The use of in sink disposal systems for the disposal of waste food can cause a rapid overload of the septic tank system and cause early failure. Its a nasty and expesive job to sort and once you mess you the system, more often that not you will have to have the tank cleaned out. Not nice and bad for the pocket. A septic tank is designed to handle and break down sewage. Other in organic and organic compounds such as detergents, sanitary towels, food, cooking oil etc should never be added to the system. Buy a compost bin. It's cheaper and better for the environment.