[en] In a field trial, selected motor car emissions were monitored for one year in roadside soils and seepage water at four investigation routes in Nordrhein-Westfalen. The investigations were carried out within the framework of the research and development project financed by the Federal Minister for Transportation: 'Determination and evaluation of road effects on the landscape factors soil and water'. The measuring and analysis program comprised the regular sampling of soils at predetermined distances, the continuous production of seepage water specimens, and their analysis at intervals of 10 days. Terrain-climatological measurements were carried out simultaneously. The set-up of the field trial and the applied methods are described and first results introduced. (orig.)

[en] Application of vibrations over the range up to 3 kHz to the sedimentation and dewatering of two-phase mixtures. The purpose of the study was the development of a new dewatering process on the basis of impulse hydraulics which offers more efficiency and flexibility than existing processes. Changing the dispersion status of a disperse system requires the existance of an additional field of forces. In this case, such field of forces is generated via directional vibrations whereby the vibration parameters -amplitude/frequency/phase angle/energy density - are continuously adjustable. Important factors to influence sedimentation by means of vibrations were found (and/or confirmed) to be the type of sludge and its dry residue. In the case of digested and water sludges, the sedimentation rate could not be increased by the introduction of vibrations; in the case of lead sludge, a certain increase was achieved. On the basis of all results as a whole, the efficiency of the process seems questionable. (orig.)

[en] Simultaneous denitrification is achieved by a measuring and control device which controls the aeration intensity of the activated sludge basin. Decisive parameters are the concentrations of nitrate or, alternatively, ammonium (higher priority) and oxygen present in the site of reaction (activated sludge tank). The ammonium control device which is to be operated in the second activated sludge unit, first cascade, is described. (orig.)

[en] The increasing use of on-line measuring systems by which vast amounts of data are obtained demands intelligent ways of processing these further. The article points out some possibilities for using knowledge-based systems in sewage treatment technology. In particular, the application of neural networks for the simulation of feedwater parameters, in plausibility control and for the simulation of the cleaning process is demonstrated. (orig.)

[en] A literature review is presented of the fate of pollutants in sediment and water systems. Topics of discussion include the following: modeling, observations, and general studies; chlorinated xenobiotic chemicals; nonchlorinated xenobiotic chemicals; pesticides; heavy metals; and radionuclides

[en] Based on the inherent benefits of these original oxidation systems, a second generation of advanced oxidation processes (AOPs) has emerged. These processes combine key features of the first generation technologies with more sophisticated advances in UV technology, such as the new pulsed plasma xenon flash lamp that emits high-energy, high-intensity UV light. Second generation systems can be equipped with a transmittance controller to prevent lamp fouling or scaling. The coupling of the first generation's technology with the new UV sources provides the rapid destruction of chlorinated and nonchlorinated hydrocarbons and humic acids from contaminated water. It also is effective in the treatment of organic laden gases from soil vapor extraction systems. AOPs may promote the oxidation (and subsequent removal) of heavy metals in water, though few data are available to verify the claim. The success of AOPs, including ozonation with UV light, hydrogen peroxide with UV light and advanced photolysis, is linked with their creation of hydroxyl-free radicals (OH·) that are effective in eliminating contaminants such as formaldehyde, chlorinated hydrocarbons and chlorinated solvents. Hydroxyl free-radicals are consumed in microsecond reactions and exhibit little substrate selectivity with the exception of halogenated alkanes such as chloroform. They can act as chain carriers. Given their power, hydroxyl free-radicals react with virtually all organic solutes more quickly (especially in water) than any other oxidants, except fluorine. There are projects that have found the combination of some AOPs to be the most efficient organic destruction techniques for the job. For example, one project successfully remediated groundwater contaminated with gasoline and Number 2 diesel through successive treatments of ozone and hydrogen peroxide with ultraviolet light, followed by granular activated carbon. 5 refs., 2 tabs

[en] Aliphatic hydrocarbons are threatening the potable water supply and the aquatic ecosystem. Given the right microbial inhabitant(s), a large portion of these aliphatic hydrocarbons could be biodegraded before reaching the water supply. The authors' purpose is to isolate possible oil-degrading organisms. Soil samples were taken from hydrocarbon-laden soils at petroleum terminals, a petroleum refinery waste-treatment facility, a sewage-treatment plant grease collector, a site of previous bioremediation, and various other places. Some isolates known to be good degraders were obtained from culture collection services. These samples were plated on a 10w-30 multigrade motor oil solid medium to screen for aliphatic hydrocarbon degraders. The degrading organisms were isolated, identified, and tested (CO₂ evolution, BOD, and COD) to determine the most efficient degrader(s). Thirty-seven organisms were tested, and the most efficient degraders were Serratia marcescens, Escherichia coli, and Enterobacter agglomerans

[en] A statistical analysis of daily water-level changes in an abandoned coal mine indicates that precipitation affects the potentiometric level of the mine, independent of associated atmospheric pressure changes and changes in the water level of an overlying aquifer. The independent statistical effect of precipitation (0.99 cm of water-level change per centimeter of rainfall) is interpreted to reflect either lateral percolation from the coalbed's subcrop (1.2 km from the mine) or rapid recharge through mine-associated pathways, such as poorly plugged shafts, boreholes, or subsidence fractures. The relationship between water-level changes in the mine's voids and changes in the overlying aquifer are also statistically significant, but the regression coefficient (0.04) is an order of magnitude smaller than that for precipitation, indicating that vertical percolation (which is represented by convariance of the two aquifers) through undisturbed overburden may be less effective than the recharge associated with precipitation that bypasses the overburden. An equivalent analysis of water-level changes in an underlying unmined coalbed indicated that precipitation had a weaker direct effect (regression coefficient of 0.34, compared with 0.99), although it was still the dominant indepedent variable. In contrast, the effect of water-level changes in an overlying aquifer (the flooded mine itself) was relatively strong (regression coefficient of 0.15, compared with 0.04), indicating that vertical percolation through interburden is more important at depth

[en] A battery of different bioassays are set up in order to characterize and determine the risk potential of landfill leachates and defined fractions. The following four project phases can be identified: 1) setting up of the tests, 2) development of a fractioning method, 3) application of the tests to fractions of leachate, 4) chemical analysis of toxic leachate fractions. Selection of the tests, which are described in detail, was preceeded by thorough bibligraphic studies. The tests are currently being used on reference substances. Preliminary testing regarding fractioning and chemical analysis is being done. (orig.)

[en] This conference was held November 14--18, 1993 in Houston, Texas for the purpose of providing a forum for exchange of state-of-the-art information on ecological risk assessment. This book is comprised of the abstracts of the presentations at this symposium. Individual abstracts have been processed separately for inclusion in the appropriate data bases