PROJECT DESCRIPTION

The existing Midmar Water Treatment Works has a design operating capacity of 250 Ml/d on a raw water intake basis (RWI). This plant was originally designed for a "Phase 2" increase to 370 Ml/d (RWI) capacity. Since losses due to sludge discharge and filter wash-water are not recycled at this plant, it is estimated that a design raw water intake of approximately 395 Ml/d will now be required in order to produce the required 375 Ml/d of saleable water. The extent of the upgrade includes construction works of a civil, structural, mechanical, electrical and control & instrumentation nature.

Key features of this project included:

MIDMAR WTW:

• Construction of new dosing lines, including intermediate manholes, for new water inlet pipe (all dosing lines are to be inserted in a nominally 300mm diameter uPVC class 34 sewer pipe sleeve)
• Chlorine dosing line: construction of one nominally 63mm diameter & 180m long PVC.
• PAC dosing line: construction of one nominally 25mm diameter & 276m long PVC.
• Bentonite dosing line: construction of one nominally 63mm diameter & 270m long PVC.
• Sampling line: construction of one nominally 50mm diameter & 273m long PVC raw water sampling line.
• Supply and install two 20m3 polyelectrolyte storage tanks to be placed onto concrete plinths.
• Integration of the existing 3no 20m3 polyelectrolyte storage tanks with the new existing 2no recycling pumps.
• Supply and install 1no polyelectrolyte recycling pumpset, to be integrated with the existing 2no recycling pumps.
• Replacement of existing 4no bentonite dosing pumps with new ones.
• Modification of existing bentonite delivery system, to tie into the new 200 second dosing connection point.
• Modification of the existing powdered activation carbon (PAC) delivery system, to tie into the new 200 second dosing connection point.
• Relocation and modification of the existing chlorine scrubber system to suit new chlorine dosing system.
• Extension of the existing chlorination to house new 17ton chlorine tanker.
• Extension to road works at the head of works.
• Supply and install 1no ammonia pumpset, to be integrated with the existing 2no dosing pumps.
• Extension to the existing splitter box.
• Construction of new Pulsator feed/overflow chamber.
• Construction of a nominally 1000mm diameter & 45m long mild steel pulsator feed pipe.
• Construction of new 100 MLD pulsator.
• Construction of a nominally 1000mm diameter & 70m long mild steel clarified water pipe to tie into existing filters, complete with drop manholes.
• Construction of 1no pipe jack crossings under service duct.
• Construction of a nominally 500mm diameter & 60m long RC pulsator underflow pipe to tie into existing Pulsator underflow pipe.
• Construction of 6no gravity sand filters to match existing.
• Removal of existing fence at some areas of the works.
• Construction of new fence line at some areas of the works.

SLUDGE WORKS:

• Modification of the existing inlet chamber to cater for the new nominally 1200 mm diameter RC overflow pipe.
• Construction of a nominally 1200 mm diameter & 115 m long RC overflow pipe (including two manholes) to tie into existing manhole.
• Removal of the existing nominally 1200 mm diameter overflow pipe due to location of the new backwash water balancing tank.
• Relocation of the existing Pista Grit Trap air blower.
• Construction of a new 1300 m3 backwash balancing tank complete with an inlet feed channel. New backwash balancing tank is to be fitted with a course air diffuser mixer system.
• Replace existing air diffuser system in existing backwash balancing tank with new course air diffuser mixer system.
• Supply and install 3 no. air blowers (Duty/Duty/Standby) for both the backwash balancing tanks.
• Construction of a nominally 500 mm diameter & 22m long uPVC overflow pipe for the existing balancing tank to tie into the existing overflow pipe. A new manhole is to be constructed over the existing overflow pipe for the tie in.
• Existing outlet chamber for the existing backwash balancing tank to be filled with soil and capped with 50 mm concrete screed.
• Construction of a nominally 500 mm diameter & 25 m long uPVC outlet pipe from both the existing and new backwash balancing tank.
• Construction of a new common outlet chamber for the two backwash balancing tanks, complete with a nominally 150 mm diameter & 13 m long uPVC scour pipe to tie into existing overflow manhole.
• Construction of a nominally 450 mm diameter & 15 m long uPVC pipe to existing Sludge Works.
• Relocation of the existing security building.
• Extension to road works.
• Re-commission existing polyelectrolyte dosing system at Sludge Works.
• Existing splitter box to be modified to suit new design. Existing splitter box has three chambers, with only one in use and the other two been sealed using bricks. The two chambers are to be broken out to feed new clariflocculators, weirs to be fitted with an adjustable weir plate.
• Construction of 2 new 17.5 m diameter Clariflocculators complete with associated pipework.
• Replace both existing thin sludge pumps with new.
• Construction of a new 15.5 m diameter Gravity Thickener complete with associated pipework and 1 No. desludge pump.
• Refurbishment of the existing flow splitting chamber to feed new Gravity Thickener.
• Supply and install 1 No. Centrifuge.

Work Considered to be complicated:

• Construction of Filter floor slabs to strict tolerances.
• Deep excavations
• Construction and installation of precast slabs, at the Filters and Pulsator.
• Piling in a boulder matrix.
• Construction of Pulsator

Additional work:

• Relocation of 11KV cable.
• Relocation of 11KV cable. Engineered Fill: Due to unfavorable ground conditions, unsuitable material was removed from excavation (Backwash Tank, Thickener and Clariflocculators). This gave way to the importation of 10000 tons of G5 material. That was to be filled (stabilized G5) to required level.
• Removal of boulder formations.
• Supplied and installed large bore concrete pipes.

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PROJECT DESCRIPTION

The project is the second phase of a new bulk water supply scheme for Umgeni Water in the Umshwathi Municipality. This phase (Phase 2) comprises of the construction of approximately 15km, 700mm diameter NB steel pipeline between Wartburg and Dalton KZN, two bulk water booster pump stations with ratings of 1050KW and 2250KW respectively, and a 10ML post tension, circular reinforced concrete reservoir in Dalton KZN.

Key features of this project included:

• Handling and installation of 15km of buried 700mm diameter continuously welded steel pipe, including the construction of 11 No. scour valve chambers, 13 No. isolation valve chambers, 2 No. meter chambers and 21 No. air valve chambers. The construction of the aforementioned includes all earthworks, reinforced concrete work, mechanical fabrication and installation and commissioning and the rehabilitation of the pipeline route post construction.
• Construction, fitment, testing and commissioning of 2 No. booster pump stations. The construction of the aforementioned includes all earthworks, reinforced concrete work, building work, mechanical fabrication and installation, electrical fabrication and installation, facilitating the design and installation of all controls, telemetry and SCADA, structural steel work and final commissioning of the system.
• Construction of the 10ML post tension, circular reinforced concrete reservoir comprises of bulk earthworks, engineered layer works, under drainage, reinforced concrete work, post tensioning, mechanical fabrication and installation.

Work Considered to be complicated:

• Multilevel reinforced concrete structures in pump station to be constructed with little to no tolerance to ensure good fitment of overhead gantry cranes, pump sets and pipework.
• Working in close vicinity of existing live Asbestos Cement water main in hard or unstable in-situ materials, without compromising the integrity of the AC water main.

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PROJECT DESCRIPTION

The works comprise the construction of a new regional water treatment works in Jozini (northern Kwazulu Natal) on a piece of land of approximately 10 ha. Key features of this project include:

• The scope of work includes clearing of vegetation (within environmental constraints) followed by approximately 24000m³ of bulk excavation to form platforms onto which the various structures are built.
• 3 sludge ponds have been constructed with a total capacity of approximately 10000m³ as well as approximately 300m of 675mm dia. concrete sludge pipework draining into these ponds from the works with associated chambers.
• Approximately 7000m of concrete is to be cast into various structures (filters, settling tanks, Clearwater tanks, pumpstation etc) as well as the construction of several service buildings (chemical building, chlorine building, workshops, administration and housing) within the site.
• Approximately 320m of 800mm dia. steel butt welded bulk water pipeline delivers raw water to the works and a further 200m of 800mm dia. steel butt welded bulk water pipeline carries treated water out of the works each with associated valves and fittings.
• A new 76KL water tank shall supply water to the various structures and buildings through new internal plumbing and drainage across the site.
• There is new fencing of approximately 1.7 km forming a perimeter fence around the site as well as 0.75km of roadways (G Block surfacing) within the site.
• Construction of stilling basin.

Work considered to be complicated:

• The logistics of maintaining progress with the many relatively small complicated concrete elements within the time frame of the contract working on all fronts at the same time.
• The mentoring and up-liftment of three local subcontractors contributing to the CPG of the contract.

Additional Work:

• The construction of a new soccer field for the community

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PROJECT DESCRIPTION

The Mvoti Bridge was an innovative engineering design to a challenging problem, and one that earned us the 2012 IMESA Award for Technical Excellence. In order to meet present and projected future water demands in the North Coast area of KZN, the bridge formed a vital part of the Umngeni Water Bulk Water Supply project. Taking just under a year to complete, we managed to come in on time and under budget. Key features of this project included:

• Handling and installation of above the ground and buried steel piping, 220m and 60m respectively, the pipe being 800mm in diameter, continuously welded and included tie-ins to existing pipes.
• Supply, fabrication and erection of steel bridge structure spanning 220m across the Mvoti River.
• Demolition of and dowelling into the existing concrete pier and abutments, as well as extension of the centre pier by 16m and counterweights at the abutments.
• Deep shoring, excavation and reinforced concrete for anchor walls, plinths and thrust blocks.
• Bridge and pipe support bearings, and construction of work platform and removal thereof, including all environmental requirements.
• Fabrication and installation of stainless steel convoluted bellows and various insulating flange gasket sets.
• Reinstatement of northern embankment.
• Allowance for the installation of a second 800mm diameter pipeline at a later stage.

Work Considered to be complicated:

• Double curvature formwork to pier extension
• Fabrication and installation of the steel bridge structure including the setting of the bridge bearings
• The installation of the pipe onto the bridge

Work Considered to be complicated:

• The temporary support of the first span to avoid un-balanced moments being applied to the centre pier, the lower existing section being found to be un-reinforced.

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PROJECT DESCRIPTION

Key features of this project included:

• A new Stone Trap
• Concrete works 5000m³
• Modifications to the Head of Works to allow for new mechanical equipment.
• Modifications to Thickened Sludge Pump station building.
• A new Dissolved Air Flotation Thickening Facility.
• Two new Anaerobic (Heated) Primary Digesters including associated pump stations and heat exchanger building.
• A new Biogas Storage Tank
• New Secondary Digesters
• New Sludge Dewatering Screw Press building.
• Modifications to existing Sludge dewatering screw press building.
• A new thickened sludge rising main.
• New access roads and existing roadway upgrades, complete with drainage.
• A new second class Booster Pump Station Building.
• New Second Class Water reticulation and upgrades to existing.
• Various minor civil, Structural and Building works.

Work Considered to be complicated

• Post Tensioning to Circular Structures.
• Working within an existing treatment works - live tie-ins.

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PROJECT DESCRIPTION

This project comprises of the construction of a 20ML reinforced concrete break pressure tank, outlet and overflow pipelines, inlet and outlet chambers and associated pipework, and a Stilling basin. Key features of this project include:

• Construction of a 20ML reinforced concrete break pressure tank.
• Installation of 1400 NB x 420m long steel outlet pipeline.
• Installation of 1050 x 632m long concrete overflow pipeline.
• Construction of inlet chamber.
• Construction of outlet chamber.
• Installation of pipework to inlet chamber.
• Construction of stilling basin.

Work considered to be complicated:

• Installing 1400 NB and 1050 concrete pipe in 11m deep trench.
• Fabrication and installation of 1400NB with 800NB stubs x 23m long manifold.
• Excavating 11m deep trench within limited space.
• Excavating 7m deep trench approx. 3m away from heritage stone wall.

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PROJECT DESCRIPTION

This pipeline project, which took just over a year to complete, involved extensive augmentation to the system supply to World's View Reservoir, in parallel to existing pipelines, in effect doubling the outlet capacity from World's View Reservoir. The pipeline connects to the Midmar outlet at DV Harris Water Treatment Works and one of the existing pipelines was also re-routed to connect to the same source. The nature of the pipeline traverse (through Queen Elizabeth Park, Victoria Country Club Golf estate, under the N3 and R103, along the Mist Belt Grassland, up to Clarendon Reservoir where the pipes joined and connect to the inlet at World's VIew reservoir) meant formidable environmental demands were placed on the teams involved. Key features of this project included:

• Laying of 3800m of continuously 900mm nominal diameter steel pipe and 1800m of 1200mm nominal diameter pipe, including on-site fabrication of pipe bends and pipe weld coating repairs.
• Six tie-in points to live, large diameter steel pipelines - two at DV Harris, one at Clarendon Reservoir, two at World's View Reservoir and one at the beginning of the Umlaas supply system.
• Various large concrete chambers and multiple smaller, in-situ reinforced concrete and precast concrete chambers.
• Restricted excavation and laying along majority of the route as well as gravel, paved and surfaced road crossings, and a river crossing, in conjunction with the protection and deviation of various services.

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PROJECT DESCRIPTION

Icon was contracted by HM Timbers to build a 15 000 square meter plywood factory including all required access, materials handling and service infrastructure. This challenging project required multidisciplinary works such as earthworks, steelworks, cladding and wet services. The substantial concrete works were undertaken by Icon and various subcontractors were managed to successfully complete the project. Key features of this project included:

• Augured piles 138 no.
• Reinforced concrete pile caps and ring beams 200 m³
• Structural steel (mill structure and machine bases) 480 tons
• Roof and wall cladding 19500 m²
• Structural concrete (buildings, steam vats, machine pits & bases) 1400 m³
• Surface beds, 200mm thick, including stabilized layer works 12300 m²
• Asphalt surfaced roads, including earthworks and layer works 8300 m²
• Interlocking cement block paving, including stabilized layer works 16800 m²
• Building works for offices, stores, ablutions, workshops, electrical substations
• Appurtenant stormwater drainage, kerbing and side drains
• Appurtenant water mains for potable supply and fire fighting
• Appurtenant gravity and rising sewers, holding tank and pumps
• The bulk earthworks to this green field site were awarded under a separate contract, which was delayed due to inclement weather resulting in about two months extension of time. The dismantling and shipping of the plywood factory machines, from Spain, and the mechanical contractors, from various European countries, could not be similarly delayed. As a result, the contracts overlapped and required a high level of coordination and cooperation by all parties.
• The civil contract coincided with a nationwide shortage of cement. This required further strategic planning and programming to avoid delays to the international mechanical contractors.
• The coordination of multiple specialist subcontractors necessitated a high level of management on the part of the main contractor and professional team.
• Various machine bases, pits and structures were constructed to suit the arrival of mechanical plant. Some of this work was done on an accelerated programme basis.
• A weighbridge, additional concrete hard standing and various other concrete works were constructed after the contract was substantially complete.

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