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501.
Kari B Fitzmorris Robert S Reimers Jan A Oleszkiewicz M Dale Little 《Water environment research》2007,79(4):388-395
From field studies conducted by Tulane University (New Orleans, Louisiana), efficiency of advanced alkaline disinfection in closed systems was found to depend on ammonia concentration, pH, exposure time, temperature, total solids content, pretreatment storage time, and mixing effectiveness. In this study of a closed alkaline system, an additional pathogen stressor pressure was tested. The effect of the alkaline dosing has been assessed for dewatered raw and aerobically and anaerobically digested municipal sludge cake that produce un-ionized ammonia at concentrations of 0.05 to 2% on a dry-weight basis. Inactivation of Ascaris suum eggs increased from 50 to 99% as the temperature was increased from 40 to 55 degrees C, thus achieving Class A levels. The systems studied were compared with an alkaline process operated under open conditions, which limited the concentrations of ammonia available because of Henry's Law. Under a closed pressurized system, the effect of un-ionized ammonia was greatly increased, and the resulting time required for inactivation was reduced from hours or days to minutes. In the next few years, it is expected that alkaline disinfection of biosolids will be optimized in relation to the factors stated above, at much lower doses of the alkaline agents. The closed-system alkaline processes that will be developed will be more energy-efficient, cost-effective, and have full control of potential odorous emissions. 相似文献
502.
Characterisation of potentially genotoxic compounds in sediments collected from United Kingdom estuaries 总被引:2,自引:0,他引:2
The mutagenic activity bioassay Mutatox was used to assess the mutagenic activity associated with sediments collected from five UK estuaries. Assays were performed on extracts of sediment pore water and residual particulate material isolated from sediment samples collected from the rivers Tyne, Tees, Mersey, and Thames as well as Southampton Water. No mutagenic activity was associated with the pore water extracts, however, 7 of the 28 organic solvent extracts of sediment particulate material contained potential genotoxins. By using Mutatox in association with bioassay-directed fractionation, attempts were made to identify the mutagenic compounds present in the extracts. The fractionation procedure used normal phase solid phase extraction, C18 reverse phase HPLC and cyano/amino bonded silica normal phase HPLC. GC-MS (EI and NICI) analysis was used to identify polycyclic aromatic hydrocarbons (PAH), alkyl substituted PAH, nitro-polycyclic aromatic compounds (nitro-PACs), polycyclic aromatic ketones, oxygenated-PACs, and other known mutagens contributing to the genotoxicity measured in the samples. Some potentially genotoxic compounds remain unidentified. 相似文献
503.
An incident is described in which polychlorinated biphenyls (PCBs) from an electro-industrial plant waste tip draining into ground-water channels in karst terrain have contaminated a potable water source. PCB composition data were obtained using quadropole GC-MS and capillary GC. The average level of PCBs determined in water was 0.3 μg 1?1 and in sediment 55 μg g?1 相似文献
504.
Walter Debruyn Gilbert Lissens Jan van Rensbergen Maria Wevers 《Environmental monitoring and assessment》1994,31(1-2):159-165
The estimation of nitrous oxide emissions is complicated by the high degree of uncertainty on the emission factors involved and by the limited acquaintance with all significant nitrous oxide sources. A potentially important source for which emission data are lacking is the sewage system transporting waste water from human activities. For this study an experimental measurement campaign has been carried out on waste water sampled at different sewage treatment plants. The nitrous oxide developing from the water samples was monitored by means of gas chromatography. The methodological analysis was based on the concentration/time curves obtained. Our results indicate that the formation of nitrous oxide from the waste water matrices results from microbiological denitrification. We deduced tentative emission factors for the waste water types studied. 相似文献
505.
Methanogenic Archaea represent a unique group of micro-organisms in their ability to derive their energy for growth from the conversion of their substrates to methane. The common substrates are hydrogen and CO2. The energy obtained in the latter conversion is highly dependent on the hydrogen concentration which may dramatically vary in their natural habitats and under laboratory conditions. In this review the bio-energetic consequences of the variations in hydrogen supply will be investigated. It will be described how the organisms seem to be equipped as to their methanogenic apparatus to cope with extremes in hydrogen availability and how they could respond to hydrogen changes by the regulation of their metabolism.Abbreviations Coenzyme F420
5-dezaflavin derivative
- F420H2
1,5-dihydro-F420
- F390
8-adenylylated-(F390-A) or 8-OH-guanylylated-(F390-G)-F420
- H4MPT
5,6,7,8-tetrahydromethanopterin
- HS-CoM
coenzyme M, 2-mercaptoethanesulfonate
- methyl-S-CoM
2-methylthioethanesulfonate
- HS-HTP
7-mercaptoheptanoylthreonine phosphate
- CoM-S-S-HTP
heterodisulfide of HS-CoM and HS-HTP
- FDH
formylmethanofuran dehydrogenase
- FRH
coenzyme F420-reducing hydrogenase
- HDR
heterodisulfide reductase
- MCR
methylcoenzyme M reductase
- MDH
5,10-methylene-H4MPT dehydrogenase
- MVH
non-coenzyme F420, Viologen-reducing hydrogenase 相似文献
506.
Jan Corfee Morlot Paul Schwengels Scott Lurding 《Environmental monitoring and assessment》1994,31(1-2):41-52
This paper summarises key results of the Joint IPCC/OECD Programme, in particular the draft IPCC Guidelines for National GHG Inventories to be released in January 1994. The focus is on how these results are likely to improve the availability and the quality of national inventories of anthropogenic GHG emission sources and removals by sinks. The IPCC/OECD has already received nearly 50 inventories from 35 countries. Most of the data are for 1988, but some reports cover 1989 and 1990. In addition to CO2, many of these inventories include CH4, N2O, NOx, CO, and NMVOC. Detailed analyses of these inventories have provided valuable insights about the strengths and weaknesses of the national inventories, differences in approach to estimation, reporting, available methods and data. These results in turn, have facilitated the development of the draft Guidelines, most notably the proposed reporting system, and also on estimation methods for the different anthropogenic sources and sinks of GHG. The paper previews key aspects of the draft Guidelines for non-CO2 GHG. Experts are urged to actively participate in the IPCC/OECD Programme to continue to improve inventory methods and overall the Guidelines.The views presented in this paper are those of the authors and do not necessarily represent the views of the OECD or their Member countries. 相似文献
507.
Jan Kuiper 《Environmental monitoring and assessment》1986,7(3):221-232
Examples are presented of different techniques which are in use, or could be used, to monitor the fate and effects of oil pollution in Dutch marine waters by oil spills and chronic contamination by rivers, processing water from the oil industry, etc.A number of techniques are presented to quantify the fate of oil in water, sediments and biota, and some readily available methods to monitor possible effects in the ecosystem.In Dutch coastal waters much effort is being given to airborne detection of oil at the sea surface in order to reduce pollution and to take rapid measures in cases of severe pollution. Oil concentrations in sediments and selected organisms can be monitored as a general quality control measure, and to check the functioning of licensed installations. If concentrations above background levels are found, research on possible effects should be initiated. In this context short term studies on stress-indicators are very useful. Laboratory based investigations, for example in model ecosystems, can be carried out to test hypotheses from such studies. Elevated oil concentrations and indications for ecological effects may result in changes in the management of the marine area in question. Monitoring of population dynamics and species composition, notably of benthic macrofauna, should be carried out to verify long-term effects on the ecosystem. 相似文献
508.
Government environment protection policies for waterways have traditionally relied on water quality indicators and their objectives. In this paper we describe the development of biological objectives based on invertebrate indicators for inclusion in a government policy for the catchment of Western Port Bay, Victoria. The first step of defining segments (areas with streams in which the same objectives are applied) was problematic, requiring two different approaches, as follows. Site groups initially based on invertebrate community composition derived using multivariate techniques (ordination and classification) proved to be unsuitable for policy segments. Segment boundaries were subsequently defined using topographical (e.g. boundary of foothills and lowland plains), climate (e.g. rainfall) and land-use (e.g. urban) features. We used information and data from reference sites inside as well outside the catchment to derive specific biological objectives based on aquatic invertebrates for these segments. Objectives were specified for the following four indicators--number of invertebrate families, the SIGNAL index, the AUSRIVAS predictive model and the number of key families. 相似文献
509.
Jan Dojlido Janusz Raniszewski Jolanta Woyciechowska 《Environmental monitoring and assessment》1994,33(1):33-42
Summary A new method of a water quality index has been proposed. The unit indices were determined from the values of individual parameters using continuous functions. The base for such functions were the four water quality classes used in Poland. The summarized WQI is the square root of the harmonic mean of squares of unit indices. Using this mean we have eliminated the use of weights of parameters. Parameters are divided into basic parameters (7) and other additional parameters (19). The additional parameter is considered only if its unit index is lower than WQI from basic parameters. For many measurements at one point the guaranteed WQI has been calculated. The points of WQI were connected and the curves of WQI along the river were obtained.A method of WQI calculating and preparation of WQI curves has been shown using as an example the Pilica river in Poland. The WQI was then calculated for 31 rivers in the Vistula river basin by measuring points. 相似文献
510.
In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state(UASS)with anaerobic filter(AF) system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0–431 m L O2/gvswere conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431 m L O2/gvsincreased the methane yield by 82.2%. Aeration intensities of 0–355 m L O2/gvswere conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen(DO) of UASS and AF reactors kept around 1.39 ±0.27 and 0.99 ± 0.38 mg/L, respectively. p H was relatively stable around 7.11 ± 0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85 ± 7 m L/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity. 相似文献