According to the Department of Water Affairs (DWAF, 2004 p.15), South Africa’s water
resources are scarce and extremely limited and much of this precious resource is utilised and
consumed in our industries. Treatment and re-use of effluent generated is, in some cases,
preferred over use of alternate water resources (Du Plessis, 2008 p.3).
The volume of effluent generated in treatment processes like ultra-filtration (UF) and reverse
osmosis (RO) units is determined by the feed water quality, with high water loss through effluent
generation at poor feed water quality. Current UF and RO applications require an increased UF
production capacity due to the use of UF filtrate for periodic backwashing of the UF membrane
units. This results in loss of water and decreases overall recovery.
The need therefore exists to increase the overall recovery of product water from the raw water
stream by reducing the amount of effluent generated. This would be possible to achieve by
using RO brine to backwash the UF unit.
The study was conducted to provide a modelling tool, assisting management to optimise the
use of RO brine as backwash water on the UF system at the Medupi power station. The
secondary objective of this study was the development of a modelling tool that can be used for
other projects, new or existing, as a measure and indication of the usability of RO brine as
backwash water on UF systems.
By successfully applying this newly developed model, the viability of utilising the RO brine as
backwash water for the UF was investigated. This modification would lead to utilizing smaller UF
units than previously envisioned, which in turn leads to reducing capital cost with 11.07% and
operating expenditure with 9.98% at the Medupi power station. This also has a positive
environmental impact by reducing the amount of raw water used monthly by 10.34% (108 000
m3/month). / MIng (Development and Management Engineering), North-West University, Potchefstroom Campus, 2014
| Identifer | oai:union.ndltd.org:NWUBOLOKA1/oai:dspace.nwu.ac.za:10394/11052 |
| Date | January 2014 |
| Creators | Fourie, Frederik Jacobus |
| Source Sets | North-West University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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