Spreading of the sludge resulting from anaerobic digestion

In order to reduce the volume of storage of the sludge, a separation of phase (pressing, centrifugation or deshydrataion), solid liquid/is possible. The sludge can then be stored on concrete slabs (digestats solid) or lagoons (digestats liquid or percolats). Because of their composition, the liquid and solid phase of the digestats are differently spread being adapted to the various types of culture. The techniques of spreading (material, cultures) are also different.

Advantages

Harmlessness

The criteria of harmlessness are divided into several points:
- the metal elements traces
- organic micropolluants
- microbiological agents
- the inert ones

Anaerobic digestion presents several fundamental assets related to the power of the concerned organizations which ensure an high rate of degradation of the organic matter and the implementation of the complementary treatments (hygenisation, pasteurization, thermal drying).

Characteristics

The solid fraction of the digestats is slightly richer in stable organic matter than the liquid fraction.

Advantages

Ammonium is the soluble shape of nitrogen. During the separation of phase the majority of mineral-bearing nitrogen is found in the liquid fraction. Moreover, Naskeo works on techniques of crystallization and stripping in order to recover nitrogen and phosphorus in the liquid fraction.
 - The liquid fraction of the digestats is rich in ammonia - manure nitrogen
 - Reccomandations of spreading: Since the ammonia is volatile under certain conditions, the techniques of spreading will have to be adapted:
 - Direct Injection -  Spraybar with pendillard