A traditional brewery of today (see model of traditional brewery below), that brews beer according to the German purity standards, produces beer, but also produces organic waste streams and lost energy. This waste from the brewery is organic material which means that its polluting effect could be seen as minimal. However, given the quantity of water needed for the large volumes of beer produced by today's breweries (up to more than 20 liters of water per liter of brewed beer), this organic waste is a problem. It is also a waste considering the amount of nutrients and protein used from the grains in the beer-brewing process. A small percentage of the nutrients are used, and the protein is left untouched in the spent grains after the process. One usage for the spent grains that is occasionally explored is that of animal feed. This is not an optimal use, though, as the spent grains are tough for the animals to digest. The result is indigestion and added amounts of methane gas emitted into the atmosphere by the animals.
Traditional Brewery Process Flow Diagram
What is Zero Emissions about? One of the aspects of Zero Emissions is to increase value added. Looking at the traditional system above, the value added generated from the waste is very low. It is actually negative if the brewery must pay for getting rid of waste water and spent grains. In order to maximize value added for the inputs of the brewery, the ZERI Foundation searches for the best possible ways of using the generated waste in a cascading manner (see model of generic ZERI brewery below).