Investigation into the denitrification of high strength landfill leachate using pine bark and raw and composted commercial garden refuse as a carbon source : column studies.
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Date
2010
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Abstract
Landfill leachate, the liquid discharge from Municipal Solid Waste (MSW) landfills, is
the combination of the surface runoff and ground water that percolates through the
waste and the liquid contained in the waste itself and is considered to be toxic and
presents a potential harm to the environment. Raw leachate contains high
concentrations of biodegradable and non-biodegradable carbon as well as high
concentrations of ammonia nitrogen. Traditionally, landfill leachate has been treated
biologically through aerobic processes which reduce the biological carbon to carbon
dioxide and biomass (bacterial growth) and ammonia nitrogen to nitrates.
Unfortunately this is not sufficient to protect the environment from harm. It is
necessary to further treat the leachate anaerobically to transform the nitrates to
elemental nitrogen which is removed from the leachate as nitrogen gas.
Biodegradable carbon is often the rate limiting substrate as carbon is consumed
during the preceding nitrifying phase. Biodegradable carbon can be supplemented
through the addition of methanol, at great expense
Leachate from the Mariannhill Landfill site is currently treated aerobically in a
sequencing batch reactor where nitrification is achieved. The nitrified leachate is then
used as a dust suppressant on the current site. It is anticipated that in 2012 the Land
fill site would have reached capacity thereby eliminating the need to irrigate and
leaving the site with an excess of nitrified leachate that will present an environmental
risk.
The denitrifying performance of raw commercial garden refuse, pine bark and
composted garden refuse as a growth medium and carbon source was investigated
through the establishment of batch and column tests.
CGR Raw proved the most successful of the three growth media, achieving full
denitrification at a loading rate of 1700 mg NO3-N/kg of substrate/day.
Description
Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.
Keywords
Leachate., Waste disposal in the ground., Refuse and refuse disposal., Theses--Civil engineering.