Sustainable recycling model: A comparative analysis between India and Tanzania

Higher economic growth in developing countries has caused higher amounts of wastes. Local government authorities in these countries usually fail to provide adequate services to dispose the increasing amounts of waste, resulting in threats for both the population and environment health. There is therefore an urgent need for recycling as a form of waste management in order to stop the devastating effects of solid waste in developing countries. Using a qualitative method of analysis, this study presents a model to measure and rank the sustainability of recycling programs in India and Tanzania. The model consists of six main constructs including “production, economic, governmental, social, technological, and international factors”. The results showed that India outperforms Tanzania in sustainable recycling programs: per capita waste generated per day in Delhi is higher than in Dar es Salaam; the government of India focuses more on developing recycling plans and techniques as compared to the government of Tanzania where the country is not actively involved in the recycling process; and the solid waste management planning in India is being performed better than Tanzania.     

Overview of non-hazardous solid waste in the small island state of Mauritius

In Mauritius, solid waste disposal has been a cause for concern since the 1980s. Currently, there is no segregation of waste and some 1200 tonnes of solid waste are generated daily by the 1.24 million inhabitants of the island. As processes such as recycling and composting are still in their infancy stage, most of the waste generated have to be disposed of at the sole landfill. The solid waste management practices of 1980s and early 1990s are no longer compatible with the changing composition and quantity of wastes now generated. As a result, there is an urgency to review the whole waste management system and come forward with sustainable solutions.This paper presents an overview of the disposal of non-hazardous solid waste in Mauritius and provides recommendations for improving the current disposal system.     

水中3种微囊藻毒素的高效液相色谱测定方法优化

对天然水体中3种痕量微囊藻毒素（MC-RR、MC-YR、MC-LR）的淋洗、洗脱、液相色谱测定等环节进行单因素不同水平考察,结果表明：以体积分数为45%的甲醇水溶液（含0.1%的TFA）为固相萃取淋洗剂、10 mL甲醇（含01%TFA）为固相萃取洗脱剂,体积分数为70%的甲醇水溶液（含0.1%TFA）为液相色谱流动相,可在6 min内有效分离MC-RR、MC-YR、MC-LR。将优化后的方法用于实际加标水样的测定,MC-RR、MC-YR、MC-LR的方法检出限分别为0.064 μg/L、0.098 μg/L、0.095 μg/L,加标回收率为87.0%~116%,RSD为10.2%~18.8%。     

Comparing the greenhouse gas emissions from three alternative waste combustion concepts

Three alternative condensing mode power and combined heat and power (CHP) waste-to-energy concepts were compared in terms of their impacts on the greenhouse gas (GHG) emissions from a heat and power generation system. The concepts included (i) grate, (ii) bubbling fluidised bed (BFB) and (iii) circulating fluidised bed (CFB) combustion of waste. The BFB and CFB take advantage of advanced combustion technology which enabled them to reach electric efficiency up to 35% and 41% in condensing mode, respectively, whereas 28% (based on the lower heating value) was applied for the grate fired unit. A simple energy system model was applied in calculating the GHG emissions in different scenarios where coal or natural gas was substituted in power generation and mix of fuel oil and natural gas in heat generation by waste combustion. Landfilling and waste transportation were not considered in the model. GHG emissions were reduced significantly in all of the considered scenarios where the waste combustion concepts substituted coal based power generation. With the exception of condensing mode grate incinerator the different waste combustion scenarios resulted approximately in 1 Mton of fossil CO₂-eq. emission reduction per 1 Mton of municipal solid waste (MSW) incinerated. When natural gas based power generation was substituted by electricity from the waste combustion significant GHG emission reductions were not achieved.     

固体废物相关概念的基本特点

固体废物法对废物的一些概念进行了定义,在固体废物环境管理当中,对这些概念缺乏深入认识,导致在实际管理中对固体废物和危险废物的调查、认定、统计、管理、预测、设施建设等一系列与废物相关的行动出现偏差甚至不准确。对固体废物、危险废物以及废物利用、处置、贮存、排放等概念包含的内容进行了研究,提出了一些新的认识观点。     

垃圾填埋场细菌种群空间分布及组成多样性研究

采用PCR-DGGE技术对垃圾填埋场细菌种群垂直分布及组成多样性进行了研究．结果表明：垃圾填埋场细菌种群组成波动较大,某些种群对环境因子的变化十分敏感．在填埋年龄已达3a的取样点,细菌种群的多样性随着垃圾填埋深度的增加而呈现“多—少—多”的变化趋势。各种群间相对密度也呈现由不均一到均一的变化规律,部分层次优势种和非优势种发生较大变化．填埋深度4．0m至6．25m左右的区域是填埋场微生物区系组成发生变化的过渡区,该区域细菌种群的多样性较小,亲缘关系相差比较大的种交叉在一起,具有明显的过渡特征．从时间因素来看,填埋场同层次微生物群落组成随时间延长,种群构成趋于稳定．表层垃圾1～2a内,细菌种群处于交替更叠的阶段,日趋发育成熟．8．25m以下层次的细菌种群主要受填埋深度影响,与填埋时间关系较小。     

Effect of steam hydration on performance of lime sorbent for CO2 capture

Lime is considered a feasible sorbent for the capture of CO₂ from large stationary sources. The positive attributes of a natural source material, low cost and lack of harmful by-products are offset by rapid deterioration in performance and high regeneration temperature. Performance can be improved by hydrating the lime using steam. We investigate a steam hydration process wherein lime is hydrated for 5 min at 300 °C and atmospheric pressure in a mixture of steam and CO₂. The experiments consisted of 10 capture cycles with 60% of the lime active at the end. Extrapolation using a decay model suggests a residual carbonation level of 48%, significantly higher than the 8% achieved by dry lime cycles. The cost of replacement sorbent under these conditions is less than $1/t of CO₂ captured. The hydrated lime process also reduces the thermal load, for heating and cooling, by half as well as the inventory, and therefore solids handling, by a factor 5 over dry lime. The introduction of the hydration reaction provides another exothermic reaction for heat management.     

Groundwater Pollution Around an Industrial Area in the Coastal Stretch of Maharashtra State, India

The main objective of this paper is to examine pollution threat, especially to the groundwater resources, around Tarapur industrial area (also called the Tarapur MIDC area) located on the Arabian Sea Coast in Thane District of Maharashtra State, India and suggest remedial measures that may also be relevant to other industrial areas on the Indian Sea Coast. One hundred and thirty one samples were collected from various sources, such as dugwells, borewells, dug-cum-borewells, effluent sumps, drainage channels (effluent channels), creeks and ocean, for chemical analyses. These analyses show that the area in general is characterized by hard water and high salinity hazard, possibly due to its proximity and hydraulic connection with the sea. Although the potability of groundwater is questionable in certain pockets, it is good enough for irrigation purposes at present. Low pH value and high heavy metal contents in the adjoining Muramba creek water is a matter of great concern and may be attributed to the indiscriminate disposal of industrial effluents to the drainage channels connecting the creek. Muramba Creek is well connected with the Arabian Sea, and there are evidences of seawater intrusion around this creek. Because of the fact that Muramba Creek is highly polluted, and is hydraulically connected with the dugwells and borewells surrounding the creek, it cannot be ruled out that the groundwater around this creek is susceptible to contamination. Unless measures are not taken immediately to stop the indiscriminate disposal of the solid wastes and liquid effluents in open ground and drainage channels, and measures are not taken to maintain the appropriate pH values at the effluent treatment facilities before their disposal, the problem would indeed be formidable one day, and it will be too late then for the authorities to take care of the resulting maladies. Few suggestions have been given for controlling and managing the industrial pollution around the Tarapur MIDC area. These suggestions are relevant to other industrial areas situated on the 7,000 km long Indian Sea Coast.     

Relation of waste generation and composition to socio-economic factors: a case study

To develop an effective waste management strategy for a given region, it is important to know the amount of waste generated and the composition of the waste stream. Past research has shown that the amount of waste generated is proportional to the population and the average mean living standards or the average income of the people. In addition, other factors may affect the amount and composition of waste. These are climate, living habits, level of education, religious and cultural beliefs, and social and public attitudes. This paper presents the findings of a study carried out in a suburban municipal area in Sri Lanka to determine the solid waste generation rate and waste composition based on field surveys and to determine the related socio-economic factors. A database was developed that included information on the quantity and composition of waste generated in a sample of households in the study area over a time period. The collected data was analysed to relate waste generation and composition data to various socio-economic factors. Over 400 sample households were selected for the study using a stratified random sampling methodology based on municipal wards and property values. A technique that considers both the number of households in a particular income group (property value range) and the standard deviation of property values within a given income group was used to determine the appropriate sample size for each municipal ward. Through category and regression analyses, the quantities of waste and waste composition were related to several socio-economic factors. The paper describes the basis for the sample selection, the methodology adopted for data collection, the socio-economic parameters used for the analysis, and the relationships developed from the analysis.     

水环境中26种类固醇激素的分析方法研究

建立了固相萃取-超高效液相-串联质谱法同时测定水环境中26种类固醇激素的分析方法。明确了取样体积为500 m L,Cleanert PEP为富集柱,乙酸乙酯为洗脱剂,甲醇为溶剂进行提取操作。选择了正离子模式,以0. 1%甲酸/甲醇-水为流动相,负离子模式以0. 1%氨水/乙腈-水为流动相,试样经AcquityTMUPLC BEH C18色谱柱分离后,选用质谱检测模式进行定性、定量分析。通过方法验证,26种类固醇激素的方法检出限为0. 3～1. 5 ng/L,测定下限为1. 2～6. 0 ng/L,代表性样品测定结果的相对标准偏差为2. 6%～13. 7%(n=6),加标回收率为71. 2%～121%。该方法操作便捷,灵敏度高,精密度和准确度良好,可适用于水环境中多种痕量、超痕量类固醇激素的定性定量分析。