Oxygen is necessary to support an aerobic microbial community. If sufficient oxygen is present in a solution rich in carbohydrates, nitrogen , phosphorus and other trace minerals, decomposition is complete with water, carbon dioxide and minerals being the end products. Septic systems were used by the Romans, but probably originated long before that as people began to build towns. In warm, dry climates wastewater soon soaks into soil. Drying, even percolating downwards draws in oxygen.
Anaerobic organisms proliferate.
Some can turn sulfates to sulfides, which then form insoluble compounds with metallic ions. That plugs soils. After the leach field infiltrative surfaces clog with biomat, effluent has no where to go so backs up into the septic tank, and maybe into the house. Another cause of problems is a build up in solids in the septic tank that pass into the field, again plugging up the soil spaces. No, while it seemed to be a viable option for treating clogged drain fields, is not.