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Soil solution nitrogen and cations influenced by (NH4(2)SO4) deposition in a coniferous forest
1997
Carnol, M. | Ineson, P. | Dickinson, A.L. (University of Liege, Dept. Botany B22, Microbial Ecology and Radioecology, 4000 Liege (Belgium))
Anthropogenic impacts on natural nitrogen isotope variations in Pinus sylvestris stands in an industrially polluted area
1997
Jung, K. | Gebauer, G. | Gehre, M. | Hofmann, D. | Weissflog, L. | Schuurmann, G. (Department of Chemical Ecotoxicology, Centre for Environmental Research Leipzig-Halle, P.O. Box 2, D-04301 Leipzig (Germany))
Crown condition of Norway spruce in relation to sulphur and nitrogen deposition and soil properties in southeast Norway
1997
Solberg, S. | Toerseth, K. (Norwegian Forest Research Institute, Hoegskoleveien 12, N-1432 As (Norway))
Effects of elevated CO2, nitrogen supply and tropospheric ozone on spring wheat-II. Nutrients (N, P, K, S, Ca, Mg, Fe, Mn, Zn)
1997
Fangmeier, A. | Gruters, U. | Hogy, P. | Vermehren, B. | Jager, H.J. (Institut fur Pflanzenokologie, Heinrich-Buff-Ring 38, D-35392 Giessen (Germany))
Ammonia emission factors for N fertilizers applied to two contrasting grassland soils
1997
Weerden, T.J. van der | Jarvis, S.C. (Institute of Grassland and Environmental Research, North Wyke, Okehampton, Devon, EX20 2SB (United Kingdom))
The influence of air pollutants on needles and stems of Scots pine (Pinus sylvestris L.) trees
1997
Kurczynska, E.U. | Dmuchowski, W. | Wloch, W. | Bytnerowicz, A. (Department of Biophysics and Cell Biology, Silesian University, ul. Jagiellonska 28, 40-034 Katowice (Poland))
Open-top chamber and field exposure of Sitka spruce to simulated acid mist: a comparison of results
1997
Sheppard, L.J. | Leith, I.D. | Morris, E. | Cape, J.N. | Roberts, D. (Institute of Terrestrial Ecology, Bush Estate, Penicuik, Midlothian, EH26 0QB (United Kingdom))
Stem growth reduction in mature Sitka spruce trees exposed to acid mist
1997
Crossley, A. | Sheppard, L.J. | Cape, J.N. | Smith, R.I. | Harvey, F.J. (Institute of Terrestial Ecology, Bush Estate, Penicuik, Midlothian, EH26 0QB (United Kingdom))
Seasonal variability of total and easily leachable element contents in topsoils (0-5 cm) from eight catchments in the European Arctic (Finland, Norway and Russia)
1997
Niskavaara, H. | Reimann, C. | Chekushin, V. | Kashulina, G. (Geological Survey of Finland, PO Box 77, FIN-96101 Rovaniemi (Finland))
Biological nutrient removal in suspended growth system
1997
Wisjnurapto, IR.
A series of experiments on biological nutrient removal using suspended growth bioreactor with a various reactor configuration have been conducted during the last five years. The first configuration applied a contact stabilization flowed by a denitrification processes in two sludge system. The two sludge systems mean that the aerobic sludge is recirculated in the aerobic circuit, and the anaerobic sludge is recirculated in the anaerobic circuit. The second configuration was conducted in a contact stabilization and denitrification processes in a one sludge system. The one sludge system meant that there are no separation between aerobic and anaerobic sludge; the aerobic and anaerobic processes are in the same circuit and all sludge are recirculated in the same circuit. The third configuration was performed in anaerobic-aerobic-anaerobic reactors and ended by the clarifier to clarify the biosludge before recirculated to the head of the circuit. This configuration was also using a one sludge system. In those three configurations, the hydraulic detention time in the reactors were varied from 2 to 6 hours, and the sludge age from 2 to 15 days. The results showed that the first configuration gave a very high performance in carbon and nitrogen removal. In terms of TOC [total oxygen concentration], the carbon removal achieved up to 92 percent or in terms of total COD [carbon oxygen demand] up to 80 percent, and 97 percent for total nitrogen removal. On the other hand, the phosphorus removal was only limited to the amount required for cells metabolism. More carbon removal were observed in the second configuration (94 percent of total COD) but less total nitrogen were removed (93), however, phosphorus were removed significantly (up to five times of the cells metabolism requirement). The best results in those three nutrients removal was achieved in the third configuration. No less than 95 percent of total COD and 96 percent of nitrogen removal were noticed, and phosphorus were removed at the level of more than six times of the cells metabolism requirement. The experiments concluded that the phosphorus removal was conducted by the aerobic microorganisms which are alternately treated in aerobic-anaerobic conditions. The degree of removal depended on how long the microorganisms were put in the aerobic and anerobic conditions. If the anaerobic condition was too long, the microorganisms would die, and no phosphorus removal took place. If it was too short, the removal would be less. For carbon and nitrogen removals in the system, the hydraulic detention time in the reactors and sludge appeared as the essential parameters in the process
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