About Salinity

About Salinity

What is Salinity?
Salinity is the presence of inorganic ions or compounds dissolved in water or soil.  The most common ions in water are sodium, chloride, calcium, magnesium, carbonate, bicarbonate, sulfate and nitrate, which we commonly refers as salts.

Why is salinity a challenge?
Salinity is a silent threat of enormous proportions.  Historically, salt has led to the fall of civilizations. If not properly addressed, salinity will impact our future water resources, resulting in the requirement of costly treatment processes before water can be used for human, agricultural or industrial consumption.  Solutions for this issue in the Central Valley depend on the development and implementation of effective land use and water supply policies.  Raising awareness of this issue and researching solutions is a must.

How do we measure salts?
An easy way to determine the amount of salts in water is to measure its electrical conductivity (EC), which is the ability of a liquid to carry an electrical current.  This ability depends on the presence of free ions.  The higher the amount of salts in a liquid or soil, the higher the EC level.  Another way to determine the amount of salts in water is to measure the total dissolved solids (TDS), which measures the dissolved portion of solids in water, including volatile and non-volatile compounds.

What causes salinity?
There are several causes of salinity:

• Natural occurrence: Salinity occurs naturally from saline springs, erosion of saline geological formations, native runoff or weathering of rock minerals.
• Irrigated agriculture: Salts concentrate in irrigated soils through the process of evaporation.  Further irrigation of the same soil leaches salt into the ground, creeks or rivers.
• Confined animal facilities: Salts concentrate in disposal lagoons or soils where evaporation and percolation occurs.
• Land discharge processes:  Salts concentrate in land where disposal of industrial processing waste occurs.
• Urban Contribution:  Salts are a result of using any type of chemicals for daily household, commercial or industrial sanitation.  Common everyday activities such as washing hands with soaps, doing laundry, sanitizing commercial buildings or rinsing a processed product can add salt to the wastewater discharge of each household, commercial business or industrial business.

Impact and Management of Salinity

What is the impact of salinity on the community?
Salinity has several impacts:

• Salinity threatens water resources and supply.  Excess salts can accumulate in surface water and groundwater, resulting in water that is not suitable for consumption or agricultural uses.
• Decreases crop yield.  Salty water results in a decline of agricultural productivity related to saline soils which, in high concentrations, could be toxic to certain plants or could restrict the plant’s uptake of nutrients.
• Limits beneficial uses.  Salts pass through conventional wastewater treatment systems.  Excessive salts in recycled water limits re-use opportunities.
• Adds costs to utilities and threatens economic growth.  Increasing costs for treatment of salts in water and wastewater could be passed on to the customer, resulting in added costs and economic hardship for the entire community.
• Shorten life of appliances.  Salt deposits caused by excessive ions in water (hard water) could shorten the life of appliances such as water heaters, coffee makers or water fixtures such as faucets, shower heads and water pipes.

How can we manage salts?
There is not one common solution.  Wastewater treatment facilities cannot economically treat salts from urban contribution.  If we don’t act today, salts will continue to accumulate in our water basin and will make our future water supply unsuitable for human or agricultural consumption.  Public education will raise awareness of the problem.  Research funding is necessary for the development of interim and long-term solutions.

Ways to Help

What can we do to help?

• Conservation is key.  The less water you use, the less you put down the drain.
• Choose liquid over powder detergents.  Fillers in powder detergents add unnecessary salts to the wastewater produced from laundering clothes.
• Use the minimum amount needed of household cleaning products.  Read the product’s instructions and avoid excess application of household or personal cleaning products when possible.
• Choose dryer sheets over liquid fabric softeners.  Avoid adding additional salts to the water used on your laundry by using dryer sheets, rather than liquid fabric softeners.
• Choose mopping pads instead of a mop and bucket of water.  Sweep floors and use dry use products in order to use as little water as possible while cleaning floors.
• Use organic compost instead of chemical fertilizers.  Organic compost releases nutrients into the ground slowly, requiring fewer applications each year.  Chemical fertilizers leach into the ground quicker.
• Disconnect self-regenerating salt-based water softeners at your home.  Salt-based water softeners seem to take care of hard water problems at your home, but they cause a different problem once water goes down the drain.  Salty water from the regeneration of these appliances is discharged into the sewer.  Salt cannot be removed using conventional treatment at the wastewater treatment plant, passing through and making its way into the soil, groundwater, or surface water.

Why do you recommend disconnecting salt-based water softeners?
The most common and least expensive water treatment systems are salt-based water softeners.  They are commonly used to avoid water spots or scale on pipes and water heaters caused by the excess of minerals in water (salts).  Brine (water and common salt) is used to recharge the resin that catches all the undesirable ions that causes the water spots.  The brine is discharged to the sewer system each time this recharge occurs.  Salt cannot be removed using conventional treatment at the wastewater treatment plant, passing through and making its way into the soil, groundwater, or surface water.

What type of water treatment system should I use?
The City provides its customers with water that meets strict federal, state and local standards.  The use of water treatment systems is not necessary.  If you still choose to have a water treatment system, select the one appropriate for your needs that has the least amount of impact on the environment.

Do I have other alternatives to soften my water?
You have to ask yourself if you really need to soften your water.  Some areas in Fresno (specifically in the northeast area) have very soft water and installing a water softener could damage your water pipes and plumbing fixtures because soft water tends to be more corrosive than hard water.

Consider replacing your salt-based system with a reverse osmosis (RO) system and have it serviced on a regular schedule.  If you still choose to install a salt-based water softener system, select those that recharge on demand rather than those that recharge based on time.  In addition, limit the areas where you want the water softened, such as the water heater only instead of a whole-house water softening system.

Does water conservation make salt accumulation worse?
No, it does not.  There is a difference between concentration and mass generated.  If you have one ounce of salt in 2 gallons of water and one ounce of salt in 1 gallon of water, you will have a more concentrated solution in the 1 gallon example.  However, the amount (or mass) of salt is the same in each case.