Brussels' only open-air swimming pool Flow remains closed due to bacteria woes
Outdoor swimming pool Flow in Anderlecht will remain closed for the time being. Bacteria levels in the water are still too high new tests reveal. "Once we have found the source of the bacteria, we can take the necessary action and reopen ASAP" the pool’s management says.
Flow depends on biological treatment of the pool’s water using plants and micro-organisms to clean the water, but the introduction of this new filtration system has not been without hiccups. Tests show the biological value of one of the three bacteria tested, Pseudomonas aeruginosa, is still too high, though it is still not clear why.
Bacteria in old pipes or refill water?
Flow has identified two possible explanations for the pollution: either bacteria were still present in equipment from last year that has now been reused, e.g. pipes. "In this case, proper cleaning of the existing equipment is necessary," organisers say.
The second (and most likely) explanation is that the bacteria entered the pool from an outside source, e.g. when the pool was refilled. The latest tests show significantly higher levels of bacteria at times when the water was refilled. "We are now investigating whether the problem is located in the pipes and hoses from the hydrant used by Flow, or whether the bacteria are already present in the fresh water that comes from the drinking water network."
As a precaution Flow is replacing the older hoses with new pipes this week to rule out that possibility. Initially, the possibility that the bacteria were in a malfunctioning part of the filtration system was also considered, but that option has since been ruled out.
Why not chlorine?
During the first two seasons, Flow relied on chlorine as a disinfectant. "Chemical water treatment with chlorine is the nuclear option. All kinds of bacteria (and other life in the water) are killed, regardless of where they originate" the pool management say.
Flow compares its use to the use of dangerous chemicals and points to higher energy requirements as a result of the need for more powerful pumps. "This is why we still believe that biological water treatment is the more sustainable and economical solution for the future."
On Wednesday 19 July, Flow will give an update on the situation.