An array of reactions involving several different types of chemical conversions: (1) loss of electrons by a chemical, (2) combination of oxygen and another chemical, (3) removal of hydrogen atoms from organic compounds during biological metabolism, (4) burning of some material, (5) biological metabolism that results in the decomposition of organic material, (6) metabolic conversions in toxic materials in biological organism, (7) stabilization of organic pollutants during wastewater treatment, (8) conversion of plant matter to compost, (9) decomposition of pollutants or toxins that contaminate the environment.