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461.
The purpose of this research was to shorten the composting period by speeding up the composting process and to obtain good quality compost that can be used in agriculture. In order to accomplish the acceleration of the process, different mixtures of feedstock were loaded to the composting containers to observe the effect of initial composition on the quality of the compost and the rate of composting. The first feedstock prepared was composed of grass, leaves and market waste whereas the second feedstock composed only of leaves and market wastes. Composting process was accomplished by applying different composting methods such as composting without manual stirring, with manual stirring, with aeration by air, with aeration by oxygen, with manual stirring and aeration by air and finally by with manual stirring and aeration by oxygen to achieve the purpose of the research. Aeration was found as a primary requirement for the acceleration of composting because it was observed that when the aeration was not applied the conversion of nutrients was very low. The high conversion efficiency of the nutrients in the feedstock with market and yard wastes-without grass-resulted in higher quality end product. The organic content of the composted yard and market wastes were monitored and the best operational parameters and methods were identified. Parameters such as temperature, moisture, pH and end-product metal contents were also monitored in the study. and the experiments were run in duplicates. Corrected C/N, (C/N)t/(C/N)initial, were used in the calculations which provided objectivity in comparison of the compost quality with respect to nutritional components. The C/N change was found to be higher in the container that was manually stirred and aerated with oxygen but with regard to the economic feasibility of the system aeration with air was preferred. Compost quality that was achieved in the study was compared to the standards of different countries with respect to the amount of metal contents in the end-product. The applicability of the end-product in agriculture depends on the level of contaminants in the compost, especially metals that have to be present only in trace amounts. 相似文献
462.
Büchert A Cederberg T Dyke P Fiedler H Fürst P Hanberg A Hosseinpour J Hutzinger O Kuenen JG Malisch R Needham LL Olie K Päpke O Rivera Aranda J Thanner G Umlauf G Vartiainen T van Holst C 《Environmental science and pollution research international》2001,8(2):84-88
Dioxin and PCB monitoring programs for food and feeding stuff in most countries of the world, including many European Countries are currently inadequate. Better control of food production lines and food processing procedures is needed to minimize entry of dioxin to the food chain and will help to avoid dioxin contamination accidents. This would also improve the ability to trace back a possible contamination to its source. European guidelines for monitoring programs should be established to ensure comparable and meaningful results. These guidelines should define the minimum requirements for the design of monitoring programs, analytical methods, and quality assurance. Though data from Northern Europe shows that the general population exposure to dioxin and PCB has decreased during the last ten years these compounds continue to be a risk of accidental contamination of the food chain. The most prominent recent example is the Belgian dioxin contamination of feeding stuff in 1999. The Belgian dioxin contamination was not detected due to dioxin monitoring programs but by their direct biological effects seen in animals. Four other cases of dioxin contamination have been detected in Europe since 1997 due to local monitoring programs. One of them (citrus pulp pellets 1998) was in a much larger scale than the Belgian dioxin contamination. The general population's exposure to dioxins and PCBs is still in the same range (1-4 pg WHO-TEQ/kg body weight and day) as the recently revised WHO tolerable daily intake (TDI). There is concern that short-term high level exposure to dioxins, furans, and PCB may cause biological effects on the human fetal development and further research is required. Further actions to control sources building on considerable advances already made in many countries may need to be supplemented by measures to prevent direct contamination of feeding stuff or food to reduce general population exposure further. 相似文献
463.
The effect of a green leaf volatile on host plant finding by larvae of a herbivorous insect 总被引:1,自引:0,他引:1
The role of a general green leaf volatile (glv) in host finding by larvae of the oligophagous chrysomelid Cassida denticollis was investigated using a new bioassay which takes into account the need for neonate larvae of this species to climb fresh
host plants from the ground. A "stem arena" was designed in which plant stems of the host, tansy (Tanacetum vulgare), and stem dummies (tooth picks), both wrapped in perforated filter paper, were offered to neonate larvae. The wrapping allowed
olfactory responses to be tested by preventing access to contact stimuli of stems and dummies. Larvae significantly preferred
to climb the wrapped tansy stems over dummies after a period of 15 min. The test glv, (Z)-3-hexen-1-ol, was not attractive when applied to dummies. However, when the glv was applied to the bottom of the arena,
the ability of larvae to discriminate between host stems and untreated dummies was significantly enhanced. More larvae climbed
wrapped host stems than dummies even within 5 min. While numerous other herbivorous insects are known to be directly attracted
by glv, this study shows that a singly offered glv on its own is unattractive to an herbivore but enhances the herbivore's
ability to differentiate between host and nonhost plants.
Received: 19 October 1999 / Accepted in revised form: 28 February 2000 相似文献
464.
The GPS recorder consists of a GPS receiver board, a logging facility, an antenna, a power supply, a DC-DC converter and
a casing. Currently, it has a weight of 33 g. The recorder works reliably with a sampling rate of 1/s and with an operation
time of about 3 h, providing time-indexed data on geographic positions and ground speed. The data are downloaded when the
animal is recaptured. Prototypes were tested on homing pigeons. The records of complete flight paths with surprising details
illustrate the potential of this new method that can be used on a variety of medium-sized and large vertebrates.
Received: 2 February 2000 / Accepted in revised form: 17 April 2000 相似文献
465.
The levels of toxaphene congeners, in addition to PCB congeners and organochlorine pesticides, were determined in various fish samples from different Danish waters. While PCB-153 and p,p'-DDE show different levels depending on the fishing area, with highest levels in fish from the Western Baltic Sea, toxaphene was detected in all the samples investigated at a more constant level. The distribution of the three toxaphene congeners Parlar #26, #50 and #62 depends on the fishing area, with the Western Baltic Sea being different from the other waters by having almost equal levels of toxaphene congeners #26 and #50. 相似文献
466.
A method for the congener-specific analysis of toxaphene in eggs of seabirds from a monitoring program from the northern part of Germany was carried out. The method was optimized in most steps of the procedure: injection temperature, HRGC with an HT-8 column, ion source temperature and the MS detection mode NCI/SIM measuring the isotope clusters of [M] , [M-Cl]-, [M-HCl]- and [M-2Cl]-. The suitability of 1,4-exo, 7,8,9,10,10-heptachloro-5-methoxytricyclo [5,2,1,0(2,6)]dec-3,8-diene as internal standard was demonstrated. 14 toxaphenes with Parlar numbers and more than 60 unknown toxaphenes could be identified. Spatial and temporal trends of toxaphene contamination are presented by using the Parlar 22 components standard for quantification. 相似文献
467.
Formation and long-term fate of non-extractable residues in outdoor lysimeter studies 总被引:5,自引:0,他引:5
Long-term outdoor lysimeter studies using (14)C-labelled compounds allow the quantification of the 'non-extractable residue fraction'. More than 20 lysimeter studies under realistic environmental conditions showed that more than 80% of residual carbon of the molecule is retained in the topsoil layer even after several years. Generally, 50-90% of this residual radiocarbon is regarded as 'soil bound residue'. Microbial biomass is present in large quantities in topsoil and continuously influences chemical and biochemical alteration of pesticide molecules that may interact directly with the total soil organic matter. Labelling techniques using radioactive isotopes like (14)C have been used to characterize these residues in the humus matrix. Our studies have been directed to the investigation of extractability and/or bioavailability of these residues in long-term investigations. 相似文献
468.
Jürgen Weber Anita Plantikow und Jupp Kreutzmann 《Umweltwissenschaften und Schadstoff-Forschung》2000,12(4):185-189
Zusammenfassung Die G?rleistung der HefeSaccharomyces cerevisiae wird als Bioindikator zur Erfassung aquatoxischer Wirkungen genutzt. Dazu wird die CO2-Produktion der Hefezellen nach einer Vermehrungsphase unter toxischen Einflüssen gemessen. Als Kennwert (EC20) dient die Schadstoffkonzentration, die die G?rung um 20% mindert. Es werden organische Verbindungen (unpolare und polare
Narkotika), anorganische Salze (insbesondere von Schwermetallen), Tenside und Pflanzenschutzmittel geprüft. Die Ergebnisse
werden, soweit verfügbar, mit den Daten eines Ciliatentestes mitTetrahymena pyriformis verglichen. Es ergab sich eine übereinstimmung von 90% bei vergleichbarer Testempfindlichkeit. Ergebnisse des Hefetests sind
damit ?kotoxikologisch aussagef?hig. Der Test ist reproduzierbar, methodisch einfach zu handhaben und bietet eine Alternative
für die Abwasserprüfung, da steriles Arbeiten nicht erforderlich ist.
Online-First: 15. Juni 2000 相似文献
469.
Katharina Bunse Matthias Vodicka Paul Schönsleben Marc Brülhart Frank O. Ernst 《Journal of Cleaner Production》2011,19(6-7):667-679
For governments and for manufacturing companies, global warming, rising energy prices, and customers’ increasing ecological awareness have pushed energy efficient manufacturing to the top of the agenda. Governments and companies are both striving to identify the most effective measures to increase energy efficiency in manufacturing processes. Based on results of a recent EU-funded roadmapping project, this paper highlights the needs of industrial companies for integrating energy efficiency performance in production management. First, it analyses concepts and tools for measurement, control and improvement of energy efficiency in production management proposed in literature. Second, the paper outlines that ICT tools and standardization are important enablers for energy efficient manufacturing. Third, industrial needs in these areas are presented based on expert interviews. The industrial needs thus identified are contrasted with concepts proposed in literature to point out the implementation gaps between practice and theory. The paper demonstrates that there exists a gap between the solutions available and the actual implementation in industrial companies. It concludes by deriving requirements for energy management in production that future collaborative research projects should address. 相似文献
470.
Modern landfill understanding points out controlled operation of landfills. Emissions from landfills are caused mainly by anaerobic biodegradation processes which continue for very long time periods after landfill closure. In situ landfill stabilization aims controlled reduction of emissions towards reduced expenditures as well as aftercare measures. Since April 2010, a new in situ stabilization technique is being applied at a pilot scale landfill (BAIV) within Landfill Konstanz Dorfweiher. This new method utilizes intermittent aeration and leachate recirculation for waste stabilization. In this study, influence of this technique on leachate quality is investigated. Among many other parameters, leachate analyses were conducted for COD, BOD5, NH4–N, NO2–N, NO3–N, TKN and chloride besides continuously on site recorded pH, electrical conductivity and oxidation–reduction potential (ORP). Results from leachate quality analyses showed that biological activity in the landfill was accelerated resulting in initial higher leachate strength and reduced emission potential of landfill. During full scale in situ aeration, ambient conditions differ from optimized laboratory scale conditions which mainly concern temperature increase and deficient aeration of some landfill parts (Ritzkowski and Stegmann, 2005). Thus, as a field application results of this study have major importance on further process optimization and application. 相似文献