Water board Rand Water is refurbishing and upgrading its Vereeniging water treatment plant (VWTP) operations and has several projects under way at the site, as well as at the Lethabo intake, with the view to maintain uninterrupted water supply to its area of supply, including Gauteng, into the future.
Over the last few years, Rand Water has been identifying ageing and obsolete infra- structure with the intent to upgrade or replace equipment where necessary. Rand Water VWTP executive manager Eddie Singo says that the improvements process is gradually taking place throughout the Vereeniging site.
Rand Water is hoping that any future infrastructure and equipment failures will be within the water board¡¯s physical scope of maintenance, and is attempting to avoid catastrophic failures such as an entire engine room failure,¡± says Singo.
Singo explains that equipment condition monitoring is being improved by effectively applying maintenance philosophies and this has assisted Rand Water in being proactive with its maintenance. With total equipment failure such as its 3630-KW Toshiba motors, the resolution of the problem could take more than three months.
Allen-Bradley¡¯s Power Flex 700 variable-speed drive (VSD) units, which are developed by Rockwell Automation, have been installed at the Rand Water Lethabo intake plant. Singo explains that the installation of these VSDs enables one drive to control two motors. Rand Water¡¯s engineering division has, after one unit¡¯s failure, suggested to Rockwell Automation to investigate the possibility of one drive controlling three motors. Rockwell has responded that it will investigate the possibility.
Meanwhile, Rand Water is ensuring standard- isation of instrumentation used at all its sites while also focusing on installing energy saving equipment to ease the demand for electricity and avoid increasing the burden on the electricity grid. The environmental effects of the technology and infrastructure that Rand Water employs are also taken into account.
The Lethabo Intake is situated opposite State power utility Eskom¡¯s Lethabo power station, which is critical to the national electricity grid. The intake supplies both the Vereeniging treatment plant and the power station, and Singo says that, if Rand Water were to fail to supply the power station, it could compromise the country¡¯s power supply. Just over R40-million has been spent in order to ensure that supply to the VWTP and the power station is not interrupted, and control panels to three of its 890-kW BBC motors have been upgraded, including an emergency cross connection pipeline for increased redundancy.
Singo says the pumps and motors at the intake are over two decades old.
He explains there are two factors that deter- mine whether infrastructure should be replaced, namely the age of the equipment and subsequent availability of spare parts, and the efficiency of the equipment.
Singo says that motors at the Lethabo intake had just started experiencing problems, particularly with rising temperatures as high as 125 ¢ªC, resulting in a conscious decision to replace two of its 3630-KW Toshiba motors earlier in the year. Rand Water can comfortably assure continued uninterrupted water supply in response to demand. The water board is also in the process of changing the other motors at the site.