复合工艺在城市污水处理厂改造中的应用

水污染控制的主要任务是有机物的降解和氮磷的去除。我国现有污水处理厂大多采用传统活性污泥法 ,对于氮、磷的去除往往不能达到新实施的《城镇污水处理厂污染物排放标准 (GB18918- 2 0 0 2 )》的要求。而生物膜、活性污泥复合工艺为我国城市污水处理厂的扩建和改造提供了一条经济、高效的途径。     

Toward maximizing the recycling rate in a Sapporo waste plastics liquefaction plant

Sapporo Plastics Recycling Co., Ltd., (SPR) started its commercial operation of waste plastics liquefaction in 2000. At first only hydrocarbon oil was reclaimed, this being derived from the waste plastics liquefaction process under the Japanese Containers and Packaging Recycling Law. Presently, thermal degradation residue and hydrochloric acid are being produced as by-products in addition to the hydrocarbon oil. As a result, the SPR plastics liquefaction plant has achieved a high reclamation rate of 96%, and 93% of the recycled products have been reused in Hokkaido, where SPR is located. The technical problems caused by corrosion and clogging have been solved. Chemical Feedstock Recycling & Other Innovative Recycling Techniques 6     

Measuring the environmental impact of waste flow management in Brazilian apartment buildings

As biodegradable material represents approximately 70% of household waste in Brazil, any strategy to divert appreciable waste quantities from landfills of necessity has to include valorization and recycling of this material. A societal change of attitude is required to perceive this challenge. Experiments in an urban apartment building are described that produced this change of attitude with a success factor of 80%. Divided waste collection was implemented that separated at the source biodegradable from inert material. Correct collection, handling and display procedures were established. Composting of biodegradable material was carried out under the rooftop of the building as an alternative to using it as animal feed. Half of the inert material entered the reverse logistics chain and was also diverted from the landfill. Waste related material flow through the building is completely quantified, food intake and waste production are related, diversion of both biodegradable and inert waste components from the landfill is measured and the composting process is described. The landfill diversion stands at 61%, mass reduction through the composting process is 80% and matured compost is returned to residents for use in flower cages. The system has been operational for two years and stands out as a precedent in successful decentralized household waste management supported by material flow analysis. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Estimation of the effect of the degree of sewage treatment on the status of pollution along the coastline of the Mediterranean Sea using broad scale modelling

A preliminary investigation was performed to estimate the effect of the degree of treatment in Sewage Treatment Plants (STPs) on the status of pollution along the coastlines of the Mediterranean Sea. Data from questionnaires and the literature were collected and processed (a) to identify 18 approximate 1D surface coastal currents, (b) to estimate their prevailing direction and average flow velocity and (c) to estimate the water pollution loads and identify their locations of discharge. Then, a simplified 1D water quality model was formulated and applied for the existing conditions and two hypothetical scenarios: (1) all coastal cities have STPs with secondary treatment and (2) all coastal cities have STPs with tertiary treatment to determine BOD(5), TN and TP concentrations in the 18 surface coastal currents. Calculated concentrations were compared and discussed. A main conclusion is that, to reduce pollution in the Mediterranean Sea measures should be adopted for upgrading the water quality of the rivers discharging into the Mediterranean Sea, along with the construction of STPs for all the coastal cities.     

Towards greening a university campus: The case of the University of Maribor, Slovenia

The environmental performance of the University of Maribor (Engineering Campus) has been assessed on a life cycle basis. The following activities have been considered in the study: the use and operation of lecture theatres (construction and maintenance, heating, lighting and water consumption) and day-to-day consumption of sundries (paper and plastic bottles). The results indicate that the heating and construction of buildings are the ‘hot spots’ in the system, for most environmental impacts. Different waste management options for the plastic and paper, including recycling, incineration and landfill, have also been compared for environmental impacts and economic costs. The option combining 70% recycling, 29% incineration and 1% landfill has been found to be most economically and environmentally sustainable.     

生态工程治理玄武湖水污染效果的监测与评价

选取总磷、总氮、叶绿素a、浮游生物、浮游植物等多项环境监测指标,对利用生态工程治疗玄武湖水环境污染的效果进行了环境监测与评价。指出生态工程治理玄武湖水环境污染效果显著,经过治理使湖水中生物多样性大大增加,浮游植物大幅减少,湖水透明度增加,总磷、总氮等主要指标大幅下降,生态工程区中的水环境已从高度富营养化降到中度富营养化。     

Size and resin fractionations of dissolved organic matter and trihalomethane precursors from four typical source waters in China

Dissolved organic matter (DOM) and its potential to form disinfection by-products (DBPs) during drinking water treatment raise challenges to water quality control. Understanding both chemical and physical characteristics of DOM in source waters is key to better water treatment. In this study, the DOM from four typical source waters in China was fractionated by XAD resin adsorption (RA) and ultrafiltration (UF) techniques. The trihalomethane formation potential (THMFP) of all fractions in the DOM were investigated to reveal the major THM precursors. The fraction distributions of DOM could be related to their geographical origins in a certain extent. The dominant chemical fraction as THM precursors in the DOM from south waters (East-Lake reservoir in Shenzhen and Peal rivers in Guangzhou) was hydrophobic acid (HoA). The size fraction with molecular weight (MW) <1 kDa in both south waters had the highest THMFP. The results of cluster analysis showed that the parameters of fractions including DOC percentage (DOC%), UV₂₅₄%, SUVA₂₅₄ (specific UV₂₅₄ absorbance) and THMFP were better for representing the differences of DOM from the studied waters than specific THMFP (STHMFP). The weak correlation between SUVA₂₅₄ and STHMFP for either size or XAD fractions suggests that whether SUVA₂₅₄ can be used as an indicator for the reactivity of THM formation is highly dependent on the nature of organic matter.     

Snow-cover environmental monitoring and assessment in Northeast China using passive microwave emission models

In this study, we present the application of the passive microwave emission models to snow-cover environment monitoring and assessment in Northeast China. The study employs the radiative transfer function and strong fluctuation theory to develop the models. We used the exponential form of a spherical symmetric correlation function to describe random permittivity fluctuations. From strong fluctuation, we then obtained the phase matrix and extinction coefficients of snow-packs for the spherical symmetric correlation function. We also used the vector radiative transfer formula for the layer of a random medium by solving Gaussian quadrature and eigen analysis. By comparing the brightness temperatures at 5, 10.7, 18, and 37 GHz, the modelling results agreed with experimental data of dry-snow physical parameters as measured in the fieldwork.     

Differences in urban and rural accident characteristics and medical service utilization for traffic fatalities in less-motorized societies

Introduction

Fatalities from traffic accidents in less-motorized societies are an important global issue. We aimed to characterize the geographic differences of fatalities in such societies to facilitate the development of targeted interventions.

Method

This study linked police reports, hospital data, and vital registration data from Taiwan with special reference to accident factors in pre-hospital deaths and medical care in hospital deaths.

Results

A higher percentage of pre-hospital deaths were observed following rural as compared to urban traffic accidents. The deaths due to rural accidents can be attributed to lower use of restraints (i.e., helmets or seat belts), lower percentage of motorcyclists, and more highway accidents. A higher percentage of victims in rural accidents were transported to distant medical centers rather than to local hospitals.

Conclusion

Specific interventions, such as intelligent emergency medical systems, campaigns for helmets and seat belt usage, enforcement of helmets and seat belt use, and speed control measures should be targeted to rural areas.

Impact on industry

Cooperation between the vehicle industry and emergency medical providers in rural traffic accident rescue teams may decrease the numbers of deaths in these regions.     

Biodiesel production from waste oil feedstocks by solid acid catalysis

Biodiesel is a non-toxic and biodegradable substitute for petroleum-based diesel. However, it is impractical to use refined edible oils to produce biodiesel due to its high cost and priority for food products, especially in China, while waste oils with high free fatty acids (FFAs) can be considered as the raw materials. In the present work, a solid acid catalyst comprising SO₄²⁻/TiO₂–SiO₂ was prepared, characterized and studied for its activity for the production of biodiesel from several low cost feedstocks with high FFAs. The solid acid catalyst can be recycled, easily removed and can simultaneously catalyze esterification and transesterification. The influence of reaction parameters was studied, and the optimized reaction parameters are reaction temperature 200 °C, molar ratio of methanol to oil 9:1 and catalyst concentration 3 wt.%. The catalyst showed good stability. A continuous process for biodiesel production from cheap raw feedstocks was proposed, and a 10,000-tonnes/year biodiesel production demonstration plant has been built.