ARCHIVES

ARCHIVES

NCSD moves to control salts

By Mike Hodgson/Associate Editor

Nipomo Community Services District is working on a plan to reduce the amount of salts being discharged from its sewage treatment plants by eliminating salt-based water softeners.

The plan also will rely on importing supplemental water from Santa Maria, which will have a lower salts content than the supplies currently being used by the district.

NCSD directors recently authorized the staff to begin working on a plan after being put on notice by the Central Coast Regional Water Quality Control Board that effluent discharges from both the Southland and Blacklake treatment plants exceeded allowable salts levels.

“(The board) advised very strongly that we bring it under control,” NCSD General Manager Bruce Buel told directors. “Future mandates will be more stringent.”

Mike Nunley of Boyle Engineering told the board it has four options for reducing the salts load in treated effluent. Those are treating water supplies, treating the effluent, reducing self-regenerative water softeners and importing supplemental water.

Because of the costs of treating water supplies and effluent, including the difficulty of disposing of the brine that’s produced, Nunley said reducing the number of self-regenerative water softeners — which use salt — and importing supplemental water will be the most cost-effective.

The goal will be to entice homeowners to replace those water softeners with cannister-type softeners that are provided by water-softener service companies and replaced every month or so.

In a report to the board, Nunley noted that a household of three people using a self-regenerating water softener would add an average of 1.79 pounds of salts per day to the wastewater stream.

However, he said, the same three people using a cannister-type water softener would only add about 0.08 of a pound of salts per day.

The salts found in NCSD water include positively charged ions of calcium, magnesium, sodium and potassium and negatively charged ions of sufates, carbonates, phosphates and chlorides.

Due to the recent failure of a proposed state law mandating the removal of salt-based water softeners, it will be difficult for the district to mandate their removal, Buel said.

Homeowners are not likely to remove them voluntarily because it generally costs more for private businesses to provide softening services than to buy and operate the self-regenerative softeners, he said.

But Buel noted homeowners might be persuaded to remove them if the district provides such financial incentives as rebates. A public education program explaining the need and possible regulatory consequences also might help.

Legal counsel Jon Seitz said NCSD can also adopt regulations prohibiting the installation of new self-regenerative softeners, which can be noted when the district issues water service intent-to-serve and will-serve letters for new developments.

Although Nunley estimated the Blacklake community might have 40 to 80 self-regenerative water softeners, Blacklake residents said the number was more likely somewhere between five and 24.

“The conclusion that we can control our salts by eliminating the remaining few (self-regenerating water softeners) is not supported by the data,” said Blacklake resident Bill Petrick.

“Another interpretation of the data would suggest that our salts problem is a direct result of the merger of the Town (Division) water with the Blacklake (Division) water back in October 2006.”

But board President Mike Winn said the problem existed before the district began pumping water from the Town Division to the Blacklake Division system through an intertie pipeline.

BY THE NUMBERS:

1.79 — Pounds of salt added to wastewater by household of 3 with self-regenerative water softener.

mhodgson@theadobepress.com