ON SITE pumped down to the water recycling dams, and from there it is transferred to a water / oil separation system, where it is further filtered for reuse in other applications.” A portion of the dams is concretelined towards the drainage end because of the sumps and manholes in that section. The rest of the dams are HDPE-lined and were installed by specialist company Aquatan. The volume of the dams is 50m × 40m by about 6 – 8m deep. The highlight of the project, however, was the wetland crossing, Keevy says with obvious pride. The piping system crossing the wetland transfers water to the ash dams.“ This entailed a suspended piping system across the wetland, on pilings. When it comes to wetlands, because of their importance to the ecology, there is a mountain of red tape around any project in which one is involved. Nevertheless, within a really limited timespan, we were able to complete a really attractive section of pipe over a wetland and rehabilitate the area, without damaging the ecological system. It was quite an achievement from an environmental point of view, but also from a quality and programming perspective. Very few people thought it was achievable, given the intricacies of working in a wetland, the delicate balance that has to be achieved, and the risk of contamination,” he beams. The challenges on this project included controlling the construction process to minimise contamination of the wetland, while adhering to deadlines and completing the project on time, before the onset of the rainy season.
The wetland crossing
A wetland is an area that is inundated or saturated by surface or underground water, which is usually small and limited as a result of the topography
Alex Keevy, contracts director at Esor Construction.
The biggest challenge of the operation was the tight schedule of five months within which to complete the construction works before completing the rehabilitation of the wetland, and avoid the rainy season.