Gulf Construction Online - Paschal eyes sewage plant projects in region

Water Technology

Work on the Madinah project was made easy by the use of Paschal’s Logo.3 wall formwork.

Paschal eyes sewage plant projects in region

01 October 2020

With the increased focus in the GCC on conserving water resources and recycling water, the region is seeing an upsurge in the development of numerous waste water and sewage treatment plants (STPs), says the General Director of Paschal Concrete Forms, the regional office of German formwork specialist Paschal-Werk G Maier.

“In addition, some of the existing STP projects, such as the Tubli Sewage Treatment Plant in Bahrain, have launched several expansions,” Amir Delghandi tells Gulf Construction.

The Saudi Water Partnership Company (SWPC) is developing a number of independent sewage treatment plants (ISTPs) in several locations in Saudi Arabia, including in Madinah, Jubail, Dammam, Buraydah and Tabuk.

Paschal Concrete Forms has supplied its systems for the swift and efficient construction of many such projects in the Gulf region, which have derived the benefits of its modular system. Paschal formwork is currently being used in the construction of two new STPs in Oman being built by Galfar Engineering. The plants, which are now nearing completion, are the Darsait Sewage Treatment Plant in Muscat and a sewage treatment facility in Salalah.

Paschal systems are currently being used on the Darsait plant project.

A major sewage treatment plant project in Madinah, to which Paschal Concrete Forms supplied its systems back in 2013, is now due for expansion, Delghandi says.

Recalling work on the project in Madinah, he says, the SR300-million ($79.88 million) sewage treatment plant is among Saudi Arabia’s largest and was built to cater to a population of one million.

“The plant cleans waste water in three steps to a level of clarity that permits the use of the water for agricultural irrigation,” he adds.

Delghandi points out that work on the project was made easy by the use of Paschal’s Logo.3 wall formwork.

The project was carried out by SysTech (Branch Office Riyadh), which began work on the building structure at the 120,000-sq-m construction site in June 2012, with a scheduled commissioning set for August 2014.

Paschal formwork ... shaping the German STP project.

According to Delghandi, new structures were built in three construction phases. Each included two large activated sludge basins measuring 98.5 by 56.7 m, equipped with six flow inversions over a span of 9 m, which move the water volume. Large round basins (outside diameter 39.9 m), small round basins (outside diameter 33.6 m) and several conventional technical infrastructure buildings were built adjacent to these.

“When the Logo.3 wall formwork arrived at the construction site, all the foundations had already been poured. The rigging supervisor from Germany instructed the crews in the best use of the formwork at the construction site,” he explains.

In order to attain the formwork height of 9.05 m, two elements with a height of 3.4 m and a width of 2.4 m were installed, and two elements with a height of 2.40 m, but widths of 1.35 m and 0.9 m, were stacked on top of these in a sideways orientation.

“Set-up, assembly and implementation proved to be surprisingly straight forward, with a concrete face of equally high grade. Using these methods, the approximately 520 m of linear wall were completed to the customer’s full satisfaction,” he remarks.

Delghandi points out that Paschal formwork was also recently used for the construction of the second largest final sedimentation tanks in its home country Germany.

These tanks, which were completed last year, were built as part of a sewage treatment plant expansion project in Forchheim that serves 600,000 inhabitants.

The sewage treatment plant expansion project includes an additional aeration tank occupying a construction area of 330 m by 150 m, two final sedimentation tanks with an external diameter of 73 m, for which parts of the footing base were about 8 m below ground level.

“Several systems from Paschal were used at the construction site by the contractor Ed Züblin for the various concrete structures – an impressive undertaking demonstrating that all formwork requirements can be addressed quickly and efficiently with formwork systems from Paschal,” he says.

Foundations and base plates were built with Paschal’s Modular universal formwork and the walls were completed using the Logo.3 system. The height extension brackets were used for certain sections of the walls to enable smaller height extensions to be constructed flexibly and without additional panel formwork. For the reinforced concrete slabs, Züblin used Paschal Deck combined with mobile, crane-borne slab tables assembled out of the GASS shoring system. And for curved structures, the TTR trapezoidal girder formwork demonstrated its versatility for forming both the floor and slab plates and the circular tank walls, and delivered impressive results in terms of precisely definable curve radiuses, Delghandi points out.

The concrete haunch on the inside of the curved tank walls was produced up to full height in a single work cycle with system parts.

KBK climbing platforms accessible via safe stair towers were used for the elevated work sites.

“Some parts of the final sedimentation tank are below the groundwater level and were constructed using a special building process, which is why underwater concrete was used,” he says.

During the formwork planning stage, Züblin relied on the skills of Paschal’s formwork experts, who used the Paschal Plan-Pro software to plan the formwork. Consequently, Züblin received comprehensive, detailed formwork plans which provided invaluable support for the entire building undertaking, Delghandi stresses.

After the reinforced concrete structures had been produced and accepted, the technical components were installed and mounted, so that the entire facility could be commissioned last year according to plan.