Construction World December 2018

SEDIMENTATION OF THE NEW STATION 5 AT ZUIKERBOSCH PUMPING STATION

T he contract was awarded in July 2015 and is scheduled to be completed in March 2019. The sedimentation contract comprises the construction of the following: • Three 14 00 diameter steel inlet pipes leading into the flocculation tanks • Three 45 metre diameter circular flocculation tanks, 2,8 metres high • A four compartment sedimentation tank approximately 300 metres long by 150 metres wide by 4,8 metres high • The installation of two 50 metre long de-sludge bridges on the sedimentation tanks • A 100 metre long carbonation tank • A sludge pump station housing the sludge pumps, Motor Control Center and Programmable Logic Controller • Associated interconnecting pipes, channels and valve chambers The contract involved the design and construction of the plant. WorleyParsons was employed for the design aspect of the Station 5a Sedimentation Plant at Zuikerbosch Pumping station is one of four construction contracts awarded by Rand Water for their 600 mega litre water purification plant. This will eventually supply much needed water from the Vaal River basin to Gauteng.

contract and the civil works for the contract was performed by a joint venture between Stefanutti Stocks Civils and Axsys Projects. Strict health and safety and environmental regulations were a requirement of Rand Water for the project. Stefanutti Stocks was able to meet these requirements. To date over one million hours have been worked on the project without a disabling incident and no major environmental incidents have occurred. A large portion of the labour force has been recruited from communities in the surrounding areas which include Sebokeng, Sharpville and Deneysville. Employees have gained valuable experience in the trades of formwork, concrete and reinforcing, as well as health and safety regulations. During the design phase of the project it was considered beneficial to use a precast solution for certain structural elements of the plant. The spiral walls to the flocculation tanks and the U-shaped launders to the sedimentation tank walls were all precast and proved to be an efficient method of construction, saving substantial time and money. This is the first time that flocculation tanks have been constructed in this manner within a water retaining structure. The quality of the concrete achieved on the project is of a superior nature and the end result is aesthetically pleasing. 

PROJECT INFORMATION

• Company entering: Stefanutti Stocks Civils • Client: Rand Water • Contract value: R395-million • Start date: August 2015 • End date: April 2019 • Main Contractor: Zuikerbosch Consortuim • Consulting Engineer: IX Engineers

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