Good practice

Significant savings through closed water cycles

Significant savings through closed water cycles
© Juhku, #78261659, 2019, source:
All manufacturing industries
High cost
Resource savings: Energy:
The heat recovered (equivalent of 250 single-family homes) is used in the heating network
Resource savings: Water:
The first project (in 2016) reduced water use by more than 30 % when the cooling water circuit of the acid concentration plant was closed; fter that, Nammo cut its water consumption by nearly half compared to the 2015 level
Associated cost savings: Water:
30 - 50%
Return on investment:
The project has been implemented as a contract service instead of self-financing the investment
Size of company:
Medium (less than 250)
Advancement in applying resource efficiency measures:

Better by half...

  • With water becoming scarce, company looks for new water-saving solutions
  • Closed cycle solution for cooling-heating keeps the water in the system

Nammo is an international aerospace and defence company. Their propellant plant is located in Vihtavuori, Finland. The plant has used water from a nearby lake for cooling, and a few years ago, they were facing a water risk as the lake water level started to drop. Nammo started to develop their water efficiency in order to reduce water consumption and protect the lake and increase its water level again.

Nammo has implemented two closed water projects with Adven, an energy and water service provider that operates in Nordic and Baltic countries. In the propellant plant, cooling water is needed in various stages of the project. Previously, the substantial volumes of cooling water used were released back into the lake.

In the first project, an acid enrichment plant’s cooling water cycle was closed, and the second project, implemented in spring 2019, closes the ether plant cooling water cycle. Together, water savings related to these to projects cut Nammos water consumption to less than half compared to the 2015 level. Closing the water cycles means there is no need to take new water from the lake, as the water is cooled between stages and the heat from it recovered.

The heat recovered, an amount corresponding to the energy consumption of 250 single-family homes, is used in the heating network of the area.

Key benefits

  • Closing water cycles cut the plants water consumption to less than half
  • Substantial energy savings are also associated with heat recovery from the closed water cycle
  • Heat recovered from the used cooling water is used in the heating network of the area
  • A propellant plant closes its cooling water cycles to protect the nearby lake and reduce water consumption

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