Brine Brine is used for food processing and cooking (pickling and brining), for de-icing of roads and other structures, and in a number of technological processes. It is also a by-product of many industrial processes, such as desalination, and may pose an environmental risk due to its corrosive and toxic effects, so it requires wastewater treatment for proper disposal. Saline water with relatively high concentration of salt (usually sodium chloride) occurs naturally on Earth's surface (salt lakes), crust, and within brine pools on ocean bottom. Numerous processes exist which can produce brines in nature. Modification of seawater via evaporation results in
Fresh water without some treatment. Fresh water can easily become polluted by human activities or due to naturally occurring processes, such as erosion. Water is critical to the survival of all living organisms. Some organisms can thrive on salt water, but the great majority of higher plants and most mammals need fresh water to live. Fresh water can be defined as water with less than 500 parts per million (ppm) of dissolved salts. Other sources give higher upper salinity limits for fresh water, e.g. 1000 ppm or 3000 ppm. Fresh water habitats are classified as either lentic systems, which are the still-waters