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4 Development of the Standard System for Differentiated …
4.3.7 Control Over Composting Technology
4.3.7.1 Primary Fermentation
1. The moisture content of the organic materials needs to be controlled within 60%.
That is, the moisture content corresponds to that on condition that water is seen
between fingers while does not drop after grabbing a handful of the materials
and clenching the fist and the materials are dispersed under a gentle touch after
relaxing the grip.
2. Windrow composting should be applied for the stacking of organic materials and
the height and width should be designed according to the composting season,
types of materials and mixed animalcule bacteria, fermentation environment, and
turning equipment. Generally, the heaps should be 0.6–2 m high and 0.8–2 m
wide.
3. During the fermentation, temperature of heaps should be measured three or four
times every day. The measuring points should be inside the heaps 10–30 cm
to the surface. The compost should be kept at 55 °C for 5–7 days to reach the
harmlessness standard and the highest temperature should not exceed 70–75 °C
(applying the temperature at which mixed animalcule bacteria are killed as the
limit).
4. After exceeding 60 °C and keeping the compost at the temperature for 48 h, the
heaps should be turned. The heaps need to be turned once every three to five
days and turned immediately after the temperature exceeds 70–75 °C. The heaps
should be turned sufficiently and evenly, to bring the bottom materials into the
upper and middle part of the heaps, so that they can be sufficiently decomposed.
5. In the forced-aeration static-pile composting, the air flow should be 0.05–
0.20 Nm
3 per minute per cubic meter of materials. The air pressure should be
increased by 1–1.5 kPa every rising the height of the material layer by one meter.
6. The period of primary fermentation generally should be longer than 15 days.
7. As the fermentation terminates, the temperature of materials does not rise any
longer and the heaps are basically not smelly and approximately grey brown.
4.3.7.2 Secondary Fermentation
1. Fresh raw materials of compost are not allowed to be added in the secondary
fermentation.
2. The moisture content should be controlled within 40–50%.
3. To reduce nutrient loss, the temperature of materials is suggested to be controlled
below 50 °C. The temperature of heaps can be controlled by adjusting the height
of material layers.
4. The value of pH needs to be within 5.5–8.5. If it is beyond this range, adjustment
measures should be taken.
5. The period of secondary fermentation basically lasts for 15–30 days.
4 Development of the Standard System for Differentiated …
4.3.7 Control Over Composting Technology
4.3.7.1 Primary Fermentation
1. The moisture content of the organic materials needs to be controlled within 60%.
That is, the moisture content corresponds to that on condition that water is seen
between fingers while does not drop after grabbing a handful of the materials
and clenching the fist and the materials are dispersed under a gentle touch after
relaxing the grip.
2. Windrow composting should be applied for the stacking of organic materials and
the height and width should be designed according to the composting season,
types of materials and mixed animalcule bacteria, fermentation environment, and
turning equipment. Generally, the heaps should be 0.6–2 m high and 0.8–2 m
wide.
3. During the fermentation, temperature of heaps should be measured three or four
times every day. The measuring points should be inside the heaps 10–30 cm
to the surface. The compost should be kept at 55 °C for 5–7 days to reach the
harmlessness standard and the highest temperature should not exceed 70–75 °C
(applying the temperature at which mixed animalcule bacteria are killed as the
limit).
4. After exceeding 60 °C and keeping the compost at the temperature for 48 h, the
heaps should be turned. The heaps need to be turned once every three to five
days and turned immediately after the temperature exceeds 70–75 °C. The heaps
should be turned sufficiently and evenly, to bring the bottom materials into the
upper and middle part of the heaps, so that they can be sufficiently decomposed.
5. In the forced-aeration static-pile composting, the air flow should be 0.05–
0.20 Nm
3 per minute per cubic meter of materials. The air pressure should be
increased by 1–1.5 kPa every rising the height of the material layer by one meter.
6. The period of primary fermentation generally should be longer than 15 days.
7. As the fermentation terminates, the temperature of materials does not rise any
longer and the heaps are basically not smelly and approximately grey brown.
4.3.7.2 Secondary Fermentation
1. Fresh raw materials of compost are not allowed to be added in the secondary
fermentation.
2. The moisture content should be controlled within 40–50%.
3. To reduce nutrient loss, the temperature of materials is suggested to be controlled
below 50 °C. The temperature of heaps can be controlled by adjusting the height
of material layers.
4. The value of pH needs to be within 5.5–8.5. If it is beyond this range, adjustment
measures should be taken.
5. The period of secondary fermentation basically lasts for 15–30 days.