However, over time, particular materials used as bulking agent can lose their stiffness as they absorb water and decompose. Paper is a good example of a bulking agent that loses structure quickly. When a pile loses structure, it collapses and becomes dense. It becomes difficult to turn and anaerobic conditions follow. The remedy is to add more bulking agent, or a different one that maintains good structure, like wood chips or shavings.
Moisture is also a factor.
A given material has more structure as it dries. The polymers act as a binding agent to settle the solids out of the wastewater. What they also do is react with water such that it becomes part of this structure. This is great during dewatering, but it creates problems about four or five days into composting. It turns to water.