What must be done to prevent a digester from becoming sour?

To prevent a digester from becoming sour, it's essential to manage the balance of material being processed within it. Reducing the sludge feed and removal rate helps maintain a stable environment that supports the optimal anaerobic digestion process. When sludge levels are managed effectively, it ensures that the microorganisms responsible for breaking down the organic matter have enough food while not overwhelming the system. If too much sludge is fed too quickly without adequate removal, it can lead to acid accumulation, creating a sour condition that stifles the digestion process and can adversely affect the health of the microbial community responsible for digestion.

Increasing the flow rate of feed could disrupt this balance, potentially leading to conditions that promote souring, while simply increasing the water temperature generally accelerates the digestion process without directly addressing the root causes of souring. Adding back washed grit is not typically a standard practice to prevent souring; rather, it's more about maintaining the quality of the digester contents and ensuring proper mixing and feeding habits. Thus, managing the feed and removal rates of sludge is crucial for maintaining a healthy anaerobic digestion process and preventing sour conditions.