Question

You are an engineer working on the design of a toilet that converts human waste into methane gas. Only solid human waste enters the toilet and is decomposed (by microorganisms) to produce methane gas and fertilizer. An undesirable by-product of the process is H2S gas, which is removed by a scrubber (it does not exit the toilet). Write an unsteady state mass balance on the H2S gas, human solid waste, and methane.

Answer 1

Answer:

Solid (s)     ⇒     $CH_{4} (g) + fertilizer$

              micro

           organisms

Explanation:

Attached below is the unsteady state mass balance on the H2S gas, Human solid waste and methane

when the solid waste is passed through the toilet the : CH4 and fertilizer are produced. while H2s  gas is an undesirable by-product from this process

Mass Balance :

Rate of mass accumulation = Rate of mass IN - Rate of mass OUT + Rate of material generation - Rate of material dissipation

solid human waste (s) = $CH_{4} (g) + H_{2} S$ + Fertilizer

unsteady state mass equation

Solid (s)     ⇒     $CH_{4} (g) + fertilizer$

              micro

           organisms