What is the identity of the 96 million black balls that filled the Los Angeles Reservoir in the United States? It is easy to think that it is intended to prevent evaporation, but it is actually intended to contain more dangerous things.
According to a YouTube channel (Veritasium) accompanying the Los Angeles Waterworks Bureau, it is necessary to remove bromic acid, a carcinogen, by oxidation through sterilization ozone treatment. The problem is that if you look into the reservoir where water is stored after purification, the moment it flows to the place, the bromic acid is still 10 times the standard value. When a disinfectant is exposed to sunlight, it grows bromic acid, a carcinogen. This is why shading is necessary.
There is a problem that bird droppings can accumulate here, and the cost itself can be increased if logs are used. For this reason, a awning ball was put into the reservoir. It is said that it was possible to prevent carcinogens just by launching a black ball.
The reason this ball is black is because it has the highest shading effect. The same goes for durability. Other colors last only a year, but black is said to be more than 10 years in direct sunlight. As it is a food material, it is not harmful to the human body. After launching this ball, it is said that it is possible to reduce the amount of chlorine input by suppressing green algae. Of course, if the ball is too light, it may fly in the wind and splash on a nearby highway, so it is said that a little water was added to the inside to make it heavy.
The black ball is cool underneath, and the ball has the effect of insulating the cold air. In addition, since the wind does not blow, of course it reduces evaporation. It is said that the amount of evaporation decreased by 80-90% compared to before the ball was put in.
The cost is also 33 to 34 cents each. It is said that half the cost can be recovered as chlorine for disinfection and evaporation are reduced. Considering that carcinogens disappear, it can be said to be inexpensive. Related information can be found here.