The Pueblo Viejo mine is one of the largest gold mines in the world. The mine is located in the south of the country in Azua Province. The mine has estimated reserves of 25.3 million oz of gold and 120 million oz of silver.

Napier-Reid provided a demineralized water treatment system to treat surface water with the peak flow rate of 240 m3/day for industrial usage. The water treatment system includes multimedia filters, polymer feed system, packed bed cation column, packed bed anion column, sulphuric acid regeneration system, and caustic regeneration system. Napier-Reid supplied all the pressure vessels and pipes. All the vessels were designed, fabricated and tested as per ASME codes.

Feed water is pretreated with polymer to produce flocs of suspended solids, water then flows into two parallel multimedia filters equipped with two common air-scour blowers (one duty and one standby). Each filter performs in down flow filtration all controlled by a PLC system. Filtered water from storage tank is used to backwash filters.

Filtered water then enters demineralization system to produce demineralized water, which finally flows to a storage tank.