Soaps and Detergents were originally made from animal fats and vegetable oil. Today we use many other products but mainly sodium hydroxide and alcohol.
How Soaps Work At one end of each soap molecule is a negative charge that attracts a water molecule (hydrophilic). At the other end of the soap molecule is a positive charge that repels water but attracts the dirt or grease (hydrophobic). This helps to remove dirt or grease from clothes being washed, and carries them down the drain with the water.
Hard Water contains a lot of calcium and magnesium salts. These salts react with soap to form a grey scum and do not wash clothes well.
Soft Water does not contain many salts, and does wash clothes well.
Biodegradable soaps and detergents are environmentally friendly because they are easily broken down by bacteria into harmless substances.
Phosphates are salts in soaps and detergents that are environmentally unfriendly because they cause algal blooms in rivers and lakes. These algal blooms take oxygen out of the water and deprive the fish of oxygen, causing death. The name for this damaging process is eutrophication.