In the basements of the UMCG at the Healthy Ageing Campus three large reservoirs are being installed to capture rainwater. It is estimated that with these reservoirs, UMCG will be able to collect and reuse an average of about thirty million liters of water annually. The first reservoir is complete, with the second and third planned for 2025 and 2028, respectively.
A large organization like UMCG uses approximately 200 million liters of water annually. This water is used for drinking and washing, as well as for cooling equipment and spaces via cooling towers and machines, which account for about fifteen percent of UMCG's total water consumption.
Millions of liters in water savings
According to Bas Alblas, a technical policy advisor, these three large water reservoirs will save about fifteen percent of UMCG's total water consumption by capturing rainwater. "UMCG has a roof area of 38,065 m². Based on 2023 figures - a wet year - over 38 million liters of rainwater fell on our roof. In a dry year like 2018, we still capture about 23.5 million liters. This is a rough estimate, not accounting for evaporation, but with these amounts of rainwater, we can save about ten to fifteen percent on our drinking water usage."
Alblas explains how the water flows from the roof through pipes into UMCG's basements. Earlier this year, the first space was converted into a reservoir with a capacity of 110 m³. Additional spaces, with capacities of 90 m³ and 200 m³, will follow in 2025 and 2028.
Basement spaces as reservoirs
With these additions, the UMCG will have three reservoirs with a total capacity of 400 m³ of rainwater. No other hospital has such a large in-house water storage, Alblas believes. "We are fortunate to have these spaces available, requiring minimal construction to prepare them for water storage. Building large tanks or reservoirs for water storage is very costly."
The first reservoir is a sunken basement where a cooling machine was previously located; this machine has now been replaced. The other two reservoirs are also basement spaces that will become available as machines are replaced. "I expect that all the water we capture will be used for the cooling towers, but other applications are also possible."
Flushing toilets with rainwater
Once all the reservoirs are operational in 2028, UMCG will have made significant progress toward meeting the goals set in the National Drinking Water Saving Plan: large consumers like UMCG must reduce their annual water consumption by twenty percent by 2035 compared to the period 2016-2019. "But we are doing more," Alblas adds. "We are critically evaluating the number of taps in UMCG. The best approach is to have as few taps as possible that are used as efficiently as possible. This prevents the need to flush unused points to prevent legionella and other infections. We are also considering the water efficiency of new equipment purchases."
There may be more places in the future where rainwater can be captured: a lot of construction is happening on the UMCG site. In the new educational building, the Anda Kerkhoven Centre, two reservoirs of 20 m³ will be installed to capture rainwater. This water will be used to flush toilets.
Water conservation is part of UMCG's ambitious goals to be circular and climate-neutral by 2035.
Author: UMCG, Lex Kloosterman
