腐植酸氯化过程中氯仿生成的基础研究

为了研究用氯消毒饮用水过程中产生氯仿等致癌性副产物,进行了采用低分子量腐植酸与次氯酸钠反应生成氯仿的实验,结果表明,在次氯钠浓度,ｐＨ和温度一定的条件,氯仿产量随腐植酸浓度的增大而增加,ｐＨ在７．３－９内,氯仿生成速度最快,ｐＨ大于９时,氯仿生成速率随ｐＨ的升高而下降,氯仿生成量与温度呈正相关关系,腐植酸氯化成氯仿的反应活化能国５１．８ＫＪ,因此设法降低原水中腐植酸含量量降低氯仿含量的有效方法。     

Engineering of mono-dispersed mesoporous TiO2 over 1-D nanorods for water purification under visible light irradiation

Environmental Science and Pollution Research - Herein we synthesized a novel structure of mesoporous TiO2 decorated on 1D ZnO nanorods for environmental remediation. The effect of mesoporous TiO2...     

Electrical and electronic waste management in China: progress and the barriers to overcome.

Serious adverse impacts on the environment and human health from e-waste recycling have occurred in the past and continue to occur in China today, due to a lack of national management strategies. China has made great efforts to face the challenges of the approaching peak increase in the domestic generation of e-waste and the illegal shipment of e-waste from other countries. This study examined recent progress and analysed the main problems associated with this issue in China. It was found that the material and the financial flows of e-waste in China had their own specific characteristics. Nearly 60% of the generated e-wastes were sold to private individual collectors and passed into informal recycling processes. More than 90% of Chinese citizens are reluctant to pay for the recycling of their e-waste. This is due to their traditional understanding that there remained value in these end-of-life products. Regulations concerning e-waste in China have been drafted but their deficiencies are obvious. The extended producer responsibilities (EPR) have been introduced but are not well defined. Eight formal facilities have been planned and are under construction or are in operation along the eastern coast of China but it will be difficult for them to compete with the informal processes for the reasons identified during the study.     

Report on hazardous household waste generation in Japan.

Surveys of over 2000 households in Japan were conducted to investigate the characteristics of hazardous household waste (HHW) generation. In Japan, about 2.5 to 4.3 kg of HHW are produced per tonne of the residential waste stream. The percentage of used batteries in HHW was over 50%. Every household using spray (aerosol) cans had more than seven cans on average. The generation of HHW, in terms of both quantities and type of waste produced, appeared to vary with dwelling type. Detached dwelling residents tended to store HHW such as used batteries, whereas apartment residents tended not to store waste. The amounts of discarded HHW were larger at the end of the year in comparison with other months. The data accumulated were used to estimate the quantities of HHW disposed off annually, and the quantities and type of waste that might be received by a typical depot collection programme in Japan.     

Characterization of i(18p) in prenatal diagnosis by fluorescence in situ hybridization

A case is presented in which chorionic villus direct preparation and cultured chorionic villus cells revealed a 47,XX, + mar karyotype. The marker was a small metacentric chromosome and appeared to be i(18p)—isochromosome 18p. Follow-up studies in both amniotic fluid and fetal fibroblasts confirmed the karyotype. In order to characterize the marker, a panel of biotinylated DNA probes was used, including a whole chromosome 18 probe, chromosome 18-specific alpha satellite DNA, Yac clones, and a pan-telomeric probe. These studies show that the marker is a monocentric i(18p) in which about 80 per cent of chromosome 18 alpha satellite DNA has been lost.     

Chemical stabilization of medical waste fly ash using chelating agent and phosphates: Heavy metals and ecotoxicity evaluation

Chemical stabilization of heavy metals in medical waste fly ash has been carried out using the following compounds: a chelating agent (Ashnite S803), a commercial acidic phosphoric acid solution (Ashnite R303) as well as basic one (Ashnite R201). In order to predict the leachability of heavy metals, Japanese Leaching Test (JLT-13) procedure was applied to the stabilized fly ash products. An ecotoxicity assessment of the stabilized fly ash products leachate and the unstabilized fly ash leachate was conducted using a battery of bioassays based on lettuce root elongation inhibition, Daphnia magna mortality and Vibrio fischeri photoinhibition. The results showed that the three stabilizing agents were able to significantly decrease (ANOVA, P < 0.05) the concentration of heavy metals in the leachates. Although the leachate from both stabilized and unstabilized fly ash were very toxic to lettuce and daphnids, the incorporation of these stabilizing agents diminished significantly (ANOVA, P < 0.05) the toxicity of the leachates towards the three tested organisms. Pearson correlation analysis was used to analyze the strength of the relationship between chemical elements concentration in the leachate and bioassays results. Most of the heavy metals in the leachate were significantly correlated (ANOVA, P < 0.05) with the toxicity values of the bioassays. However, the correlation was not found between the concentration of dissolved organic carbon (DOC) and the toxicity effect of the leachate to the tested organisms.     

Public coordination for escaping from technological lock-in: its possibilities and limits in replacing diesel vehicles with compressed natural gas vehicles in Tokyo

This paper analyzes a recent attempt by the Tokyo Metropolitan Government to replace diesel vehicles with low-emission vehicles, particularly, compressed natural gas vehicles. As commonly observed in the transportation sector, when strong complementarities among the components of a complex technological system exist, a failure in coordination results to a state of technological lock-in. In this respect, the public sector can serve a focal role in coordination to promote new technologies. The Tokyo experience illustrates the potentials and limitations in overcoming a state of technological lock-in by effective management of the behaviors and expectations of the relevant actors involved in using, producing, and supporting alternative clean vehicles.     

Photodecomposition of humic acid and natural organic matter in swamp water using a TiO2-coated ceramic foam filter: Potential for the formation of disinfection byproducts

This paper reports on the photodecomposition of aqueous humic acid (HA) by a TiO₂-coated ceramic foam filter (TCF) reactor and on the potential for the formation of disinfection byproducts (DBPs) upon chlorination of the photocatalytically treated solutions. This photocatalytic reactor can also be applied to the removal of natural organic matter (NOM) in swamp waters. The proposed photocatalytic reaction system was operated as per standardized methodologies. First, the ability of the TCF to decompose HA (a representative compound of NOM) was evaluated from the changes in the total organic carbon (TOC) and UV₂₅₄ with the reaction time. Remarkably, TOC removal and UV₂₅₄ values ranging from 44% to 61% and from 60% to 83%, respectively, were achieved. The potential for the formation of DBPs (total trihalomethane and total haloacetic acid) by chlorination of the phototreated solution was strongly dependent on the TOC removal and UV₂₅₄ values in the solution. The degree of photodecomposition of NOMs in the swamp water samples and the DBP formation potential showed similar trends as in the case of the standard solutions containing HA. The method used in this study could be effectively used to evaluate the efficiency of TCF for reducing HA and NOM, while suppressing the formation of DBP products.     

Resolving complexities in healthcare waste management: a goal programming approach.

The wide variety of activities at healthcare facilities generates different types of waste. There is always a danger of spreading infection due to mishandling of infectious waste or sharps. Hence, a variety of policies and actions have been taken to improve healthcare waste management systems. A large body of literature is available which suggests methods for tackling different problematic situations but management is confronted with a variety of complex problems, such as the choice of technological options to control infection, legal and budget restrictions and the timely removal of waste, which can, at times, conflict with each other. Hence, a planning model is presented that is based on a trans-shipment goal programming approach wherein the waste flow is optimized for multiple objectives under different priority structures or with different relative importance (weights). The use of the model is demonstrated as a decision-making tool that would help the management to understand the effects of their policies on the system performance. The model is validated for a case application representing a real-life situation. It can be easily seen that, in the case in which the management is biased toward a higher level of safety protection towards infection control, they have to compromise on cost control and to some extent on environmental pollution control.