Today AP had an interesting article on Rio De Janeiro's water quality leading up the olympics

In the USA, we often take clean water in rivers, lakes, and beaches as a given. However, even large bodies of water can become contaminated quickly with raw sewage entering the water. Besides the immediate potential for disease, the environment becomes less likely to support healthy animal and plant life. So what can be done to cleanup the water in Rio before the olympics? I would do suggest the following;

• Discover the main sources of raw sewage entering the bay
  
• Improve lift stations and sewer lines to bring raw sewage to the treatment plant
  
• At the treatment plant focus on getting good primary treatment and then treat the soluble organics in a biological treatment unit
  
• Ensure adequate disinfection of sewage treatment plant effluent
  
• The collection system can be used to initiate biological treatment by dosing waste degrading microbes upstream in the gravity mains.
  
• Use biofilters/vegetation to treat polluted storm water & sewage during rain events.
  

AP test: Rio Olympic water badly polluted, even far offshore RIO DE JANEIRO (AP) — Olympic sailor Erik Heil floated a novel idea to protect himself from the sewage-infested waters he and other athletes will compete in during next year's games: He'd wear plastic overalls and peel them off when he was safely past the contaminated waters nearest shore.

Heil, 26, was treated at a Berlin hospital for MRSA, a flesh-eating bacteria, shortly after sailing in an Olympic test event in Rio in August. But his strategy to avoid a repeat infection won't limit his risk.
A new round of testing by The Associated Press shows the city's Olympic waterways are as rife with pathogens far offshore as they are nearer land, where raw sewage flows into them from fetid rivers and storm drains. That means there is no dilution factor in the bay or lagoon where events will take place and no less risk to the health of athletes like sailors competing farther from the shore.

"Those virus levels are widespread. It's not just along the shoreline but it's elsewhere in the water, therefore it's going to increase the exposure of the people who come into contact with those waters," said Kristina Mena, an expert in waterborne viruses and an associate professor of public health at the University of Texas Health Science Center at Houston. "We're talking about an extreme environment, where the pollution is so high that exposure is imminent and the chance of infection very likely."

In July, the AP reported that its first round of tests showed disease-causing viruses directly linked to human sewage at levels up to 1.7 million times what would be considered highly alarming in the U.S. or Europe. Experts said athletes were competing in the viral equivalent of raw sewage and exposure to dangerous health risks almost certain.

The results sent shockwaves through the global athletic community, with sports officials pledging to do their own viral testing to ensure the waters were safe for competition in next year's games. Those promises took on further urgency in August, after pre-Olympic rowing and sailing events in Rio led to illnesses among athletes nearly double the acceptable limit in the U.S. for swimmers in recreational waters.