Perceiving the Environment from the Lay Perspective in Desertified Areas,Northern China

Investigating local people’s environmental perceptions can produce useful information that could be incorporated into decision making processes that help resolve environmental problems. Although China is undergoing severe desertification, the perceptions of the local people toward their degraded environment and the related issues have so far not been actively solicited. This article, which is a supplement to Lee and Zhang’s (2004, 2005) studies, seeks to further investigate the lay public’s general environmental attitudes, perceptions of desertification, interpretations of land-degrading activities, and particularly their interrelations in severely desertified areas. Minqin County in Gansu Province, northern China, was chosen to be the study area. Data was collected via a questionnaire survey (n = 1138) administered in December 2002. Major findings were: (1) Most respondents had only weak altruistic environmental attitudes, with educational level to be a significant determinant. (2) Respondents’ perceptions of desertification and interpretations of land-degrading activities were contingent on personal attributes, general environmental attitudes, and other conceptions related to desertification. It is recommended that the interrelations between the various aspects of the public’s environmental perceptions should be thoroughly examined to facilitate their participation in environmental management.     

Accelerated seeded precipitation pre-treatment of municipal wastewater to reduce scaling

Membrane based treatment processes are very effective in removing salt from wastewater, but are hindered by calcium scale deposit formation. This study investigates the feasibility of removing calcium from treated sewage wastewater using accelerated seeded precipitation. The rate of calcium removal was measured during bench scale batch mode seeded precipitation experiments at pH 9.5 using various quantities of calcium carbonate as seed material. The results indicate that accelerated seeded precipitation may be a feasible option for the decrease of calcium in reverse osmosis concentrate streams during the desalination of treated sewage wastewater for irrigation purposes, promising decreased incidence of scaling and the option to control the sodium adsorption ratio and nutritional properties of the desalted water. It was found that accelerated seeded precipitation of calcium from treated sewage wastewater was largely ineffective if carried out without pre-treatment of the wastewater. Evidence was presented that suggests that phosphate may be a major interfering substance for the seeded precipitation of calcium from this type of wastewater. A pH adjustment to 9.5 followed by a 1-h equilibration period was found to be an effective pre-treatment for the removal of interferences. Calcium carbonate seed addition at 10 g l⁻¹ to wastewater that had been pre-treated in this way was found to result in calcium precipitation from supersaturated level at 60 mg l⁻¹ to saturated level at 5 mg l⁻¹. Approximately 90% reduction of the calcium level occurred 5 min after seed addition. A further 10% reduction was achieved 30 min after seed addition.     

Biodegradation of microcystins and nodularin in freshwaters

Microcystin-LR (MC-LR) was readily biodegraded on addition to six different water samples irrespective of their previous exposure to microcystins. Subsequent studies with water from three of these water bodies confirmed the degradation of MC-LR and also demonstrated the biodegradation of MC-LF, nodularin and mixture of microcystins and nodularin. Rates of degradation of MC-LR, MC-LF and NOD in individual water samples ranged from a half-life of 4 to 18d. Analysis by HPLC-PDA-ESI+ and MALDI MS/MS revealed novel intermediate degradation products of MC-LF and nodularin which included demethylation, hydrolysis, decarboxylation and condensation of the parent compound(s). Our study suggests a possible diversity of micro-organisms and/or pathways which has not been previously observed.     

The Iowa Graduated Driver Licensing program: effectiveness in reducing crashes of teenage drivers

PROBLEM: Graduated Driver Licensing (GDL) programs vary in the United States in terms of implementation and restrictions. The State of Iowa's GDL program is assessed for its effectiveness in reducing crashes among teenage drivers. METHOD: Time series analysis was used to evaluate police documented crashes involving 16-, 17-, and 18-year-old drivers over a 10 year period, with an intervention identified at the point of GDL implementation. RESULTS: After controlling for seasonal trends and auto-correlative effects, a significant reduction in the crash rate of and 16- and 17-year-old drivers was observed due to the GDL implementation. However, there were no significant reductions in crash rates for 18-year-old drivers. DISCUSSION: The analyses suggest that the Iowa GDL program is effective in reducing the crash rates of 16- and 17-year-old drivers but the effects do not sustain for 18-year-old drivers. IMPACT ON INDUSTRY: The results suggest that the program appears to be working, however further analysis is needed to determine what factors are preventing lasting effects for these teenage drivers.     

Co-combustion of dried sewage sludge and coal in a pulverized coal boiler

More than 1.1 million tons of municipal and industrial sewage sludge is produced annually in Poland. Most of this sewage sludge is landfilled or used for recultivation and fertilization of soil. After accession of Poland to the EU, large investments are planned for wastewater treatment, so it is expected that the amount of sewage sludge produced in Poland will grow in the near future. It is well known that the combustion of sewage sludge is becoming a more and more popular utilization method of such waste. Unfortunately, the current situation in Poland makes it impossible to incinerate the sewage sludge because of a lack of incinerators. One possible solution for Poland is the co-firing of dried sewage sludge in existing coal-fired utility boilers. This article presents results of initial Polish industrial trials of dried municipal sewage sludge and hard coal co-combustion in an OP-230 pulverized coal boiler. Such a solution was shown to be technically viable and not to require changes to the existing technological system. Cocombustion of sewage sludge with coal in power plants seems to be the best solution for sludge utilization in the near future in Poland.     

Combustion characteristics of Malaysian municipal solid waste and predictions of air flow in a rotary kiln incinerator

Malaysia is in dire need of alternatives to landfilling for solid waste management. Recently, landfills have faced the problems of overfilling, overflowing of leachates leading to pollution of water resources, and uncontrolled dust emissions adversely affecting the local environment. With the rising cost of urbanization coupled with the high rate of waste generation, one possible method of waste treatment that is receiving particular attention by the government is incineration. Incineration of solid waste is rather new in Malaysia, with limited usage in handling small sources of waste generation such as the municipal solid waste (MSW) of resort islands; however, its potential in ameliorating the problems associated with solid waste treatment may make it an attractive alternative to landfill. This article presents the results of test runs conducted to investigate the performance of a locally designed and manufactured rotary kiln incinerator (RKI). The test runs were conducted using MSW collected from the Shah Alam municipality. The combustion efficiency was analyzed by looking at the temperature profiles and chemical species concentrations. To complement the combustion characteristics measurements, predictions of the air flow in the incinerator during the process were also investigated. The overall performance of the RKI suggests that it is suitable for treating MSW.     

Enhancement of turbulent scalar mixing and its application by a multihole nozzle in selective catalytic reduction of NOx

The mixing characteristics of a passive scalar in the turbulent flow of a selective catalytic reduction process were numerically and experimentally investigated, focusing especially on an injection nozzle with multiple holes for the reducing agent. The multihole injection nozzle studied has six holes that are perpendicular to the ambient flue gas flow and are located near the tip of the nozzle. Large eddy simulation was applied to the turbulent flow and mixing fields to elucidate the mixing mechanism of the proposed nozzle compared with the single-hole nozzle that is commonly used in the conventional selective catalytic reduction process. From the results, there exist broader regions of higher turbulent intensities for the multihole nozzle than for the conventional single-hole nozzle. These regions are well matched with the positions of high vorticity in the near upstream region of the jet flow issuing from the multiple holes of the nozzle. Consequently, the high turbulent intensities and vorticity magnitudes lead to intensified mixing between the flue gas and the reducing agent. Hence, the most suitable molar ratio between NOx and the reducing agent for the catalytic reaction can be easily obtained within a shorter physical mixing length as a result of the enhanced scalar mixing. Finally, the numerical results were applied to a trial design version of a multihole nozzle, and this nozzle was experimentally tested to confirm its mixing performance.