WESTERN Australia’s new $28 million Kwinana water reclamation plant, Australia’s largest municipal wastewater reuse facility, houses the country’s most comprehensive application of Profibus DP and PA.
These networks are integral to improving water efficiency in the Perth Basin as well as environmental management in the Kwinana industrial area, south of Perth. The Water Corporation, which owns and operates the Kwinana plant, commenced its implementation of Profibus DP and PA networks in its water and wastewater treatment plants over four years ago.
Over the next five years, the corporation plans to extend this coverage to its five largest water treatment plants (all located within a 50 kilometre radius of Perth), with a centralised operations room at Leederville. Coverage will then be farther extended state-wide. WA’s numerous water treatment plants, including over 980 pumping stations, are spread across some 2.5 million square kilometres.
The Water Corporation needs to maximise the information it obtains from these sites, many of which are remote.
The Kwinana project was awarded to John Holland Engineering, which engaged a specialist water and wastewater engineering company, Veolia, to undertake process design and plant commissioning. PCT Engineers provided the electricals and instrumentation.
Maintenance is handled by KBR Water Services, the corporation’s maintenance provider.
“We chose Profibus because we wanted a fieldbus technology that would enable us to optimise our management decisions,” said Dennis Yovich, principal engineer, electrical, mechanical and electrical services branch.
The Kwinana facility, which was commissioned late last year, treats 24 million litres per day of secondary treated wastewater from the nearby Woodman Point wastewater treatment plant.
Its daily output of 17 million litres of high-quality (350 mg/L TDS average) industry-grade water is sold to industrial customers on the Kwinana strip.
Since these users represent some of the largest of Perth’s public water supply, the plant plays an important role in helping the state government to achieve its goal of 20 percent state-wide re-use of wastewater by 2012.
At the same time, the Kwinana plant is helping to reduce industry demand for scheme water by approximately 6 GL/year - about two percent of Perth’s total unrestricted scheme water use.
Endress+Hauser Australia was selected as the preferred supplier of process instrumentation.
Over 150 devices, including Promag electromagnetic flow meters, t-mass gas mass flow meters, Prowirl vortex flow meters, Cerabar pressure transmitters, conductivity, pH and turbidity systems, as well as level switches and ultrasonic level monitors, were linked up on Profibus PA segments in the microfiltration feed system, CMF-S trains (Continuous Micro Filtration-Submerged), RO feed systems and RO CIP systems.
E+H was involved in designing the Profibus topology, accommodating the Profibus PA segments that connect the instrumentation to the plant’s automation system.
Related activities included system integration planning and realisation in the precommissioning phase, and complete application commissioning for all plant instrumentation.
E+H FieldCare is used as the plant’s asset management system, coupling the instrumentation fieldbus to a single workstation PC-based tool that conducts plant inventory, device configuration and documentation, and storage of device parameters.
Used in conjunction with E+H Fieldgate, operators are able to perform detailed troubleshooting of each measuring instrument from any Internet-linked site in WA.
“The future-proofing of the Kwinana plant using Profibus technology, in conjunction with FieldCare and FDT/DTP tools, will bring us close to our centralised ops room vision,” said Yovich.
“The integration of digital I/O, utilising ASi bus, in the Profibus world - such as alarms, chlorine gas leaks, chlorine residual, low level alarms and empty pipe detection - is exceptional,” he noted.
“We use ASi bus combined with Profibus PA, making all analogue measurement - such as flow, temperature, pressure and level - and digital switching completely homogeneous.”
According to Yovich, this homogeneity is “a unique advantage of Profibus, making so much more data available”.
“The more information we have, the better management decisions we can make,” he said.