The influence of effluent addition on denitrification potential in the
Thredbo Wetland was observed by comparing an area of the wetland
receiving secondary treated effluent with another area receiving no
effluent addition.
Physico-chemical measurements (Eh, pH and temperature) of the soil were
conducted in both sampling areas to characterise the denitrifying
environment. Levels of nitrate plus nitrite and ammonium ion in the
soil from 0-30cm depth were recorded on a seasonal basis to identify the
role of effluent addition and vertical distribution of inorganic nitrogen species in controlling the distribution of denitrification
potential in the soil.
Denitrification potentials of soils and decaying plant material were
evaluated by the acetylene blockage technique. This involved laboratory
incubations under optimum conditions of pH, temperature, nitrate
concentration, carbon supply, and diffusion. The influence of these
physico-chemical factors on denitrification was also investigated.
It was found that the effluent addition caused higher denitrification
potential in soils and surface decaying plant material by raising soil
temperature, lowering Eh, and increasing concentrations of nitrate plus
nitrite and ammonium ions. The highest denitrification potential was
recorded in the decaying plant material on the soil surface. The highest
soil denitrification potential occurred in the 0-6cm depth segment.
Carbon supply and pH had no influence on denitrification potential
whilst low temperature (5ºC), and restricted diffusion limited
denitrification.
In terms of tertiary water treatment denitrification in Thredbo Wetland
makes a significant-contribution to the removal of nitrogen year-round.
However, total nitrogen removal could be increased by increasing the
residence time of water in the wetland thereby encouraging greater
spatial and temporal interaction between the denitrifiers and the
wastewater nitrogen.
| Identifer | oai:union.ndltd.org:ADTP/218793 |
| Date | January 1985 |
| Creators | Brodrick, Stephanie J., n/a |
| Publisher | University of Canberra. Natural Resources |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | ), Copyright Stephanie J. Brodrick |
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