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Review of a state of know-how on the biochemical changes of mineral nitrogen during waste water treatment process

100%

Podedworna J. , Zubrowska-Sudol M.

nr 1

127-141

The paper presents review of a state of know-how on the biochemical changes of mineral nitrogen. New ways of nitrogen elimination from waste water were described: autotrophic nitrification/autotrophic oxygen denitrification, autotrophic nitrification/autotrophic anaerobic denitrification (anaerobic ammonium oxidation), heterotrophic nitrification/heterotrophic oxygen nitrification.

Denitrification in the sediments of the inner Puck Bay -preliminary results

100%

Graca B.

nr 4

73-91

Denitrification was measured in the sediments of the Inner Puck Bay using the acetylene inhibition technique and pertinent environmental data. This process was not found to be particularly significant for the nitrogen budget of the ecosystem. The rate ranged from 0 to 40.2 mmol N m-2 h-1, which is equivalent to 151 t N per year. This constitutes 6.5% of the external nitrogen input to the investigated water body. The denitrification rate reached the highest values in spring, after the first algal blooms, when relatively fresh organic matter had amassed in the sediments and nitrate concentrations in interstitial waters peaked. The rates were almost sixfold lower than the maximal value in summer and fall. The main nitrogen source for denitrification in the investigated area was nitrification within the sediments. The deciding parameter determining the variability of the denitrification rate was the nitrate concentration in interstitial waters.

Removal of nitrogen compounds in aerobic activated sludge process

88%

Bernat K. , Wojnowska-Baryla I. , Dobrzynska A.

nr 1

194-206

In sequencing reactors without separate nitrification and denitrification zones, controlling of oxygen and organic compounds concentration influences activated sludge nitrogen removal from wastewater. Under oxygen limited conditions, autotrophic nitrifying bacteria are able to nitrate or nitrites reduction to nitrous oxide or gaseous nitrogen. However, denitrifying microorganisms can carry out heterotrophic nitrification or aerobic denitrification at high oxygen concentration. Constant amount of oxygen concentration was supplied to the sequencing batch reactor with activated sludge, which indicates that oxygen concentration could change during the reaction time. It was assumed that control oxygen supply on the level of 2 mg/dm3 covers an oxygen demand in organics, ammonium nitrogen oxidation and endogenous respiration. In the initial phase of the reaction, total oxygen exhaustion was observed. After the reaction of oxidation, there was an increase in oxygen concentration to the value of 2 mg/dm3. In the presented experiment, it was shown that permanent complete oxygen using and the accessibility of readily biodegradable organic compounds in wastewater stimulate simultaneous nitrification and denitrification in activated sludge. Nitrogen removal effectiveness under constant aeration depending on COD/N ratio in wastewater supplying to the reactor ranged from 30 to 70%.

Genetic variation in the efficiency of nitrogen utilization and photosynthetic activity of flag leaves among the old and modern germplasm of winter wheat

75%

Gorny A. G. , Garczynski S. , Banaszak Z. , Lugowska B.

tom 47

nr 3

231-237

Genotypic variation in major components of the efficiency of nitrogen utilization and photosynthetic activity of flag leaves among old (released 1881?1963) and modern (released 1969?2003) cultivars of winter wheat was studied in field conditions under varied N fertilization levels (110, 90 and 80 kg N ha?1). Significant genotypic differences were observed for all characters. Their heritabilities ranged from 0.37 to 0.93 and were the lowest for the leaf efficiency of gas exchange, photosynthetic rate, straw N content and the economic index of N utilization efficiency (NUE). Some modern cultivars exhibited an enhanced tolerance to N shortage and several attributes of efficient N utilization (e.g. later senescing and more photosynthetically active flag leaves, increased ability to redistribute N into grains). The genotypes may serve as donors of appropriate characteristics for breeding. The observed cultivar-by-fertilization interactions suggest, however, that evaluations under diverse fertilization regimes may be necessary when searching for improved wheat efficiency and adaptation to less favourable environments.

The potential impact of a sewage discharge through the ?Gdansk -Wschod? sewage-treatment plant collect-or on the chemical composition of the Gulf of Gdansk sediments

75%

Uscinowicz S. , Zachowicz Z. J. , Zachowicz J. , Sokolowski S. K. , Sokolowski K.

tom 29

nr 4

65-80

The potential chemical impact of a treated sewage discharged from the ?Gdansk-Wschod? Sewage Treatment Plant to the Gulf of Gdansk was studied. A physical and chemical investigation of the sediments sampled in the area of the planned collector outlet as well as results of an earlier research were the basis for the present paper. A spatial distribution of majority of the studied sediment components shows a distinctive zoning that is clearly due to them being supplied by the Vistula River (Wisla River). This is particular for the mercury, lead, zinc and chromium as well as organic carbon and phosphorus. A distribution of the redox potential shows too a distinctive relation to the Vistula River mouth. Starting a sewage discharge through a new collector located between the two river mouths of the Wisla Smiala and the Wisla Przekop can move westwards the presently observed zoning of increased concentrations of some chemicals. However, most probably such changes will be small and they will not cumulate themselves over time.