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On the kitchen garbage leachate treatment difficulties and key points!

2021-02-05 14:10:13

  Kitchen waste in our life holds a heavy proportion in the garbage, but at the same time it also has the dual characteristics of co-existence, harmfulness and resources have two kinds of speech, a complete kitchen waste, in order to avoid bad for the environment, another expression is to begin from their advantages and disadvantages and the present situation, research and development of new technology, and share with you today the eat hutch garbage leachate treatment difficulty and the point!



Food waste can produce a lot of pollutants, such as ammonia and hydrogen sulfide, during transportation and accumulation. These substances dissolve directly in the leachate of kitchen waste and become a major disposal problem.

Since the country vigorously promoted garbage classification in 2019, all parts of the country have formed a three-year plan to implement garbage classification at local level. After garbage classification, the water quality of leachate is bound to have a great impact. The landfill leachate and the water quantity and quality of the leachate of the waste incineration power plant will have a great impact. Relatively speaking, the two kinds of leachate have many cases and are relatively mature, which will be improved and adjusted to some extent on the basis of the original.

The leachate of kitchen waste after garbage classification has become the focus of more attention. After the distribution of garbage, the on-site disposal of kitchen waste (wet garbage) ushered in the "spring", and it is showing an outbreak trend at present. At the same time, one of the environmental problems limiting the promotion of the local treatment system is the standard discharge of the leachate (sewage).

To consider how to reach the standard of leachate (sewage) of kitchen waste, we first understand the composition of kitchen waste, and analyze the water quantity and quality of the leachate (sewage) from the moisture content of kitchen waste, so as to design accordingly.

On July 17, 2020, the analysis of the composition and nature of terminal household waste in Guangzhou in 2019 was published on the official website of Guangzhou.

In 2019, according to analysis of guangzhou city living garbage physical (weight percentage) is as follows: kitchen waste class (mainly for perishable organic garbage) 8.66% 55.04% 23.03%, rubber and plastic, textile, paper, glass, MuZhu 2.22% 6.99% and 1.64%, mixed 0.93%, brick and tile ceramic, metal, 0.80% 0.68%, other 0.01% (among them, the "mixed type" refers to the particle size of less than 10 mm, a mixture of classification is difficult; "Other" refers to materials such as discarded batteries). The main properties of MSW are as follows: bulk density 266kg/m3, moisture content 54.54%, wet base low calorific value 6869kJ/kg.

Specifically, according to the analysis of relevant papers, the average moisture content of kitchen waste (kitchen waste) components is as high as 79.5%, and the main dry-based components are food waste and bone shellfish, with high total oil and rich nutrients. In the kitchen waste, solid waste accounts for 18%, waste oil accounts for 3%, and kitchen waste water accounts for 79%. Food solid waste mainly contains starch, crude protein and crude fat, accounting for 32%, 20% and 29% of the total weight respectively.

According to the paper "Analysis of Physical and Chemical Characteristics of Household Kitchen Waste after Classification in Shanghai"

Kitchen waste was carried out on the selected six streets and fully tested the physical and chemical properties, the test result shows that Shanghai kitchen waste moisture content is between 73% ~ 89%, C/N ratio between 14 to 20, fat content is between 0.7% ~ 2.1%, protein between 1.25% ~ 2.15%, the salt rate is between 0.09% ~ 0.29%, heavy metal content is below the contaminants in food limited (GB2762-2012) limit standard.

China municipal engineering design & research institute of north China senior engineers, senior leachate treatment expert du yu was in May 2020 live, eat hutch garbage leachate executive level 3 standards mostly, but more strict to the requirement of total nitrogen, and eat hutch waste liquid waste plant cannot be given, so the membrane in the heart of the eat hutch garbage leachate has more application prospects.

If using anaerobic fermentation processing of eat hutch garbage, as happened in the anaerobic ammoniation, high concentration of ammonia nitrogen in the biogas slurry (established project measured values as high as 4000 mg/l), in the light of the characteristics of high water total nitrogen applied to the kitchen waste leachate treatment, will be within the scope of the whole process considering the problem of denitrification, and should not rely on a certain point.

The whole process of removing nitrogen from kitchen waste leachate and the process without concentrated solution will meet the social demand, and it is also the difficulty and key point of kitchen waste leachate.