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AMBIOGAS, THE NEW DRY DIGESTER.
Why dry anaerobic digestion?
The technique of “dry anaerobic digestion”, based on the
fermentation processes of solid matrixes with content of dry
substances up to 50%, has indubitable advantages of a
technical order in comparison with traditional wet digestion
(d.s. max 10%) inasmuch as it avoids the dilution of the
materials set to the process with large quantities of water.
The result is a considerable reduction of volumes to be
treated, with all the benefits that derive (smaller digesters
and smaller quantities of digestate to dispose of).
Digester
The AmBiogas dry anaerobic digester, fine tuned by Ambientalia, is
based on the system of the front loading tubular module, with some
important singularities that distinguish it from other solutions.
As is well known, the outgoing material from the anaerobic phase
(digestate) can be transformed into soil improver by subjecting it to
aerobic bioxidation processes, thus completing a virtuous circle that
permits disposal, or better, the recovery of waste and the production
of energy through biogas. Transformation of the digestate into compost
usually takes place through mixing it with a ligno-cellulose support
fraction and carrying our aerobic processes in special reactors
(bio-cells, bio-tunnels etc.) and subsequently in maturation heaps,
concluding the cycle with refinement of the compost obtained.
Ambientalia’s AmBiogas reactor was conceived for management of both
the anaerobic and aerobic phases of the process, without transferring
the material and envisaging the addition of the ligno-cellulose
support at the start of the work cycle. The plant constructional and
management simplifications resulting from this solution are evident.
The horizontal modules are usually fed by mechanical shovels through a
frontal opening, which means the heights of the reactors have to be
around 2-2.5 metres greater than the height of the deposited material
(space necessary for emptying the material from the dumping bucket).
This space creates a void between the material and the ceiling of the
sheath, equal to about half the latter’s total volume.
As is well known, the heat and damp emerging from the mass rise into
the empty space. To obviate this dispersion, more energy must be used
to keep the mass at the right temperature.
This empty space is avoided in the Ambientalia digester by equipping
it with a mobile false ceiling, using cylinders: during loading and
emptying, the false ceiling is raised to the necessary height so the
operator can enter with the mechanical means.
On completion of loading, the ceiling is lowered, maintaining a
minimum cavity between it and the deposited material. The retaining of
heat and humidity within the reactor is ensured by the false ceiling.
On completion of the cycle the false ceiling is returned to the
uppermost position so the operator can enter with the mechanical
shovel and work in maximum safety.
In the phases of emptying and loading the reactor, its system of
forced aeration – necessary to support the aerobic phase – is used to
maintain environmental conditions suitable for entrance of the
operators by sucking great quantities of air.
All these solutions make the Ambientalia digester a unique and highly
innovative system.
> Description of the Reactor
> Biogas Management
> Management of the
Process in the Digester
>
Presentation and data sheet (PDF)
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