Food waste is the most common kind of waste in our daily life, which is produced by the processing of animal and plant raw materials, which is rich in organic and inorganic substances. With the rapid development of China’s economy and the adjustment of economic structure, the demand for environment, energy, especially green renewable energy is becoming more and more urgent. Efficient use of energy in these wastes is the future direction of development. In recent years, cities have actively carried out garbage classification. After the implementation of garbage classification, kitchen waste can be directly disposed of, which is much more convenient. So what are the ways of food waste disposal? How to deal with food waste is the most environmentally friendly?
The following are the food waste treatment processes and comparisons:
| Anaerobic fermentation process | Aerobic fermentation proces | Feed chemical process | Landfill process | Incineration process | |
| Process introduction | The anaerobic bacteria are fermented in a closed container, the macromolecular substances are degraded into micromolecular substances, and finally biogas, biogas slurry and biogas residue are produced. The product composition is complex, and the subsequent treatment is complex | Through special high-temperature fermentation equipment, intelligent fermentation, independent research and development of operation process, material stirring and fan ventilation and oxygen supply, the effect of material decay and heat is good. | After solid-liquid separation, sterilization and drying are carried out, and then fungi are added for biodegradation to obtain feed. | It is mixed with other garbage and landfilled in the landfill site, with simple process, low operation cost and large treatment capacity. | Combustible substance in that garbage are combusted to generate heat for pow generation |
| Processing capacity | Large, more than 200t/d | Small, 10-100t/d | Small, 0.3-5 t/d | Large | Large |
| Dwell time | 20-25 days | 7-12 days | 1 day | Long term | none |
| Warehouse type | Cloverleaf | Cloverleaf | Horizontal | Trough type | Incinerator |
| Closed or not | Can be completely closed | Can be completely closed | Can be completely closed | Open or covered with soil | Closed |
| Equipment condition | Pretreatment + anaerobic reactor | Pretreatment + Itchy Fermentation Equipment | Pretreatment + bio-drying | Landfill | Pretreatment + incinerator |
| The amount of dry material added | Do not add | Little or no addition | Do not add | Mixed with other garbage | Little or no addition |
| Odor pollution | No odor is generated | Yes, it is completed through the combination of the closed bin and the deodorization system | Basically no other emissions | There is odor or liquid leakage and overflow, and it is difficult to control. | Emissions of gaseous and solid products, hazardous to health |
| Product | Biogas, biogas slurry and biogas residue need further treatment before they can be used. | Organic fertilizer | Feed + biodiesel feedstock | none | Burning ash |
At present, the most environmentally friendly treatment methods of food waste are aerobic fermentation and anaerobic fermentation. Aerobic fermentation is mainly through the aerobic respiration of microorganisms, and anaerobic fermentation is the fermentation of organic matter in an environment with little oxygen. Although both aerobic fermentation and anaerobic fermentation use organic wastes such as kitchen waste, straw, feces and sludge as raw materials, there are still great differences in essence.
Difference between anaerobic fermentation and aerobic fermentation in food waste treatment:
- Fermentation microorganisms are different. Most of the itchy fermentation microorganisms are obligate and facultative itchy bacteria, while anaerobic fermentation microorganisms are anaerobic bacteria and methanogenic bacteria.
- The fermentation time is different, the fermentation time is short, and the anaerobic fermentation time is longer.
- The fermentation process is different. The fermentation process is relatively simple. The organic matter is crushed and pretreated before stacking and adjusting the temperature and humidity. The anaerobic fermentation is relatively complex. After pretreatment, it needs liquefaction, acid production and methane production. There are many treatment processes.
Advantages of anaerobic fermentation:
- The operation technique is easy to master and the success rate is high.
- High yield per unit area
- Nutrients are well preserved and the loss is less than 5 percent
- Produce organic acids and lactobacillin
- No pollution to the environment
Advantages of aerobic fermentation:
- The fermentation speed is fast, and the quantity of probiotics generated is large.
- It can produce high value-added products, such as antibiotics and single vitamins.
- Small floor area and no potential safety hazard
If you still want to know the process of food waste pretreatment, you can visit the food waste crushing and dewatering system of Siedon Technology.