After using it for a while, Mr. Li found that the shredder was really easy to use. "My family doesn't cook much, and there are no big bones. If you throw the peel and stone directly in, there will be no wet garbage at home, which is very convenient. " So, Mr. Li also made Amway for relatives and friends, which he thought was a must-have product at home.
In fact, the garbage crusher bought by Mr. Li has become the latest explosive product. A big data from domestic retail platforms shows that in June1-June 13, the omni-channel sales of garbage processors increased by 6 12.85% year-on-year, with Shanghai increasing by 99 1.96% year-on-year. Moreover, the prices vary a lot, from cheap equipment of more than 300 yuan to high-end products of more than 8,000 yuan. The installers are too busy.
Then the question is, is the shredder really worth popularizing?
Deng Jianping, director of the Shanghai Municipal Bureau of Greening and City Appearance, made it clear at a recent press conference that at present, families in Shanghai are not encouraged to use wet garbage shredders. He analyzed three hidden dangers of wet garbage being directly discharged into sewage pipes after being crushed.
First of all, there is a phenomenon that rain and sewage are mixed in Shanghai. If the crushed wet garbage is discharged into the river, it is likely to aggravate the pollution of the river.
Secondly, the fine particles of wet garbage are easy to deposit in the pipeline, which increases the risk of pipeline blockage. In addition, considering the dining habits of China people, wet garbage has a high oil content, which is easy to adhere to pipelines, and may also cause pipeline blockage.
In addition, the wet garbage deposited in the pipeline has a high organic content, which is prone to anaerobic digestion, producing biogas and hydrogen sulfide, which poses a safety hazard to the pipeline.
Therefore, Deng Jianping said: "Before the transformation of rain and sewage mixed discharge in the whole city is completed, we do not encourage families to use wet garbage shredders. We hope that the citizens will do a good job in garbage sorting according to the relevant requirements of the municipal government on garbage sorting. Next, the relevant departments of the municipal government will speed up investigation and research and give guidance on the use of wet waste pulverizers. "
In fact, experts have discussed and argued about the new way out of kitchen waste.
The research team of Wang Kaijun, a professor at Tsinghua University Environmental Research Institute, pointed out in the topic "Reduction of Household Kitchen Waste Based on Crushing Treatment and Its Impact on Sewage" that the crushing and direct discharge of kitchen waste can alleviate the current situation of carbon source shortage in urban sewage treatment plants in China to some extent. At present, China's urban sewage treatment plants have enough surplus capacity to absorb domestic kitchen waste, which can solve the problem of lack of infrastructure after the separation of domestic kitchen waste and urban domestic waste, and is also conducive to landfill, incineration or other garbage.
However, some experts believe that direct discharge of kitchen waste does more harm than good.
Zheng Xingcan, chief engineer of china municipal engineering North China Design and Research Institute, believes that on the one hand, it will undoubtedly increase the amount of sludge if the kitchen waste is directly discharged into the sewer after being crushed, which will make it more difficult and costly to treat and dispose. In addition, a large number of inert solids and insoluble biodegradable organic matter enter the sewage biological treatment system, which has limited contribution to the improvement of ammonia-nitrogen ratio, but has great influence on the increase of sludge volume, the decrease of sludge activity and the stable discharge of effluent.
Wang Jiazhuo, director of the Institute of Resources and Energy of Water Branch of China Urban Planning and Design Institute, also pointed out that the operation and maintenance of sewage pipe network in China is not enough. After the kitchen waste enters, it is necessary to increase the frequency of operation and maintenance, professionals and funds, which are not realistic in most cities at present.
Tang Jianguo, chief engineer of Shanghai Urban Construction Design & Research Institute (Group) Co., Ltd., made a clearer analysis. He believes that kitchen waste will be "fished out" in different parts when it enters the drainage pipeline.
After the kitchen waste is crushed, it enters the drainage pipe, most of which is insoluble, and some of which enters the water body through the drainage pipe. In the case of polluting the water body, the water body cleaning staff still have to fish out the garbage. Fine kitchen waste will increase the workload of the already hard cleaning staff. A part of kitchen waste gathered in the pipeline and was cleaned up by the maintenance personnel of the drainage pipeline as pipeline sludge. Because of the high viscosity of kitchen waste, it is more difficult to maintain the drainage pipeline. Part of the kitchen waste enters the sewage treatment plant with the sewage, and is intercepted as grid slag, which will increase the workload of the grid of the sewage treatment plant. "Foreign families can do this, there must be its specific conditions and related countermeasures. In Germany and Japan, household kitchen waste is not allowed to enter the drainage pipeline. "
Tang Jianguo emphasized that kitchen waste is a valuable resource and should not be discarded. "Kitchen waste contains high organic matter. As long as the technical route is used correctly, the processed products can be recycled. For example, anaerobic digested biogas is biomass energy that is not included in carbon emissions, and biogas residue is biochar soil rich in precious humic acid. "
In addition to experts' arguments, sewer workers who are struggling in the front line also have something to say. Generally, the community will have its own septic tank, and the discharged domestic sewage will enter the septic tank through the pump. Several septic tanks will discharge the sewage containing less solid substances into the pipeline after flotation and precipitation, and the pipeline will lead to the sewage treatment plant, and then it will be treated into reclaimed water through similar processes and dosing.
Both septic tanks in residential areas and treatment tanks in sewage treatment plants need to remove sediments and floating objects. More garbage will be crushed, even if the kitchen waste is so discharged, the most intuitive effect is to increase the number of cleaning and storage.
"It seems that your home is convenient, but in fact you left the trouble to others." Although sewage treatment plants can treat more "dirty" sewage, there is an upper limit to this treatment capacity. He is worried that if more families discharge garbage into sewers, the sewage treatment plant will be overwhelmed.
However, some bungalows and a few old buildings with a long history have no septic tank design, and the sewage directly flows into the pipeline to the sewage treatment plant, which directly increases the treatment burden. "Sewers should not be rubbish. Cooking and washing dishes will bring some garbage, which is inevitable If our pipeline is small, it can be tolerated. If it is big, it is hard to say. "
Garbage sorting is not only to reduce the generation of garbage, let people live within their means, but also to turn waste into treasure. It is not a kind of resource utilization that wet garbage is crushed and sent to sewage treatment plant. It seems that everyone is still working, so throw it away and wash it in time!