During the periodic shutdown of part of its plant, our client contacted CTP environnement for the complete cleaning of facilities in which the method used could no longer be sustained because of changes to regulations.

As a result, CTP environnement proposed a solution, which involved carrying out the following two distinct operations:

• Internal cleaning of four 15 m x 15 m (49 ft x 49 ft) cells including mist separators, walls, ramps, nozzles, etc. and cleaning of the lower sections (packing, pillars and walls)
• Scraping, drying and cleaning the cold water (1 435 m³or 15 763 ft²) and hot water (396 m³ or 4261 ft²) tanks, and dewatering the sludge extracted.

CTP environnement provided the human and physical resources needed to fulfil the client’s requirements, especially in terms of schedule. Three teams of seven people worked on site for four days. Some team members were entrusted with cleaning the cells (internal and lower sections) while others worked in clearing and drying the two tanks:

• Cold water tank: two backhoe loaders were used to quickly and effectively scrape away the sludge in the bottom. The use of hydro-jet cleaning trucks allowed deadlines to be met, despite the presence of significant leaks.
• Hot water tank: cleaning was all carried out manually, using shovels, buckets and big bags.
• Dewatering using a geotextile membrane: not performed because the effluent was eventually too light to implement such method.

Excellent cooperation and responsive communication between the various people involved allowed this service to be provided by the deadline with satisfactory results. This trial project was successfully repeated two years later on another unit’s cooling tower where sludge dewatering using a geotextile membrane was a huge success.