The implementation of the "Shanghai Municipality's Regulations on the Management of Domestic Garbage" not only brought fires to the trash bins, but also increased sales of degradable garbage bags. Open the e-commerce website, enter the degradable wet garbage bag, and the products that popped out are many, and many of them are marked with the words "for the future, fully biodegradable, and only want to contribute to environmental protection."
"This is a degradable and environmentally friendly plastic bag that can be thrown with wet garbage!" Since the implementation of waste classification, some residents feel that it is troublesome and dirty to put in wet bags, which is troublesome and dirty. Degradable garbage bags in ordinary plastic bags. "The smell of wet trash cans is too pungent, and mosquitoes are much older in summer! Environmentally friendly plastic bags do not need to be 'broken bags' and can reduce odors," said a resident. Can these so-called "degradable garbage bags" be put together with wet garbage? For this purpose, the reporter interviewed Yang Fuxin, deputy director of the Green Packaging Committee of the Chinese Society for Environmental Protection and professor of the School of Food Science at Shanghai Ocean University.
"Citizens will see businesses showing a lot of qualification certifications, but these are standards in specific environments and are not combined with environmental parameters such as actual land, temperature, and humidity." Yang Fuxin told reporters. At present, there are many types of environmentally friendly plastic bags on the market, but many of them are the products of plastic and starch. After leaving the factory, they are marked with "environmental protection", but the price is not cheap. "Starch does degrade in a wet compost environment, but plastic stays in the soil."
But even biodegradable plastic bags are not as "perfect" as everyone thinks. Yang Fuxin introduced that in a strong acid and alkali environment, that is, when the pH value is between 1-2 or 11-13, it takes one or two months for the molecular chain of the degradable plastic bag to break. "If put into the natural environment, the molecular chain of the degradable plastic bag lacks sufficient stable conditions to break the chain, and the degradation time will be longer. The temperature, moisture content, and different bacteria will also affect the degradation rate."
How long does it take for the degradable plastic bag to degrade? There is no research data and it is not practical to conduct research. "It is impossible to artificially create conditions like in the laboratory." Yang Fuxin said, "but there is no doubt that they will still pollute water quality and air during the degradation process."
In addition, the so-called "degradable garbage bags" on the market are not cheap, and are almost 1.5 times the price of ordinary plastic bags. "Consumers buy these things for peace of mind and think they have contributed to environmental protection." Some experts also said that when the degradable plastic bags enter the end-of-life disposal process with wet garbage, it is undoubtedly a tortoise. The race is up—wet trash can be as fast as five or six hours, and as slow as two weeks, it can be turned into an organic medium, and the degradable plastic bag is even a month and a half later. In this way, the fertilizer and feed that was originally expected to be converted by wet garbage after "aerobic exercise" will be mixed with undegraded plastic. "By contrast, the" broken bag artifact "invented by residents themselves is more environmentally friendly, and it can also solve the problem that the" broken bag "is not dirty." Yang Fuxin said.