by Ali Kriscenski

Salinity is an important attribute of water that conveys the concentration of salt compounds within it. Industrial processes depend on salinity for processes related to manufacturing, biopharmaceutical, agriculture, and wastewater management, among others. Controlling salinity in process and wastewater systems is central to quality control and regulatory compliance. In this article we’ll provide an overview of salinity, its relevance in industrial manufacturing, and how to monitor salinity levels.

What is Salinity?  

Salinity refers to the amount of dissolved salts in a body of water. In nature, freshwater typically has a salinity of 0.5 parts per thousand (ppt) while ocean water ranges from 33-37 ppt. Freshwater is fundamental to sustaining the life of humans, reptiles, birds, and many other creatures and plants. Saltwater is host to a range of creatures and plants that have adapted to higher salinity. Salts are versatile compounds that are useful in food production, food preservation, and also serve functions in the human body’s muscle and nerve system.

Salinity in Manufacturing

Solutions that have a salinity of 35 ppt are considered brine and used in a wide range of manufacturing and maintenance processes. In manufacturing, brine is a useful medium for food production and preservation acting as a preservative and also as a temperature control material. Brine can be used to de-ice infrastructure and mechanical components, and also in industrial refrigeration. 

Controlling salt mixtures and salinity is critical to manufacturing operations, transportation networks, and processing equipment efficiency. About 13% of all water used in the U.S. is saline, and most of the saline water used is for cooling electricity-generating equipment, with a smaller portion used in mining and manufacturing. When used in industrial facilities, brine, and saltwater can become contaminated solutions that fall under state and federal regulations to control industrial pollution. Industries such as agriculture, food manufacturing, and textile production are examples of manufacturing processes that produce high-salinity wastewater. 

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Environmental Impact of High Salinity Wastewater 

Industrial processes can impact the salinity in rivers, streams, and groundwater. When salinity levels are altered in the ecosystem, it can change the health of wildlife, vegetation, and affect balances in atmospheric systems, such as temperature. Salinity also affects agricultural soils, changing the capacity of crops to absorb nitrogen and also changing balances in soil bacteria.

How Salinity is Measured

Salinity can be monitored through different attributes of a water solution. Measuring liquid density with a salometer can convey the percentage of salt in water. This method depends on temperature and oxygenation stability. Refractometers use a refractive, light-dependent measurement to indicate salinity. Electrical conductivity (EC) is a way to measure salinity in water and soil by passing an electrical current through a sample. As salt increases electrical conductivity, salinity levels can be measured with a salinity meter expressing salinity relative to the EC value.

Measuring Salinity in Manufacturing

While salts are natural compounds, they can have a significant impact on ecological systems. For this reason, discharge wastewater from manufacturing processes must meet requirements under federal and state regulations. Manufacturing facilities can control wastewater impact on surrounding plants, animals, and ecosystems through effective in-line monitoring solutions that document salinity level data along processing systems. This measure can work to protect surrounding waterways from wastewater, runoff, and discharge into groundwater.

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Water Quality Management

As water resources are highly regulated, water quality management is a priority for manufacturing facilities. Protection of natural water sources is backed by strict penalties including criminal charges, significant fines, and imprisonment. Even water quality monitoring failures can be subject to considerable criminal provisions.  

Fortunately, maintaining wastewater salinity compliance can be achieved through the implementation of system monitoring and mediation. Manufacturing and processing systems can be fitted with sensors to track salinity throughout equipment lines, and at wastewater discharges. The capacity to identify and correct salinity levels through innovative technologies alleviates the operational risk of impacting natural resources and the regulatory ramifications.

Finding the right partner for industry expertise and system design in wastewater monitoring is central to operational efficiency. Find expert guidance with Therma.


Ali Kriscenski was trained in high-performance building design at Boston Architectural College. She has worked with leading architecture and construction firms in NYC and New England and served on the executive team at the Forest Stewardship Council International. She was the managing editor at Inhabitat and has worked pro bono for the Green Building Institute, ISEAL Alliance, and Habitat for Humanity.



USGS – Wastewater Treatment Water Use

NIH – High Salinity Wastewater Treatment