Moisture is one of the biggest challenges in water and wastewater installations. If not properly managed, it can cause corrosion, mold growth and other moisture-related damage. If not managed properly, it can also lead to unnecessarily high energy consumption. Here we share insights and solutions to optimize moisture management and minimize risks.
What is moisture and why is it a problem?
The amount of moisture in air is measured using two metrics: relative humidity (RH) and absolute humidity (AH).
- Relative humidity indicates how much water the air can hold at a given temperature.
- Absolute humidity is measured in grams of water per cubic meter of air and describes the actual amount of water in the air.
As air cools, its ability to hold water vapor decreases, which can lead to condensation on cold surfaces. This is a common cause of corrosion and mold in humid environments such as pressure risers, pipe galleries and reservoirs.
Typical challenges in moisture management
In water and wastewater installations, there are several factors that make moisture management particularly challenging:
- Cold pipes and surfaces: Condensation forms easily on cold pipes, which can lead to corrosion and electronic damage.
- Underground installations: Moisture levels are often high in caverns and other spaces below ground level.
- Open water surfaces: Evaporation from open water surfaces can increase humidity and contribute to corrosion and mold growth.
- Ventilation and temperature control: Ventilation is often used to regulate humidity levels, but this can be ineffective if it is not adapted to the seasons.
Solutions for better moisture management
To avoid damage and inefficient energy use, the following measures are recommended:
- Keep the relative humidity below 55%: This reduces the risk of corrosion and mold.
- Use dehumidifiers instead of heating: Studies show that energy consumption can be reduced by up to five times by using dehumidifiers instead of heating to control the indoor climate.
- Take into account temperature and humidity variations throughout the year: in winter, the air is naturally drier outdoors, while in summer it may contain more moisture (even if it feels dry).
- Optimize ventilation: Improper ventilation can lead to the introduction of moist air, which can increase indoor relative humidity levels to inappropriate levels.
- Use the Mollier chart to analyze moisture load: This tool helps to understand how moisture levels are affected by temperature changes and can be used when planning moisture management measures.
Major energy savings and reduced climate impact
Many municipalities have ambitious climate targets, and by optimizing moisture management, large energy savings can be made. An analysis of pumping stations showed that energy costs can be reduced by SEK 7,000-10,000 per station per year by switching from heating to dehumidification. For municipalities with many pumping stations, this can mean both economic and environmental benefits.
Moisture management in water and wastewater installations is an important factor in avoiding corrosion, mold growth and unnecessarily high energy consumption. By using modern dehumidifiers, adapting ventilation and monitoring moisture levels, significant savings can be made - both financially and from a climate perspective.