Detailed Engineering for the Civil Works for BOTNIA, New Pulp Mill in Fray Bentos, Uruguay

Client: Jaakko Pöyry - Kakko Oy para BOTNIA
Industry & Construction
Civil Engineering, Transportation Engineering, Structural Engineering, Mechanical, Electrical and Plumbing Engineering (MEP)

CSI Ingenieros was hired to carry out the detailed structure and infrastructure engineering of a bleached
eucalyptus pulp mill, located in a greenfield of 104 hectares in the outskirts of the city of Fray Bentos, Río
Negro, Uruguay. The production capacity of the plant is 1 million tons per year. Total investment: 1.1 billion US$
Plant equipped with the best worldwide available technology (BAT).

Proect Scope

- Detailed structure and infrastructure engineering for the civil works of BOTNIA Pulp Mill, in Fray
- Detailed engineering of the road management and transport for the main access and internal roads
of the industrial plant area and its paving.
- Design of the underground pipe networks for stormwater and processes.
- Detailed engineering of the following areas:
- Design and calculation of the reinforced concrete structure for a water treatment plant to collect water from Río Uruguay, and use it later in the cellulose pulp production processes. This treatment plant was designed to have a production capacity of 1,720 l/s as well as a waterfall, sand filters, filtered and raw water tanks, sludge thickeners, pump rooms and cooling towers. The plant’s total area is 8,000 m2 and the total volume of the concrete used is 11,000 m³.
- Design and calculation of reinforced and prestressed concrete structures for an industrial wastewater treatment plant in the process of the eucalyptus pulp mill production, before its final disposal into Río Uruguay. This treatment plant has a primary clarifier tank of 46 m in diameter and 5.2 high; three equalization and homogenization tanks of 120 m long, 40 m wide and 7.3 m high; two secondary clarifier tanks of 65 m in diameter and 5.4 m high; two aeration tanks of 190 m long, 42 m wide and 10 m high, and a set of cooling towers. The total area of the plant is of 400,000 m², and the
total volume of the concrete used is 39,000 m³.
- Design and calculation of reinforced concrete structure for the main building, comprised of five levels, where the offices of Botnia, Andritz and Kemira are located as well as the plant control room, the chemical analysis laboratory, the auditorium, the plant’s personnel restaurant and a room of valuable objects. Also, design and calculation of reinforced concrecte structure for the buildings that are part of the access: customs, weighing and scale rooms. The total area of the main building is of 10,000 m² and the total volume of the concrete used is 4,700 m³.
- Design and calculation of a mixed structure of reinforced cast-in-place concrete, precast
concrete and a steel roof for the mainteinance building. It consists of different maintenance workshops
for the plant equipments, material warehouses, fire station and electrification and automation workshops.
The total area of the mainteinance building is of 4,800 m² and the total volume built is 8,000 m³.