Challenges of waste management in a Nigerian leper colony

Quantities and types of solid wastes generated at Ogbomosho leprosarium (Oyo State, Nigeria) have been investigated. Data collection, through waste sampling and analysis, interviews, questionnaire surveys and field observations, was conducted between August and November 2006. Results indicate a notably low mean waste generation rate of 241.5 g/h/d, which included bandages, paper, food waste, animal waste, wood ash, yard trimmings, amongst others. There is no national policy on waste handling. Domestic waste is mixed with biomedical waste without sorting. Moreover, waste‐handlers deal with waste materials by hand and without protective clothing or gloves, which needlessly exposes them to greater health risks. Similarly, primitive hygiene facilities (e.g. pit latrines, plus inadequate and intermittent water supplies) constitute a health risk to patients, staff and visitors. Recommendations include i) provision of separate waste receptacles at generation points to facilitate proper sorting and segregation; ii) adequate training and protective clothing for waste handlers; and iii) national and international action for leprosy patients housed in these ‘out of sight, out of mind’ communes.     

废弃混凝土对水泥熟料煅烧过程矿物形成的影响

以废弃混凝土、石灰石、砂岩、铁矿石、煤粉为原料,采用普通煅烧工艺烧制了不同煅烧温度下的水泥熟料,利用XRD、SEM等表征手段考察了不同目数的混凝土对水泥煅烧过程中熟料主要矿物形成的影响,并将煅烧生成的水泥熟料与标准熟料进行了对比分析。结果表明,在不同煅烧温度下烧成的水泥熟料中主要矿物的XRD特征峰明显,矿物形成正常,并与对比试样水泥熟料的矿物化学成分相近。不同目数混凝土代替部分生料烧制的水泥熟料组成及形貌的变化有明显的区别,60~80目烧制的水泥熟料因Al、Fe和Si元素含量较高而出现主要矿物黏结和熔蚀现象,阻碍C3S的形成,水泥矿物发育较差,而大于120目烧制的水泥熟料矿物发育良好,主要矿物黏结和熔蚀较少,但f-CaO量高于标准熟料。     

Emission of pollutants from wood waste incineration at sawmills in Abeokuta metropolis,Nigeria

This paper reports an assessment of the effects of wood waste burning on air quality and the perceived human health in an urban setting. The concentrations of particulates and selected gases were monitored within the vicinity of sawmills in Abeokuta metropolis. The levels of CO, CO₂, SO₂, NO_x, NO₂, H₂S, CH₄ and particulates at distances from sawmill dumps were measured using portable samplers. Additionally, information on sawmill operations and health problems encountered by the exposed population were collected from a community survey. From the data analyses, between 60 and 100% of wood waste generated by sawmills were burned openly, leading to pollutants emission. The mean concentrations of PM_0.3–0.5 (32 523–40 284 μg/m³), NO₂ (1.0 ppm), SO₂ (3.3 ppm), CO (759 ppm) and CO₂ (4.9%) were higher than the permissible limits at 0–15 m from the dump sites. Almost all sampled parameters showed positive association (R = 0.90–0.98; p < 0.05) at sample sites. Moreover, distance of sites to the dumps explained 51–93% of the variation in parameters levels. Both respiratory and dermal diseases were frequently experienced by the exposed population. Strict land-use zoning, pollution abatement measures, environmental quality monitoring and waste-to-energy interventions are urgently required in the study area.     

Genotoxicity of recycling electronic waste in Idhna,Hebron District,Palestine

Most Electronic waste (e-waste) ends up in landfills while some is recycled. A major site for e-waste recycling in Palestine is the village of Idhna in the Hebron District and most of this waste originates from Israel. The objective of this study was to evaluate the effects of e-waste on human DNA damage and chromosome breaks. The test sample was 46 non-smoker individuals with direct exposure to e-waste, either employed in the workshops or resident in Idhna. Genotoxicity data were compared with a control sample of sixteen unexposed individuals from Bethlehem and Al-Aizariya (Bethany). DNA damage was evaluated using the Comet assay while chromosome aberrations were tested by using conventional cytogenetic techniques. We noted an average of 4.83 aberration/cell/subject in test samples while in controls the average was 0.75. Chromosome aberration frequency was statistically different between exposed and control samples for total aberrations, for chromatid and chromosome breaks, and for formation of rings but not for dicenterics and tetraploidy. The Comet assay likewise showed that there was significant difference between exposed and control samples for DNA damage (p < 0.05). We therefore recommend measures to mitigate the health impact of e-waste recycling.     

帷幕灌浆在龙泉山垃圾处理场工程中的应用

结合合肥市龙泉山垃圾处理场防渗工程实例,详细分析了帷幕灌浆工艺的设计方法、试验和施工工艺,并对其实施效果进行了分析与总结,为同类工程的实践积累了经验,具有很好的借鉴作用。     

Identification of organic compounds in leachate from a waste tip

Two different types of leachate from a municipal waste tip have been analyzed. The first type of leachate was collected from a waste tip in the acidification stage. The organic load of this leachate was high and consisted mainly of free volatile acids (over 95% of the TOC). Volatile amines and ethanol were also present (0.8 and 0.7% of the TOC respectively). The leachate was extracted with hexane and the extract was analyzed with infrared and nuclear magnetic resonance spectroscopy and a gas chromatograph-mass spectrometer combination. In the extract alcohols, hydrocarbons, esters, terpenes and phthalates have been identified. High molecular weight compounds were present only in a low concentration.The second type of leachate was collected from a waste tip in the methane fermentation stage. The organic load was relatively low. An important part of the organics was identified as high molecular weight compounds. About 32% of the organic carbon consisted of compounds with a molecular weight over 1000. Acids, amines and alcohols could not be detected. This means that the organic compounds present were end products of degradation processes.Furthermore there was a remarkable difference in heavy metal content between the two types of leachate.     

Differential management of waste by construction sectors: a case study in Michigan,USA

Waste is a great problem in the world of construction. If dealt with appropriately, there can be many benefits, including lower overall cost, faster production, a higher quality and more sustainable buildings. There are many solutions available for minimizing waste during construction. However, a great amount of waste still exists, whether in residential, commercial, industrial, infrastructural or other constructions. The purpose of this investigation is to ascertain key sources of waste, and whether generation varies with the type and size of the constructors. A sample of 30 general contractors was studied, and several null hypotheses on waste generation and minimization differences among sectors were tested using the Kruskal–Wallis H‐test. Although subtle shifts were observed in the aspects of waste behaviour that seemed predicated on construction sectors and capital base, to some extent the proposition that the construction type and size can influence waste generation and minimization was validated. Based on this study, some solutions are provided as viable avenues to managing and minimizing construction waste across sectors.     

固废基胶凝材料在干旱地区公路基层中的路用性能研究

针对水泥稳定材料引起的基层开裂及缓凝时间短的问题,采用粉煤灰、矿渣粉、脱硫石膏、电石渣为主要原料,配制道路水稳层路用胶凝材料,代替缓凝硅酸盐水泥。结果表明,固废基胶凝材料凝结时间相较水泥延迟了2h,其7d和28d抗折、抗压强度均满足规范要求;固废基稳定混合料14d及28d无侧限抗压强度与水泥稳定混合料7d及28d基本相等,同时28d冻融循环残留强度与30次抗硫酸盐耐腐蚀系数均大于85%,高于水泥稳定材料;固废基稳定混合料90d时试验段贯通裂缝数量4～5条,小于水泥稳定混合料数量的1/7。     

Impact of open dumping of municipal solid waste on soil properties in mountainous region

This paper presents the effect of open dumping of municipal solid waste (MSW) on soil characteristics in the mountainous region of Himachal Pradesh, India. The solid waste of dumpsite contains various complex characteristics with organic fractions of the highest proportions. As leachate percolates into the soil, it migrates contaminants into the soil and affects soil stability and strength. The study includes the geotechnical investigation of dump soil characteristics and its comparison with the natural soil samples taken from outside the proximity of dumpsites. The geochemical analysis of dumpsite soil samples was also carried out by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Visual inspection revealed that the MSW consists of high fraction of organics, followed by paper. The soil samples were collected from five trial pits in the dumpsites at depths of 0.5 m, 1 m and 1.5 m. Then the collected soil samples were subjected to specific gravity test, grain size analysis, Atterberg's limit test, compaction test, direct shear test, California bearing ratio (CBR) test and permeability analysis. The study indicated that the dumpsite soils from four study regions show decreasing trends in the values of maximum dry density (MDD), specific gravity, cohesion and CBR, and increasing permeability as compared to the natural soil. The results show that the geotechnical properties of the soils at all four study locations have been severely hampered due to contamination induced by open dumping of waste.     

Impact of compression ratio analysis in waste cooking oil biodiesels–diesel blends as fuel

ABSTRACT

The objective of this study is to investigate the effect of compression ratio on combustion characteristics of diesel engine with waste cooking oils methyl ester–diesel blends as fuel. The DI engine fuelled with Waste Cooking Rice Bran Methyl Ester (WCRBME) and Waste Cooking Cotton Seed Oil Methyl Ester (WCCSME) prepared by the transesterification process was investigated for its combustion and then compared with petroleum-based diesel fuel (PBDF). Experiments were conducted at a constant speed of 1500?rpm and maintained at a full-load condition for the compression ratio of 17:1, 18:1 and 19:1 and blending ratios B20, B40, B60 and B80.The fuel properties were strictly measured as per ASTM testing methods and these observed properties are verified to be well within the limits of ASTM D 6751 biodiesel standards. The combustion characteristics of heat release rate and combustion pressure of WCRBME & WCCSME were found closer to diesel.     

Three decades of urban growth in the city of Shiraz, Iran: A remote sensing and geographic information systems application

Although remotely sensed images have been used to study urban growth patterns the world over, very few studies have employed these methods to examine the growth of Iranian cities. Shiraz is perhaps the most important city in the southern part of Iran and, thus, was selected for this study. We used satellite images of the study area from the period between 1976 and 2005, and population censuses of Shiraz. By applying classification methods to the satellite images four main types of land use were extracted: water, built-up, vegetation and bare land. Then, the area coverage for all the land use types at different points in time were measured and coupled with population data. The results demonstrate that, over the entire study period, development in Shiraz cannot be characterized as sprawl. Since 2000, however, one can see evidence of sprawl. These results are also supported by calculations using Shannon’s entropy. A further finding is that vegetation growth did not keep pace with that of population or the built-up area; more recently, vegetation has greatly declined. It is advisable that future plans for the city give serious consideration to the preservation of available vegetation and, when possible, the restoration of vegetation that was destroyed in the past.     

Occurrence of pharmaceuticals in Taiwan's surface waters: Impact of waste streams from hospitals and pharmaceutical production facilities

We investigated the occurrence and distribution of pharmaceuticals (including antibiotics, estrogens, non-steroidal anti-inflammatory drugs (NSAIDs), beta-blockers, and lipid regulators) in three rivers and in the waste streams of six hospitals and four pharmaceutical production facilities in Taiwan. The most frequently detected pharmaceuticals were acetaminophen, erythromycin-H₂O, sulfamethoxazole, and gemfibrozil. NSAIDs were the next most-often detected compounds, with a detection frequency > 60%. The other analytes were not detected or were seen in only a few samples at trace concentrations. The present study demonstrates a significant discharge of human medications from hospital and drug production facilities into surface waters in the Taipei district. The high concentrations of pharmaceuticals found in the Sindian and Dahan rivers demonstrate the alarming degree to which they have been impacted by urban drainage (waste effluents from hospitals, households, and pharmaceutical production facilities). The ubiquitous occurrence at extremely high concentrations of acetaminophen and erythromycin-H₂O in both rivers (up to 15.7 and 75.5 µg/L) and in wastewater from hospitals and pharmaceutical production facilities (up to 417.5 and 7.84 µg/L) was unique. This finding, in combination with acetaminophen's status as the drug most often prescribed by Taiwan's dominant clinical institute, suggests the potential use of acetaminophen as a molecular indicator of contamination of Taiwan's aqueous environments with untreated urban drainage.     

Landfill sites,solid waste management and people’s resistance: a study of two municipal corporations in Kerala

This paper examines some issues associated with the centralised waste management system and the ways in which urban local bodies tackled the resistance against centralised waste management. The study is based on a sample survey of 175 households located in the landfill sites connected with two Municipal Corporations, viz. Thrissur and Kochi. The study observed that the local government resists change in solid waste management. When the resistance is strong alternative methods like decentralised waste management are chosen; and where the resistance is weak there is a tendency to maintain the centralised waste management system.     

Fate of LCFA in the co-digestion of cow manure, food waste and discontinuous addition of oil

Different concentrations of oily waste were added in a discontinuous mode and recurrently to anaerobic continuous stirred tank reactors fed with cow manure and food waste. Four continuous stirred tank reactors were run in parallel. A control reactor (R1) received no additional oil and R2, R3 and R4 received increasing concentrations of oil in two different experimental approaches. First, the lipids composition was forced to change suddenly, in three moments, without changing the total chemical oxygen demand (COD) fed to the reactors. The only long chain fatty acid (LCFA) detected onto the R1 solid matrix was palmitic acid (C16:0). Nevertheless in the solid matrix of R2, R3 and R4 C16:0 and stearic acid were detected. For occasional increase in the oil concentration up to 7.7 gCOD_oil/L_reactor (55% Oil_COD/Total_COD) no statistical differences were detected between the reactors, in terms of methane production, effluent soluble COD, effluent volatile fatty acids and total and volatile solids removal. Therefore this experiment allowed to conclude that cow manure–food waste co-digestion presents sufficient buffer capacity to endure solid-associated LCFA concentration up to 20–25 gCOD-LCFA/kgTS.In a second experiment higher concentrations of oil were added, raising occasionally the concentration in the reactors to 9, 12, 15 and 18 gCOD_oil/L_reactor. All pulses had a positive effect in methane production, with the exception of the highest oil pulse concentration, that persistently impaired the reactor performance. This experiment demonstrates that threshold values for LCFA and C16:0 accumulation onto the solid matrix, of about 180–220 gCOD-LCFA/kgTS and 120–150 gCOD-C16:0/kgTS, should not be surpassed in order to prevent persistent reactor failure, as occurs in some full scale co-digestion plants.     

Characterization of indoor air quality in primary schools in Antwerp, Belgium

The indoor air quality of 27 primary schools located in the city centre and suburbs of Antwerp, Belgium, was assessed. The primary aim was to obtain correlations between the various pollutant levels. Indoor:outdoor ratios and the building and classroom characteristics of each school were investigated. This paper presents results on indoor and local outdoor PM2.5 mass concentrations, its elemental composition in terms of K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Pb, Al, Si, S, and Cl, and its black smoke content. In addition, indoor and local outdoor levels of the gases NO2, SO2, O3, and BTEX (benzene, toluene, ethyl benzene, and xylene isomers) were determined. Black smoke, NO2, SO2 and O3, occurred at indoor:outdoor ratios below unity, indicating their significant outdoor sources. No linear correlation was established between indoor and outdoor levels for PM2.5 mass concentrations and BTEX; their indoor:outdoor ratios exceeded unity except for benzene. Classroom PM2.5 occurred with a different elemental composition than local outdoor PM2.5. The re-suspension of dust because of room occupation is probably the main contributor for the I/O ratios higher than 1 reported for elements typically constituting dust particles. Finally, increased benzene concentrations were reported for classrooms located at the lower levels. PRACTICAL IMPLICATIONS: The elevated indoor PM2.5, and BTEX concentrations in primary school classrooms, exceeding the ambient concentrations, raise concerns about possible adverse health effects on susceptible children. This is aggravated by the presence of carpets and in the case of classrooms at lower levels. Analysis of PM2.5's elemental composition indicated a considerable contribution of soil dust to indoor PM2.5 mass. In order to set adequate threshold values and guidelines, detailed information on the health impact of specific PM2.5 composites is needed. The results suggest that local outdoor air concentrations measurements do not provide an accurate estimation of children's personal exposures to the identified air pollutants inside classrooms.     

植被生态对城市垃圾的处理利用及改良

在城市垃圾填埋场上种树、种草进行植被恢复的基础上 ,分析测定了垃圾土中营养元素被植被吸收利用 ,其中有机质为 70 .2 8%、N为 60 .2 9%、P为 81 .85 %、K为 88.0 7% ,有效成分促进了植物生长 .植物对垃圾土中有害物—重金属可吸收积累 ,减少污染 ,对七种重金属污染削减率 ,灌木植物为 3 2 .2 5 %～ 5 4.46% ,草皮植物为 1 8.68%～ 78.46% .为植被生态处理、改良垃圾废弃地提供依据     

Stiffness and strength characteristics of demolition waste,glass and plastics in railway capping layers

The increased generation of demolition waste has led to the successful implementation of its utilization in civil engineering projects. The combination of recycled aggregates and supplementary materials can potentially improve the quality of geomaterials when constructing alternative railway capping layers. In this research, two types of demolition waste, namely, Recycled Concrete Aggregates (RCA) and Crushed Brick (CB), were studied in comparison to two Conventional Capping Materials (CCMs), which are currently used for railway track construction. Recycled Glass (RG) and Mixed Recovered Plastic (MRP) were also blended with RCA to assess their performance. All the materials and mixtures were evaluated in terms of both stiffness and strength. A new Repeated Load Triaxial (RLT) testing protocol was introduced based on the stress induced in the capping layers to determine the stiffness of the materials. A comparison was made among the current resilient modulus prediction models to find a model that would better fit the results for the demolition waste and mixtures. Multistage triaxial tests were also conducted to determine the strength, friction, stiffness and energy absorption capacity of the materials. It was found from this research study that RCA, CB and mixtures of RCA with RG and MRP have equivalent or higher levels of stiffness and strength than CCMs and are suitable alternatives for sustainable railway capping layer construction.     

In‐vessel composting under air pressure of organic fraction of municipal solid waste in Azemmour,Morocco

This study aims to evaluate the performance of laboratory‐scale in‐vessel composting bioreactor for the Organic Fraction of Municipal Solid Waste treatment in Azemmour, Morocco. The bioreactor was specially designed and used for this study, and it was operated semicontinuously under 0.6 bar pressure. The evaluations studied included the operational indices, the compost maturity indices and the quality of the final compost. Obtained results showed that organic fraction of municipal solid waste could be composted successfully in 12 days. Moreover, high CO₂ generations involve high temperature and high internal air pressure change, revealing vigorous microbial activity. The final compost was satisfactory for its agricultural application.     

重庆市某卫生填埋场陈垃圾土的工程特性研究

陈垃圾土是一类非常特殊的土,结合重庆一封场六年多的填埋场,对陈垃圾土的物理指标,工程力学性质进行实验研究。总结了陈垃圾土的主要组成成分,得出了陈垃圾土的含水率,密度和孔隙比的具体范围,并与新鲜垃圾作了比较。探讨了垃圾各组分对土体各物理指标的影响。深入研究了陈垃圾土的三轴应力应变曲线特征,并把曲线划分了四个阶段,分析了各个阶段的特点,阐述了其产生的原因。指出陈垃圾土是具有一定的结构,但结构性很弱的土体,3σ是强度形成的主要原因。同时探讨了陈垃圾土有机物纤维,土体颗粒对陈垃圾的C,φ值影响。     

The Beishan underground research laboratory for geological disposal of high-level radioactive waste in China: Planning,site selection,site characterization and in situ tests

With the rapid development of nuclear power in China, the disposal of high-level radioactive waste (HLW) has become an important issue for nuclear safety and environmental protection. Deep geological disposal is internationally accepted as a feasible and safe way to dispose of HLW, and underground research laboratories (URLs) play an important and multi-faceted role in the development of HLW repositories. This paper introduces the overall planning and the latest progress for China's URL. On the basis of the proposed strategy to build an area-specific URL in combination with a comprehensive evaluation of the site selection results obtained during the last 33 years, the Xinchang site in the Beishan area, located in Gansu Province of northwestern China, has been selected as the final site for China's first URL built in granite. In the process of characterizing the Xinchang URL site, a series of investigations, including borehole drilling, geological mapping, geophysical surveying, hydraulic testing and in situ stress measurements, has been conducted. The investigation results indicate that the geological, hydrogeological, engineering geological and geochemical conditions of the Xinchang site are very suitable for URL construction. Meanwhile, to validate and develop construction technologies for the Beishan URL, the Beishan exploration tunnel (BET), which is a 50-m-deep facility in the Jiujing sub-area, has been constructed and several in situ tests, such as drill-and-blast tests, characterization of the excavation damaged zone (EDZ), and long-term deformation monitoring of surrounding rocks, have been performed in the BET. The methodologies and technologies established in the BET will serve for URL construction. According to the achievements of the characterization of the URL site, a preliminary design of the URL with a maximum depth of 560 m is proposed and necessary in situ tests in the URL are planned.