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Organic waste disposal in the marine enrivonment. - AE0511

R&D Summary objectives:- 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 sediment. 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
From: 1988

To: 1994

Cost: £390,209
Contractor / Funded Organisations
Natural Environment Research Council
Fields of Study
Environmental Protection - Marine