The fermentation of organic raw materials is the most basic and core part of the production process of organic fertilizer, it also affects the most critical part of the quality of organic fertilizer, the fermentation of organic raw materials is actually the interaction of the physical and biological characteristics of raw materials in the process of composting. On the one hand, the fermentation environment is interactive and harmoniously promoted. On the other hand, different raw materials are mixed together, due to different properties, the rate of decomposition is also different.
We control the fermentation process mainly from the following factors:
Moisture content.
The relative water content of composting raw materials in the composting process is 40% to 70%, and the most suitable water content is 60-70% in order to ensure the smooth progress of composting. The high or low moisture content of the material will affect the activity of aerobic microorganisms and need to be adjusted for moisture before fermentation. When the water content of the material is less than 60%, the temperature is slow and low decomposition is poor. Humidity of more than 70% affects ventilation to form anaerobic fermentation heating slow decomposition effect is not ideal.
Studies have shown that water in compost heaps can promote the decay and stability of compost during the most active stages of microorganisms. The amount of water should be maintained at 50-60% at the beginning of composting. Since then, moisture remains at 40 to 50 per cent and in principle no water droplets can be seeped out. After fermentation, the moisture content of the raw materials should be controlled below 30%, if the water content is high should be 80degrees C drying.
Temperature control.
Temperature is the result of microbial activity. It determines the interaction between raw materials. At an initial temperature of 30 to 50 degrees Celsius, heat-obsessed microorganisms℃ degrade large amounts of organic matter and quickly break down cellulose in a short period of time, thereby promoting the increase in compost temperature. The optimum temperature is 55 to 60 degreesCelsius. High temperature is necessary to kill pathogens, eggs, weed seeds and other toxic and harmful substances. Kill hazardoussubstances for hours、at high temperatures of 55degrees C, 65℃、degrees C, and70 degrees C. It usually takes 2 to 3 weeks under normal temperature conditions.
We mentioned earlier that moisture content is a factor affecting compost temperature. Too much water will reduce the compost temperature, adjusting the moisture is conducive to the late warming of compost. It is also possible to reduce the temperature by increasing moisture to avoid high temperatures during composting.
Turning the pile is another way to control the temperature. By flipping the heap can effectively control the temperature of the reactor to increase the evaporation of water so that fresh air into the heap. Walking dumper is an effective way to reduce the body temperature of heap. It has the characteristics of simple operation and good price and good performance. The fermentation temperature and high temperature time can be effectively controlled by constant dumping.
Carbon-nitrogen ratio.
Proper carbon nitrogen can promote the smooth fermentation of compost. If the carbon-nitrogen ratio is too high, the degradation rate of organic matter slows due to the lack of nitrogen and the limitation of the growth environment, resulting in longer fertilizer composting time. If carbon-nitrogen ratio is too low-carbon can be fully utilized, excess nitrogen in the form of ammonia loss. It not only affects the environment, but also reduces the effectiveness of nitrogen fertilizer. Microorganisms form microbial progeny during organic fermentation. The progeny contains 50% carbon,5% nitrogen and 0. 25% phosphoric acid. The researchers recommend a suitable compost C/N 为 of 20-30%.
The carbon-nitrogen ratio of organic compost can be regulated by adding high carbon or nitrogen. Some materials, such as straw, weeds, dead branches and leaves, contain fiber, ligand and pectin. Due to its high carbon/nitrogen content, it can be used as a high carbon additive. The high nitrogen content of animal and poultry manure can be used as a high nitrogen additive. For example, the utilization rate of ammonia nitrogen in pig manure is 80% of microorganisms, which caneffectively promote the growth and reproduction ofmicroorganisms and accelerate the decay of compost.
Ventilation and oxygen supply.
It is very important to have enough air and oxygen for manure fermentation. Its main function is to provide the necessary oxygen for the growth of microorganisms. The maximum temperature and time of occurrence of compost are controlled by controlling ventilation to regulate the temperature of the compost. Increasing ventilation while maintaining optimum temperature conditions removes moisture. Proper ventilation and oxygen can reduce nitrogen loss and odor production in compost.
The moisture content of organic fertilizer has an effect on breathability, microbial activity and oxygen consumption. It is a decisive factor in aerobic composting. It needs to control moisture and ventilation according to the properties of the material, to achieve water and oxygen coordination. At the same time, both, to promote microbial growth and reproduction to optimize fermentation conditions.
The results show that oxygen consumption increases exponentially below 60 degrees C, relatively slowly at 60 degrees C or above, and close to 0 above 70 degrees C. The amount of ventilation and oxygen should be adjusted according to different temperatures.
pH control.
The pH affects the entire fermentation process. In the initial stages of composting,pH affects the activity of bacteria. For example, pH?6.0 is the critical point for pig manure and sawdust. It inhibits the production of carbon dioxide and heat at pH slt;6.0. At PH values of 6.0, its CO2 and heat increase rapidly. When entering the high temperature phase, the joint action of high pH and high temperature causes ammonia volaten. Microbes break down organic acids through compost, reducing the pH to about 5. Volatile organic acids can evaporate as temperatures rise. At the same time, the erosion of ammonia by organic matter increases the pH. Eventually it stabilizes at a higher level. At high compost temperatures,pH from 7.5 to 8.5 can reach the maximum composting rate. Too high a pH can also cause too much ammonia volatilization, so you can reduce pH by adding alum and phosphoric acid.
In short, controlling the efficient and thorough fermentation of organic raw materials is not simple. This is relatively easy for a single raw material. However, different raw materials interact and inhibit each other. To achieve the overall optimization of composting conditions, the cooperation of each process is required. When the control conditions are appropriate, fermentation is carried out smoothly, thus laying the foundation for the production of high-quality organic fertilizers.
Post time: Sep-22-2020