Where Water Works

After transforming the quality and reliability of water supply to Metro Manila over the last decade, Manila Water is now intent on achieving ever higher levels of operating efficiency through adoption of the latest automation technology. Bob Gill reports.

It has been called the World Water Crisis. That may seem rather dramatic – until you look at some of the figures included in a United Nations report, Water in a Changing World, released last March: 20 percent (1.1 million) of the world’s population lack access to safe drinking water; by 2030, nearly half of the world’s population will be living in areas of acute water shortage; and the demand for fresh water is rising annually by 64 billion cubic meters.

Increasing populations, rapid urbanization, and underinvestment in infrastructure are three cited factors behind the crisis. And it should not be too surprising to learn that it is the developing countries of Asia – along with sub-Saharan Africa – that are those most affected and at risk.

Back in the mid-1990s, the Philippines was one country where there was already a sense of crisis, to the extent that in 1995, the government enacted the National Water Crisis Act in an effort to address the urgent need for improved water services. For example, in the key district of Metro Manila, the metropolitan area that comprises Manila and 16 surrounding cities, water supply was inconsistent with only a minority of its burgeoning population experiencing 24-hour access. Unregistered connections to aging mainlines as well as leaks were commonplace.

In 1997, responsibility for water supply to the Metro Manila East Zone, a district comprising some five million people, was transferred from the existing, government-run Metropolitan Waterworks and Sewerage System (MWSS) to the privately-held (by Ayala Group) Manila Water Company.

With a management team intent on tackling the existing deficiencies and authorizing capital investments of the order of PHP27 billion (US$580 million) over the next decade, the results have been remarkable: an increase in customers with 24-hour water availability from 26 percent in 1997 to 99 percent in 2007; a reduction in water losses from 63 percent to 24 percent, in the same period; and full compliance to water quality standards.

Becoming clearer

“We have two major treatment plants serving the East Zone,” says Engr Walter Tendencia, manager, Production Planning & Control Section, Manila Water. “Balara Treatment Plant 1 and Balara Treatment Plant 2. They take water pumped from source reservoirs and, through appropriate treatment processes, transform it so it becomes fit for human consumption – i.e. potable.”

The key water treatment stages are (successively): coagulation/flocculation – where suspended solid particles in the raw water intake are formed into flocs via the addition of coagulants and an extended mixing process; sedimentation – where the floc is settled out in basins, and sediment sludge is removed; filtration – where the water is passed through filters comprising layers of sand and anthracite; and finally, chlorination to disinfect the water.

“For the filtration equipment, an important maintenance step is that of ‘backwashing’,” explains Tendencia. Here, clean water is passed back through the filters order to blast off clogged particles that would otherwise adversely affect the quality of the filtration process.

At both plants, for many years, backwashing was a labor-intensive process that required operators to go out and manually adjust valves for each filter basin. In 2006, with a primary aim to achieve a more efficient backwashing operation, Manila Water began to look at options for automating the process.

For Walter Tendencia and his team, their first point of contact was with EESI, a specialist systems integrator with headquarters in Quezon City. “We approached EESI and described our backwashing operation and outlined our key control requirements,” recalls Tendencia.

“Before setting up EESI, Nestor and I actually used to work for Siemens,” explains engineering manager Ronilo Laurel. The Nestor he is referring to is Nestor Hadap, EESI’s president and general manager. “We set up EESI to be a system integrator for Siemens. And so all our projects involve Siemens products.”

Visualize & control

The Balara project proceeded in two phases: Plant 1 in 2007, and Plant 2 in 2008. For each, the backwash automation system comprises PLCs (S7-400) that connect up to a WinCC HMI system for operator control and visualization, and down to filtration valves and instruments. From a single WinCC station, an operator can now control all the motorized valves necessary for the backwashing process in the respective plant, as well as monitor key parameters such as turbidity and level.

“The automation is appreciated by both the operators and the plant managers,” says Tendencia. “The operators no longer have to move and walk around the facility in order to perform backwashing. They can visualize everything from the terminals in control room, and initiate and adjust the process from there.

“And for the plant managers, the automation system enables them to realize a more efficient, accurate operation with no time delays. The reduced need for labor in the process has also allowed redeploying of operators to other parts of the water treatment plants,” he notes.

The emphasis on upgrading and improvement that came in when Manila Water took over the Metro Manila East Zone concession franchise can be seen in the company’s openness and willingness to explore and invest in new technologies – like Profibus.

“In 2006, we attended a roadshow held in Manila organized by the regional Profibus association. We were able to learn more about the benefits of this industrial networking technology and see how it could potentially be applied to bring about greater efficiencies in our plants,” says Walter Tendencia.

So when it came to the automation project, Tendencia’s team decided to specify Profibus PA for instruments (that had that capability), as well as Profibus DP for the main facility network connecting the PLCs to the PA segment and ET 200 remote I/O stations.

That proved to be a good decision, affirms Tendencia, citing savings in cabling cost as well as a smooth installation. According to EESI’s Ronilo Laurel, the total design and installation time for each project was three months.

In the pipeline

Elsewhere at Manila Water, Siemens automation technology has also been applied at the major downstream pumping stations to control the outflow of water to the customers. This has led to improved efficiencies from operators no longer having to go out and open intake valves manually. “They just need to press ‘Start’ on the operator panel, with another layer of confirmation to proceed, and then everything will be run in sequence,” explains Laurel.

Walter Tendencia reveals that further automation projects are being planned for Manila Water’s complex of facilities. “Of course, there would be benefits in choosing Siemens technology again,” he says. Our staff have been trained and become familiar with the products, and there would be obvious efficiencies in spare parts inventories.”

He also notes that Manila Water has built up a good professional relationship with integrator EESI and been very pleased with the after-sales service provided. “Given that we are a utility company that operates 24/7, this is obviously a key aspect of vendor performance. No matter how good the design or the engineering, it means nothing if your supplier cannot provide a sufficiently high level of service that you can trust in to keep you going. Or in our case, to keep the water flowing.”