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361.
Wittig R König K Schmidt M Szarzynski J 《Environmental science and pollution research international》2007,14(3):182-189
BACKGROUND, AIM AND SCOPE: During the last decades ecological conditions in West Africa have dramatically changed. Very evident is the climate change, which has resulted in a southward shift of the climate zones, e.g. a spread of the desert (Sahara) into the Sahelian zone. After the drought period of the early 1970s and 1980s, livestock density increased resulting in an intensification of grazing pressure. This anthropogenous phenomenon leads to similar landscape changes as those caused by the climate. Only very few investigations exist on vegetation dynamics, climate changes and land use changes for the Sudanian zone. The paper presents data on changes of precipitation, of land use, of the geographical range of species, and of the composition of the flora, which have to be regarded as proofs of the sahelisation of large areas of the Sudanian zone. MATERIALS AND METHODS: Area of investigation: Burkina Faso. Precipitation data analysis: precipitation data from 67 stations; time series analysis and geo-statistical spatial interpolation. Analysis of land use change: Landsat satellite MSS and ETM+ data, acquired for two different dates between 1972 and 2001 analyzed by the software ERDAS/IMAGINE version 8.6 and ArcView 3.2 with the Spatial Analyst extension. Intensive ground truthing (160 training areas). Inventory of the flora: based on the data of the Herbarium Senckenbergianum (FR) in Frankfurt, Germany, and of the herbarium of the university of Ouagadougou (OUA), Burkina Faso, as well as on various investigations on the vegetation of Burkina Faso carried out in the years 1990 to 2005 by the team of the senior author. Life form analysis of the flora: based on the inventory of permanent plots. RESULTS AND DISCUSSION: Precipitation: Remarkable latitudinal shift of isohyets towards the South translates to a general reduction of average rainfall in great parts of the country. The last decade (1990-1999) shows some improvement, however, the more humid conditions of the 1950's and 1960's are not yet established again. Landcover change: In the study region the extent of arable fields and young fallows increased during the last 30 years from 580 km(2) in 1972 to 2870 km(2) in 2001. This means an average land cover conversion rate of 0.9% per year for the 6 departments considered. Change of the distribution of Sahelian and Sudanian species: Several species, mentioned in older literature as strictly Sahelian, today also occur in the Sudanian zone. Parallel to the spread of former strictly Sahelian species into the Sudanian zone, some former Sahelo-Sudanian species have withdrawn from the Sahel. Changes of the life form spectra of the flora: Considering their life form spectra, the flora of heavily grazed and of protected areas in the Sudanian zone show great differences. On areas intensively grazed the percentage of therophytes is evidently higher than on protected areas. Just the opposite is true for the phanerophytes. Their percentage is higher on the protected area than on the grazed zones. At the first glance, it is obvious to link the changes in flora and vegetation with the climate changes that have occurred during the last five decades (decrease of annual precipitation). However, not only climatic conditions have changed, but also population has increased, the percentage of land intensively used for agriculture and pasturing has increased and the time for soil regeneration today is much shorter than it was some decades ago. Thus, the landscape of the Sudanian zone has become a more Sahelian character. A comparison of the flora of an intensively used area of the Sudanian zone with that of a protected area shows a remarkable change in the life form spectra. The spectrum of the intensively used area is almost identical with that of the typical Sahelian flora. This comparison shows that the anthropogenic influence plays a greater role in the sahelisation of the Sudanian zone than the climate change. CONCLUSION: Climate change and anthropogenic influence both, lead to a sahelisation of landscape and flora. Thus in many parts of the Sudanian zone of West Africa sahelisation phenomena will remain and even increase independently from the reestablishment of the more humid climate conditions of the 1950ies. RECOMMENDATIONS AND PERSPECTIVES: In order to maintain some parts of the characteristic Sudanian landscape with its characteristic flora and vegetation, the number and size of protected areas should be augmented. For all protected areas it has to be ensured, that protection is reality, i.e. respected an understood by local people, not only fiction. As long as the enlargement of intensively used areas continues the sahelisation of flora, vegetation and landscape will continue too. 相似文献
362.
Impact of Bioaugmentation with a Consortium of Bacteria on the Remediation of Wastewater-Containing Hydrocarbons (5 pp) 总被引:1,自引:0,他引:1
Domde P Kapley A Purohit HJ 《Environmental science and pollution research international》2007,14(1):7-11
Goals, Scope and Background It has been observed that hydrocarbon treated wastewaters still contain high COD and a number of intermediates. This suggests
that the required catabolic gene pool for further degradation might be absent in the system or, that its titer value is not
significant enough. By providing the desired catabolic potential, the overall efficiency of the treatment system can be improved.
This study aims to demonstrate this concept by bioaugmentation of a lab-scale reactor treating refinery wastewater with a
consortium having the capacity to complement the alkB genotype to the available microbial population.
Methods Two reactors were set up using activated biomass collected from a refinery treatment plant and operated at a continuous mode
for a period of 8 weeks. The feed to both reactors was kept constant. Crude oil was spiked regularly. One reactor was bioaugmented
with a consortium previously described for crude oil spill remediation. The efficiency of the bioaugmented reactor was demonstrated
by reduced COD. The changes in the microbial population over a period of time were analyzed by RAPD. Catabolic activity of
the biomass in both reactors was monitored by PCR. The presence of the catabolic loci was confirmed by Southern Hybridization.
Results and Discussion 52.2% removal of COD was observed in the bioaugmented reactor while only 15.1% reduction of COD was observed in the reactor
without bioaugmentation. The change in microbial population can be seen from the 4th week, which also corresponds to improved
catabolic activity. The presence of the bedA locus was seen in all samples, which indicates the presence of aromatic degraders,
but the appearance of the alkB locus, from the 6th week onwards, which was observed only in the samples from the bioaugmented
reactor. The results suggest that the gene pool of the bioaugmented reactor has catabolic loci that can degrade accumulated
intermediates, thus improving the efficiency of the system.
Conclusions In this study, improvement of efficiency of bioremediation was demonstrated by addition of catabolic loci that are responsible
for degradation. Bioaugmentation was carried out in biomass that was collected from an ETP (effluent treatment plant) treating
hydrocarbon containing wastewater to study the strategies for improvement of the treatment system. Biostimulation, only marginally
improved the efficiency, when compared to bioaugmentation. The improved efficiency was demonstrated by COD removal. The presence
of the alkB locus suggests the importance of a catabolic gene pool that acts on accumulated intermediates. It is well documented
that straight chain aliphatics and intermediates of aromatic compounds after ring cleavage, accumulate in refinery wastewater
systems, thereby hindering further degradation of the wastewater. Supplementation of a catabolic gene pool that treats the
lower pathway compounds and alkanes will improve the overall efficiency. In this study, results suggest that the alkB locus
can also be used to monitor the degradative mode of the activated biomass.
Recommendations and Perspective . Pollution from petroleum and petroleum products around the globe are known to have grave consequences on the environment.
Bioremediation, using activated sludge, is one option for the treatment of such wastes. Effluent treatment plants are usually
unable to completely degrade the wastewater being treated in the biological unit (the aerator chambers). The efficiency of
degradation can be improved by biostimulation and bioaugmentation. This study demonstrates the improved efficiency of a treatment
system for wastewater containing hydrocarbons by bioaugmentation of a consortium that supports degradation. Further experiments
on a pilot scale are recommended to assess the use of bioaugmentation on a large scale. The use of molecular tools, like DNA
probes for alkB, to monitor the system also needs to be explored. 相似文献
363.
364.
Aishah S. A. K. Sharifah Hanafiah Zainal Abidin Mohamad R. Sulaiman Kheng H. Khoo Hairi Ali 《Journal of Material Cycles and Waste Management》2008,10(2):116-123
Malaysia is in dire need of alternatives to landfilling for solid waste management. Recently, landfills have faced the problems
of overfilling, overflowing of leachates leading to pollution of water resources, and uncontrolled dust emissions adversely
affecting the local environment. With the rising cost of urbanization coupled with the high rate of waste generation, one
possible method of waste treatment that is receiving particular attention by the government is incineration. Incineration
of solid waste is rather new in Malaysia, with limited usage in handling small sources of waste generation such as the municipal
solid waste (MSW) of resort islands; however, its potential in ameliorating the problems associated with solid waste treatment
may make it an attractive alternative to landfill. This article presents the results of test runs conducted to investigate
the performance of a locally designed and manufactured rotary kiln incinerator (RKI). The test runs were conducted using MSW
collected from the Shah Alam municipality. The combustion efficiency was analyzed by looking at the temperature profiles and
chemical species concentrations. To complement the combustion characteristics measurements, predictions of the air flow in
the incinerator during the process were also investigated. The overall performance of the RKI suggests that it is suitable
for treating MSW. 相似文献
365.
Markéta Julinová Marie Dvořáčková Jan Kupec Jitka Hubáčková Martina Kopčilová Jaromír Hoffmann Pavol Alexy Anna Nahálková Ida Vašková 《Journal of Polymers and the Environment》2008,16(4):241-249
Improving biodegradability of PVA/starch blends is a reality already documented by a number of works. Admittedly, mechanical
properties of products (for example, tensile strength) are somewhat worse, but suitable composition optimizing or chemical
modifying of starch may eliminate the problem to a large degree. This work is an attempt to find another potential effect
influencing biodegradability, that of technological procedure for producing films from these blends on an extruder. The procedure
with a so-called pre-extrusion step (two-stage) and dry-blend (single-stage) produced blends of slightest differences in achieved
biodegradability (virtually within limits of experimental error) in aerobic (76 vs. 79%) as well as anaerobic breakdown (48
vs. 52%). Conversely, morphological analysis exhibited superior homogeneity of films prepared by the two-stage process; their
tensile strength was also higher. 相似文献
366.
367.
Sławomir Stelmach Ryszard Wasielewski 《Journal of Material Cycles and Waste Management》2008,10(2):110-115
More than 1.1 million tons of municipal and industrial sewage sludge is produced annually in Poland. Most of this sewage sludge
is landfilled or used for recultivation and fertilization of soil. After accession of Poland to the EU, large investments
are planned for wastewater treatment, so it is expected that the amount of sewage sludge produced in Poland will grow in the
near future. It is well known that the combustion of sewage sludge is becoming a more and more popular utilization method
of such waste. Unfortunately, the current situation in Poland makes it impossible to incinerate the sewage sludge because
of a lack of incinerators. One possible solution for Poland is the co-firing of dried sewage sludge in existing coal-fired
utility boilers. This article presents results of initial Polish industrial trials of dried municipal sewage sludge and hard
coal co-combustion in an OP-230 pulverized coal boiler. Such a solution was shown to be technically viable and not to require
changes to the existing technological system. Cocombustion of sewage sludge with coal in power plants seems to be the best
solution for sludge utilization in the near future in Poland. 相似文献
368.
Jörg Luster Manoj Menon Sandra Hermle Rainer Schulin Madeleine S. Günthardt-Goerg Bernd Nowack 《Water, Air, & Soil Pollution: Focus》2008,8(2):163-176
Soil translocation for recultivation of soil removed from construction sites and for the preparation of refilled lysimeters
inevitably involves disturbance of soil structure, and, if intermediate storage is included, also drying and rewetting of
the soil. We report on an experiment with model forest ecosystems, where uncontaminated forest subsoils were covered with
non-contaminated or freshly heavy metal (mainly Zn and Cu) contaminated topsoil in large lysimeters. Monitoring of the chemical
composition of the drainage water revealed two distinct soil conditioning phases. During an initial phase of about a year
strongly elevated nitrate and sulfate concentrations occurred that were attributed to a mineralisation flush caused by the
increased accessability of mineralisable nitrogen and sulfur in destroyed aggregates. These effects were significantly larger
in lysimeters with calcareous subsoil than in those with acidic subsoil. The second phase was characterised by a gradual decrease
in dissolved organic carbon and sulfate concentrations, in particular in the acidic subsoil. This decrease may be attributed
to the depletion of pools made accessible during aggregate destruction or the formation of new aggregates. These chemical
changes had only little effects on the concentrations of copper and zinc in the drainage water. Based on our results, it can
be concluded that large refilled lysimeters can be used for many purposes without risk of compromised results, if a conditioning
phase of about 1 year with sufficiently moist soil conditions is respected. Nevertheless, gradual changes in soil chemical
characteristics still occur after this initial phase. Implications for the recultivation of sites using relocated soils are
discussed. 相似文献
369.
370.
Reiner Schroll Sabine Grundmann Ulrike Dörfler Bernhard Ruth Jean Charles Munch 《Water, Air, & Soil Pollution: Focus》2008,8(2):209-216
Several lysimeter scenarios and approaches exist to study the fate of agro-chemicals or contaminants from deposition in soil
columns. In many systems just transport and leaching of the parent compound is followed, in some systems the leaching and
transport of the metabolites is investigated as well. In more sophisticated lysimeter systems the volatilization and also
the mineralization of the applied chemicals can be additionally monitored. Depending on the lysimeter system used and on the
fact whether the applied chemicals are 14C-labeled or not, different results and various interpretations of the results might be achieved. Different lysimeter systems
are described in this paper and a real dataset of a specific lysimeter experiment was transferred and evaluated in a virtual
approach in the different lysimeter systems in order to show the advantages and disadvantages of the various systems. 相似文献