They were introduced to the functioning of the pumps in the metal workshop, studied the electric installations of the wastewater treatment plant, analyzed samples in the wastewater laboratory, and benefited from the opportunity to meet their German colleagues. The exchange with the South African visitors was also an inspiring experience for the OOWV trainees.

 
Different sections of the wastewater treatment plant were discussed in detail: Of particular interest to the six-member delegation South African team was the sewage sludge management. In Oldenburg, the sewage sludge from surrounding wastewater treatment plants is first drained, the digested and fed to the incinerator. Both processes generate sustainable electricity that is used immediately at the plant or fed into the grid. Two large digesters, a cellar and storage sites serve the process and were visited by the South African team with great interest. A long-term goal of the South African team is to implement similar mechanisms for sewage sludge treatment.

Olaf Sonnenschein, who has been involved in the operator partnership with Buffalo City right from the start, underlined a "good understanding of each other" from OOWV's point of view. Jonathan Clarke, acting head of BCMM's coastal wastewater treatment plants, called the cooperation a "fantastic partnership" and described the program for this meeting as "first class".

 
Based on the insights gained from the training, the South African team is also planning to make adjustments in some other technical areas at their own facilities. In addition, some surprisingly simple tips and tricks came up: For example, using bicycles at the plants to move faster across the site, as well as improving communication between the lab and the wastewater treatment attendants to respond promptly to changes.

The overarching goal of this exchange at the international level is to find joint solutions to similar challenges, each benefiting from the experience of the other. Here, the project is making good progress. "We have shown how pumps are dismantled and what special tools we use for this," reported Jan Fischer, coordinator of the OOWV metal workshop at the Oldenburg wastewater treatment plant, as an example. In South Africa, this task is carried out by external service providers, he said. With Ingo Schriever, responsible for electrical engineering, the guests examined, among other things, the direction of rotation of the pumps.

 
One advantage of the systems in Buffalo City, South Africa, is that the rainwater is discharged in separate pipes, which reduces the overall amount of wastewater that has to be treated. In contrast, in the historically grown urban areas of Germany, wastewater and rainwater flow together through a single pipeline system. After heavy rainfall on the last day of the delegation's trip, all the additional basins at the wastewater treatment plants were consequently completely full, and these volumes of water had to go through the entire purification process over the next few days.

"For me, this was an enriching exchange," Tina Petershagen looked back. In the wastewater laboratory, she and her colleague Angelika Wiecker examined water samples from the OOWV wastewater treatment plants together with the visitors. "That went totally well," she was pleased to say. She described her guests as "inquisitive".

Trainee Ole Lübsen had only heard about OOWV's cooperation with the Buffalo City Metropolitan Municipality before. "It was interesting to get a first-hand impression now," he said.

 
There was no language barrier during the time spent together at the Oldenburg wastewater treatment plant. "Everyone was able to communicate in English," said Meike Lenzen, project engineer in the International Cooperation and Water Innovation Networks (IZW) department at OOWV. What she particularly remembers is that "after a short welcome, everybody was immediately in the thick of things and busy working. And we got along very well."