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At least 145 records · Page 8Linked to original sources
PubMed2006

Visual diagnosis of solid waste contamination of a tourist beach: Pernambuco, Brazil.

The solid waste accumulation patterns on Tamandaré beach, Pernambuco State (Brazil), was assessed from February 2001 to July 2002. This beach is easily accessible, frequently used, and there is a public cleaning service. The beach is under the influence of three small coastal drainage basins. The study visually divided the beach into 15 segments according to the level of solid waste contamination into absent (A), trace (B), unacceptable (C) and objectionable (D). The lowest levels of contamination were found at the middle part of the study area, the most vulnerable in respect to coastal erosion presenting numerous interventions on the beach, absence of native vegetation and lesser width. The highest levels of contamination were at the northern and southern ends of the area, where there are no developments, the beach morphology favours deposition of sediments, there is native vegetation and the beach is wider. The D level did not occur within the area.

Bathing Beaches↗
PubMed2005

Determination of solid waste sorption capacity for selected heavy metals in landfills.

The adsorption process is largely a surface-action phenomenon. In this study, sorption capacities for heavy metals on a solid waste matrix were investigated. Five heavy metals (iron, copper, zinc, nickel and cadmium) were chosen because of their availability in any landfill site. The conditions during all the experimental runs were pH 7.0, temperature 32 degrees C and suppressed microbial degradation. For adsorption isotherm (Freundlich and Langmuir) calculations, fixed quantities of heavy metal ions were mixed with variable quantities of solid waste. The ratio of mass of adsorbate per unit mass of adsorbent was changed five times, by changing only the adsorbent amount. The results showed that the time required to reach equilibrium varied from metal to metal but all reached equilibrium within the first 32 h. The relative potential of sorption of the individual metals and mixed metals on the solid waste matrix is Fe > Zn > Cu > Ni > Cd. The sorption capacity of domestic solid waste matrix for heavy metals is quite significant and this property might prove helpful for the in situ removal of heavy metals in landfill operation.

Adsorption↗
PubMed2006

Study of the operational conditions for anaerobic digestion of urban solid wastes.

This paper describes an experimental evaluation of anaerobic digestion technology as an option for the management of organic solid waste in developing countries. As raw material, a real and heterogeneous organic waste from urban solid wastes was used. In the first experimental phase, seed selection was achieved through an evaluation of three different anaerobic sludges coming from wastewater treatment plants. The methanization potential of these sludges was assessed in three different batch digesters of 500 mL, at two temperature levels. The results showed that by increasing the temperature to 15 degrees C above room temperature, the methane production increases to three times. So, the best results were obtained in the digester fed with a mixed sludge, working at mesophilic conditions (38-40 degrees C). Then, this selected seed was used at the next experimental phase, testing at different digestion times (DT) of 25, 20 and 18 days in a bigger batch digester of 20 L with a reaction volume of 13 L. The conversion rates were registered at the lowest DT (18 days), reaching 44.9 L/kg(-1) of wet wasteday(-1). Moreover, DT also has a strong influence over COD removal, because there is a direct relationship between solids removal inside the reactor and DT.

Animals↗
PubMed2001

An integrated programme for municipal solid waste management.

A mathematical model is used in planning an integrated programme for the management of municipal solid waste to solve an economical optimisation problem and allow preliminary decisions to be made at the operational planning phase. The model, based on networks depicting the municipal solid waste management cycle, is simple to apply and furnishes easily assimilated results that facilitate management choices. Its application in an optimised area within the Regione Campania in Italy demonstrates how it may be used to evaluate the economic advantages pertaining to different municipal solid waste collection and treatment options.

Conservation of Natural Resources↗
PubMed2004

Cytogenetic effects of leachates from tannery solid waste on the somatic cells of Vicia faba.

The contamination of surface- and groundwater by the leaching of solid wastes generated by industrial activities as a result of water runoff and rainfall is a matter of great concern. The leachates from tannery solid waste (TSW), a major environmental pollutant, were examined for their possible genotoxic effects on the somatic cells of Vicia faba. Leachates were prepared from solid wastes procured from leather-tanning industrial sites, and V. faba seedlings were exposed to three test concentrations, 2.5%, 5%, and 10%, through soil and aqueous media for 5 days. The root tips examined for cytogenetic damage revealed that leachate of TSW significantly inhibited the mitotic index and induced significantly frequent chromosomal and mitotic aberrations (CA/MA) in a dose-dependent manner. The chemical analysis of TSW samples revealed that the chief constituents were chromium and nickel, which may cause genetic abnormalities. The frequency of aberrations was found to be higher in the root meristematic cells of Vicia faba exposed through the aqueous medium than those exposed through the soil medium. The results of the present study indicated that contamination of potable water bodies by leachates of TSW may cause genotoxicity. For the biomonitoring of complex mixtures of toxicants with the V. faba bioassay, the use of the aqueous medium seems to be a more promising method than the use of the soil medium.

Chromosome Aberrations↗
PubMed2003

Partitioning gas tracer tests for measurement of water in municipal solid waste.

A key component in the operation of almost all bioreactor landfills is the addition of water to maintain optimal moisture conditions. To determine how much water is needed and where to add it, in situ methods are required to measure water within solid waste. Existing technologies often result in measurements of unknown accuracy, because of the variability of solid waste materials and time-dependent changes in packing density, both of which influence most measurement methods. To overcome these problems, a new technology recently developed by hydrologists for measuring water in the vadose zone--the partitioning gas tracer test--was tested. In this technology, the transport behavior of two gas tracers within solid waste is used to measure the fraction of the void space filled with water. One tracer is conservative and does not react with solids or liquids, while a second tracer partitions into the water and is separated from the conservative tracer during transport. This technology was tested in four different solid waste packings and was capable of determining the volumetric water content to within 48% of actual values, with most measurement errors less than 15%. This technology and the factors that affect its applicability to landfills are discussed in this paper.

Bioreactors↗
PubMed2006

Predicting uncertainty in the ecotoxicological assessment of solid waste leachates.

Environmental managers need suitable technological methods to use in optimization studies to improve management of hazardous waste. One of the challenges to achieving a reliable hazardous waste classification is the improvement of procedures used forthe ecotoxicological characterization of solid waste leachates. Indeed, this step requires data that meet levels of acceptable quality if scientifically based decisions are to be made. In this study, we illustrate how the variability associated with the successive steps of a procedure used to assess ecotoxicological hazard of solid waste (i.e., primary sampling, laboratory sampling, toxicity measurements) can contribute to the overall variability of the ecotoxicity results. To this end, a municipal solid waste incinerator bottom ash and a slag from a second smelting of lead were studied using a nested experimental design. The results showed that the waste sampling design is of major importance for limiting the final variability of toxicity test parameters. At the opposite, increasing the number of replicates at the toxicity test level has negligible impact on this variability. Our approach could be of great practical interest in ecotoxicological studies not only for ensuring a safe classification for these materials, but also for improving sampling protocols and facilitating less time-consuming and less expensive ecotoxicological evaluations.

Ecology↗
PubMed2005

Life-cycle assessment of municipal solid wastes: development of the WASTED model.

This paper describes the development of the Waste Analysis Software Tool for Environmental Decisions (WASTED) model. This model provides a comprehensive view of the environmental impacts of municipal solid waste management systems. The model consists of a number of separate submodels that describe a typical waste management process: waste collection, material recovery, composting, energy recovery from waste and landfilling. These submodels are combined to represent a complete waste management system. WASTED uses compensatory systems to account for the avoided environmental impacts derived from energy recovery and material recycling. The model is designed to provide solid waste decision-makers and environmental researchers with a tool to evaluate waste management plans and to improve the environmental performance of solid waste management strategies. The model is user-friendly and compares favourably with other earlier models.

Aluminum↗
PubMed1975

Development of the solid waste resource.

This paper describes the waste processing and boiler feed facilities which serve as the prototype for Union Electric Company's proposed Solid Waste Utilization System for recycling essentially all the solid waste generated in the metropolitan St. Louis area. The recently announced system, capable of processing up to 8,000 tons of raw refuse per day and estimated to cost $70 million, will be built and operated without government subsidy. Solid waste will be processed for the recovery of recyclable noncombustibles and use as a supplementary fuel to electric utility boilers.

Costs and Cost Analysis↗
PubMed2005

Biostabilization-biodrying of municipal solid waste by inverting air-flow.

The process of biodrying could be a good solution for municipal solid waste management, allowing the production of fuel with an interesting energy content. Previous work (Adani, F., Baido, D., Calcaterra, E., Genevini, P.L., 2002. The influence of biomass temperature on biostabilization-biodrying of municipal solid waste. Bioresource Technology 83 (3), 173-179) has indicated that appropriate management of the processing parameters (air-flow rate and biomass temperatures) could achieve biomass drying in very short times (8-9 days). However, the data of that work also evidenced that if the conditions do not consider pile turning, and the air-flow is always from one direction, temperature gradients arise within the biomass, resulting in a lack of homogeneity in the moisture and energy content of the final product. Therefore, a new laboratory study was conducted on municipal solid waste biodrying-biostabilization in an effort to obtain homogeneous final products. Our proposal to solve this lack of homogeneity is to periodically invert the air-flow direction. Thus, in line with a previous study, two trials, A and B, were carried out, dividing the biomass into three layers to study temperature and moisture gradients throughout the process, and a third trial (C) simulating air-flow inversion at regular intervals was introduced. The results suggest that the daily inversion of air-flow eliminates marked temperature differences and leads to a homogeneous final product.

Bacteria↗
PubMed1999

[Association between household solid waste disposal and health, Belo Horizonte (MG), Brasil].

There are few published studies about the effects of inadequate solid waste collection on the health of the population exposed to this situation. The objective of the present work was to describe this association in a sample of children under 5 years of age living in seven low-income neighborhoods and favelas in the city of Belo Horizonte, state of Minas Gerais, Brazil. We defined as "exposed" those children whose families were not served by waste collection; "not-exposed" were children who lived in areas with waste collection. The study employed data collected in 1994 and organized as a database by the municipal department of health. We employed a cross-sectional design, in which a "case" was defined as a child whose outpatient clinic record indicated a diagnosis of diarrheal, parasitic, or dermatological disease. Other diagnoses for the same age group composed the control group. Our epidemiological study revealed an association between the absence of domestic solid waste collection and public health. Our results suggest that the children exposed to the absence of solid waste collection have a 40% higher odds (OR = 1.40) of presenting diarrheal, parasitic, and dermatological diseases than not-exposed children. In addition, the calculation of attributable risk revealed that the presence of waste collection could prevent (based on the 1995 situation) 512 cases in the neighborhoods studied and (based on the 1994 conditions) 2316 cases among children in the entire city of Belo Horizonte.

Brazil↗
PubMed2003

[Rapid evaluation of the quality of municipal solid waste incineration bottom ash].

Incinerators do not achieve a complete mineralization of organic constituents of municipal solid waste. Bottom ash (main solid residue from incineration process) still contains a small quantity of carbon (1 to 5% in weight). This study is about characterisation of the carboned fraction (without carbonates) present in Municipal Solid Waste Incineration (MSWI) bottom ash as well as its influence on the short and long-term behavior of bottom ash. Qualitative and quantitative characterisation of different carbon species (refractory carbon, labile organic carbon, water dissolved organic carbon, maximum extractable organic carbon and non extractable organic carbon) are realised with various analytical methods (DSC, GC/MS, liquid phase carbon analyser). In this work, whatever studied sample, the same proportion of labile organic carbon is mobilisable by water. This labile organic fraction corresponds to the maximum quantity of extractable carbon and refractory carbon to non extractable organic carbon. This fine characterisation of the carboned fraction has allowed the evaluation of the quality and the short- and long-term non negligeable influence of the organic reservoir present in MSWI bottom ash.

Carbon↗
PubMed2004

Volatile organic compounds produced during the aerobic biological processing of municipal solid waste in a pilot plant.

The volatile organic carbon (VOC) and odours emitted during the aerobic biological processing of municipal solid waste (MSW) was studied in a pilot-scale reactor. VOCs were detected by different techniques on solid waste samples and the outlet air stream, before and after a biofilter. Organic compounds (alpha-pinene, beta-myrcene, D-limonene) were also measured in condensate water and leachate from the process. Results showed uniformity in the composition of the air in the solid waste samples, air sampled during the process and condensed water, indicating a matrix-derived origin of these compounds. Leachates, however, contained substances with a quite different molecular structure from the compounds identified in the gaseous fraction. Most of the substances in the gaseous effluent had a hydrocarbon-like structure, mainly terpenoids. The odour produced and detected through olfactometry agreed with GC-MS analyses. This was true above all for terpenes.

Air Pollutants↗
PubMed2001

Effect of inoculum-substrate ratio on the start-up of solid waste anaerobic digesters.

The anaerobic systems start-up for solid waste treatment is a fundamental step, especially for those with two phases. It is necessary to know both the waste characteristics and the inoculum conditions. The objective of this work was to study the inoculum-substrate ratio (ISR) influence as a previous step of the start-up of an anaerobic system for the solid waste digestion. During this research spent grain was chosen as residue, working at three different concentrations (7; 13 and 20% w/v), studying the ISR effect in terms of anaerobic degradability (AD) and specific methane productivity (SMP). The initial acetoclastic activities (A0) were calculated based on the equation which describes the methane accumulation during each test. The model constants were also calculated and were adjusted to the experimental data. The results showed that in general the ISR variation has less impact on AD than on SMP. While maximum AD were reached in those tests with high ISR, the greatest values of SMP were with the lowest values of ISR ratio. A low ISR caused a slow hydrolysis, although the methane production was fast. So, during the start-up of a two-phase anaerobic system an elevated ISR would not be necessary in order to reach a good AD and a good intermediate products production, because the hydrolysis and the VFA production must be optimised in the first phase of these systems. While in conventional systems, where phases are together, it is much better to optimise the methane production. The ISR and the SMP indicated which inoculum percentage would be interesting based on the objective of the whole system; methane or intermediate compounds (VFA) production. All this information is important during the conventional anaerobic reactors operation because these tests would show which ISRs avoid inhibition.

Bacteria, Anaerobic↗
PubMed2002

Immobilisation of beryllium in solid waste (red-mud) by fixation and vitrification.

The objective of this study was to obtain information on the immobilization of beryllium (Be) in solid waste generated in the extraction process of beryllium from its ore, Beryl. This solid waste, termed red-mud, contains oxides of iron, aluminium, calcium, magnesium and beryllium. The red-mud waste contains beryllium at levels above the permissible limit, which prevents its disposal as solid waste. The total beryllium content in the red-mud analysed showed value ranging from 0.39 to 0.59% Be The studies showed that 50% of the total beryllium in red-mud can be extracted by water by repeated leaching over a period of 45 days. The cement mix, casting into cement blocks, was subjected to leachability studies over a period of 105 days and immobilization factor (IF factor) was determined. These IF values, of the order of 102, were compared with those obtained by performing leachability study on vitrified red-mud masses produced at different temperature conditions. Direct heating of the red-mud gave the gray coloured, non-transparent vitreous mass (as 'bad glass') showed effective immobilisation factor for beryllium in red-mud of the order of 10(4).

Beryllium↗
PubMed2006

Environmental assessment of solid waste systems and technologies: EASEWASTE.

A new model has been developed for evaluating the overall resource consumption and environmental impacts of municipal solid waste management systems by the use of life cycle assessment. The model is named EASEWASTE (Environmental Assessment of Solid Waste Systems and Technologies) and is able to compare different waste management strategies, waste treatment methods and waste process technologies. The potential environmental impacts can be traced back to the most important processes and waste fractions that contribute to the relevant impacts. A model like EASEWASTE can be used by waste planners to optimize current waste management systems with respect to environmental achievements and by authorities to set guidelines and regulations and to evaluate different strategies for handling of waste. The waste hierarchy has for decades been governing waste management but the ranking of handling approaches may not always be the most environmentally friendly. The EASEWASTE model can identify the most environmentally sustainable solution, which may differ among waste materials and regions and can add valuable information about environmental achievements from each process in a solid waste management system.

Environment↗
PubMed2006

[Inoculating microbes on municipal solid wastes composting affects organic acids and maturity].

Inoculating microbes (Meishang compound microbes, MS; Zhongjia fermentation microbes, ZJ) on municipal solid wastes composting which adopted industrialized technology was studied. The dynamic changes of low molecule weight organic acid and high molecule weight humic substance were discussed. The results show that inoculating microbes on municipal solid wastes composting could increase the content of organic acid at initial stage of composting, and decrease that at final stage. But humic substance and humic acid decline at the initial stage, then increase at the final stage of composting. The dynamic changes of organic acid and humification index indicate that inoculating microbes on municipal solid wastes can obviously increase the maturity of composting, and order as follow: MS+ ZJ>ZJ > MS>CK.

Acids↗
PubMed2003

Solid waste management in Indian Himalayan tourists' treks: a case study in and around the Valley of Flowers and Hemkund Sahib.

Solid waste generation in sensitive tourist areas of the Indian Himalayan region is approaching that of some metro cities of the country. The present study showed approximately 288 g waste generation visitor(-1) day(-1) compared with the nation-wide average of 350 g capita(-1) day(-1). About 29 metric tonnes (MT) solid waste is generated along a distance of about 19-km trek (a stretch of land or distance between two or more places covered by a walk) during a 4-month tourist season every year. Treks and trek stalls are the two major places where the visitors generate solid waste. Waste estimated from stalls accounted for about 51% by weight of the total waste generation in the trekking region. The native villagers generally construct stalls every year to meet the requirement of visitors going to Valley of Flowers (VOF) and Hemkund Sahib. The average annual results of 2 years (or equivalent to the average of one, 4-month tourist season for the region) showed non-biodegradable waste (NBW) to be 96.3% by weight whereas biodegradable waste (BW) amounted to merely 3.7%. From management point of view of the government, 96% NBW could easily be reused and recycled. Nevertheless, the need is to manage this waste by bringing it from the trekking areas to the road head (Govind Ghat) first and then to transport it to adjacent recycling centers. Cold drink glass bottles (68%), plastic (26%) and metal (2%) were the major items contributing to non-biodegradable waste. The remaining organic waste could be used as feedstock for composting. A well coordinated effort of public participation is necessary at all the levels for managing waste. There is a need to educate the visitors to instill in them the habit of considering discarded waste as potentially valuable and manageable.

Biodegradation, Environmental↗