dry anaerobic digestion of municipal solid waste and digestate ...

feedstocks were sub-sampled and freeze-thawed under ambient temperature for loading
into the reactor. The simulations were also characterized in different time intervals during
the long time storage. The average total solid (TS), volatile solid (VS) and ca rbon (C)
contents of the Feedstocks 1 & 2, and Feedstock 3 were 20.2%, 85%TS, 51.5%TS and
17%, 86%TS, 51%TS respectively.
3.2 Experimental Set-up
3.2.1 Experimental set-up for gas formation potential test
Gas formation potential test (also called GP21 test) was conducted for Feedstock 1 and 2.
The experimental set-up for it has been shown in Figure 3.2. Laboratory glass bottle of 500
mL with a thick Teflon/silicon (0.01”/0.05”) septum in its arms were used as reaction
vessels for waste. The reaction vessel was connected to a long cylindrical approximately
1L glass tube called eudiometer by plastic tube that was used for measurement of volume
of biogas produced. The eudiometer had barrier solution that was free to move by the
pressure of produced biogas to another 1L plastic bottle (called reservoir tank) connected
to the other end of eudiometer. The reaction vessel was placed in a water bath to attain the
required temperature of 35 ºC (Heerenklage and Stegmann, 2005).
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2
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79 cm
4 cm
Figure 3.2 Experimental set-up for gas formation potential test
3.2.2 Experimental set-up for pilot-scale experiments
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A stainless steel inclined thermophilic dry anaerobic digestion system (ITDAR) was
designed with the total and working volume of 0.69 and 0.55 m 3 , respectively. The internal
diameter of the reactor was 0.6 m and the total height was 2.4 m. It was placed in an
inclination of about 30 o from the ground level to facilitate easy flow of the waste as shown
in Figure 3.3. The ITDAR was externally connected with the waste feeding hopper, screw
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GC
1. Sample + inoculum
2. Reaction vessel, 500 mL
3. Water bath
4. Liquid sampling
5. Plastic tube
6. Gas collection tube
(Eudiometer tube ~ 1L)
7. Gas sampling
8. Barrier solution
9. Reservoir tank, 1L