Engineering, project and construction management firm Zimile Consulting Engineers has been contracted to work on a bulk sewer rising main and pumpstation project, in KwaZulu-Natal.

The project aims to minimise the overflow of sewerage to uMzimkhulu river by pumping sewage to the nearby existing waste water treatment works. The project also aims to address any other sewer infrastructure challenges of the growing uMzimkhulu town falling under the Harry Gwala district municipality.

The project began in October 2022 and is expected to be completed in May 2024.

The scope of work includes the construction of the gravity bulk sewer, pumpstation  and sewer rising main, which includes excavation of pipe trenches, installation of pipe bedding, and laying of the pipes complete with fittings and couplings.

The rising main pipeline comprises 1 300 m of 350-mm-diameter Class 12 unplasticised polyvinyl chloride (uPVC), and about 250 m of 355 mm diameter Grade A steel pipe.

The project includes the construction of a reinforced concrete sewer pumpstation and sumps, and the provision of electricity from State-owned utility Eskom.

The project also involves the installation of three 630 000 ℓ/h electrified sewer pumps and motors; a 45 000 ℓ/h electrified sewer pump and motor for sump dewatering; a 316 kVA substation; a 300 kVA generator; isolation and air valves; a flow meter; check valves and an electrical motor control centre.

Zimile is responsible for designing the project and compiling the tender document, as well as for site supervision, monitoring and quality control.

“Our task is to help the client achieve its objectives by delivering the project and seeing it through to the end,” says Zimile’s David Ralebipi, who is the resident engineer on the project.

Despite being on track to meet the deadline, the high groundwater table has been challenging, causing dewatering pumps to have to operate continuously throughout the day, he explains.

Moreover, the team encountered a boulder at a depth of about 10 m during the final phase of the drilling and excavation process that required blasting which was not initially planned for.

“The blasting process did delay us a bit because of the administration behind it that required the obtaining of, for example, a method statement for blasting and approvals from safety agents,” says Ralebipi.

He notes that rain has also been a challenge during the project.

Despite setbacks, he enthuses that the excavation was successfully completed and the successful pouring of a concrete base has allowed for more efficient water control.

The project is more than halfway to completion, with concrete ready to be poured for the first wall that will surround the concrete base slab.

In addition to assisting in upgrading the infrastructure, the project has also created about 20 jobs for people residing in local communities.

The Zimile team actively collaborated closely with the community and facilitated a holistic approach to problem-solving and innovation that is relevant in addressing community needs.

Ralebipi attributes teamwork as one of the key drivers of the success of the project.

“Through teamwork and adherence to construction principles, we will see the project being successful. We aim to inspire engineering across Africa and beyond while delivering an uncompromising service to clients that meets high standards of engineering,” he concludes.