Review of the technological approaches for grey water treatment and reuses.
ABSTRACT Based on literature review, a non-potable urban grey water reuse standard is proposed and the treatment alternatives and reuse scheme for grey water reuses are evaluated according to grey water characteristics and the proposed standard. The literature review shows that all types of grey water have good biodegradability. The bathroom and the laundry grey water are deficient in both nitrogen and phosphors. The kitchen grey water has a balanced COD: N: P ratio. The review also reveals that physical processes alone are not sufficient to guarantee an adequate reduction of the organics, nutrients and surfactants. The chemical processes can efficiently remove the suspended solids, organic materials and surfactants in the low strength grey water. The combination of aerobic biological process with physical filtration and disinfection is considered to be the most economical and feasible solution for grey water recycling. The MBR appears to be a very attractive solution in collective urban residential buildings.
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ABSTRACT: The present study focuses on the decolourization of crystal violet (CV) using TiO2 supported on glass slides under natural sunlight (sunny days, June 2013). The commercial Degussa P25 TiO2 was used as a photocatalyst in this study. The P25 TiO2 deposition process was achieved using acetone as precursor. The effect of some process parameters (CV concentration, number of TiO2 glass slides, pH and presence of metallic cations as interfering ions such as Cu2+, Fe2+, Fe3+, Mn2+ and Zn2+) was investigated. It was found that the decolourization process follows a pseudo-first order with respect to the substrate concentration. The pH had a net effect on the decolourization process. The apparent rate constants increased proportionally to the number of TiO2 glass slides. The results show that the presence of Fe2+, Mn2+ and Cu2+ cations with CV decreases the decolourization rate by varying degrees (22.1–35.3%) while Zn2+ has a negligible effect. However, the presence of Fe3+ led to an acceleration of the CV decolourization. The P25 TiO2-supported can be reused several times under the present working conditions. Finally, the photoactivity efficiency of P25 TiO2-supported was compared to that of P25 TiO2-dispersed under artificial UV (single lamp, 300–400 nm) and natural sunlight. Under the present experimental conditions, a complete decolourization was achieved less than 6 h of solar irradiation at natural pH and using two TiO2 glass slides.Desalination and water treatment 12/2013; · 0.99 Impact Factor
- Chinese Journal of Oceanology and Limnology 09/2014; 32(5):1092-1104. · 0.68 Impact Factor
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ABSTRACT: With accelerating global changes, cities have to cope with growing pressures, especially for resource supply. Cities may be considered as resources reservoirs and producers of secondary resources. This paper introduces the concept of urban harvesting as a management tool to change inefficient linear urban resource usage and waste production into sustainable urban metabolism. The Urban Harvest concept includes urban metabolism and closing urban cycles by harvesting urban resources. The purpose of this study was to quantify the potentials to harvest water and energy at different scales. We investigated potentials for the Netherlands. Results show that at national scale, potentials can cover up to 100% of electricity demand, 55% of heat demand and 52% of tap water demand. At neighborhood level, similar percentages were found for energy. Only 43% of water demand was achieved, due to fact that treatment measures were not considered. These results indicate the large potential of cities as providers of their own resources. Therefore urban resources management is a key element of future city design towards more resilient cities.Resources Conservation and Recycling 07/2012; 64:3-12. · 2.69 Impact Factor