Characteristics of Organic Waste Generation and Present Situation of Decentralized Processing Mode
In the narrow sense, organic waste is mainly composed of kitchen waste from catering service institutions, kitchen waste from residents' families, fruit and vegetable waste from vegetable markets, etc., as well as garden greening waste from parks and expired food from supermarkets. In a broad sense, it also includes residual sludge from municipal sewage treatment plants, livestock and poultry manure, and agricultural organic solid waste.
The present situation and characteristics of organic waste
There are various types of organic wastes in China and their output is huge, among which the largest scale is livestock and poultry manure, which reaches 1.9 billion tons/year. The second is urban garden waste, up to 90 million tons/year; The third is kitchen waste, the output of more than 40 million tons/year. The urban organic garbage in our country has four remarkable characteristics: high ratio; fast growth; strong seasonality; highly dispersed production points but relatively concentrated in scale.
Development and problems of distributed processing technology
It is a common garbage disposal mode in China to collect domestic garbage uniformly within a city and send it to a centralized treatment plant for processing. However, due to the complexity, high cost and many problems of independent organic waste collection and transportation system, some researchers put forward and began to try to use the decentralized processing technology model to deal with organic waste.
1. Decentralized processing technology in the world
Decentralized processing technology and equipment are intermediate between centralized processing and home processing. A British company has designed and built a containerized mobile composting system with a processing scale of 1 to 40 tons/day, providing a technology to dispose of organic waste for groups or units that do not have enough space. Small distributed kitchen waste disposers in Japan range in scale from 50 kg to 1000 kg/day. The main technical routes include reduction and recycling.
2. Decentralized processing technology in China
In recent years, China has carried out a lot of work in the field of organic waste decentralized treatment. Before the 2008 Olympic Games, Beijing built a number of on-site kitchen waste disposal projects for the Olympic site. In 2014 and 2015, Zhejiang Province built small bio-fermented compost treatment facilities in 146 villages. At present, more than 30 provincial-level administrative regions have begun to popularize decentralized organic waste treatment technology and equipment.
3. Advantages of decentralized processing technology
The main advantages of decentralized processing mode are as follows: small footprint and flexible location; rational scale and implement in stages; short collection and transportation distance, low transportation cost; decentralized waste treatment and product consumption; short construction period and strong emergency capacity.
4. The problems of decentralized organic waste processing technology in China
There are still some problems to be solved in the decentralized organic waste processing technology, such as: lack of basic technical and theoretical support; lack of accurate concept and meaning; insufficient capability of equipment design and development; high investment and operating costs in decentralized processing mode.