Page 19 - mobile Workbook-chapter 2

Example 2-12

A sample of refuse is analyzed and found to contain 10% water (measured as weight loss on
evaporation). The Btu of the entire mixture is measured in a calorimeter and is found to be 4000

Btu/lb. A 1.0 g sample is placed in the calorimeter, and 0.2 g ash remains in the sample cup after

combustion. What is the comparable, moisture - free Btu and the moisture - and ash - free heat
value?

Solution

10% water means % moisture, LHV = 4000 Btu/lb
Apply two equations to calculate HHV in both cases

Answer

2.10 Biodegradability

In applications where the organic fraction of MSW is used as feedstock for compost or

biological conversion into methane and ethanol, information on the essential nutrients in the waste
materials is important. Both composting and biogas production are carried out by diverse

consortia of heterotrophic microorganisms. Therefore, the microbial nutrient balance of the MSW
should be assessed to allow for maximal conversion for final uses. The organic fraction of most

MSW (i.e., food waste, yard waste, paper products, textiles) can be classified according to their

relative degree of biodegradability as follows:
• Sugars

• Starches and organic acids
• Proteins and amino acids

• Hemicellulose

• Cellulose and lignocellulose
• Lignin

• Lipids: fats, oils, and waxes

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