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N. Cheng K. V. Lo K. H. Yip 《Journal of environmental science and health. Part. B》2013,48(3):379-398
Abstract A laboratory scale two‐stage sequencing batch reactor (TSSBR) was used to study the effectiveness of pH as a real‐time control parameter in swine wastewater treatment. A Ringlace media was inserted into the A/O (Anoxic/Oxic) reactor for bacteria immobilization. The TSSBR was subjected to three levels of organic loading. The pH and ORP (Oxidation Reduction Potential) patterns obtained were consistent with distinct features, enabling the real‐time control strategy to effectively set a flexible aeration time pending on influent concentration, hence resulting in flexible cycle time and HRT (Hydraulic Retention Time) for the system. The real‐time process ensured a removal efficiency of over 99% and 95%, respectively, for ammonia and TOC (Total Organic Carbon). For NO3 ‐‐N and PO4 ‐3, the run with influent TOC = 4,000 mg/L yielded the most efficient removal of 61% and 95%, respectively. Test results suggest that pH can be a viable tool for on‐line real‐time control of a biological treatment process. 相似文献
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Bass B Economou V Lee CK Perks T Smith SA Yip Q 《Environmental monitoring and assessment》2003,85(2):199-219
Indoor environmental health is now recognized as an important factor in preventing respiratory health problems in the United States. It is also a concern in Canada due to the amount of time that Canadians spend indoors because of cold weather and the potential for increased time indoors during the summer if theclimate warms. The negative health effects are often labeled assick building syndrome, but diagnosing a building or itsoccupants as sick is complicated by the variety of symptoms, thepresence of chronic versus acute symptoms and social andpsychological (socio-psychological) factors that may reduce theeffectiveness of an engineering solution. As a case study, thecontribution of various factors to indoor environmental health,in three buildings at the University of Toronto, was examinedusing five different methods. The results indicate that theinhabitants of the buildings consider features other than airquality in considering building health such as design,maintenance, funding cuts and socio-psychological factors. 相似文献
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Carlos Wing-Hung Lo Plato Kwong-To Yip 《Journal of Environmental Planning and Management》1999,42(3):355-374
Cross-city analysis in environmental regulation within non-democratic political systems is a neglected area. Taking policy convergence and styles of regulation as the focus, this paper has taken an initial step to compare the environmental impact assessment (EIA) regulation in Hong Kong and Shanghai. In this comparative exercise, it is identified that policy convergence occurs more explicitly in policy ideology and policy consequences, whereas divergence takes place in policy content, regulatory process and public consultation. Convergence, however, is only superficial whereas divergence is substantial. Indeed EIA systems of these two jurisdictions have displayed contrasting styles of regulation. The formal EIA system in Shanghai is dominated by the environmental agency, which regulates informal politics in the EIA process within a legal format. The informal EIA system in Hong Kong is co-ordinated by the environmental agency, which seeks active co-operation with the clients in a consultative EIA process in an informal and discretionary manner. What makes the Hong Kong system superior to the Shanghai system is the existence of institutional channels for public consultation. Within a non-democratic political setting, the EIA process in Hong Kong is more transparent and the EIA system is more accountable to the public, whereas the EIA process in Shanghai is lacking in transparency and the EIA system is under tight bureaucratic control. 相似文献
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Sujit K. Sahu Stan Yip David M. Holland 《Atmospheric environment (Oxford, England : 1994)》2009,43(3):494-501
There is an urgent need to provide accurate air quality information and forecasts to the general public and environmental health decision-makers. This paper develops a hierarchical space–time model for daily 8-h maximum ozone concentration (O3) data covering much of the eastern United States. The model combines observed data and forecast output from a computer simulation model known as the Eta Community Multi-scale Air Quality (CMAQ) forecast model in a very flexible, yet computationally fast way, so that the next day forecasts can be computed in real-time operational mode. The model adjusts for spatio-temporal biases in the Eta CMAQ forecasts and avoids a change of support problem often encountered in data fusion settings where real data have been observed at point level monitoring sites, but the forecasts from the computer model are provided at grid cell levels. The model is validated with a large amount of set-aside data and is shown to provide much improved forecasts of daily O3 concentrations in the eastern United States. 相似文献
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In this case study of a degraded tropical landscape, we examine how the protected area system in Hong Kong, China, should be modified to improve its efficiency in protecting the surprisingly rich biota. The challenge lies in the fine scale of site selection, and the absence of a core area with high species richness and rarity. Site selection was first conducted in 1 km grid units by selecting hotspots and irreplaceable sites using field records for eight groups of species (amphibians, reptiles, mammals, breeding birds, ants, butterflies, dragonflies and rare vascular plants). The habitats of conservation value within the selected grid units were then delineated on the basis of expert knowledge. Recommendations for increasing the total existing protected area by 6% (i.e. an additional 2% of Hong Kong's total land area) were submitted to the Government in August 2000. To test the robustness of the results, site selection was repeated in 2001 using updated data and different selection methods. The numbers of squares selected by complementarity-based algorithms were similar to those by the hotspots and irreplaceable site method. Sites selected for rare species were very sensitive to data completeness, implying that the application of complementarity-based algorithms at fine scales might be limited. 相似文献
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Yip Hing Lum Azizah Shaaban Nona Merry M. Mitan Mohd Fairuz Dimin Noraiham Mohamad Nadiah Hamid Sian Meng Se 《Journal of Polymers and the Environment》2013,21(4):1083-1087
The influence of the blending ratio of biodegradable starch/polyvinyl alcohol (PVA)/glycerol in encapsulating urea has been investigated. It is found that water absorption capacity increased approximately 135 % as the amounts of starch, PVA and glycerol in the composite film increase. Therefore, the swell ability of the composite film is increased and the urea is released from the composite film in the wet environment. The FTIR shows that the urea had been encapsulated successfully in the composite films. Moreover, the soil burial biodegradation results indicated that the biodegradability of the starch/PVA/glycerol/urea composite film strongly depended on the PVA proportion in the composite film matrix. The DSC results show that the higher the amount of PVA in the composite film, the less change of the melting enthalpy value. The crystalline region of PVA remains after biodegradation. 相似文献
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Chelating agents have been widely studied for extracting heavy metals from contaminated soils, and the effectiveness of EDDS ([S,S]-ethylene-diamine-disuccinic acid) has aroused extensive attention because of its biodegradability in the natural environment. However, in the course of EDDS-flushing, metal exchange of newly extracted metal-EDDS complexes with other sorbed metals and mineral cations may result in metal re-adsorption on the soil surfaces. Therefore, this study investigated the relative significance of metal exchange under different travel distances of chelant complexes, characteristics of soil contamination, and solution pH in the column experiments. As a result of metal exchange, the elution of Zn and Pb was retarded and the cumulative extraction was lower than those of Ni and Cu, especially over a longer travel distance. Compared with the field-contaminated soils, the effects of metal exchange were even more substantial in the artificially contaminated soil because of a greater amount of extractable metals and a larger proportion of weakly bound fractions. By contrast, metal exchange was insignificant at pH 8, probably due to less adsorption of metal-EDDS complexes. These findings highlight the conditions under which metal exchange of metal-EDDS complexes and the resulting impacts are more significant during EDDS-flushing. 相似文献