processing and conveying depends on the type of material to be used. One of the most
important problems in substrate management to be considered is the problem of scum.
Effluent sludge
The sludge resulting from the digestion process represents a very valuable material for
fertilization. The following aspects of sludge treatment and use are considered here:
• Sludge storage
• Composition of sludge
• Fertilizing effect of effluent sludge
• Sludge application and slurry-use equipment
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