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Reducing Chloride in the Wastewater Stream

Kinetico Water Softener

One of the roles I play in society is secretary of the Macbride Sanitary Sewer District, a public entity that manages wastewater treatment for our group of  about 84 homes. I recently spent time writing a questionnaire about water softener usage and tabulating the results from a user survey. The report I sent to members this month has broader application so I’m publishing it here for my WordPress community. Your feedback would be welcome.

Thanks to the 66 home owners who submitted a survey on home water softener use. Before discussing the survey results, you may be wondering why we are working to reduce chloride in our wastewater. Short answer: the rules changed after our previous NPDES permit expired. Our new one, issued May 1, 2017, has new requirements for chloride and other elements. Here is some information about the new standard from the Iowa Department of Natural Resources which manages NPDES permits for the U.S. Environmental Protection Agency:

Iowa adopted water quality standards for chloride and sulfate in November 2009. These two new standards replaced the previous water quality standard for total dissolved solids. “Total dissolved solids” is a measure of all chemical elements that have become dissolved in water. It includes chloride, sulfate, nitrate, sodium, potassium, and magnesium, among other chemicals. The total dissolved solids standard was designed to protect aquatic life from toxic conditions caused by these chemicals. However, research by DNR showed that in Iowa waters, chloride and sulfate are more accurate predictors of toxicity to aquatic life than the combined measurement of total dissolved solids. DNR thus undertook to replace the water quality standard for total dissolved solids with specific standards for chloride and sulfate.

Of the people who responded to our survey, 31 use a timed-cycle water softener, 30 use on demand-initiated cycling, and 5 didn’t know.

Reported annual salt usage ranged from zero to 2,000 pounds. 20 homes used less than 250 pounds, 21 between 251 and 480, 15 used more than 480 pounds, and ten didn’t know.

A couple of things are clear from the data: 1. Many people don’t think much about their water softener or keep records about how much salt they use. One 40-pound bag per month is 480 per year and several people used that as an estimate; 2. We use a wide variety of brands of water softeners. Kinetico was most popular. There are a half dozen others; 3. Most families installed their softener and seldom had maintenance done on it; 4. The three most popular plumbers were Water Conditioning Systems (Kinetico), Affordable Soft Water, and Neal’s Water Conditioning; and 5. Most homes have a separate line to run untreated water outside for lawn, garden and cleaning.

What should home owners do regarding salt use?

  1. Contact a plumber to have your water tested for hardness and your water softener checked for proper functioning and adjustment. Have the plumber program your softener to a low-salt setting appropriate for the water hardness in your home.
  2. If you plan to replace your water softener, get one that cycles based on demand rather than on a timer. This will ensure all the water used is properly softened and save salt if your usage is lower.
  3. Install high-efficiency water fixtures, like low-flow shower heads, to reduce your home’s soft water use.
  4. Have a plumber disconnect water that doesn’t need to be soft, like toilets and lines to outdoors, from the water softener.
  5. If your household is using more than 480 pounds of salt annually look at replacing your water softener to take advantage of new technology and use less salt. A new Kinetico softener will use about 250 pounds of salt annually for a household with two people.
  6. Water is not an unlimited resource so develop creative ways to conserve water at home, such as taking shorter showers, running only full loads in the dishwasher and clothes washer, and turn the faucet off when taking care of personal hygiene or doing dishes — break the bad habit of letting it run. Consider getting EPA WaterSense-certified toilets which use less water for flushing.

At this time the Macbride Sanitary Sewer District is not considering a mandated salt reduction program. We are to be in compliance with the new chloride standard by April 1, 2022, and if voluntary efforts produce the desired results, that will be that. If we don’t meet standards, the board of trustees will revisit the issue of more specific requirements.