What is the recommended method to control excess foaming during the startup of a digester?

The recommended method to control excess foaming during the startup of a digester is to stir gently to release excess gas. Foaming can occur when gas bubbles are trapped in the mixture, and this can lead to operational issues such as blockages or overflow. By stirring gently, you can help break these bubbles and allow the gas to escape, which reduces the foaming effect. This technique is important because it maintains the integrity of the digester operation and allows for proper digestion processes without interruptions.

While increasing the temperature may facilitate digestion rates, it does not specifically address the immediate issue of foaming. Adding chemicals might aid in controlling foaming in certain situations, but it can also introduce other complexities and may not be an appropriate first-step method in a start-up scenario. Reducing waste input could be a way to decrease the formation of foam due to less organic material, but it does not address the foaming that is already present during the startup. Stirring gently is the most direct and effective method to manage foaming in this context.