AWWA-64376 Lime Softening Techniques for Operators DVD


Lime Softening Techniques for Operators DVD illustrates and explains the lime-softening chemistry, processes, and feed rate calculations.

Hard water (water with elevated levels of primarily calcium and magnesium) is commonly softened using the chemical lime. Produced specifically for water treatment operator training, this new video illustrates and explains lime softening processes, chemistry, and feed calculations.Water treatment operators benefit from watching this DVD by better understanding what hard water is, the problems it causes in the distribution system and for consumers, and how and why lime softening reduces hardness. Importantly, operators learn how to precisely calculate lime and soda ash dosages for removing hardness.

What the video covers:
• The video shows softening equipment and facilities, including lime silos, dry feeders, lime slakers, accelators (lime treatment units), and launders. Operators learn where the softening process fits into the water treatment train.
• The video explains what types of contaminants are removed from water during lime softening, what chemicals are used for softening, and the importance of pH in the softening process.
• Most of the video concentrates on the chemical reactions taking place during softening, how to calculate lime and soda ash dosages, and the resulting water quality after softening. The video presents two methods of dosage calculation: a conventional method and one using milliequivalent diagrams.
• The program presents typical operational problems created by lime softening, and offers solutions. The video briefly discusses the pros and cons of two other hardness removing techniques: spiractors and sodium hydroxide. Rounding out this practical program are the safe handling of lime and soda ash, the disposal of residuals and sludge, and recordkeeping. (48 minutes)

ISBN: 9781583218679

Publisher: American Water Works Association

Publication date: 2012

AWWA catalog no: 64376

Media Type: DVD