Rocla delivers Paarl Waste Water Project

Johannesburg - July 2009 – Rocla, the leading specialist in precast concrete infrastructural products and solutions in Southern Africa, was awarded the contract to supply pipes for the project to upgrade and prolong Paarl's current waste water works system. Operating from their Blackheath factory in Cape Town, Rocla is supplying precast concrete sewerage pipes to the Drakenstein Local Municipality for this project

The town's sewage system was not providing enough carriage of waste water for the town, processing only 24 Ml of waste water per day. The upgrade of the sewage water works system, which commenced in March 2008, will see the system increase its capacity to digest 35 Ml of waste water per day.

Rocla is required to include bends in the pipeline to meet the need for the free flow of the waste water. Phase 1 of the pipeline comprises 1,050mm, 1,200mm, 1,500mm and 1,650 mm concrete pipes with an internal sacrificial layer made from Calcium Aluminate Cement (CAC) to deal with the corrosive nature of the contents.

Another specialised product that Rocla used in Phase 2 of the project was the HDPE (High Density Polyethylene) liner, manufactured by Engineered Linings. The HDPE liners can withstand aggressive water conditions inside the pipes, which assists in prolonging the lifespan of the sewer system. Rocla used a 3mm thick lining with 10 mm knobs, which can sustain approximately 40 kg of reverse pull forces.

Rocla custom-made a 45 degree pipe using a top cast mould, where each bend is divided into two components, each with a 22.5 degree bend, instead of the normal lobster back bend with corners and edges.

According to Hendrik Stander, Rocla's Sales Executive at the Blackheath plant, manufacturing the bend in two parts means that the handling of the bend is easier and quicker. Each bend weighs 6.3 tons per 22.5 degree bend.

"One of the trickier parts of this particular project", adds Stander "was laying the bended pipes in the correct position of up to 6 metres deep. Access holes were precast into the bends to ensure easy access during inspection. Manhole rings will be placed on top of these access holes to facilitate easy inspection."

To further facilitate the free flow system, Rocla Blackheath designed a 90 degree bend which is divided into three 30 degree bends. "The thrust block on the bend played a dual role in supporting the seam and the bend in the ground", says Stander

Kempen van Wyk, Director of Exeo Khokela Construction, the project's main contractor says, “Rocla has delivered timeously on all deadlines so far. Their constant communication with us regarding manufacturing and our visits to their Blackheath plant ensured that the project has run smoothly from the start. Our close working relationship has played an important role in delivering a customised solution for Drakenstein municipality."

Phase 1 of the project is 60% complete and Phase 2 recently commenced with completion scheduled for December 2010.

More about Rocla

Rocla (Pty) Ltd, part of the Murray & Roberts group, is a leading manufacturer of precast concrete products for infrastructure, including pipes, culverts, manholes, poles and other related and customised products.

Rocla partners with customers to design and develop solutions for specific applications. With over 91 years of experience in precast concrete technology, Rocla provides extensive backup and technical expertise to its customer base. Rocla has an extensive network of factories throughout South Africa, Namibia and Botswana, and is an ISO 9001:2000 certified company.

More about Exeo Khokela Construction
Exeo is a well-established construction company actively involved in the Civil Engineering Construction Industry in the Western Cape.

The company has a staff complement in excess of 150, which includes a professional registered engineer, as well as a professional registered technician. All site staff on technician level have obtained appropriate tertiary qualifications and are guided by experienced contract managers.