The appearance of agricultural plastic film is called a white revolution in the history of agriculture. It not only benefits crop yield and labor productivity, but also provides a new method for the storage of agricultural products. Accompanied by the demand and production of agricultural film in China. Gradually increasing, the number of used agricultural film is also increasing, and then its recovery rate is not high.
As of the beginning of 2012, the use of agricultural land for agricultural use in China has reached 1.45 million tons. The recovery rate of agricultural film is only 50%, which means that nearly half of the agricultural film has not been recovered. According to the monitoring results of typical film mulch residue in Gansu Province. It shows that all monitoring plots have different degrees of residual film. The residual amount per mu ranges from 5.23 kg to 14.67 kg.
1, China's agricultural film recycling status
The recycling of waste agricultural film in China is mainly based on manual picking, and the mechanical recovery rate is less than 20%. The reasons are as follows:
The cost of agricultural film is low and the recycling efficiency is relatively low.
The fields of different planting methods have different mechanical requirements for recycling waste film, and the mechanical adaptability of machinery is poor.
Farmers do not recognize the serious harm of waste agricultural film residues in the field
The government's supervision and support is not enough, and there is no correct guidance for the recycling of used agricultural film.
According to relevant information: It takes 7-8 days for a person to recycle an acre of agricultural film. Therefore, the farmer will let the waste film rot or burn in place.
2, waste agricultural film recycling technology
At present, basically the way farmers treat waste film is as follows: Reuse, land burying, recycling and reuse.
Reuse : It is to continue to use the old agricultural film twice. The agricultural film with relatively good quality can realize dual use of one membrane or multiple membranes. With the development of new technology of agricultural film, the market for reusable agricultural film is vast.
Buried on site: This kind of treatment is simple and easy, but the pollution caused will be very serious.
recycle and re-use: It is the most ideal way to save resources and protect the environment.
Recycling technology
Incineration to recover heat
This kind of recycling efficiency is low, and the cost of collection and storage is high, and the problem of tail gas pollution caused by incineration is also very serious.
Pyrolysis
The waste agricultural film is subjected to pyrolysis reaction, and the monomer and the mixed low molecular oil are recovered. The advantage of this method is that the resource utilization rate is improved. The disadvantage is that the process is complicated, the technical requirements are high, the investment is large, and the current utilization rate is relatively low. Japan is one of the countries with developed pyrolysis technology.
Regeneration granulation
Heating and plasticizing the discarded agricultural film, then extruding and granulating, and then continuing to process the product. The recycled pellets prepared by the discarded PE film can still be used to produce agricultural film, and can also be used to manufacture fertilizer packaging bags. Garbage bags, agricultural reclaimed water pipes, fences, tree supports, pots, barrels, garbage bins, geotechnical materials, etc. PVC film recycled pellets can be used to produce heavy bags, agricultural water pipes, soles and other products.
3, there is a problem with the current film recycling
Uneven distribution of recycling sites
The development of processing enterprises is uneven, and some places are far from being remote. They are still in the recycling blind zone. At the same time, some places have established large-scale leading enterprises, and there are cases of insufficient food.
Ultra-thin film is difficult to effectively eliminate
Ultra-thin film recycling is difficult. Ultra-thin film aging is fast, easy to break, manual picking up or mechanical picking is very difficult, the residual film is barely cleaned, the common residual area is small, mixed with roots and soil. There is almost no recycling. The value of recycling.
4, countermeasures and suggestions
Strengthen financial support and support the development of processing enterprises
Since 2011, Gansu has been listed as one of the second batch of national rural environmental contiguous demonstration provinces by the Ministry of Environmental Protection. In recent years, Gansu Province has tried to establish a system for recycling and recycling of farmland residual membranes in pilot areas, and gradually formed farmers. Picking up - outlet recycling - three steps of enterprise processing support each other. Restricted waste plastic film recycling network. The project has achieved very significant results. At present, the recovery rate of greenhouse film in Gansu reaches 100%, and the film recovery rate is close to three-thirds. two.
Financial subsidies directly target farmers
In view of the rare problem of ultra-thin film recycling: At present, China has established the thickness standard of agricultural film. In order to avoid increasing the burden on farmers, we should study and formulate a financial subsidy policy. Subsidize the increased input cost of farmers using standard membranes. Ensure farmland residues from the source. Membrane recyclability.