The production of organic fertilizer from livestock manure by aerobic composting can not only solve the non-point source pollution problem, but also promote the development of ecological recycling agriculture and efficient animal husbandry. When livestock and poultry manure is treated, there are two states: liquid manure and solid manure. The composting methods of liquid manure include anaerobic fermentation technology and natural biological treatment technology. The main treatment method of solid waste is composting technology. Composting refers to the process in which organic matter is mineralized, humified and harmless by high-temperature fermentation under the action of microorganisms and becomes a mature fertilizer.
The whole process can be divided into three parts: pretreatment of raw materials, aerobic fermentation and granulation.
1. The pretreatment of raw materials includes solid-liquid separation, excipient crushing, water content and C/N ratio of raw materials. The pH is worth adjusting.
2. Aerobic fermentation includes flipping, ventilation and other measures, which can supplement oxygen, control temperature, release moisture and restore porosity of raw materials.
3. Pelletizing is a systematic project, which is centered on pelletizing. There are grinding, mixing and proportioning processes in front, drying, cooling and sieving processes afterwards.
I.Fermentation
compost equipment
Fermentation methods of livestock and poultry manure include stacking fermentation, tank fermentation and tower heating fermentation. Strip stacking fermentation is the most original fermentation method. It has long fermentation cycle, general effect and large area, but its production process is simple and its cost is low. Tank fermentation has strong controllability, can effectively shorten the fermentation cycle, fermentation effect is good, but the cost of soil construction is relatively high, equipment often needs customization, installation costs are high and so on. The sealing performance of tower heating fermentation is stable, movable, and the fermentation effect is good. The fermentation period is generally about one week, but the equipment investment is high.
Trough fermentation equipment mainly refers to trough flipper. The general trough flipper is equipped with a machine with multiple troughs. The transfer of the flipper between fermentation tanks can be realized by a transfer machine. The trough flipper is mainly composed of frame, flipping device, walking mechanism, cable winding device, electronic control system, etc. It is mainly driven by electric power. The trough fermentation system has the advantages of small space, high composting depth (0.8-2.5m), fast heating and large processing capacity. It is widely used in China and is the main turning device for livestock and poultry manure composting in China. In the process of tank fermentation, it can maintain and ensure the alternating state of medium temperature - high temperature - medium temperature - high temperature, and effectively shorten the fermentation period. A device for adding bacteria was installed on the flipper, which can spray alcohol evenly and proportionally during the fermentation process. At the same time, ventilation pipes can be laid at the bottom of the groove, and ventilation capacity can be increased. The trough dumper is suitable for fine and large-scale production, which is conducive to production management and production cost control. Produced products with high efficiency, stable and reliable operation, durable, even turning, by the market praise of the turning machine.
II.
Fertilizer granulation equipment
Granulation is a unique link between China and Europe and the United States. Granular fertilizer has good commodity properties, and it will not be automatically graded in storage and transportation. It has slow release property and can create aggregate structure for the soil. At present, the main methods of organic fertilizer granulation in the market are extrusion granulation and agglomeration granulation. The commonly used equipment for extrusion granulation is roller extrusion granulator, which is widely used in organic fertilizer granulator. It belongs to extrusion slip model and can continuously produce one roll forming. Material is added from the feeding hopper, extruded by roll, demoulded and pelletized, then transferred to the screen to screen and separate the finished particles, and then returned to mix with the new material, and then granulated. In addition, extrusion granulation equipment also has flat-die pelletizer and ring-die pelletizer. The commonly used equipment for agglomeration granulation is disc granulator and drum granulator. Disc granulator is a kind of mature organic fertilizer granulating equipment. The angle of the granulating disc adopts body arc structure. The material entering the disc is made of atomizing nozzle, spraying appropriate amount of liquids, and then rotated by the granulating disc to produce granulated products, forming a certain amount of inertia after rotating with the disc. Rotary drum granulator has a special structure inside the simplex. The material to be granulated is rotated through the rotary motion of the simplex to produce rolling rotation in the cylinder. The ball is bonded to form a ball at a certain humidity and temperature to complete the ball-making.
