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How to Use Lime in Waste Water Treatment Plants

One of the most common ingredients in all waste water treatment processes is lime, which is used to raise the pH level of sludge, improve its odor and kill pathogens. Lime is most often administered through a large silo-like machine called a doser that stores and disperses lime into a water source at given intervals. Dosers are the easiest and most effective way to use lime regularly in waste water treatment.

Things You'll Need

Powdered lime
Mechanical doser

Instructions

- 1
  Add powdered lime into the sludge mixture using a metered doser to be sure the proper amount is used. Metered dosers exist in all waste water treatment plants and can be bought by consumers to dose private lakes, streams or rivers.
- 2
  Watch the meter on the doser carefully, as a 5 percent lime-to-sludge mixture is desired. This amount will eliminate most pathogens in the water and reduce sludge odor without making the water toxic.
- 3
  Keep the doser's lime supply stocked at all times. Some machines dose small amounts of lime every five minutes; others dose large amounts only once an hour. Regardless, dosers are only effective if they continue to dose the water flowing through.
- 4
  Test the lime-dosed water regularly to be sure the doser is working properly and the sludge contains the correct proportions of lime. If the doser is adding too much or too little lime to the sludge, it may need to be recalibrated.

Nature