We are having problems with sludge that has been treated with lime (dryness at 29%) and that does not hold together in a pile, making it difficult to store in the fields. Have you ever encountered this problem?
Dewatering sludge reduces its water content, while chemical conditioning with slaked or quick lime improves the cake’s physical characteristics and ability to hold together in a pile. With your degree of dryness, you should have no problem reaching 1.2 to 1.5 m.
Did you check to see whether the leachate is properly evacuated from the storage area?
Sludge recovery for transport alters its structure. Even at 29%, any agitation in the bin eventually decreases the sludge's ability to hold together. Have you noticed a change from one year to another?
No, this only started in the last month. And it's the first time it has happened to us.
When held in a storage area, sludge is prevented from spreading by the container walls. Without these walls, the top layer flattens out and the pile collapses. That is what happens in the field. This phenomenon is accentuated by sludge with a wetter content or when there is a mixture of sludge of varying ages.
Other factors that could explain your problem:
- The sludge is old, so the pile collapses faster.
- The lime-sludge mixture is not homogenous.