Is disposable paper cup more environmentally friendly than disposable plastic cup? No!

- Jul 25, 2019-

Is disposable paper cup more environmentally friendly than disposable plastic cup? No!

According to relevant reports, China's annual use of disposable water cups reached 20 billion, which caused a great burden on the environment and resource recycling. People use disposable products for convenience, but at present, with the improvement of people's awareness of environmental protection, consumption concepts will make appropriate adjustments. Standing in front of the supermarket's dazzling counter and commodities, the public will choose disposable water cups when the following choice questions arise:

Which is more environmentally friendly, disposable paper cup or disposable plastic cup?

In answering this question, we will take it for granted that plastics are an oil-based product, which consumes oil and energy in the production process and is difficult to degrade after use. It is one of the white pollution. The main component of paper cup is cellulose, which is a natural renewable resource. Although the production process may also produce pollution, but it does not consume petroleum products, energy consumption should be relatively low. The most important thing is that cellulose is easy to degrade and will not produce white pollution. Therefore, most people would think that disposable paper cups are more environmentally friendly than disposable plastic cups. However, the simpler the problem is, the more interesting the story is, and the fact is not as simple as imagined.

At the same time, data is the most influential: Canadian scientist Hawking made a serious analysis of this and compared disposable hot drink containers. He conducted a complete set of environmental value assessments of disposable paper cups and disposable foam plastic cups (PS, PS) from raw materials to processing procedures, materials and recycling options to final use and treatment. The final conclusion is surprising. Paper cups are not only not more environmentally friendly than plastic cups, but also several times more polluted than plastic cups in the production process.

Part A: Biotoxicity.

At present, there are three kinds of disposable paper cups on the market: the first is made of white cardboard, which is mainly used for filling dry things and can not be used for holding water and oil; the second is wax-coated paper cup, which is thicker and waterproof because it has been soaked in wax, but if the temperature of water in the cup exceeds 40 degrees C. Wax will melt, and wax contains carcinogenic polycyclic aromatic hydrocarbons; the third is now commonly used paper cup, outside is a layer of paper, inside is a layer of film paper, if the material used is not good or processing technology is not appropriate, will produce harmful substances. In addition, some manufacturers add a lot of fluorescent whitening agents to make the cup look whiter, which is also a potential carcinogen.

And disposable plastic cups often add some plasticizers, which contain many harmful substances. When they are used to fill hot water, harmful substances will dilute into the water, and the inner micro-porous structure of plastic cup body has many holes, which are easy to contain dirt and fouling, and unclean cleaning will lead to germination bacteria.

Part B: Raw materials.

Raw materials, paper for disposable cups is made from wood pulp, while hot-drink foam cups are hydrocarbons extracted from petroleum. Wood is a renewable resource, but in the process of pulp production, it is necessary to build roads and cut down trees in large quantities. These factors will have a negative impact on the natural environment. Especially if these deforestation areas occupy a large part of the watershed, it will lead to the increase of the maximum stream flow and the decrease of the minimum flow in the watershed, which will lead to the instability of the environment, sometimes drought, sometimes flooding, seriously affecting the local people's livelihood and production.

In the process of oil exploration and exploitation, it will also have an impact on the local environment and ecosystem, but because of the limited area of an oil well, its impact on the surface is smaller than that of forest cover with the same amount of wood. Therefore, from the negative environmental impact of raw materials, the same number of disposable paper cups has a wider impact than disposable plastic cups.

Part C: Manufacturing process and energy consumption.

Paper cups are made from bleached pulp, and inorganic substances are needed in the process of paper making. When unusable leaves, bark and roots are cut, nearly half of the pulping quality will be lost. Therefore, an average of 33 g wood and 4 g residual fuel are required for a 10.1 g cup to be prepared. If a paper cup needs a plastic or waxy coating, more oil will be needed. In addition, the utilization of inorganic substances in kraft pulping process is very low, resulting in an average of 1.8 g of non-recyclable chemicals per disposable cup. As far as foamed plastic cups are concerned, the required materials are only 1/6 of disposable paper cups, and solid catalysts are used in the synthesis process, which greatly improves the utilization rate and conversion rate of chemical substances. Each metric ton of polystyrene requires 33 kg of chemical input, and each cup requires an average of 0.05 g. The same quality of polystyrene only uses 3% of the chemical substances used in paper cups. In terms of energy consumption, each cup consumes six times as much wood pulp as polystyrene. Therefore, compared with foam cups, the steam consumption of paper cups is 12 times, the electricity consumption is 36 times and the cooling water consumption is 2 times. In addition, the amount of sewage produced by pulp in the process of making paper cups is 580 times that of polystyrene in the process of making foamed plastic cups. The degree of pollutant transfer from pulp production and bleaching process in sewage is determined by specific details, but other pollutants, except metal salts, are still 10 to 100 times the pollutants in sewage produced by polystyrene production.

Part D: Degradation and recovery.

Although disposable paper cups are made of cellulose and renewable, they can only be regarded as non-recyclable in technology by using water-insoluble thermoplastic resins or solvent-based adhesives, because the adhesive resin can not be removed during the refining process, and if the outer bread of the paper cup is wrapped in plastic. Films or paraffins are used to improve their performance, which also hinders the recovery of fibers. Moreover, cellulose degradation requires a certain temperature and humidity, that is to say, waste paper cups in garbage dumps may not be completely biodegradable, especially in arid areas.

Therefore, as far as disposable plastic cups are concerned, there are three main disposal methods for disposable plastic cups: landfill, incineration and recycling.

Landfill method. Although this method is simple, low cost, no need for any equipment, and because of its chemical inertia, it will not pollute the surface or endanger vegetation after deep burial. It can solve the environmental pollution at the fastest speed, but this method is not in line with the strategy of sustainable development, and there will be some potential hazards.

Incineration method. This method can convert the heat generated in the burning process of a large number of discarded plastic cups into electric energy, realize the utilization of resources and obtain economic benefits. It is economically desirable for developed countries with expensive labor force, but the burning process will produce a large number of greenhouse gases such as CO2 and polycyclic aromatic substances with strong carcinogenicity.

Recycling and reuse. This technology is the most effective way to solve the shortage of energy resources. Although the application of recycled resins in food industry is limited, it is only one of the ways to recycle plastics. They can also be used in packaging materials, insulation materials, flotation blanks, furniture, drainage pipe tiles and so on.

In recent years, plastic cups and plastic water bottles are also working towards recyclability. Biome Bioplastics also produces a bio-plastic cup using Eucalyptus as raw material, as well as biodegradable polylactic acid (PLA) plastic cup. It is reported that the new cup consists of three parts. The surface of the cup is covered with bioplastics. The inside of the cup is made of wood paper cup. The cup cover is also made of different forms of bioplastics. According to reports, the cup made of Eucalyptus material is completely recyclable, after testing, the cup can be completely decomposed after three months in the soil, which means that the landfill treatment of this cup will not appear "white pollution".

From the above analysis, it can be seen that there have been some misunderstandings about the environmental protection of disposable paper cups and disposable plastic cups. In fact, disposable paper cups are not as environmentally friendly as disposable plastic cups. Especially, the large amount of energy consumption produced in the manufacturing process of disposable paper cups is a great waste of resources and environment. And disposable cups are not as easy to degrade as you might imagine, and there are potential carcinogenic risks.

With the development of science and technology, disposable bio-plastic cups may gradually replace disposable paper cups and disposable plastic cups in the future. Considering your health and sustainable development of resources, we should use as few disposable cups as possible instead of glass cups and glazed ceramic cups. These two kinds of cups not only contain no organic chemicals in the firing process, but also have smooth surface, easy to clean, bacteria and glass. Dirt is not easy to grow on the cup wall.