Calculation of feeding ratio for 1000 liter biogas digester

To my understanding 1000 liter/40 = 25 liter. So it is advisable to feed 25 liter of food waste mixed with water. It means, your food waste is already included in that 25 liter. I have read from this elsewhere, the maximum ratio of food waste to water you can apply is 1:1 (though to me its too much for the microbes to handle). Roughly the maximum weight of food waste you can put is 12.5 kg in which you add another half of water to add up to 25 liter as total mixed. However its up to you what level of total solids you want to practice by reducing the food waste within that 25 liter. The more effluent you take out from the digester, the more bacteria you will discard and that may affect whole digestion process and becoming slower in producing gas.