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Er L.,Wuhan Municipal Engineering Design and Research Institute | Xiangying Z.,Wuhan Municipal Engineering Design and Research Institute
Water Science and Technology | Year: 2014

To simulate the variation of biochemical oxygen demand (BOD) in the tidal Foshan River, inverse calculations based on time domain are applied to the longitudinal dispersion coefficient (E(x)) and BOD decay rate (K(x)) in the BOD model for the tidal Foshan River. The derivatives of the inverse calculation have been respectively established on the basis of different flow directions in the tidal river. The results of this paper indicate that the calculated values of BOD based on the inverse calculation developed for the tidal Foshan River match the measured ones well. According to the calibration and verification of the inversely calculated BOD models, K(x) is more sensitive to the models than E(x) and different data sets of E(x) and K(x) hardly affect the precision of the models. © IWA Publishing 2014. Source


Zeng X.,Wuhan Municipal Engineering Design and Research Institute | Li E.,Wuhan Municipal Engineering Design and Research Institute
Fresenius Environmental Bulletin | Year: 2015

In this paper, the properties and characteristics of diat-omite treated with manganese oxide (MTD) for the removal of chromium(III) ions in aqueous solution was studied. The characters and performance of sorption MTD were compared with that of raw diatomite (RD). The results indicate that the trivalent chromium(III)) ion sorption capacities of diatomite were considerably improved after treated by manganese oxide. Due to the formation of manganese oxide (MnO) on the diatomite surface, the surface area of MTD was improved. And the sorption of chromium(III) by MTD was more than that in RD owing to the different electrostatic forces between the heavy metal ions and the surface of the diatomite. The removal of chromium(III) ions by RD and MTD were both improved with the increment of synthetic solution concentration. © by PSP. Source


Li E.,Wuhan Municipal Engineering Design and Research Institute | Zeng X.,Wuhan Municipal Engineering Design and Research Institute
Water Science and Technology | Year: 2012

Raw diatomite modified by microemulsion (DMM) and manganese oxide (MnD) were used for the removal of Cr(III) ions from aqueous solution. The characteristics and performance of these two types of modified diatomite on Cr(III) ion adsorption were compared. The results indicate that the Cr(III) ion adsorption capacities of diatomite were considerably improved after modifications by manganese oxide (MnOon performance of Cr(III) ions in DMM was better than that in MnD. Within the experimental range of pH (i.e. 2.2-6.3), the Cr(III) ion removal of DMM (35-70%) and microemulsion. The surface area of MnD was increased because of the formation of MnO on the diatomite surface, and that of DMM was promoted owing to the existence of the hydrolyzed aromatic acid. Because of the stronger surface ionized function, the adsorpti) was higher than that of MnD (33-59%) owing to the different electrostatic forces between the Cr(III) ion and the surface of the modified diatomite. The Cr(III) ion removal in MnD and DMM was improved with the increase of synthetic solution concentration in volumes from 0 to 2,500 mL. © IWA Publishing 2012. Source


Li E.,Wuhan Municipal Engineering Design and Research Institute | Zeng X.,Wuhan Municipal Engineering Design and Research Institute
Fresenius Environmental Bulletin | Year: 2012

Diatomite modified by microemulsion (DMM) was used for the removal of heavy metal ions, such as lead (Pb), copper (Cu) and chromium (Cr), from aqueous solution. Character and performance of DMM on heavy metal ion adsorption were compared to raw diatomite (RD). The results indicate that Pb(II), Cu(II) and Cr(III) ions sorption capacities of diatomite were considerably improved after microemulsion modification. The surface area of modified diatomite was increased due to the present hydrolyzed aromatic acid in DMM. Because of the stronger surface-ionized function, the performance of the sorption rates of Pb(II), Cu(II) and Cr(III) in DMM were better than that in RD. Adsorption of heavy metals onto DMM and RD decreased in the order: Pb(II) > Cu(II) > Cr(III). Within the experimental range of pH (2.2-6.3), the heavy metal removal of DMM was higher than that of RD owing to the different electrostatic forces between heavy metal ions and the surface of the modified diatomite. The heavy metal removal rates by RD and DMM were improved with the increase of synthetic solution concentration (when the solution volume varies from 0 to 100 ml). by PSP. Source


Li E.,Wuhan Municipal Engineering Design and Research Institute | Zeng X.,Wuhan Municipal Engineering Design and Research Institute
Fresenius Environmental Bulletin | Year: 2011

When fine bubble diffused aerations run in shallow open channels, the performances of aeration systems are influenced by such factors: the relationship between the airflow rate of the aeration system and the water-flow rate of open channels, the layout and initial fine bubble diameters of the aeration systems, the sizes, the water depth and the flow state of the channels. And the following 6 parameters can be represented as the key indices of these factors: the air-water ratio (expressed as λ) which is the ratio of air demand to the polluted water volume, the initial diameter of fine air bubble entering the aeration channels (d 0), the layout parameters of the aeration systems (LPA), the ratio of the channels' length to its width (L/W), the water depth (H c) and the Reynolds number (Re) of the channels. To evaluate the performances of aeration systems, a new aeration performance index (API) is proposed. The relationship of API and the above 6 indices is established based on fuzzy theory, and weighted sums of the similarity degrees derived from the extensions of fuzzy c-means (FCM) are used to construct API. The performances of 4 different fine bubble diffused aeration systems evaluated by API are compared with those by conventional characteristic criteria, and their evaluation conclusions are consistent with each other. Moreover, API is demonstrated to be more remarkable for the evaluation of the performances of the aeration systems than the other characteristic criteria. © by PSP. Source

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