Page 213 - Materials Chemistry, Second Edition

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Sustainable Industrial Design and Waste Management
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10 cm cover layer

Perforated pipes

FIGURE 5.25 Passive aeration process

Advantages

• Natural aeration
• Low cost

Disadvantages

• Odor emission
• Needs long time for maturation
• Needs labor for turning

Passive composting
Parallel rows of perforated high pressure PVC piping are placed at the bot-
tom, of the compost. The pipes are perforated with 10 cm holes to allow air
to enter the composting piles as shown in Figure 5.25. The pipe manifold
helps in distributing the air uniformly. This system is better than the natu-
ral system because of the limited flow rates induced by the natural ventila-
tion. This method needs limited areas of land, has lower running costs, and
does not need skilled workers. This method is recommended for its cost
effectiveness. Therefore, it is the most suitable method for the developing
communities that want to achieve maximum benefit from food recycling with
the minimum capital investment. This process, known as passive compost-
ing, produces good quality soil conditioner and organic fertilizer if NPK