ABSTRACT
There is currently a ubiquitous drive for South African industries to improve on
water usage as large volumes of raw water are consumed and saline effluents
(brines) are produced during their operations. This dissertation addresses the use
of paste technology to co-dispose brines as well as solid wastes, from the SASOL
Secunda complex in a sustainable manner.
The findings from this study indicated that the properties of pastes with relatively
high solids concentrations (e.g. 70%) are dependent on the physical properties of
fly ash, such as carbon content and fineness thus impacting on the transportability
of the paste. In order to overcome this effect, the paste with a 65% solids
concentration will be less sensitive to the physical properties of the fly ash.
Furthermore the chemical composition and salt load of brines affect the
transportability and salt retention of paste. It was also observed that salinity of
the brine affects the settling rate of the paste. The availability of various brines at
SASOL provides an opportunity to investigate the blends of brines that will
provide suitable settling and salt retention of paste. The other opportunity
identified was the use of SASOL solid wastes such as incineration ash (IA) and
gasification ash as additives to improve paste properties. It was also discovered
that the mode of salt retention is predominantly chemical rather than physical,
which increases the credibility of this technology.
The overall conclusion is that paste technology is a potential solution for
sustainable co-disposal of ash and brines. Further research areas are proposed to
improve the understanding of paste technology and its implementation.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/4741 |
| Date | 08 April 2008 |
| Creators | Mahlaba, Samuel Jabulani |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 1427301 bytes, application/pdf, application/pdf |
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