Organic Waste Recycling

142 Organic waste recycling: technology and management

3.10 Exercises

3.1 You are to conduct a batch composting experiment at home using raw

materials generated in your home. Prepare a report describing the

composition and characteristics of the organic wastes used as raw

materials, types of composting (aerobic, anaerobic, aeration or pile

turning, etc), temperature profiles, composting period, and changes

(physical, chemical, biological characteristics) observed in the compost

materials.

3.2 You are to conduct a survey of fertilizer usage in your country. Then

estimate the amount of compost fertilizer that can be produced from the

organic wastes, and calculate economic savings that could be achieved

from usage of the compost fertilizer.

3.3 You are to conduct a public opinion survey to assess social

acceptability of the usage of compost fertilizer in your community. The

survey is to be done through questionnaire in which you (or a group of

colleagues) need to set up suitable questions. The main aim of the

survey is to find out means to increase public acceptability of the

compost fertilizer.

3.4 A farm in Cambodia has 10 beef cattle. The cattle manure is to be

composted together with rice straw, and the composted product used as

fertilizer. The composting is carried out one batch each month. From

the data in Tables 2.7 and 3.1, estimate the quantity of rice straw

needed to mix with the cattle manure to obtain a C/N ratio of 25/1.

Other data necessary for the estimation are as follows:

Manure:

Total solids = 10%

Rice straw:

C/N ratio = 80/1

Moisture content = 30%

Bulk density = 150 kg/m^3

N content = 0.2% of dry weight

3.5 In Exercise 3.4, calculate the initial moisture content of the manure-

straw mixture. What would you suggest if the moisture content is

greater than 70%?