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Strengthening water resilience in rapidly urbanising areas is a significant challenge for many countries. For the last four decades, Metro Manila’s population growth has far outpaced investments in water infrastructure. Urgent supply demands around the capital city of the Philippines have been exacerbated by the few available water resources close by.
Laguna Lake, one of the largest inland water bodies in Asia, is located close to the capital. Yet, these waters have remained relatively untapped due to their high levels of pollution and changes in water quality, making them some of the most challenging waters in the world to treat.
Arup worked closely with Maynilad Water Services (Maynilad) to develop the Putatan Water Treatment Plant 2 (WTP2), a new treatment facility that delivers 150 million litres of water (MLD) per day to one million people in Metro Manila – in a time span of five years.
In recognition of the plant’s world-class technology, innovative design and its role in transforming a challenging water source, the Putatan WTP2 was honoured with a ‘Distinction’ in the Water Project of the Year Category at the Global Water Awards 2020.
Project Summary
150million litres volume of water delivered per day
1millionpeople’s worth of additional water capacity
7,600m²size of compact site
Planning for complex water stresses
Arup was appointed by Maynilad to lead the feasibility work and manage project implementation. Our feasibility study utilised data from the nearby Putatan Water Treatment Plant 1 to more deeply understand the trends of lake water quality.
Understanding the complex issues surrounding water quality in Laguna Lake was critical to the project’s success. In particular, the study highlighted the importance of designing for rapid and potential worsening of water quality to ensure a reliable water service.
These insights enabled us to select, identify and specify a process which could provide robust treatment across a range of different conditions. We were then able to specify a number of advanced technical pre-treatment processes, including dissolved air floatation (DAF), biological aerated filtration (BAF), ultrafiltration (UF), followed by reverse osmosis (RO) before a final chlorination step.
The Putatan WTP2 is now the most advanced water treatment plant in the Philippines, delivering 150ML of water per day.
“The addition of Putatan Water Treatment Plant 2 increases our ability to meet the needs of our customers and provides enhanced water security. The new plant can handle the highly variable quality of raw water coming from Laguna Lake, thus helping to sustain reliable water services. ” Ramoncito Fernandez President and CEO, Maynilad Water Services, Inc
Three-storey “stacked” treatment facility
An innovative design on a small footprint
Apart from the complexities of the water treatment process, Arup was tasked to design the plant on an extremely small footprint. Such limitations are common with water and wastewater projects in Metro Manila, due to the huge pressures on developable space.
Arup was responsible for developing solutions to accommodate a tight site of less than 100m wide and 300m long. This posed substantial challenges for the team, as a typical water treatment plant would usually be designed across a much larger land area. We also had to consider constraints such as site flooding in the high seismic region and existing drainage paths. To counter these constraints, we successfully planned a three-storey treatment plant which allowed the plant’s facilities to be “stacked” across different levels.
This award-winning project is helping Metro Manila relieve major water shortages and safeguard the city’s future water supplies. The success of Putatan WTP2 offers potential for the implementation of such advanced water treatment facilities in similar scenarios in other parts of the world.
“Using our knowledge of water and processing engineering, the Putatan WTP2 project shows that effective technical solutions can be achieved even with complex water sources. Arup is proud to help strengthen water security for Metro Manila and find solutions to bolster water resilience around the world in the face of increased urbanisation and climate risk. ”
Adrian Marsden Associate Director
