How many grams of oxygen are required per electron equivalent of lactate in wastewater when subjected to aerobic biological treatment if fs is 0.4 (assume sufficient ammonia is present for cell synthesis).

each chemical family is represented as a group or column on the periodic table. based on chemical properties, there are 6 types of chemical families. group 1 represents alkali metals, group 2 represents alkaline earth metals, groups 3 to 12 represent transition metals, groups 13 to 16 represent non-metals and other metals, group 17 represents halogens and group 18 represents noble gases.