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  • Waste Water Treatment Plants (WWTP)
  • Drinking Water Treatment Plants (DWTP)
  • Water Catchment Plants
  • High Capacity Urban Sewerages

The Environment engineering division focuses on maintenance and rehabilitation projects in water and waste water plants and large sewerages.

The rehabilitation works aim at requalifying the concrete structures through structural interventions and specialised repairs.

The most frequent concrete structures in water and waste water plants are completely-buried, half-buried and above-ground tanks, caissons and pumping stations. The main elements of a large sewerage are of different types: besides the manholes and pumping stations, large sewerages are made of rectangular, circular or ovoid structures in precast concrete. The common denominator of all these concrete structures is the need to waterproof reinforce, rehabilitate and re-operationalise.

Main phases of the rehabilitation works

Part of the preparatory works, the first phase is to empty the concrete tanks (sludge digesters, primary and secondary clarifiers, gravity thickeners, pumping stations, caissons, desilting and grease separator units etc) with high capacity submersible or motor-driven pumps (usually from 2 to 5 m3/min) and deposit the sludge on platforms for drainage and dehidration. In the case of sewerages, the prerequisite of any rehabilitation works is to isolate the segment under repairs from the rest of the network. This is done by sealing off the inlet and outlet either with reinforced concrete slabs or with inflatable rubber balloons.

The second phase consists of waterblasting at minimum 860 bar or sandblasting at 500 bar all the concrete surfaces to remove the degraded plaster/rendering and reveal the cracks and other possible structural problems.

The rehabilitation work start after a technical expertise is drafted (the third phase), that evaluates the functional and safety necessities of the constructions that need rehabilitation and modernisation and that identifies specific solutions (procedures, materials and equipment) to eliminate the causes of the degradations. Most often, the degradations in concrete structures are of a structural nature.

The fourth and most important phase consists of the rehabilitation an modernisation works (according to SR EN 1504 for concretes), that may include an entire range of procedures, according to the conclusions of the technical expertise: mechanical or manual scrapings, hydro-demolition, passivation and anti-corrosion treatment of metal works and reinforcement bars, replacement of deteriorated reinforcements through chemical anchoring, application of fiber and composite materials (glass, carbon or metal fibers in woven, bar or sheet/blade products), waterproofing with rigid or flexible anticorrosive cements, polyurea and other specific materials, injection of epoxy, polyurethane or acrylic resins etc.

When dealing with concrete tanks of any type, the rehabilitation works conclude with a wattertightness test.

Recently implemented projects: