Showing papers on "Waste disposal published in 2001"
TL;DR: It is demonstrated that tet genes occur in the environment as a direct result of agriculture and suggested that groundwater may be a potential source of antibiotic resistance in the food chain.
Abstract: In this study, we used PCR typing methods to assess the presence of tetracycline resistance determinants conferring ribosomal protection in waste lagoons and in groundwater underlying two swine farms. All eight classes of genes encoding this mechanism of resistance [tet(O), tet(Q), tet(W), tet(M), tetB(P), tet(S), tet(T), and otrA] were found in total DNA extracted from water of two lagoons. These determinants were found to be seeping into the underlying groundwater and could be detected as far as 250 m downstream from the lagoons. The identities and origin of these genes in groundwater were confirmed by PCR-denaturing gradient gel electrophoresis and sequence analyses. Tetracycline-resistant bacterial isolates from groundwater harbored the tet(M) gene, which was not predominant in the environmental samples and was identical to tet(M) from the lagoons. The presence of this gene in some typical soil inhabitants suggests that the vector of antibiotic resistance gene dissemination is not limited to strains of gastrointestinal origin carrying the gene but can be mobilized into the indigenous soil microbiota. This study demonstrated that tet genes occur in the environment as a direct result of agriculture and suggested that groundwater may be a potential source of antibiotic resistance in the food chain.
766 citations
TL;DR: The percent adsorption increased with increase in pH from 2 to 6 and remained constant up to 10 and the resulting carbon is expected to be an economical product for the removal of toxic heavy metals from industrial wastewaters.
750 citations
TL;DR: Red mud, an aluminium industry waste, has been converted into an inexpensive and efficient adsorbent and used for the removal of lead and chromium from aqueous solutions and the data follow both Freundlich and Langmuir models.
743 citations
TL;DR: The conversion of organics in wastewaters into hydrogen gas could serve the dual role of renewable energy production and waste reduction and the highest conversion efficiency was 46.6 mL H2/(g COD/L).
Abstract: The conversion of organics in wastewaters into hydrogen gas could serve the dual role of renewable energy production and waste reduction. The chemical energy in a sucrose rich synthetic wastewater was recovered as hydrogen gas in this study. Using fractional factorial design batch experiments, the effect of varying pH (4.5-7.5) and substrate concentration (1.5-44.8 g COD/L) and their interaction on hydrogen gas production were tested. Mixed bacterial cultures obtained from a compost pile, a potato field, and a soybean field were heated to inhibit hydrogen-consuming methanogens and to enrich sporeforming, hydrogen-producing acidogens. It was determined that the highest rate (74.7 mL H2/(L*h)) of hydrogen production occurred at a pH of 5.5 and a substrate concentration of 7.5 g COD/Lwith a conversion efficiency of 38.9 mL H2/(g COD/L). The highest conversion efficiency was 46.6 mL H2/(g COD/L).
710 citations
TL;DR: In this paper, a GIS-aid to the geo-environmental evaluation for urban land-use planning is illustrated for the urban area of Lanzhou City and its vicinity in Northwest China.
431 citations
TL;DR: 1H NMR spectra revealed that the HyI fractions were almost devoid of aromatic protons and the aliphatic region featured more sharp signals than HA and FA fractions, indicating that HyI fraction were consisted of more simple compounds and less complex mixtures.
401 citations
TL;DR: NP and OP were widely distributed in the river sediments in Tokyo, and relatively high concentrations (0.5-13.0 microg/g dry) of NP were observed in a long reach (approximately 10 km) in the Sumidagawa River.
Abstract: Distributions of alkylphenols (APs) [i.e., nonylphenol (NP), octylphenol (OP)], and nonylphenol monoethoxylate (NP1EO) in wastewater effluents, river water, and riverine and bay sediments in the Tokyo metropolitan area were demonstrated. During sewage treatments, NP and OP were efficiently removed from the sewage effluents through activated sludge treatments. Greater removal for NP (93% on average) than OP (84% on average) was consistent with their partitioning behavior to particles in primary and secondary effluents. NP concentrations in the river water samples ranged from 0.051 to 1.08 microg/L with higher concentrations in summer and spring than in colder seasons. In the river water samples, approximately 20% of NP was found in the particulate phase. Organic carbon-normalized apparent partition coefficients (K'OC) for NP (10(5.22 +/- 0.38)) and OP (10(4.65 +/- 0.42)) were 1 order of magnitude higher than those expected from their octanol-water partition coefficients (K(OW)), indicating strong affinity of APs to aquatic particles. Among NP isomers, no significant differences in their K'OC values were suggested. This is consistent with surprisingly uniform isomer peak profiles among the technical standard and all the environmental samples analyzed. NP and OP were widely distributed in the river sediments in Tokyo, and relatively high concentrations (0.5-13.0 microg/g dry) of NP were observed in a long reach (approximately 10 km) in the Sumidagawa River. In situ production of APs in the river sediment was suggested. Seaward decreasing trend in APs concentration was observed from the estuary to the Tokyo Bay. APs were well preserved in a sediment core collected from the bay. The profile shows subsurface maximum of AP concentrations in the layer deposited around the mid-1970s. The recent decrease in AP concentrations can be attributed to the legal regulation of industrial wastewater in the early 1970s.
363 citations
TL;DR: A gas chromatography/mass spectrometry method for the simultaneous quantitative determination of natural and synthetic estrogens and phytoestrogens in effluents of sewage treatment plants (STPs) was developed and selected substances were detected in the majority of samples.
Abstract: The proliferation test with human estrogen receptor-positive MCF-7 breast cancer cells (E-Screen assay) was applied for quantitative determination of total estrogenic activity in 24-h composite effluent samples from 16 municipal and two industrial sewage treatment plants (STPs) in the state of Baden-Wurttemberg, southwestern Germany. The estrogenic efficacy relative to the positive control, 17beta-estradiol, was between 26 and 74% (median, 48%) for the 16 municipal STPs. Estradiol equivalent concentrations (EEQs) were between 0.2 and 7.8 ng/L (median, 1.6 ng/L) and, thereby, were lower than those found in a pilot study, which revealed EEQs of greater than 10 ng/L in the effluents of two other STPs. The EEQs in 14 of the 16 effluent samples were very similar (0.9-3.3 ng/L), indicating a rather constant input of estrogenic substances via STPs into rivers. Additional activated charcoal filtration turned out to be very efficient in further eliminating estrogenic activity from effluents. The EEQs of the E-Screen assay and those calculated from the results of extensive chemical analysis using the estradiol equivalency factors determined for 13 natural and synthetic estrogenic substances were comparable for most of the effluent samples. 17beta-Estradiol, 17alpha-ethinylestradiol, and, to a lesser extent, estrone contributed to 90% or more of the EEQ value.
338 citations
TL;DR: In this article, the authors present methods for modeling geochemical systems that emphasize the involvement of the gas phase in addition to liquid and solid phases in fluid flow, mass transport, and chemical reactions.
Abstract: Reactive fluid flow and geochemical transport in unsaturated fractured rocks have received increasing attention for studies of contaminant transport, ground- water quality, waste disposal, acid mine drainage remediation, mineral deposits, sedimentary diagenesis, and fluid-rock interactions in hydrothermal systems. This paper presents methods for modeling geochemical systems that emphasize: (1) involvement of the gas phase in addition to liquid and solid phases in fluid flow, mass transport, and chemical reactions; (2) treatment of physically and chemically heterogeneous and fractured rocks, (3) the effect of heat on fluid flow and reaction properties and processes, and (4) the kinetics of fluid-rock interaction. The physical and chemical process model is embodied in a system of partial differential equations for flow and transport, coupled to algebraic equations and ordinary differential equations for chemical interactions. For numerical solution, the continuum equations are discretized in space and time. Space discretization is based on a flexible integral finite difference approach that can use irregular gridding to model geologic structure; time is discretized fully implicitly as a first-order finite difference. Heterogeneous and fractured media are treated with a general multiple interacting continua method that includes double-porosity, dual-permeability, and multi-region models as special cases. A sequential iteration approach is used to treat the coupling between fluid flow and mass transport on the one hand, chemical reactions on the other. Applications of the methods developed here to variably saturated geochemical systems are presented in a companion paper (part 2, this issue).
316 citations
TL;DR: The rules for management and handling of biomedical wastes are summarised, giving the categories of different wastes, suggested storage containers including colour-coding and treatment options, and existing and proposed systems of health-care waste management are described.
249 citations
TL;DR: The literature on the arsenic disposal practices of the metallurgical industry and the long term stability of the disposed arsenic compounds were reviewed from a Canadian perspective as discussed by the authors, and the review was complemented with visits to selected operating metallurgy sites to obtain information on their specific arsenic disposal practice and the behaviour of their impounded residues.
TL;DR: The bagasse fly ash system has been used for the removal of DDD and DDE from the wastewater and the developed system is very useful, economic, and reproducible.
TL;DR: Dried waste slurry generated in seafood processing factories has been shown to be an effective adsorbent for the removal of heavy metals from dilute solutions and predictions of sorption in binary-adsorbate systems based on single-adsolved data fits represented competitive sorption data reasonably well over a wide range of conditions.
TL;DR: In response to increasing volumes of returned products, firms are establishing programs to guide the reversal of flows in the supply chain, i.e., reverse logistics as mentioned in this paper, which seeks cost savings and efficiencies related to reclamation, redistribution, and disposal of products returned “upstream” to the retailer or manufacturer.
Abstract: In response to increasing volumes of returned products, firms are establishing programs to guide the reversal of flows in the supply chain, i.e., reverse logistics. With reverse logistics programs firms seek cost savings and efficiencies related to reclamation, redistribution, and disposal of products returned “upstream” to the retailer or manufacturer. This paper reports on a recent survey of electronics catalog retailers regarding reverse logistics program involvement. In addition to creating a profile of current reverse logistics activities in an industry characterized by high volumes of returns, the research also examines the relationship between investment in reverse logistics related resources and reverse logistics program performance.
TL;DR: In this paper, the effects of municipal solid waste (MSW) compost and mineral-N amendments in a 2-year field trial on some physical-chemical properties, some enzyme activities and the genetic diversity of cropped plots (sugar beet-wheat rotation) and uncropped plots were investigated.
Abstract: Municipal solid waste (MSW) composts have been frequently used as N and C amendments to improve soil quality and to support plant growth, with the additional benefit of reducing waste disposal costs. However, attention has been paid to the risks of MSW use for the soil environment. The presence of heavy metals in MSW composts can affect some microbiological characteristics of soil such as the structure of the soil microbiota, which are responsible for the transformations making nutrients available to plants. The effects of MSW compost and mineral-N amendments in a 2-year field trial on some physical-chemical properties, some enzyme activities and the genetic diversity of cropped plots (sugar beet-wheat rotation) and uncropped plots were investigated. Variations of pH were not statistically related to MSW compost and mineral-N amendments, or to the presence of the crop. Amendment with MSW compost increased the organic C and total N contents, and dehydrogenase and nitrate reductase activities of soil. In cropped plots amended with MSW compost, dehydrogenase activity was positively correlated with β-glucosidase activity, and both enzyme activities with organic C content. No MSW compost dosage effect was detected. No effects were observed on denaturing gradient gel electrophoresis and amplified rDNA restriction analysis patterns, indicating that no significant change in the bacterial community occurred as a consequence of MSW amendment.
TL;DR: In this article, the authors presented estimates of atmospheric emissions of mercury from anthropogenic sources in Europe in 1995 with the information on emissions of both total mercury and its major chemical and physical forms.
TL;DR: Removal of waste, natural leaching and biological activity, in time, led to an effective decrease in electrical conductivity and phenolic compounds, although residual levels can be important even 2 years later.
TL;DR: The results indicated that the second derivative method for nitrate analysis needed to be modified to include a longer digestion time (60 min) and dilution of samples prior to digestion (if needed), and that nitrogen recoveries were not significantly different from samples with known N concentrations.
TL;DR: This work investigated the characteristics of the Fenton system using high concentrations of iron and interpreted the results from the known reaction mechanisms, finding the use of high ferrous ion (> or = 1 mM) is believed to be appropriate for producing large quantities of OH.
TL;DR: In this article, a life cycle assessment was conducted on a coal-fired power system that co-fires wood residue, and it was found that cofiring significantly reduced the environmental footprint of the average coal fired power plant.
Abstract: The generation of electricity, and the consumption of energy in general, often result in adverse effects on the environment. Coal-fired power plants generate over half of the electricity used in the U.S., and therefore play a significant role in any discussion of energy and the environment. By cofiring biomass, currently operating coal plants have an opportunity to reduce the impact they have, but to what degree, and with what trade-offs? A life cycle assessment has been conducted on a coal-fired power system that cofires wood residue. The assessment was conducted in a cradle-to-grave manner to cover all processes necessary for the operation of the power plant, including raw material extraction, feed preparation, transportation, and waste disposal and recycling. Cofiring was found to significantly reduce the environmental footprint of the average coal-fired power plant. At rates of 5% and 15% by heat input, cofiring reduces greenhouse gas emissions on a CO2-equivalent basis by 5.4% and 18.2%, respectively. Emissions of SO2, NOx, non-methane hydrocarbons, particulates, and carbon monoxide are also reduced with cofiring. Additionally, total system energy consumption is lowered by 3.5% and 12.4% for the 5% and 15% cofiring cases, respectively. Finally, resource consumption and solid waste generation were found to be much less for systems that cofire.
TL;DR: This study compares the different digester systems in terms of organic loading rates and biogas yields considering differences in input waste composition to show that from a technical viewpoint the "dry" systems are more robust and flexible than "wet' systems.
TL;DR: An overview of the applications of wet disintegration in wastewater and sludge treatment is provided and thermal, freeze/thaw and biological treatments can be realized at low costs if the conditions are appropriate.
TL;DR: In this article, the authors describe the coupled physical processes taking place in waste rock piles undergoing acid mine drainage (AMD) production, where the oxidation process initiates coupled processes of gas transfer by diffusion and convection as well as heat transfer.
TL;DR: Chlorinated derivatives of bisphenol A were detected in the final effluents of eight paper manufacturing plants in Shizuoka, Japan, where thermal paper and/or other printed paper is used as the raw material.
TL;DR: In this article, the authors evaluate the current knowledge in modeling seedling emergence and residue decomposition, seedbed structure and its resulting physical conditions, and how tillage operations affect on seed bed structure and residue distribution.
Abstract: There is considerable discussion about the influence of soil management techniques on soil erosion, water use and conservation, and more recently carbon dioxide sequestration and waste disposal. The soil–atmosphere interface, particularly the seed bed layer is of particular concern to agronomists and soil scientists because it is the focus of the physical processes affecting crop establishment and biological activity. This paper evaluates the current knowledge (1) in modeling seedling emergence and residue decomposition, (2) seedbed structure and its resulting physical conditions, and (3) tillage operations affect on seedbed structure and residue distribution.
TL;DR: Results suggest the feasibility of recovering ESP from waste sludge for use as adsorbent and correlated satisfactorily with the adsorption data of Ni2+, Cu2+, Cd2+, and CrO4(2-) (R2 ranging 0.89-0.97), whereas Langmuir isotherm correlated poorly for those of Co2+.
TL;DR: It was concluded that the Tama River, a typical urbanized river in Tokyo, Japan, is also contaminated with antibiotic resistant coliform group bacteria and E. coli, and that the wastewater treatment process works against most of resistant bacteria in sewage.
TL;DR: In this paper, the authors developed a model of production and consumption that incorporates life-cycle externalities and used it to solve for alternative policies to achieve a social optimum, finding that no single instrument can solve multiple problems, contrary to what some observers have suggested.
TL;DR: Administration of an hydroxytyrosol-rich OMWW extract to the rats was associated with an increase of their plasma antioxidant capacity and future experiments will eventually further clarify its metabolic fate and its in vivo actions.
Abstract: Hydroxytyrosol is the most potent phenolic antioxidant of olive oil and olive mill waste water (OMWW) and its biological activities have stimulated research on its potential role in cardiovascular protection. However, evidence of the absorption of OMWW phenolics and on their possible in vivo activity has, until now, never been provided. Three groups male Sprague-Dawley rats were administered 1, 5, or 10 mg/Kg of the OMWW extract, respectively, providing 41.4, 207, and 414 microg/Kg of hydroxytyrosol, respectively. Urine was collected for 24 h and the urinary levels of hydroxytyrosol were quantified by mass spectrometry. Hydroxytyrosol was dose-dependently (R(2) = 0.95) absorbed and excreted in the urines mostly as a glucuronide conjugate. Further, the administration of an hydroxytyrosol-rich OMWW extract (10 mg/kg) to the rats was also associated with an increase of their plasma antioxidant capacity. Future experiments will eventually further clarify its metabolic fate and its in vivo actions.
TL;DR: Comparisons of pulsed-field gel electrophoresis patterns of fecal isolates from piggeries, waste slurry, and agricultural soil amended withSalmonella-contaminated animal waste showed identical patterns, indicating long-term persistence of the Salmonella enterica serovar Typhimurium DT12 clone in the herd environment.
Abstract: Prevalence of Salmonella enterica on a Danish pig farm presenting recurrent infections was investigated. A comparison of the pulsed-field gel electrophoresis patterns of fecal isolates from piggeries, waste slurry, and agricultural soil amended with Salmonella-contaminated animal waste (slurry) and subclinical isolates from the same farm (collected in 1996 and later) showed identical patterns, indicating long-term persistence of the Salmonella enterica serovar Typhimurium DT12 clone in the herd environment. Furthermore, when Salmonella-contaminated slurry was disposed of on the agricultural soil (a common waste disposal practice), the pathogen was isolated up to 14 days after the spread, indicating potentially high risks of transmission of the pathogen in the environment, animals, and humans.