1. Oxygen supply by turning piles is one of the basic conditions for aerobic fermentation production. The main function of turning over:
①Provide oxygen to accelerate the fermentation process of microorganisms; ②Adjust the pile temperature; ③Dry the pile.
If the number of turnings is small, the ventilation volume is not enough to provide sufficient oxygen for the microorganisms, which will affect the rise of the fermentation temperature; if the number of turnings is too high, the heat of the compost heap may be lost, which will affect the degree of harmlessness of fermentation. Usually according to the situation, the pile is turned 2-3 times during fermentation.
2. The content of organic matter affects the stockpiling temperature and ventilation and oxygen supply.
The content of organic matter is too low, the heat generated by decomposition is not enough to promote and maintain the proliferation of thermophilic bacteria in the fermentation, and it is difficult for the compost heap to reach the high temperature stage, which affects the hygienic and harmless effect of fermentation. Moreover, due to the low content of organic matter, it will affect the fertilizer efficiency and use value of fermented products. If the content of organic matter is too high, a large amount of oxygen supply will be required, which will cause practical difficulties in turning over the pile for oxygen supply, and may cause partial anaerobic conditions due to insufficient oxygen supply. The suitable organic matter content is 20-80%.
3. The optimum C/N ratio is 25:1.
In fermentation, organic C is mainly used as an energy source for microorganisms. Most of organic C is oxidized and decomposed into CO2 and volatilized during microbial metabolism, and part of C constitutes the cell matter of microorganisms themselves. Nitrogen is mainly consumed in the synthesis of protoplasts, and the most suitable C/N ratio is 4-30 in terms of the nutritional needs of microorganisms. When the C/N ratio of organic matter is around 10, the organic matter is decomposed by microorganisms at the highest rate.
With the increase of C/N ratio, the fermentation time was relatively prolonged. When the C/N ratio of the raw material is 20, 30-50, 78, the corresponding fermentation time is about 9-12 days, 10-19 days, and 21 days, but when the C/N ratio is greater than 80 When : 1, fermentation is just difficult to carry out.
The C/N ratio of each fermentation raw material is usually: sawdust 300-1000, straw 70-100, raw material 50-80, human manure 6-10, cow manure 8-26, pig manure 7-15, chicken manure 5-10 , Sewage sludge 8-15.
After composting, the C/N ratio will be significantly lower than that before composting, usually 10-20:1. This kind of C/N ratio of decomposing and fermenting has better fertilizer efficiency in agriculture.
4. Whether the moisture is suitable directly affects the fermentation speed and the degree of decomposing.
For sludge fermentation, the appropriate moisture content of the pile is 55-65%. In actual operation, the simple method of determination is as follows: hold the material tightly with your hand to form a ball, and there will be water marks, but it is better that the water does not drip out. The most suitable moisture for raw material fermentation is 55%.
5. Granularity
The oxygen required for fermentation is supplied through the pores of the fermentation raw material particles. The porosity and pore size depend on the particle size and structural strength. Like paper, animals and plants, and fiber fabrics, the density will increase when exposed to water and pressure, and the pores between particles will be greatly reduced, which is not conducive to ventilation and oxygen supply. The suitable particle size is generally 12-60mm.
6. pH Microorganisms can reproduce in a larger pH range, and the suitable pH is 6-8.5. There is usually no need to adjust pH during fermentation.
Post time: Feb-27-2023
