Dishwashers impact a Septic system in 3 ways.
They add more water to the system.
They use chemicals to clean the dishes
They add undigested food to the septic.
To minimize the effect of adding water to the septic system, wash full loads of dishes and set the dishwasher to run in the middle of the night so water will not be added at peak demand time. Slowing the process gives the bacteria in TankTechs Rx for Septic systems time to eliminate the solids.
Common House hold dishwashing packets used in moderation as instructed will not harm the Septic tank.
Dishwashers do have a mini garbage disposal in them but it is best to scrape the heavy stuff off dishes and utensils before washing. Undigested food creates a scum layer in the septic tank. See FAQ How does a garbage disposal effect the septic system.
If the dishwasher develops and odor, add a cap of TankTechsRx for Septic Systems to the bottom in a glass of water after the dishes are done. This will sit in the line and the sump at the bottom of the dishwasher until the next use.