Veolia Water Technologies South Africa (Veolia) completed a civil-based sewage treatment plant (STP) for CLN Nacala Corridor Project, the port and railway link in Mozambique. The STP was a turnkey project consisting of civil, electrical and mechanical installation, designed with trickling filter technology to cater for a maximum of 500 people per day (500 PE).

The plant has the capacity to process 100 m³ of sewage per day, servicing the port’s administration block. As a turnkey project, civil design and construction formed part of Veolia’s scope of work, in addition to the supply and installation of all mechanical and electrical equipment.

Veolia employed trickling filter technology as the most appropriate technology to ensure that the STP discharge water was treated to the client’s specification. “It is the ideal sewage treatment solution for this application,” explains Hirsheda Jeram, Project Manager, Veolia Water Technologies South Africa. “It works well in high temperatures and in remote locations, and is used to treat domestic sewage high in organic matter like BOD, COD and various other pollutants.” The turnkey sewage treatment plant replaces multiple septic tanks previously used by the coal terminal port.

She adds that, in addition to high temperature suitability, the benefits of trickling filter technology include lower running and operating costs, and requires reduced energy input. It is simple to use and actual maintenance itself is much lower. “All of these contribute to minimal costs over the plants lifespan,” Jeram points out, “and additional benefits include easy recovery from power outages, bio digestion at a high rate with nominal resource use, less sludge production and minimal operator intervention.”

Veolia’s ability to adapt to client requirements while ensuring all specifications are met meant Veolia could easily comply with the client’s electrical specifications and site specific conditions. For example, the motor control centre (MCC) designed for the plant is housed in a separate room to ensure its environment is kept at a lower temperature than the rest of the site. Veolia personnel were required to undergo site induction and safety training, necessary to conduct the mechanical and electrical installations in accordance with the client’s safety standards. “It also gives Veolia personnel a better understanding of the customer’s challenges, enabling us to adapt to conditions and work safely.”

“We outsourced the civil works and electrical connections to authorised contractors already established on site. However, all other work, as defined by the scope of work, including the installation of the MCC, was conducted by Veolia personnel.”

Commissioning took place during November 2015, with Veolia’s EC&I manager and technicians, along with CLN Nacala Corridor Project contract manager, supervisors and operators. “Post-commissioning required three days of training for the client’s personnel, which included covering the contents of Veolia’s operating and maintenance manual,” Jeram concludes.

Caption to picture 1:The recently commissioned sewage treatment plant for CLN Nacala Corridor Project, Mozambique.

Caption to picture 2:The plant services the port’s administrative block, replacing septic tanks previously used by the client.