Water To Drink Water Quality The degree of purity of water, determined by measuring the substances physical, chemical and biological in water, besides water molecules Turbidity a measure of water clarity how much the material suspended in water decreases the passage of light through the water. pH (potential Hydrogen's) How acidic or basic a substance is, measure on a scale of 1 (very acidic) to 14 (very basic). Hardness The level of the minerals calcium and magnesium in water. Concentration The amount of one substance in a certain volume of another substance. Filtration The process of passing water through a series of screens that allow the water through, but not larger solid particles. Seen on page H85 Flocs Sticky globs created by adding a chemical such as alum during water treatment. Coagulation The process by which particles in a liquid clump together; a step in the water treatment process. Sewage Water containing human wastes. Sludge Deposits of fine solids that settle out from wastewater during the treatment process Septic tank An underground tank containing bacteria that treat wastewater as it passes through. Leach Field The ground area around a septic tank through which wastewater filters after leaving the tank. Balancing Water Needs Drought A water shortage caused by scarce rainfall in a particular area. Conservation The process of using a resource wisely so it will not be used up. Desalination The process of obtaining fresh water from salt water by removing the salt. Freshwater Pollution Water Pollution The addition of any substance that has a negative effect on water or the living things that depend on the water. Point Source Pollution A specific source of pollution that can be identified, such as a pipe. Nonpoint Source Pollution A widely spread source of pollution that is different to link to a specific point of origin, such as road runoff The fertilizer (high in nitrogen and phosphorus) carried from runoff goes into the pond and is absorbed by the algae resulting it algal blooms. Algal Blooms using cellular respiration at night, use oxygen lowering the dissolved O 2 levels in the pond Acid Rain Rain that is more acidic than normal, caused by the release of molecules of sulfur dioxide and nitrogen oxide into the air. Pesticide A chemical intended to kill insects and other organisms that damage crops. Hydroelectric Power Electricity produced by the kinetic energy of water moving over a waterfall or dam.