According to the source of solid waste and the degree of harm to the environment, solid waste can usually be divided into three categories: domestic waste, general industrial solid waste, and hazardous waste. The possible pollution hazards caused by solid waste to the environment are multi-faceted. It will not only cause direct pollution of water, soil and atmosphere, but also damage the ecological environment and threaten human health. Under normal circumstances, these solid wastes need to be treated and disposed of safely to eliminate environmental and ecological risks.

Solid waste treatment

Solid waste treatment, the full name of solid waste treatment, usually refers to the process of converting solid waste into physical, chemical, biological, physicochemical and biochemical methods suitable for transportation, storage, utilization or disposal. The goal of solid waste treatment is harmless reduction, reduction, and resource utilization.

compaction technology

Compaction is a pretreatment technology that reduces the volume of waste, reduces transportation costs, and prolongs landfill life. Compaction is a commonly used pretreatment method for solid waste, such as cars, cans, plastic bottles, etc. Usually, compaction is used first. It is suitable for compacting solid wastes to reduce volume. It is not suitable for compaction. Some wastes that may cause operational problems, such as tar, sludge or liquid materials, are generally not suitable for compaction. deal with.

crushing technology

In order to reduce the shape of the waste entering the incinerator, landfill, composting system, etc., the solid waste must be crushed in advance. The crushed waste, due to the elimination of large gaps, is not only uniform in size, but also in texture. Also uniform, compacted during the landfill process. There are many crushing methods for solid waste, including impact crushing, shear crushing, extrusion crushing, friction crushing, etc. In addition, there are proprietary low-temperature crushing and hybrid crushing. The most widely used and most effective solid waste shredder is the shearing shredder, and for landfill and composting waste, the spiral roller shredder is more effective.

Sorting technology

Solid waste sorting is an important means to realize solid waste recycling and reduction. Through sorting, the useful ones are fully selected and utilized, and the harmful ones are fully separated; the other is to separate the wastes of different particle size levels. , The basic principle of sorting is to use some differences in the properties of materials to separate them. For example, use the magnetic and non-magnetic difference in waste for separation; use the particle size difference for separation; use the specific gravity difference for separation, etc. According to different properties, various machines can be designed and manufactured to sort solid waste, including manual sorting, screening, gravity sorting, magnetic sorting, eddy current sorting, optical sorting, etc.

Curing technology

Solidification technology is a harmless treatment process that adds solidified substrates to wastes, so that harmful solid wastes are fixed or contained in inert solidified substrates. The treated solidified products should have good penetration resistance, good Mechanical properties, anti-leaching, anti-drying, anti-freezing and thawing properties, curing treatment can be divided into precipitation curing, asphalt curing, glass curing and colloidal curing according to the different curing substrates.

Incineration and pyrolysis technology

Incineration is a comprehensive treatment process of solid waste pyrolysis and deep oxidation. The advantage is that a large number of harmful wastes are decomposed and turned into harmless substances. Due to the gradual increase in the proportion of combustibles in solid waste, it has become a necessary development trend to use incineration to treat solid waste and to utilize its heat energy. Environment and incineration plants are mostly located in large cities with more than 100,000 people, and are equipped with energy recovery systems. Due to the shortage of land in Japan, the use of incineration methods has gradually increased. The heat energy obtained during the incineration process can be used for power generation, and the heat produced by the incinerator can be used for heating the residents and maintaining the room temperature of the greenhouse. Currently, Japan and Switzerland burn more than 65% of their municipal waste each year to regenerate energy. However, the incineration method also has shortcomings, such as large investment, secondary pollution caused by smoke exhaust during the incineration process, and serious equipment corrosion. Pyrolysis is to heat organic matter at high temperature (1000℃-1200℃) under anaerobic or anoxic conditions to decompose it into three types of products: gas, liquid and solid. Compared with incineration, pyrolysis is a more promising treatment. The most significant advantage of this method is that the capital investment is less, and the gas generated after pyrolysis can be used as fuel.

Biological treatment technology

Biological treatment technology is the use of microorganisms to decompose organic solid waste to make it harmless, which can convert organic solid waste into energy, food, feed and fertilizer, and can also be used to extract metals from waste products and waste residues. The most effective technical methods are currently widely used: composting, biogas production, sugar production from waste cellulose, feed production from waste fiber, and bioleaching.

Iron and steel solid waste treatment technology

As the urban haze has become more and more serious in the past two years, the environmental protection work of the steel industry has also been put on the agenda. Sludge) technology, dust sludge ash recycling cold solid pellet technology, gas energy-saving lime shaft kiln technology are the most advanced solid waste treatment technologies in the iron and steel industry.