A plan to filter bacteria from the water around Odaiba Beach Park in Tokyo Bay was announced Friday by 2020 Olympic and Paralympic organizers and the Tokyo Metropolitan Government.
Tests performed in July and August confirmed that polyester screens can contain the flow of contaminants such as E. coli bacteria. Organizers envision a three-layer screen to protect water quality at the location, where a portion of the triathlon and other open-water competitions will be held.
Over a 22-day test this summer, water quality met standards set by the international federations that will sanction events there. But while water quality was maintained, the filter barrier prevented the natural flow of water and temperatures frequently rose above federation-set limits. Organizers are now looking into ways to circulate the water to keep temperatures at acceptable levels.
Another downside to the plan is cost: Installing and removing the barrier for testing cost ¥75 million ($657,000).
This summer when water was tested without the screens installed, E. coli levels exceeded the International Triathlon Union's standards on 13 days during a 27-day period. Unacceptable water-quality readings coincided with passing typhoons, with one day's reading more than 140 times the ITU's acceptable limit.
According to Tokyo government officials, when rainfall exceeds the capacity of sewage facilities, sewage diluted with rain water may be released into the bay, leading to poor water-quality readings.
"We will be diligent in applying countermeasures to ensure safety," said Hidemasa Nakamura, delivery officer for the 2020 Games.