76 L/d to 6.45 L/d during the operation by re-utilizing the residual substrates from the first reactor effluent. The two stages showed a similar metabolic pathway for biohydrogen fermentation. The hydrogen production yield (HY) and acidification efficiency increased markedly by more than 70% and 50% respectively, which indicated the hydrogen recovery and anaerobic acidification of organic substrates can be improved by the combined continuous two-stage hydrogen production process.

Abstract: Continuous dark fermentative hydrogen production technology is suitable for commercial application. This review summarized several main basic factors influencing the operation of the reactor, followed by some suggestions and outlooks. The factors included temperature, pH, HRT and COD were briefly introduced and discussed. This review demonstrated that the optimal value of a given factor under different conditions was great different. This indicates that reactor operation is affected by many factors and sensitive to environmental change. To make the technology more feasible into practice, deeply understanding about the characteristics and rules of the operation is necessary. Thus more researches in this respect are recommended.