Huge sludge drying system in Singapore uses PROFIBUS

As well as being the largest facility of its type in the world, the new Changi Water
Reclamation Plant (CWRP) in Singapore boasts the largest Profibus installation yet in Southeast Asia comprising close to 8,000 nodes. Aided by advanced process automation, the centralization of used water treatment at Changi allows for greater economies of scale and higher productivity.
The  Andritz Group supplies customized plant, systems and services for the pulp and paper, hydropower, steel and other specialized industries. The used water treatment process is an extensive one, involving all manner of sedimentation tanks, bioreactors, anaerobic digesters, and the sludge drying comes right towards the end.

Profibus being mandatory for all CWRP equipment packages was a welcome specification item for Heinrich Bertl of the Andritz Group, who was able to claim a number of years’ knowledge and experience of working with the European-developed fieldbus network technology. As for Profibus, aside from the obvious installation advantages from having a single cabling architecture, Heinrich Bertl cites the diagnostics capabilities through GSD and EDD files as being a major benefit. “You can identify every node on the network, and so can quickly know if there is a problem with a device, even if it’s not fully faulty.” What this means is that preventive maintenance can be initiated on the basis of abnormalities detected well before a device has the chance of reaching failure point.


After eight years of construction and intense engineering work, the CWRP Phase 1 was set for operational start at the end of 2008, with a total treatment capacity of 800,000 cubic meters per day. “It has been a challenging project – the largest dryer Andritz has ever supplied. We made a deliberate decision to allocate a lot of time and effort to the factory acceptance test, to ensure that all the instruments worked as they should and reduce the chances of any surprises in actual operation,” he says. This has definitely been a successful project, and with such an extensive deployment and the high profile of the CWRP, it has been a great opportunity to showcase the benefits of adopting Profibus technology.