In the face of increasing plastic pollution, especially the one-off plastic waste, some industries, such as express delivery, take-away, and related policies, have begun to propose the use of biodegradable plastics instead of traditional plastics as a solution. However, what is currently in China? Degraded degradable plastics lack scientific, clear definition and understanding to solve the problem of disposable plastic waste. Can degradable plastics really become a savior to replace traditional plastics?
At the September 19th Get Ridition Joint Action Public Welfare Forum, we invited Dr. Mao Da, the chairman of the environmental protection organization Shenzhen Zero Disposal, to share, to clarify what is a degradable plastic, and proposed a degradable plastic. How can we not become a new type of pollution, the following is based on the sharing of Dr. Ma Da.
When we talk about the so-called environmentally friendly biodegradable plastics, we are generally talking about 'biodegradable plastics'.
Current plastics can be divided into two categories from the perspective of biodegradability: biodegradable and non-biodegradable.
Biodegradable means that 100% can be converted from inorganic to inorganic components, water and carbon dioxide; rather than biodegradable, it will not be biodegraded into inorganic matter or water and carbon dioxide.
Among them, plastics can be divided into bio-based and fossil-based materials according to the raw materials. Bio-based plastics are plastics made from biomass (including animals, plants and microorganisms); fossil-based plastics are raw materials derived from fossil raw materials. .
Traditional plastics are neither biodegradable and made of fossil based.
Non-degradable plastics are also likely to be made from biological materials, such as quadrant A. Many of our polyethylenes are now made from bio-based materials. We can call them bioplastics. In fact, it is the same as traditional plastics. After entering the environment, it will also cause persistent pollution problems due to non-degradability, so if bioplastics = degradable plastics, it is not correct.
The material is not made from biological materials, but can be completely degraded by organisms, such as PBAT and PCL, which are refined from petroleum and biodegradable.
At present, we talk about more biodegradable plastics. More refers to C-quadrant materials, which are made from biomass, such as corn starch or sugar cane, and can be biodegraded.
Mauda mentioned that no matter what kind of material supplies, there are three fundamental reasons for pollution problems:
1. No closed cycle: Large products are not recycled, entering landfills, incineration sites and entering the environment;
2. There is no total control: the material flow consumption is always too large, and the circulation cannot solve the problem;
3. Add toxic and hazardous chemicals to the manufacturing process.
First, raw materials must be sustainable and not put too much pressure on the environmental system. For example, traditional oil is unsustainable, first, raw materials are not sustainable, and second, petrochemical products will produce various environmental pollution throughout the life cycle.
Second, full recycling. The recycling rate of traditional plastics is very low, but it does not mean that other alternative materials can have high recycling efficiency. The correct treatment of biodegradable plastics is compost, but in existing recycling. In the case of imperfect channels, it is a challenge to ensure that biodegradable plastics can be sent to the composting channel separately from other waste.
Third, non-toxic addition. There are many toxic additives in plastics. If biodegradable plastics are not well done, it is also possible to produce toxic and hazardous substances. Material substitution should reduce harmful additives.
Promote biodegradable plastics? Is the cultivated land enough?
According to the need of 0.18 hectares of arable land for each biodegradable plastic, if the current national 80 million traditional plastics are replaced by biodegradable plastics, the required cultivated area is equivalent to that of Henan Province and Shandong Province.
Let's count the disposable plastic packaging – the main plastic waste entering the environment. About 1/4 of the existing plastic production is used for packaging. If this part of the plastic is replaced by degradable plastic, then you need a Hunan province. Large arable land can meet such needs. These are obviously unsustainable, so there must be some control over the consumption of plastic products.
Can biodegradable plastics really degrade in nature?
Previously, there were experts from China Post's industry, the plastic bags that are commonly used at present, need 200 in natural conditions to achieve degradation, while biodegradable plastic express bags are discarded, under natural conditions (such as soil, sand, etc.) and specific Under conditions (such as composting, anaerobic digestion, aqueous culture), natural degradation caused by the action of microorganisms in nature, after 6 months can be completely decomposed into carbon dioxide, methane, water and its mineralized mineral salts 4. The impact on the natural environment is basically negligible.