Question

# Determine the amount of air required to compost 7 tons of solid wastes using in vessel...

Determine the amount of air required to compost 7 tons of solid wastes using in vessel composting systemwith forces aeration. Assume that the composition of the organic fraction of the MSW to be composted is given by C60H100O40N. Assume that:

a.       Moisture content or organic fraction of MSW:25%

b.      Biodegradable volatile solids = 0.60 x TS

c.       Air contains 21% oxygen and the specific weight of air is 1.2 kg/m3 at 20 oC.

1. Determine the mass of biodegradable volatile solids in 7 tons of solid waste

Biodegradable volatile solids = 0.60 x TS

Moisture content or organic fraction of MSW:25%

TS(TOTAL SOLIDS ) = 75%

mass of biodegradable volatile solids (BVS)= 0.6*0.75*7*1000 kg = 3150kg

2.Determine the amount of oxygen required for decomposition of 1 kg of BVS

C60H100O40N + 64.25 O2 → 60.0 CO2+ 48.5 H2O + N

Molecular wt of C60H100O40N =1474g

Molecular wt  64.25 O2 = 2056g

O2 required =2056/ 1474 = 1.39 kgO2 /kgBVS

3.Determine the total amount of air required for 7 ton of MSW, containing 3150 kg of BVS, as determined in Step 1

Air Required= (3150kg*1.390)/(0.21*1.2kg/m3)= 17375m3