How to Kill Bacteria in Lake Water

Although you may be deceived into thinking that lake water is pristine, looks can be deceiving. Lurking in the water are bacteria such as giardia and cryptosporidium, both of which cause diarrhea, fatigue and cramping if you drink the water. Lake water requires a healthy balance of both good and bad bacteria. When the bad bacteria levels become too high as a result of algae growth, extreme weather such as drought, flooding or pollution, then it becomes necessary to treat the water and restore it to a healthy balance. However, restoring the lake water may mean you can use it for recreational purposes such as swimming but not necessarily drinking. The good news is there are ways to kill the bacteria and make the lake water drinkable.

Things You'll Need

• Pot
• Stove or open fire
• Containers
• Household chlorine bleach
• Measuring utensils
• Algae control treatment system, such as ultrasonic algae control device

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Instructions

• 1

  Boil a sample of lake water. This will kill most types of bacteria and disease-bearing organisms that can make you ill. Filter any cloudy water through clean cloths and let it settle. Draw off clean water and boil for one minute. Cool it and store in sterile, clean containers.

• 2

  Add household bleach. Bleach will kill some, but not all, types of bacteria. Again filter cloudy water and draw off the clear water for disinfecting. Add 1/8 teaspoon (or 8 drops) of liquid household bleach for each gallon of water (or two drops per liter). Stir and let it stand for 30 minutes before you use it. Store disinfected water in clean containers with covers. If the strength of the bleach is unknown, add 10 drops per quart or liter of settled water. If the water is murky or extremely cold, double the amount. If after the 30 minutes you drink it and you don't taste chlorine, you should treat it again.

• 3

  Eliminate the algae. Algae can saturate lake water and cause a bloom, which results in an oily scum forming over the water surface and causes toxicity to the water system. A particularly toxic algae is the cyanobacterial or blue-green algae. It can kill fish and waterfowl and sicken humans by causing skin rashes, hives and throat irritations. Long-term exposure has been found to cause liver tumors in a few animals. According to the U.S. Environmental Protection Agency, water treatment techniques for algae overgrowth can be 100 percent effective. A few that work in combating algae are sedimentation, filtration, disinfection, ozonation and ultraviolet radiation.

• 4

  Ultrasonic algae elimination systems are an underwater, chemical-free way to eliminate algae. The method works by emitting ultrasonic waves. The device is installed and floats underwater. Using the ultrasonic method can eliminate many common algae, including the toxic blue-green algae, without harming the surrounding environment.