Thesis-2006-Deng.pdf (35.67 MB)
Combined anaerobic respiration (CAD) of sewage sludge and other urban solid wastes
thesis
posted on 2011-02-14, 15:50 authored by Hong DengThe UK buries about 100 million tonnes of waste a year, of which 25% is municipal
solid waste (refuse). The environmental impacts from gas and leachate releases
are known and direct risks to health from landfill are reported. Europe has agreed
to a Landfill Directive which has set targets for the stepwise reduction in
biodegradable municipal waste going to landfill. The anaerobic digestion of
municipal solid waste in controlled bioreactors is an area that could play an
important role in overall evolution towards sustainability by recovering biogas and
organic matter.
Separated hydrolysis and subsequent anaerobic codigestion was demonstrated
from the literature review to have the best potential for biodegradable municipal
waste diverted from landfill. The rate of hydrolysis of solids wastes remains an
outstanding problem.
In this research, firstly the codigestion of industrial effluent (coffee wastewater),
food wastes and garden wastes were investigated for their impact on hydrolysis and
digestion. The results show that there were no treatability problems for coffee
wastes up to 37.5% of volume feed per day at the HRT of 9 days. The results
supported the view that dilute biodegradable streams such as coffee waste may
improve digestion by promoting mixing. Fruit and vegetable wastes were highly
biodegradable and can have a major improvement in biogas production of the
whole codigestion process, whereas garden waste was not as successful as a cosubstrate,
probably because of the predominant celluloses and lignocelluloses with
a low biodegradability.
The literature review also revealed that washing or elutriation can remove organic
matter from municipal waste. This is an important hydrolytic process in which a
solubilised acidic organic matter is obtained. The codigestion of refuse hydrolysate
with sewage sludge was therefore studied. A control digester treating sewage
sludge only was compared with an experimental reactor fed mixed refuse
hydrolysate with sewage sludge. It was possible to add the solubilised hydrolysate to existing anaerobic digesters designed at a standard sludge solids loading rate without causing overloading. (Continues...).
History
School
- Architecture, Building and Civil Engineering
Publisher
© Hong DengPublication date
2006Notes
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.487660Language
- en