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Organic waste disposal in the marine enrivonment. - AE0511
Determine the degradibility and fate of three types of
organic waste (fish farm food, sewaage sludge, drill
cuttings) in the marine environment and develop indicators
for safeloading limits.
Key customer purpose:-
Assist MAFF in formulating its policy on the discharging of
organic wastes under FEPA through an assessment of the
environmental impact of such discharges.
1) Relative degradability. These will be assessed under two
different regimes Viz: where aerobic oxidation is the
dominant process, and where anaerobic proc esses are
dominant ( and the degradation is via sulphate reduction).
The results will be expressed as a half life for the
different substrates under different loadings using standard
2) Ability of the sediments to cope with additional organic
input. Loading will be by continual addition. Loading will
be by continual addition. Loading rates and frequency will
be checked on the basis of the initial degradability
experiments. Very light loading will be investigated by
decreasing the loading until observable effects are lost. In
all cases C & N analyses will be performed regularly to
monitor any build up. All three substrates mentioned above
will be used. Coping will be assessed using several criteria
as the loading increases. At low/medium loading the change
from predominantly aerobic degradation to predominantly
anaerobic (sulphate reduction) degradation will
be assessed. At medium - high loading the onset of the build
up of free sulphide and free organic acids will be assessed.
In this case the sediment type will have an influence since
high availability of iron will delay the appearance of free
sulphide. Therefore these experiments will be performed with
various different sediments.
3) Fate of nitrogen. Nitrogen in the organic input will be
released during mineralization. It could be lost as nitrogen
gas or nitrous oxide gas through denitrification or reduced
to ammonium and transferred to the water column.
4) Indicators of overloading. Correlation's will be made of
rates of sulphat reduction with sediment parameters such as
pore water sulphide and pore water acetate concentrations to
see if these build up as loadings which give rise to an
accumulation of the organic enrichment.
Time-Scale and Cost
Contractor / Funded Organisations
Natural Environment Research Council
Fields of Study
Environmental Protection - Marine