analysis of a pilot-scale anaerobic baffled reactor treating domestic ...

esulted in more even flow distribution and reduced dead-space. CFD tests were visually reproduced
using a single compartment laboratory-scale ABR and dye in water (Figure 3.3 c).
The Fluent simulations were used to assist in selection of design features of the baffles. They were not
intended to be used in prediction of flow patterns in an ABR treating domestic wastewater since the
presence of two additional phases (solid and gas) can substantially alter flow patterns, as compared to
clean water flow patterns.
3.1.1.1 Construction of reactor
The pilot-scale ABR was designed to have a total working volume of 3 000 ℓ. The hanging baffles
were attached to the top of the reactor to separate the headspaces of subsequent compartments. The
heights of the standing baffles were reduced across the reactor so that each subsequent compartment
had a slightly lower level then the previous one. Diagrams of the pilot-scale reactor are shown in
Figure 3.4 and Figure 3.5. The pilot reactor was constructed of mild steel.
The walls and baffles were laser cut from mild steel sheets and welded together to form gas-tight
compartments.
The following sampling ports were included in the reactor design and construction (Figure 3.5)
(Dama, (in preparation)):
• 4 or 5 × 25 mm diameter ports on the upflow side of each compartment on one side of the
reactor. Galvanised ball valves were attached to the top and bottom port of each compartment
for sampling. Galvanised plugs were used to seal the other ports.
• A 75 mm diameter port at the bottom of each compartment to facilitate emptying of the
compartment. These ports were closed using galvanised 75 mm plugs.
• 75 mm diameter ports on the top of both the upflow and downflow compartments for
sampling, fitted with PVC plugs.
• 6 mm diameter gas vents above the upflow area of each compartment for venting and
collecting biogas.
Inlet
Sample Ports
Hanging Baffles
Figure 3.4: Diagram of the pilot-scale ABR with a cut-away to give an indication of the baffle
configuration. (Dama et al., 2001)
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Gas Ports
Standing Baffles Outlet