Kitty litter made from natural sources (such as paper, grass, wood, wheat, corn, nuts) are good to compost and can even assist with the composting process, so it is perfectly good to add them to an EnsoPet. Kitty litters made from synthetics are not compatible with composting as they can damage the structure of the soil and cause synthetic toxins to leak into your garden. Clay based kitty litters do not compost well and can slow down the composting process. 

Composting needs oxygen, especially in ground composters such as the EnsoPet. If you add kitty litter to your EnsoPet, be mindful not to add too much at once. If a EnsoPet is filled up too quickly, it can become air locked and the composting process will slow down or even stop. Aerating the waste is of enormous benefit, use a composting aerator, garden fork or trowel to mix the waste, the more the waste aerated the better it will compost.

Temperature and moisture levels are relevant, the warmer the weather the quicker the composting, if your garden needs watering so will the EnsoPet. Too much water hinders the composting process, therefore it is recommended to install the EnsoPet where there is good drainage. Better results will be achieved if waste is added in small amounts often rather than large amounts infrequently. 
The EnsoPet starter will accelerate the breakdown of the waste by at least 50%.