Evaluation of electronic components in life cycle assessment

Life cycle assessment (LCA), a quantitative method for evaluating the total environmental impact of a product, from the materials in its manufacture to its final disposal, is playing an increasingly important role in manufacturing. When the LCA method is applied to a product containing many kinds of electronic components, there is a need for life cycle inventory (LCI) data on the components. This paper provides an original calculation of the LCI data for each electronic components industry. These data show the amount of input energy and emissions into the atmosphere per yen of production yield. It is demonstrated that the magnitude of the LCI data for each industry is essentially equal to that of the other industries. Furthermore, we conclude that the LCI data for all electronic components are roughly equivalent, making it possible to calculate the LCI data of any electronic component by simply multiplying the LCI data for the industry by the price of the component. Furthermore, after comparing the materials production stages with the component manufacturing stage in the calculation, it became clear that for several component industries the materials production stage could not be omitted from the calculation. Received: April 10, 1998 / Accepted: February 8, 1999     

Optimization of co-digestion of various industrial sludges for biogas production and sludge treatment: Methane production potential experiments and modeling

Optimal biogas production and sludge treatment were studied by co-digestion experiments and modeling using five different wastewater sludges generated from paper, chemical, petrochemical, automobile, and food processing industries situated in Ulsan Industrial Complex, Ulsan, South Korea. The biomethane production potential test was conducted in simplex-centroid mixture design, fitted to regression equation, and some optimal co-digestion scenarios were given by combined desirability function based multi-objective optimization technique for both methane yield and the quantity of sludge digested. The co-digestion model incorporating main and interaction effects among sludges were utilized to predict the maximum possible methane yield. The optimization routine for methane production with different industrial sludges in batches were repeated with the left-over sludge of earlier cycle, till all sludges have been completely treated. Among the possible scenarios, a maximum methane yield of 1161.53 m³ is anticipated in three batches followed by 1130.33 m³ and 1045.65 m³ in five and two batches, respectively. This study shows a scientific approach to find a practical solution to utilize diverse industrial sludges in both treatment and biogas production perspectives.     

Natural and Anthropogenic Effects On Phytoplankton Primary Productivity in Mangroves

Spatial and temporal variations and the factors influencing primary production have been studied in three different mangrove waters (Pichavaram, Ennore Creek and Adyar Estuary) of South India characterised by different anthropogenic impacts. the gross primary productivity in the unpolluted Pichavaram mangrove was 113 g Cm^-2yr^-1 exhibiting natural variability with the environmental forcing factors. Human activities have elevated primary productivity in the Ennore Creek mangrove (157g Cm^-2yr^-1) primarily through the direct discharge of fertilizer effluents. By contrast, a combination of domestic and industrial effluent discharges into the Adyar Estuary mangrove has considerably reduced phytoplankton primary productivity 83g Cm^-2yr^-1 the Redfield N: P ratio varies from 0.96 N: 1P at Ennore Creek, 1.75N: 1P at Adyar Estuary to 15.2 N: 1P at Pichavaram mangroves. This suggests that the Pichavaram mangroves represent a well equilibrated ecosystem with N: P ratio close to steady-state values in contrast to the anthropogenically altered mangrove ecosystems studied. Results show a significant temporal variability in nutrient concentration in the three mangrove areas. Distinct differences in nutrient concentrations between the dry and the wet seasons have been observed.     

Bio-Hydrogen Synthesis from Wastewater by Anaerobic Fermentation Using Microflora

Biological hydrogen production was investigated using biomass in palm oil mill effluent (POME) and artificial wastewater containing 10g glucose under anaerobic fermentation in a batch process. Activated POME sludge and different types of composts were collected as sources of inocula for the study. The anaerobic microflora was found to yield significant amounts of hydrogen. The experimental results show that the gas composition contained hydrogen (66–68%) and carbon dioxide (32–34%). Through out the study, methane gas was not observed in the evolved gas. The hydrogen production was accompanied with the formation of acetate and butyrate. Furthermore, the cumulative hydrogen data were fitted to a simple model developed from Gompertz Equation, where the lag phase time, hydrogen production potential and hydrogen production rate at various conditions were quantitatively estimated.     

Sustainable consumption and production: Trends, challenges and options for the Asia-Pacific region

This paper highlights current trends in consumption and production patterns in Asian developing countries and emerging economies. It describes the main challenges and opportunities for Asian countries making the transition towards sustainable consumption and production patterns. The main challenge for Asian economies is to address the unsustainable consumption patterns of urban consumers, which entails a policy shift from the current focus on pollution and inefficient industrial production. In view of future consumption trends and the global convergence of consumption patterns, the characteristics of the emerging 'global consumer class' are examined, with particular focus on urban ecological footprints and carbon emissions. Furthermore, the difference between urban and rural consumption is discussed, together with opportunities for low-carbon urban development in the megacities of Asian developing countries. To conclude, the paper presents an overview of current policy measures taken in Asian countries to green economic development and realise sustainable consumption and production patterns.     

Recovery of different waste vegetable oils for biodiesel production: A pilot experience in Bahia State,Brazil

In Brazil, and mainly in the State of Bahia, crude vegetable oils are widely used in the preparation of food. Street stalls, restaurants and canteens make a great use of palm oil and soybean oil. There is also some use of castor oil, which is widely cultivated in the Sertão Region (within the State of Bahia), and widely applied in industry. This massive use in food preparation leads to a huge amount of waste oil of different types, which needs either to be properly disposed of, or recovered. At the Laboratorio Energia e Gas-LEN (Energy & Gas lab.) of the Universidade Federal da Bahia, a cycle of experiments were carried out to evaluate the recovery of waste oils for biodiesel production. The experiences were carried out on a laboratory scale and, in a semi-industrial pilot plant using waste oils of different qualities. In the transesterification process, applied waste vegetable oils were reacted with methanol with the support of a basic catalyst, such as NaOH or KOH. The conversion rate settled at between 81% and 85% (in weight). The most suitable molar ratio of waste oils to alcohol was 1:6, and the amount of catalyst required was 0.5% (of the weight of the incoming oil), in the case of NaOH, and 1%, in case of KOH.The quality of the biodiesel produced was tested to determine the final product quality. The parameters analyzed were the acid value, kinematic viscosity, monoglycerides, diglycerides, triglycerides, free glycerine, total glycerine, clearness; the conversion yield of the process was also evaluated.     

闽江口鳝鱼滩芦苇湿地沉积物甲烷产生与氧化潜力对外源物质输入的响应

研究河口湿地沉积物甲烷(CH4)产生和氧化对外源物质输入的响应,对环境保护及温室气体减排具有重要意义.本研究基于室内培养-气相色谱法,探讨了闽江河口半咸水芦苇(Phragmites australis)沼泽湿地沉积物CH4产生与氧化对不同外源物质(底物、电子受体和营养物质)输入的响应.结果表明:CH3OH(500 mg·kg-1)、C3H9N(500 mg·kg-1)和Fe2+(0~500 mg·kg-1)对CH4产生潜力起促进作用(p0.05);NO-3(0~500 mg·kg-1)、NO-2(0~500 mg·kg-1)、Fe3+(50 mg·kg-1)和NH+4(50~500 mg·kg-1)表现为抑制CH4产生潜力(p0.05);而0~50 mg·kg-1的CH3OH和C3H9N、0~500 mg·kg-1的CH3COOH、SO2-4、Mn4+、PO3-4和低剂量的NH+4(0~5 mg·kg-1)对CH4产生的影响不显著(p0.05).实验剂量内(0~500 mg·kg-1),Fe3+和Mn4+的添加可促进CH4氧化(p0.05);CH3COOH、CH3OH、C3H9N、NO-3、NO-2、SO2-4、NH+4和低剂量的PO3-4(0~50 mg·kg-1)对沉积物CH4氧化潜力均有显著的抑制作用(p0.05);而Fe2+对CH4氧化没有显著影响(p0.05).综合分析表明,CH3COOH、CH3OH、C3H9N、NO-3、NO-2、SO2-4、PO3-4、NH+4和Fe2+的输入对沉积物CH4产生和氧化的综合作用为增加CH4排放通量,而Fe3+和Mn4+输入的综合作用则与之相反.     

基于粗糙集和IPA的煤矿生产物流系统安全影响因素分析

针对煤矿生产物流系统安全影响因素众多、各因素对煤矿安全影响作用复杂的问题,提出基于粗糙集和IPA定位分析法的煤矿生产物流系统安全影响因素分析模型。首先运用粗糙集属性重要度思想对煤矿安全影响因素进行排序,然后采用IPA定位分析法识别不同安全状态煤矿安全生产的制约因素,最后通过对河南义马煤业集团跃进煤矿进行实证分析验证模型的可行性。结果表明,各因素对煤矿安全影响的重要度由大到小排序为通风设施、通风安全监控、通风技术管理、排水设备配置、机电安全管理、排水技术人员配备(采掘关系)、采掘机械、排水机构设置、安全运输、应急救援、采掘技术管理,且对于不同安全状态等级的煤矿而言,制约其安全的主要因素也不相同。     

厌氧发酵连续运行中有机负荷与工艺参数相互作用研究

以餐厨垃圾为研究对象,在高温(55±1)℃条件下,采用连续湿式厌氧发酵技术研究发酵过程中进料有机负荷、日产气量、pH值、挥发性有机酸(VFA)质量浓度等参数的变化情况及相互作用关系.结果表明:厌氧消化过程中出现了4个阶段,即适应阶段、提高阶段、稳定阶段和超负荷阶段;反应达到稳定阶段时,反应器运行有机负荷为3.9 kg/(m3·d),系统pH值稳定在7.8左右,平均产气速率达到5.26L/d;负荷达到4.2 kg/(m3·d)时,对系统产生明显抑制作用.     

Greener growing: assessing the influence of gardening practices on the ecological viability of community gardens in South East Queensland,Australia

While claims about the environmental benefits of community gardens abound, few researchers have systematically assessed the ecological integrity of gardening practices. This study investigated gardening practices in 50 community gardens in Brisbane and Gold Coast cities, Australia. The study aimed to better understand how gardening practices might affect the ecological viability of community gardens. Factors investigated included: garden bio-physical characteristics, operators’ motivations, gardeners’ socio-demographic backgrounds, garden facilities and types of plants grown. Two broad types of gardens were identified: permaculture (21 gardens) and non-permaculture (29 gardens). Permaculture gardens used lower-impact gardening practices. Findings have policy implications for environmental planning and management.