The performance of electroflotation (EF) is strongly influenced by the size of O2 and H2 bubbles. Therefore, in this study, the bubble sizes are measured in a lab-scale EF cell using a high-speed camera. The mean bubble size is found to vary in the range of 32.7–68.6 μm under different operating conditions. This study shows that the electrode material, current density, water pH, ionic strength, and frother (Tennafroth 250) concentration are important factors in controlling the bubble size. Furthermore, four mathematical distributions (normal, log-normal, Weibull, and gamma distributions) are fitted to the experimental data, among which the log-normal distribution is found to be the best fit based on the lower Anderson-Darling (AD) value. 相似文献
Restoration of urban streams and rivers has increased rapidly in developing countries in recent years. Estimating river health provides a new perspective on evaluating the ecological conditions of streams and rivers. The Suzhou Creek restoration project in Shanghai, China is a milestone for environmental protection. Based on the environmental and ecological data, including 17 indicators in five categories, collected from March 11 to April 20, 2007, the river health index (RHI) for Suzhou Creek was constructed and analysed to quantify the ecosystem of this urban river after a restoration project. The RHI scores of 34 sites ranged from 19.24 to 33.36, i.e. from poor to good. There were no significant RHI differences among stream orders, while differences in land use resulted in significant differences in channel flow status (B12), channel alteration (B21), channel sinuosity (B22), bank stability (B23), bank profile type (B25) and riparian vegetative zone width (B31). River restoration led to improved hydrological condition and channel physical form, while ammonia nitrogen (B44) and indicator scores of the presence of macro-invertebrate families (B51) were the lowest of any indicator. This case study supports the use of river health assessment as a supplement to water quality analysis in China. 相似文献
Reasonable structure, adaptive patterns and effective regulation of society, economy and environment subsystems should be
taken into account in order to obtain harmonious development of urban eco-industrial system. We simulated and evaluated a
redesigned eco-industrial system in Changchun Economic and Technological Development Zone (CCETDZ) in the present work using
system dynamics and grey cluster methods. Four typical development strategies were simulated during 2005–2020 via standard
system dynamic models. Furthermore, analytic hierarchy process and grey cluster allowed for the eco-industrial system evaluation
and scenarios optimizing. Our dynamic simulation and statistical analysis revealed that: (1) CCETDZ would have different development
scenarios under different strategies. The total population in scenario 2 grew most rapidly and reached 3.28 × 105 in 2020, exceeding its long-term planning expected population. And the GDP differences among these four scenarios would amount
to 6.41 × 1010 RMB. On the other hand, environmental pollution would become serious along with economy increasing. As a restriction factor,
positive or negative increment of water resource will occur according to the selected strategy. (2) The fourth strategy would
have the best efficiency, which means that the most efficiently development of CCETDZ required to take science, technology,
environment progress and economy increase into account at the same time. (3) Positive environment protection measures, such
as cleaner production, green manufacture, production life cycle management and environment friendly industries, should be
attached great importance the same as economy development during 2005–2020 in CCETDZ. 相似文献
Diet is an important exposure route for phthalates, such as di-iso-butyl phthalate (DiBP), dibutyl phthalate (DBP), bis(2-ethylhexyl) phthalate (DEHP), and benzyl butyl phthalate (BBP). In this study, we aimed to estimate phthalate exposure in the diet of pregnant women and assess the health risk. A total of 517 pregnant women in the first trimester were recruited, and food frequency questionnaires were collected. A simple distribution assessment method was used to estimate daily exposure, and the hazard index (HI) method was used to assess cumulative risk. The maximum daily dietary exposure to DEHP, DBP, DiBP, and BBP was 5.25, 3.17, 2.59, and 0.58 μg/kg bw/day, respectively, and did not exceed the safety limit values. Cereals and vegetables were the main sources of the estimated daily intake (EDI) of phthalates in the diet. The cumulative risk assessment, based on the European Food Safety Authority tolerable daily intake (TDI) and the US Environmental Protection Agency reference dose (RfD), did not exceed the threshold of 1. DiBP, DBP, and DEHP had higher hazard quotient (HQ) values for cumulative health risk than BBP. In conclusion, a low health risk was posed by the cumulative dietary exposure to phthalates for pregnant women in Beijing.
Environment, Development and Sustainability - A novel model has been proposed for the methodical development and safe utilization of the lower Yellow River floodplain to provide flood control with... 相似文献
Environmental Science and Pollution Research - In this paper, Pd-Sn modified Ru-Ir electrode was prepared by thermal oxidation method, and the effects of doping amount of Pd-Sn and synthesis... 相似文献
Journal of Polymers and the Environment - Epoxy resin (EP) is a thermosetting resin with prominent performances and wide applications. However, the inherent brittleness limits its development in... 相似文献