Water Softening with Potassium Chloride: Process, Health, and Environmental Benefits
1 WHAT IS POTASSIUM CHLORIDE?
Saskatchewan Potash History.
Processing Potash Ore.
Storage, Transportation, and Distribution of Potash.
2 WHAT IS HARD WATER?
Definition of Hard Water.
How Hard Water is Created.
Problems Associated With Hard Water.
How Hard Water is Measured.
Uniform Degrees of Hardness.
Types of Hardness.
3 LOWERING WATER HARDNESS.
Deionization or Demineralization.
4 THE ION EXCHANGE PROCESS.
Synthesis and Structure of Ion Exchange Resins.
Types of Ion Exchange Resins.
Household Water Softening.
Typical Household Water Softening.
Cocurrent and Countercurrent Regeneration.
Mathematical Treatment of Ion Exchange Equilibria.
Selectivity of Ion Exchange Reactions.
5 BASIC CHEMISTRY OF ION EXCHANGE.
The Building Blocks of Matter.
Atomic and Molecular Weights.
Cations and Anions.
6 OPERATION AND TYPES OF WATER SOFTENERS.
Historical Methods of Regeneration.
Operation of a Typical Water Softener.
Common Sequences of Cycles.
Types of Water Softeners.
Sizing a Water Softener.
7 POTASSIUM CHLORIDE REGENERANT FOR WATER SOFTENING.
Potassium Chloride Regenerant.
Initial Comparison of KCl and NaCl.
Challenges When Using KCl as a Regenerant.
Frequently Asked Questions.
8 COMPARISON OF KC1 AND NaCl AS REGENERANT.
Definition of Terms.
Theoretical Capacities of KCl and NaCl Regenerants.
Calculation of Regeneration Efficiency.
Sizing a Softener for Salt Efficiency.
Implications for Salt Consumption.
Total Salt Released to the Environment.
Comparison of KCl and NaCl: Solubility.
Comparison of KCl and NaCl: Speed of Dissolution.
Comparison of KCl and NaCl: Capacity.
Comparison of KCl and NaCl: Used and Unused Regenerant.
Comparison of KCl and NaCl: Release of Chlorides to the Environment.
Comparison of KCl and NaCl: Taste.
Comparison of KCl and NaCl: Generation of Fines.
Comparison of KCl and NaCl: Sodium Content of Softened Water.
Comparison of KCl and NaCl: Potassium Content of Softened Water.
Comparison of KCl and NaCl: Total Dissolved Solids.
9 ENVIRONMENTAL CONSIDERATIONS.
Potassium versus Sodium: Impact on Soil.
Potassium versus Sodium: Impact on Septic Systems.
Potassium versus Sodium: Impact on Sewage Treatment Systems.
Potassium versus Sodium: Sewage Sludge.
Potassium versus Sodium: Algae Growth.
Potassium versus Sodium: Impact on Plants and Animals.
Potassium versus Sodium: Use of Recycled Graywater.
Recycling Regenerant Wastewater.
Use of Regenerant Wastewater Studies at University of California, Davis.
10 POTASSIUM AND HUMAN HEALTH.
Cellular Physiology of Potassium.
Defects in Potassium Elimination.
Medical Conditions Related to Potassium Excess.
Medical Conditions Related to Potassium Deficit.
Indirect Role of Potassium in Health.
11 ONGOING RESEARCH.
Iron and Manganese Removal.
Grade of KCl Regenerant.
Cocurrent versus Countercurrent Regeneration.
Portable Exchange Tanks.
Research into Alternate Regenerants.
APPENDIX 1 STANDARD TEST PROTOCOL FOR COMPARISON OF KCl AND NaCl REGENERANTS.
Standard Test Protocol.
APPENDIX 2 LABORATORY DATA OBTAINED WITH THE STANDARD TEST PROTOCOL.
APPENDIX 3 ACCELERATED MUSH TEST.
JAY H. LEHR holds a PhD in environmental science from the University of Arizona and an engineering degree from Princeton University. He is the author of twenty-eight books and over 600 journal and magazine articles. He has taught at the University of Arizona and The Ohio State University, directed a professional society of environmental scientists, and formed a variety of environmental teaching and consulting firms.
ROD McEACHERN holds a PhD in chemistry from the University of Saskatchewan. He currently works as the Director of R&D with the Potash Corporation of Saskatchewan Inc. in Saskatoon, Canada. His research interests include the application of new technology to environmental stewardship through improved air pollution abatement equipment, improved waste management practices, and process improvements to potash operations.