Organic Waste Recycling

10 Organic Waste Recycling: Technology and Management

produce food, fuel and fertilizers. The conversion processes are combined and
balanced to minimize external energy inputs and maximize self-sufficiency. The
advantages of the integrated system include (NAS 1981):

• Increased resource utilization,


• Maximized yields,


• Expanded harvest time based on diversified products,


• Marketable surplus, and


• Enhanced self-sufficiency.

Figure 1.4 Some integrated systems of organic waste recycling program

Some of the possible integrated systems of organic waste recycling are shown in
Figure 1.4. In scheme (a), organic waste such as excreta, animal manure or sewage
sludge is the raw material for the composting process; the composted product then
serves as fertilizers for crops or as soil conditioner for infertile soil. Instead of
composting, scheme (b) has the organic waste converted into biogas, and the
digested slurry serves as fertilizer or feed for crops or fish ponds, respectively.
Schemes (c)-(f) generally utilize organic waste in liquid form and the biomass

Organic waste

Biogas digester

High-rate algal

pond

Composting

Biogas

Duckweed

ponds

Wastewater Irrigated land

Organic waste

Organic waste

Organic waste

Organic waste Humans

Waste

stabilization /

fish ponds

Shrimp

Fish ponds

Crops

Algae

Duckweeds

Slurry

Fish ponds

Crops

Soil

conditioner

Crops

Irrigation

Fish ponds

Animals

Humans

(a)

(b)

(c)

(d)

(e)

(f)