Accompanied by the waste classification boom in Shanghai, household food waste disposal equipment has quietly become a hot product. This equipment can take on this important task?

Kitchen waste processor installed in the kitchen downpipe, can be fruit and vegetable skin, residues and leftovers crushed off, and ultimately discharged into the sewage pipe. Obviously, this kitchen "magic weapon" can reduce wet garbage from the source.

However, with the sale of food waste processor hot, there are more issues of concern: the effect of food waste crushing is good? Is there enough capacity in the city's underground pipeline network? Because of the history and other reasons, most of the cities in China have a mixed rainwater and sewage phenomenon, whether the direct discharge of food waste will aggravate the pollution of the river?

Sales on e-commerce platforms have increased dramatically

According to official statistics, in recent years, Shanghai produces more than 20,000 tons of household garbage every day, and food waste accounts for more than 60%.

June 17, surging news (www.thepaper.cn) reporter from the e-commerce platform search to see that the household food waste treatment equipment has more than 300 yuan of cheap equipment, but also as high as more than 8,000 yuan of the "magic weapon".

A big data from the domestic retail platform shows that from June 1 to 13, the garbage disposal all-channel sales increased by 612.85% year-on-year, of which 991.96% year-on-year growth in Shanghai, becoming the hottest domestic sales of similar products in the city.

According to industry insiders, different equipment running costs average less than 5 dollars a month, each family can buy different grades of configuration according to different needs, generally can afford.

In fact, in Europe and the United States, food waste crushing and direct discharge system has been quite common.

Public information shows that in 1927, the first food waste crusher was born in the United States. Currently, 80% of the new homes in the United States are equipped with food waste processors.

In Asia, in 2000, Japan enacted the Food Waste Recycling Law, the purchase of electric food waste shredding device families only need to pay for their own 10,000 yen. Once shredded, household food waste can be discharged directly into the sewer, or dried with hot air into a powder that can be processed into organic fertilizer.

Therefore, some people believe that installing household food waste shredding equipment can reduce the amount of wet waste produced, which reduces the pressure on both source separation and end-of-pipe treatment.

The underground pipeline network was not designed to accept food waste

Can food waste disposers solve the problem of wet waste in Shanghai?

"The food waste shredder has its value, but it's not possible to treat all household wet waste with it and then drain it straight into the sewage pipes." A source close to Shanghai's water department told reporters that this is a major test for the city's underground pipeline network that connects homes and sewage treatment plants.

Generally speaking, the municipal sewage network in the beginning of the design and did not consider the acceptance of food waste, after crushing food waste can be successfully transported to the sewage plant, the pipe diameter of the network, slope, water level, pumps and so on are all influential factors.

Jiang Jianguo, a professor at Tsinghua University's School of the Environment, said that food waste is not liquid when it is cracked, and it will settle in the pipeline over time. Especially in winter, the grease in the meal into the pipeline, mixed in the garbage together with the frozen, even if the pipe diameter is large, it is very likely to cause clogging.

At the same time, food waste into the pipeline, the concentration of organic matter in the sewage will be increased, such as COD (Chemical Oxygen Demand) and BOD (Biochemical Oxygen Demand) concentration will change, so the supporting facilities of the sewage treatment plant must be improved in a timely manner. In essence, crushing wet waste and discharging it to a sewage treatment plant is not a form of resource utilization.

In addition, many municipal pipe networks have the problem of mixing rainwater and sewage, which means that some of the sewage formed by crushing food waste may be discharged directly to rivers and oceans through the stormwater network, becoming a new source of pollution in rivers.