In order to promote the green development of agriculture in China, the Ministry of Agriculture and Rural Affairs has launched five major actions, including the action of utilizing livestock and poultry manure resources and the action of replacing chemical fertilizers with organic fertilizers for fruits, vegetables, and tea. Strive to basically solve the problem of large-scale livestock and poultry farm manure treatment and resource utilization by 2020.

Not long ago, the General Office of the Ministry of Agriculture and Rural Affairs issued a notice on the establishment of a leading group for the treatment and resource utilization of livestock and poultry breeding waste in the Ministry of Agriculture. The group aims to coordinate the treatment and resource utilization of livestock and poultry breeding waste, study and solve major problems, strengthen top-level policy design, coordinate and promote key work, and organize supervision and inspection.

Minister of Agriculture and Rural Affairs Han Changfu stated that the use of chemical fertilizers in fruit and vegetable tea accounts for 40%, and promoting the replacement of chemical fertilizers with organic fertilizers in fruit and vegetable tea is a key focus!

One is to strengthen the resource utilization of livestock and poultry manure.

Based on the benchmark of resource and environmental carrying capacity, optimize the layout of livestock and poultry breeding areas, fully implement the local governments territorial management responsibility and the main responsibility of livestock and poultry farmers for the resource utilization of organic fertilizers from livestock and poultry manure, support the promotion of livestock and poultry manure resource utilization in all counties, and promote the formation of a sustainable operation mechanism for the resource utilization of livestock and poultry manure.

The second is to strengthen the reduction and efficiency improvement of chemical fertilizers and pesticides.

Continue to implement the action of replacing chemical fertilizers with organic fertilizers for fruits, vegetables, and tea, and zero growth in the use of chemical fertilizers and pesticides. Increase efforts in green prevention and control of crop diseases and pests, and carry out pilot projects for green prevention and control throughout the entire process of fruits, vegetables, and tea.

Thirdly, we need to strengthen the protection and improvement of farmland quality.

We will continue to promote the replacement of chemical fertilizers with organic fertilizers, deepen the improvement of rural living environment, reduce the use of agricultural inputs such as fertilizers and pesticides, and recycle organic fertilizers from livestock and poultry manure waste.

Composting treatment technology

Animal manure is generally treated in two forms: liquid manure and solid manure. The treatment methods for liquid feces include anaerobic fermentation technology and natural biological treatment technology, while the main treatment method for solid feces is composting. Composting refers to the process in which organic matter is mineralized, humified, and rendered harmless (by killing pathogens, insect eggs, weed seeds, etc.) through high-temperature fermentation under the action of microorganisms, and becomes composted fertilizer.

The composting process can be summarized into three stages: 1. Raw material pretreatment, 2. Aerobic fermentation, and 3. Granulation and shaping.

Raw material pretreatment includes solid-liquid separation, auxiliary material crushing, and adjustment of raw material moisture content, carbon nitrogen ratio, and pH value. The aerobic fermentation process includes measures such as flipping and ventilation, which play a role in supplementing oxygen, controlling temperature, dissipating moisture, and restoring porosity to the raw materials. Granulation molding is a systematic engineering process that revolves around the core of granulation molding. It involves processes such as crushing, batching, and mixing, followed by drying, screening, and cooling.

Raw material pretreatment and equipment

Raw material pretreatment mainly involves preparing fermentation materials that meet the requirements of aerobic fermentation. The main process includes solid-liquid separation of animal manure, crushing of auxiliary materials, and mixing ratios of various raw materials.

Solid liquid separation equipment

The raw material for composting treatment is solid feces. The sources of solid feces are dry and clean feces, as well as solid substances separated from "blister feces" through solid-liquid separation methods. To achieve solid-liquid separation, mechanical separation is widely used and has good separation effect. Mechanical separation equipment can be divided into four types: screening separation, centrifugal separation, pressure filtration separation, and spiral extrusion separation.

1) Screening and separation machinery: The screening machinery used for separating livestock and poultry manure mainly includes inclined plate screens and vibrating screens. The inclined plate sieve with a wedge-shaped cross-section is used for fecal separation and has the characteristics of simple structure and non clogging. But the removal rate of solid matter is relatively low, generally less than 25%.

2) Centrifugal separation machinery: Centrifugal solid-liquid separators used for livestock and poultry manure mainly include filtration centrifuges and horizontal spiral centrifuges. The advantages of centrifugal separators are fast separation speed and high separation efficiency; The disadvantages are large investment, complex structure, and high energy consumption.

3) Filter press separation machinery: The filter press has the advantages of large processing capacity, easy operation and management, low moisture content in the filter cake, no vibration, no noise, and low energy consumption. Due to the use of filter belts to separate solids and liquids, high-pressure water is required to continuously flush and increase the sewage treatment capacity to prevent filter belt blockage, resulting in high costs.

4) Spiral extrusion separation machinery: Spiral extrusion separator is a relatively new type of solid-liquid separation equipment, which is currently widely used in the solid-liquid separation of livestock and poultry manure. Its drawback is that before separation, the original fecal water needs to be stirred evenly with a stirrer, which causes a large amount of solid organic matter in the fecal water to dissolve in the water, making the post-treatment of wastewater extremely difficult and the treated effluent difficult to meet discharge standards. In response to some of the existing shortcomings, a new type of solid-liquid separator can be researched and designed to improve the separation mechanism, prevent fecal liquid from directly entering the separation system, enhance the anti blocking ability of the screen mesh, greatly improve the working efficiency and separation effectiveness of the equipment, and reduce the solid moisture content.

01

Crushing equipment

02

mixing equipment

Mixing refers to the process of uniformly mixing solid feces, excipients, and various conditioning agents according to a predetermined formula ratio. Pre mixing the raw materials can achieve the required carbon to nitrogen ratio throughout the reactor, ensuring the survival and reproduction of microorganisms. According to the properties of the mixed materials, it is advisable to use a dual axis gravity free mixer. The horizontal cylinder of the machine is equipped with dual axis rotating blades that rotate in the opposite direction. The blades form a certain angle to circulate and stir the material along the axial and radial directions, allowing the material to mix quickly and evenly. The rotational speed of the shaft driven by the reducer and the structure of the blades will weaken the gravity of the material. Even if there are differences in the specific gravity and particle size of the material, it can still achieve good mixing effect under the rapid and intense rolling and throwing of the staggered mixing blades. If the function automatically controls the mixing time based on the properties of the raw materials, better results and efficiency can be achieved.

03

fermentation equipment

The fermentation methods for producing organic fertilizer from livestock and poultry manure include: stack fermentation, trough fermentation, and tower heating fermentation. Stacking fermentation is a relatively primitive fermentation method with a long fermentation cycle, average fermentation effect, and a large footprint. However, the production process is simple, equipment debugging is convenient, and the cost is low. Slot fermentation has strong controllability, can effectively shorten the fermentation cycle, and has good fermentation effect. However, the construction cost is relatively high, and the equipment often needs to be customized, resulting in high installation costs. The tower heating fermentation has stable sealing performance, strong mobility, good fermentation effect, and a cycle of generally less than one week, but the equipment investment cost is high.

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Stacked fermentation equipment

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Tank fermentation equipment

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Granulation molding equipment