Biological properties of MSW

Excluding plastic, rubber, and leather components, the organic fraction of most MSW can be classified as follows:

1. Water-soluble constituents, such as sugars, starches, amino acids, and various organic acids,

2. Hemicellulose, a condensation product of five- and six-carbon sugars,

3. Cellulose, a condensation product of the six-carbon sugar glucose,

4. Fats, oils, and waxes, which are esters of alcohols and long-chain fatty acids,

5. Lignin, a polymeric material containing aromatic rings with groups, the exact nature of which is still not known,

6. Lignocellulose, a combination of lignin and cellulose,

7. Proteins, which are composed of chains of amino acids.

Perhaps the most important biological characteristic of the organic fraction of MSW is that almost all of the organic components can he converted biologically to gases and relatively inert organic and inorganic solids. The production of odors and the generation of flies are also related to the putrescible nature of the organic materials found in MSW (e.g., food wastes).

Task 9. Find English equivalents for the following words and phrases in the text:

clinker, commingle, compacted waste poros­ity, dry-weight method, field capacity, fuel, in excess, landfill, loose,uniformity, moisture con­tent, organic fraction, particle size, permeability, trammel screens, recovery of materials, size distribution, specific weight, storage, wet-weight method of measurement,

Task 14. Complete the following sentences:

1. …, …, … and …, …, and … are physical characteristics of MSW.

2. … is defined as the weight of a material per unit volume.

3. … of measurement of the … of solid wastes is used most commonly in the field of solid waste management.

4.… of solid waste is the total amount of moisture that can be retained in a waste, sample subject to the downward pull of gravity.

5. … of compacted wastes to a large extent governs the movement of liquids and gases in a landfill.

6. The most important … of the organic fraction of MSW is that almost all of the organic components can he converted biologically to gases and relatively inert organic and inorganic solids.

Task 14. Find in the text answers to the following questions. Work in pairs.

1. What kind of physical properties of municipal solid waste do you know?

2. What does specific weight mean?

3. What factors affect value of specific weight?

4. What method of moisture content measurement is commonly used? How does it work?

5. How can we classify the organic fraction of MSW?

Task 15. Match the following definitions with their terms:

1.… refers to those actions necessary to stop and clean up unplanned contaminant releases to the environment.	a. postclosure care
2.… refers to the activities associated with the long-term maintenance of the completed landfill (typi­cally 30 to 50 years).	b. remediation
3.… involves the activities associated with collection and analysis of water and air samples used to monitor the movement of landfill gases and leachate at the landfill site.	c. environmental monitoring
4. … ratio of weight (mass) to volume of a material, usually in grams per cubic centimeter or pounds per gallon.	d.density

Task 16. Explain in your own words following words and phrases:

Дата добавления: 2015-10-29