Papers by Author: Hua Yong Zhang

Abstract: Eco-exergy which is a thermodynamic indicator is applied to assess the ecosystem health status of QiXing Lake. And effects of nitrogen and phosphorus on ecosystem health status have been investigated. The results indicate that the ecosystem which contains macrophytes has the better health status than that does not contain macrophytes when they have the same concentration of nitrogen or phosphorus. The ecosystem health status decreased as the concentration of total nitrogen increased when the ecosystem contains macrophytes. However, the ecosystem health status has not significant change as the concentration of total nitrogen increased when the ecosystem does not contains macrophytes. It has the same law for total phosphorus.

Abstract: The effect of nickel ions on the anaerobic digestion of phragmites australis and cow dung were investigated in batch experiments. Five levels of nickel ions were set as 0, 0.2, 0.8, 1.4 and 2.0 mg Ni/L. The results indicated that anaerobic digestion started on about 3^rd day 26 days of anaerobic digestion, the highest cumulative biogas was 32.70 mL/g·TS^-1 when nickel concentration was 0.8 mg Ni/L. The nickel ions in certain concentration range significantly affected biogas production rate, and effectively shorten reactor startup period. Biogas which was produced from phragmites combined with cow dung provided a new insight for bioenergy production whose process can be promoted by nickel ions addition.

Abstract: The effects of red mud on growth of Alternanthera philoxeroides were examined. A. philoxeroides were planted at density of five individuals/ (0.2*0.2 m²) in wastewater with five dosage (0, 2, 5, 7 and 10 g/L) of red mud, and the experiment was carried out from December, 2012 to January, 2013. Our results revealed that it showed significant effects (p<0.05) of treatment by-red mud dosage on internode numbers before and after processing; significant differences were also shown in leaf numbers under red mud concentration of 10g/L comparing with 0 and 5 g/L. Also, stem diameter had a significant difference between 10 g/L and 0g/L of red mud concentrations. Leaves fell off a lot, and root-shoot ratio was only 0.2-0.3, significantly lower than the wild free state. These results suggested that the growth of A. philoxeroides used for sewage treatment added red mud for auxiliary were affected by red mud. By influencing the elongation or increase of some traits, a relatively higher concentration of red mud could slow down their growth.

Abstract: Power model, linear model and hyperbolic model were commonly used to estimate forest biomass via stand volume, however the relative accuracy is unclear for Pinus tabulaeformis forests in China. In order to compare the accuracies of these models, data from 130 Pinus tabulaeformis forest stands were compiled from published literatures. Data of 100 stands were randomly selected to establish regression equations, the other 30 data were used to compare the accuracies of equations either established in this study or in previous studies. The results show that biomass of Pinus tabulaeformis forests could be well estimated by power model and linear model, while hyperbolic model is likely to result in enormous overestimation or underestimation. The mean relative errors of the power model and linear model established in this study are-0.3% and 1.8% respectively. In comparison with models established by previous studies, these two models have better prediction accuracies.

Abstract: In order to investigate the effect of stand age and climate hydrothermic factors on aboveground biomass accumulation (ABA), data from 65 typical Pinus tabulaeformis forest stands were compiled from published literatures. By means of stepwise multiple regression, the variations in ABA were examined across the range of stand age and gradients of mean annual precipitation (MAP) and mean annual temperature (MAT). For comparison, stand age was also used as explaining variable alone. The results show that, stand age and MAP could explain 85.1% of variation in ABA, the predictive power is much better than stand age alone. The explanatory power of stand age and MAP were 70.7% and 15.3% respectively. In comparison with stand age, MAP has a relatively poor but significant effect. ABA is not significantly related to MAT, which implies that water availability is more important than thermal condition for ABA of Pinus tabulaeformis forests.

Abstract: The feasibility of using honeycomb-cinder slag as an adsorbent for phosphate removal from aqueous solution was investigated in batch experiments as a function of initial pH, contact time, adsorbent dose, and solution temperature. The results indicated that the solution pH significantly influenced the phosphate adsorption; 1440 min was enough to reach equilibrium for any concentration. Langmuir isotherm model gave well fit for phosphate adsorption, and the adsorption process followed pseudo second-order model. Desorption study exhibited that the phosphate adsorption on the honeycomb-cinder slag is not completely reversible. Results showed that honeycomb-cinder slag could be used as an adsorbent to uptake phosphate from wastewater.

Abstract: Experiments are conducted to study the change of Manning coefficient of reed population along the channel in gradually varied flow. Water depth and velocity are investigated under various reed densities, corresponding to a set of discharge values. The corresponding Manning coefficients along the channel and the functional relationships with vegetation density are studied. The results show that the Manning coefficient is more volatile in vegetation zone and the average Manning coefficient exhibits a linear relationship with the vegetation density. The conclusions can provide some guidance and reference for cofferdam design in natural and constructed wetland and the research on vegetated channel erosion.

Abstract: The flow field of constructed wetland plays an important role in wetland stabilization and efficient operation. TengZhou Quanshang constructed wetland was taken as the research object. The RNG k-ε two-equation turbulence model equations coupling with the volume of fluid (VOF) model are introduced to simulation the vegetation cover flow. And the flow velocities of 37 measured points in wetland were measured by using the ADV instrument. Then the simulation velocity was compared with the field measured velocity. The results are shown to be satisfactory, and basically meet the large-scale flow analysis requirements. The problems of flow field distribution on the initial state was analyzed and optimized. The uniformity of velocity in wetland increased, and water mobility improved after optimization. Our results provide guidance for the 2D water quality simulation, pollutants migration and combination of plant purification effect in natural and constructed wetland.

Abstract: Two ecological indicators, exergy (Ex) and structural exergy (Exst), and two ecological indexes, biodiversity and trophic state are calculated using the parameters of water quality and plankton investigated in five different ponds in Shandong province in China. The exergy and structural exergy are applied to evaluate the health state of ecosystems of the five ponds, whereas the biodiversity and trophic state are employed to make eutrophication assessment of the ponds. Via analyzing the relationships among the ecological indicators, the ecological indexes and the biomass of macrophytes, it is revealed that exergy, structural exergy and biodiversity is positive correlated to the biomass of macrophytes and that the trophic state decreases with the biomass of macrophytes. This result demonstrates that the ecosystems with more macrophytes can be regarded to hold better health state.

Abstract: The feasibility of coal gangue as an adsorbent for phosphate removal from wastewater was investigated. The results showed that the equilibrium data were well fit to Langmuir isotherm model and the maximum adsorption capacity calculated was 2.49 mg/g at 25°C. The adsorption process followed pseudo-second order model. And the practical waste water experiment indecated that the phosphate concentration of real sewage decreased from 0.625mg/L to 0.121mg/L. These results suggested that coal gangue can be used as an adsorbent to removal phosphate from wastewater.