dc.contributor.advisor |
Larkin, T |
en |
dc.contributor.advisor |
Singhal, N |
en |
dc.contributor.author |
Lee, Jiae |
en |
dc.date.accessioned |
2011-02-24T23:46:07Z |
en |
dc.date.issued |
2010 |
en |
dc.identifier.uri |
http://hdl.handle.net/2292/6445 |
en |
dc.description |
Full text is available to authenticated members of The University of Auckland only. |
en |
dc.description.abstract |
Biosolids, known as dewatered sludge, are waste-products from wastewater treatment plants. The biosolids produced by the wastewater treatment plant in Mangere, operated by Watercare Services Limited, have been in use to rehabilitate an area called "Pond 2", which is expected to reach its final volume by 2013. Therefore a new scheme of using the biosolids to rehabilitate a disused quarry on Puketutu Island has been proposed by Watercare Services Limited. Rehabilitation using stabilised biosolids with a depth up to 26 m is under consideration. In order to achieve this height, an increase in shear strength of the biosolids to approximately 20 kPa in a drained state after many years of consolidation at a depth of 20 m has been considered appropriate. In order to increase the shear strength of biosolids, lime and two industrial by-products, fly ash and works debris, were mixed with biosolids. The amendments and biosolids were mixed in a number of proportions, and the specimens were subjected to two major experiments for this study: unconsolidated drained PVC tube experiments and consolidated (drained) biorig experiments. At the end of the experiments, geotechnical and environmental engineering properties of the specimens were determined. This study suggests that the addition of industrial by-products to biosolids enhances the shear strength effectively, lowers the water content, increases the pH to above 11, which satisfy the minimum requirement, and lowers the volatile solid content. All mixtures achieved the target strength of 20 kPa under the conditions suggested above by Watercare Services Limited. Among nine different mixtures, the 20 % lime and 20 % fly ash mixture achieved the highest shear strength being in excess of 58.5 kPa, as measured by a hand shear vane. After a comparison with the study conducted at the University of Auckland by Kayser (2010), it was found that consolidation (therefore overburden pressure) enhances the shear strength beyond that resulting from the addition of amendments. The amended biosolids were consolidated for longer periods which achieved higher shear strengths. It was also found that even a small overburden pressure of 3.2 kPa may affect the properties of amended biosolids. |
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dc.publisher |
ResearchSpace@Auckland |
en |
dc.relation.ispartof |
Masters Thesis - University of Auckland |
en |
dc.relation.isreferencedby |
UoA99222024514002091 |
en |
dc.rights |
Restricted Item. Available to authenticated members of The University of Auckland. |
en |
dc.rights.uri |
https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm |
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dc.title |
Shear strength enhancement of biosolids using industrial by-products |
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dc.type |
Thesis |
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thesis.degree.discipline |
Environmental Engineering |
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thesis.degree.grantor |
The University of Auckland |
en |
thesis.degree.level |
Masters |
en |
dc.rights.holder |
Copyright: the author |
en |
pubs.elements-id |
206516 |
en |
pubs.record-created-at-source-date |
2011-02-25 |
en |
dc.identifier.wikidata |
Q112883752 |
|