Proposed Sidwadweni Regional Water Supply Scheme (RWSS), near Tsolo, Eastern Cape, South Africa

PROJECT DESCRIPTION
OR Tambo District Municipality (ORTDM), also known as the “Employer” has appointed Zutari South Africa (Pty) Ltd as lead consultant and Beacon Consulting Engineers (BCE) to plan, design and implement the Sidwadweni Regional Bulk Water Supply Scheme to improve the treated drinking water supply to Mhlontlo Local Municipality. To complete this assignment, certain planning and supportive studies are required. Environmental authorisation also needs to be obtained.
The project has the following components:
New abstraction works on the Tsitsa River, with the intake structure diversion angled 30 to 45 degrees relative to the river flow direction.
Low-lift pumping main connecting the abstraction works with the WTW via a 706 m long DN 250 PE 100 PN 12.5 pipe. A motive pumping main will be used to supply the jet pumps - a 682 m long, DN 315 PE 100 PN 12.5 pipe is proposed. This pipeline will be adjacent to a proposed access road between the abstraction works and WTW and will cross a water course/drainage line discharging into the Tsitsa River.
The proposed access road between the abstraction works and the WTW will require the construction of culvert-type road crossing across drainage channels.
New water treatment works (WTW) on the bank of the Tsitsa River, with capacity to treat 6Ml over a 24h period. The footprint of the WTW site is approximately 3 hectares.
The WTW will include the following components:
Removal of bulk sediment via mechanical hydrocyclones.
Coagulation, flocculation and sedimentation via Flocculation and Sedimentation Complex.
Filtration via a set of three rapid gravity sand filters with autonomous backwashing.
Disinfection by gaseous chlorine dosing.
1.5 Ml concrete clearwell.
Stabilisation by lime slurry dosing.
Chemical building for storage and dosing coagulant and lime.
Chlorine gas storage and dosing room for disinfection.
Transformer and MCC room.
Concrete-filled geocell-lined sludge lagoons.
Residue holding tank.
Administration building.
Three operator houses.
Service water and fire water system for the WTW.
Small workshop for maintenance purposes.
Perimeter fencing, guard house, paved internal roads and walkways.
New high-lift pumpstation and rising main from Malepelepe WTW to Nduku Reservoir. The pumpstation has been designed for a pumping rate of 84 l/s (i.e., 6 Ml/d delivered over a 20 h period) assuming an aged pipeline. A multi-stage pump will be specified to achieve the duty head and flow rate, in a two duty, one standby configuration. The pumps located in the pumpstation will have a drywell configuration and use the clearwell structure as a sump.
The pumping main will be required to convey 84 l/s from the high-lift pumpstation to the Nduku Command Reservoir. The pipeline is approximately 6 360 m long. Due to the high static head (>250 m), limited options are available for selection of pipeline material and a DN 350 steel pipeline is proposed, joined with bell and spigot connections with external fillet welds.
New command reservoir - 6 Ml reinforced concrete command reservoir, catering for 48 h storage of the current GAADD, with new access road.
Village reticulation for villages along the bulk infrastructure and between the Ncolosi and Kubedlana rivers, currently without water supply. The Scheme will supply 18 villages with a communal standpipe level of service (LOS). Secondary bulk pipelines are proposed to convey treated water from Nduku Command Reservoir to nine smaller distribution reservoirs, from where the villages will be reticulated.
Overhead Electrical Powerline (22kv) to supply power to the WTW from the existing Eskom network (Qumbu substation).