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Table 4 Cha rac teristics of water treatment utility in the lower catchment part of the Guapi-Macacu watershed in 2011

From: Priority areas for watershed service conservation in the Guapi-Macacu region of Rio de Janeiro, Atlantic Forest, Brazil

Treatment unit: Laranjal - CEDAE

Municipality: São Gonçalo

Captivation area from the GMW

1,263 km2

Forest cover in the watershed


Treatment type


General treatment phases

Captivation, sedimentation, coagulation, flocculation, decantation, filtration, disinfection, water fluoridation and pH correction

Treated water flow

Average flow in 2011, 5.35 m3 s-1

Population supplied with treated water

2,000,000 inhabitants

General chemical products used

Aluminium sulphate Al2(SO4)3, polyelectrolyte, hexafluorosilicic acid H2SIF6, chlorine, calcium oxide CaO

Costs with chemical products for the treatment of raw water

2.31 × 106 BRL (year 2011)

Turbidity of raw water, average values

17.10 NTU

Treated water characteristics

Colour, 2.50 uH

Turbidity, 0.34 NTU

Total costs with chemical products and electricity in a year for the water treatment unit

For the treatment of 6 m3 s-1,

• 300,000 [BRL] (monthly expenditure for chemical products)

• 100,000 [BRL] (monthly expenditure for electricity in the captivation and production area within the unit)