Bosch Munitech recently completed the Mtubatuba Emergency Water Supply Project for the provision of drought relief to Mtubatuba and surrounding areas, on behalf of Umkhanyakude District Municipality. The tender called for the design of a subsurface abstraction system to supply the Mtubatuba Water Treatment Works with raw water to ensure a minimum of 10 MI/d water supply to the community in the dry season.
Bosch Munitech proposed a system comprising 7 large diameter well points drilled into the river bed, to access subsurface water flow, each well equipped with a wedge wire screen encased borehole pump connected to the existing raw water rising main. A significant benefit of the system includes the natural filtration of the river water by the river bed, which eliminates solids loading on the plant, significantly reducing chemical flocculant dosing and cost. The lack of solids in the raw water also protects the pumps from sand abrasion and extends the life of the pumps considerably.
Bosch Munitech further proposed the installation of a 20 MI/d system to meet the full raw water treatment capacity of the water plant. This system was installed and comprises 13 well points in the river bed.
The installation of the pumps was preceded by river bed soil resistivity analysis and test drilling to determine bedrock depths, yield potential and optimal siting of the pumps in relation to sub-surface water flow.