Most simply an in-ground tube with no sun protection and effluent flow into collection pit. Most of the time called Salchicha or Sausage system but also by its technical term plug-flow system. The materials move from one side of the tube (inlet) to the other side of the tube (outlet)

Materials

PE

PE (poly ethylene) tube digesters are applied in Bolivia (Peru, Ecuador, Colombia and Mexico). The tube PE film is about 300 microns thick. It is bended at the ends and has PVC drainage pipe. PE tubes are very cheap but quite fragile. Also available as LLDPE (linear low density poly ethylene

EPDM

Sausages can be produced using EPDM (ethylene polypropylene diene monomer (M-class).

PVC

Polyvinal chloride is a widely used plastic polymere

Variants

Mexican Salchicha

No info yet

Kenya Flexibiogas

The Kenya based company Flexibiogas offers a system that includes the flexible digester bag as well as a foil greenhouse cover.¹

Puxin bags

Digesters solde by the Chinese company Puxin - they are available up to 10qm

Systema Biobolsa

Bag consists of linear low density polyethylene (LLDPE) membrane of 1 to 1.5 mm thickness. Tubes and assemblies: hydraulic and sanitary PVC.² The system is available up to a size of 40m³.

Solar C³ITIES Salchicha

In 2016 Solar C³ITIES developed a PVC based salchicha style membrane digester.

Links

http://www.sgpindia.org/documents/Biogas_Plants.pdf

References