贵屿的教训

当前,随着电子产品的更新换代,废旧电脑、电视机等电子"垃圾"在大量产生,却无任何好的回收渠道,肆意侵蚀着我们的环境.一段时间以来,广东省潮阳市贵屿镇因废旧电脑回收造成的环境污染问题,引起了社会各界的广泛关注,为我们拉响了环境污染防治的警钟.

Comparative Study on the E-waste Recycling Systems in Japan and China

This study aims to identify processes, current situations and issues of recycling systems for four home appliances, namely, air conditioners, television receivers, refrigerators, and washing machines, among e-wastes in China and Japan for understanding and comparison of their characteristics. In accordance with results of a literature search, review of information disclosed online, and questionnaire survey conducted, the findings of this study are summarized in the following two points： （1） The results show that in Japan most of the home appliances mentioned above have been collected through home appliance recycling tickets, resulting in an issue of ＂requiring some effort＂ in treatment and recycling stages, and most plants have contracted out their e-waste recycling; （2） It is found out that advantages of the recycling system in Japan include easiness to monitor concrete data and thorough environmental friendliness ensured while its disadvantages include illegal dumping and export. It becomes apparent that advantages of the recycling system in China include a high reuse rate, low treatment cost, and fewer illegal dumping while its disadvantages include less safe reused products, environmental pollution caused by e-waste treatment, illegal import and difficulty in obtaining data.

Thoughts on e-waste recycling

This paper summarizes the situation of e-waste recycling in China, points out several key problems, identify the causes and draw lessons and experiences abroad about e-waste management, propose systematic suggestions from the production side, the recovery side, consumers side, government departments and thelegislation.

Glass-ceramics made from arc-melting slag of waste incineration fly ash

Grate fly ash and fluidized bed fly ash mixed with glass cullet additive respectively were melted in the electronic arc-furnace. The product, arc-melting slag, was further treated by crushing, pressing and heat treatment in order to make the glass-ceramics. The crystallization behaviors of the produced glass-ceramics were examined by differential thermal analysis （DTA）, X-ray diffractometry （XRD） and scanning electron microscopy （SEM）. Results show that main crystalline phase of the glass-ceramics fi＇om grate fly ash is wollastonite （CaSiO3） with small amount of diopside （Ca（Mg,Al）（Si,Al）206）, and that from fluidized bed fly ash is diopside （Ca（Mg,Al）（Si,Al）206）. It is found that the glass-ceramics sintered at 850 ℃and 1 000℃ from grate fly ash and fluidized bed fly ash respectively have the optimal physical, mechanical and chemical characteristics. Glass-ceramics samples, produced from incinerator fly ash with desirable properties and the low leaching concentration of heavy metals, can be the substitute of nature materials such as marble, granite and porcelain tiles.

Long-term nitritation performance of ammonium-rich landfill leachate

This study presents a biological system combined upflow anaerobic sludge bed(UASB) with sequencing batch reactor(SBR) to treat ammonium-rich landfill leachate.The start-up and operation of the nitritation at low temperatures were investigated.The synergetic interaction of free ammonia(FA) inhibition on nitriteoxidizing bacteria(NOB) and process control was used to achieve nitritation in the SBR.It is demonstrated that nitritation was successfully started up in the SBR at low temperatures(14.0 ℃-18.2 ℃) by using FA inhibition coupled with process control,and then was maintained for 482 days at normal/low temperature.Although ammonia-oxidizing bacteria(AOB) and NOB co-existed within bacterial clusters in the SBR sludge,AOB were confirmed to be dominant nitrifying population species by scanning electron microscopic(SEM) observation and fluorescence in situ hybridization(FISH) analysis.This confirmation not only emphasized that cultivating the appropriate bacteria is essential for achieving stable nitritation performance,but it also revealed that NOB activity was strongly inhibited by FA rather than being eliminated altogether from the system.

Tropical Leachate Properties as a Growing Media for Algae as a Source of Biodiesel Production

Algae can be found in ponds, rivers, lakes, abandoned ponds and also can grow abundantly in the aged pond of leachate landfill since there is the source of sunlight, CO2 （carbon dioxide） and nutrients. Like plants, algae make their own food by photosynthesis but differ from the plant; algae do not have roots, petals, stems or leaves. Leachate is the water that contains dissolved and suspended solids resulting from the percolation of water that drains through the waste in the landfill. The constituents of the leachate include organic matters and inorganic matters which depend on the age of landfill and type of the waste. The aim of this research study is to identify the characteristics of the leachate from aged landfill that cause the growth of the algae. Metals that act as the nutrients that exist in the leachate were measured using ICP-OES （inductively coupled plasma-optical emission spectroscopy）. BOD5 （biochemical oxygen demand that is measured in 5 days） and COD （chemical oxygen demand） were measured using DO （dissolved oxygen） meter and spectrophotometer, respectively. The pH of the leachate was measured using pH meter. The results showed that the highest metal that exists in the leachate was magnesium in quantity of 8.52 ppm. BOD5 and COD of the leachate gave the results of 5.24 mg/L and 99.67 mg/L, respectively. The pH of the leachate is considered as alkaline since the value of the pH is 8.38. This indicates that the characteristics of the leachate for algae growth was aged landfill with the alkaline condition and the nutrient needed by the algae for growing is magnesium.

Atmospheric levels and distribution of Dechlorane Plus in an E-waste dismantling region of East China

Atmospheric concentrations of Dechlorane Plus(DP)were investigated in Taizhou,an electronic-waste(E-waste)dismantling region in East China.Passive air samplers with polyurethane foam(PUF)disks were deployed every three months during the sampling period of September 2009-August 2010.The total DP(syn-and anti-DP)concentrations in air ranged from not detected to 277 pg/m^3,with a mean concentration of 53.9 pg/m^3.A generally declining trend of DP levels was found from the E-waste dismantling region to the peripheral areas.The median values of total DP concentrations in autumn,winter,spring and summer were 52.2,28.8,39.7 and 30.1 pg/m^3,respectively.The seasonal variations of DP concentrations were mainly associated with the intensity of E-waste dismantling activities and meteorological conditions.The mean value of anti-DP fractional abundance(f_(anti))was 0.74±0.08,which was consistent with those in the commercial DP products.This study confirmed a significant emission source related to the distribution of atmospheric DP in the E-waste dismantling area and supplied information for the seasonal variation of DP in the atmosphere.