Methods and preventive measures for handling solid waste pollution 

With the rapid development of the social economy, the living standards of residents have been continuously improving. The amount and types of solid waste have also been increasing along with the economic growth, leading to the continuous deterioration of the living environment in our country. Solid waste pollution has become a serious environmental problem in our country. 

I. Classification of Solid Waste 

Waste is classified into general waste and hazardous solid waste. 

(1) General solid waste (recyclable, non-recyclable). 

① Recyclable 

Office waste: Waste newspapers, waste paper, waste packaging boxes, wooden boxes 

Construction waste: Scrap metal, packaging boxes, empty material barrels, broken glass, steel bar ends, welding rod ends 

② Not recyclable 

Construction waste: rubble, concrete, concrete test blocks, waste gypsum products, sediment. 

Domestic waste: Food processing residues; 

⑵ Hazardous solid waste 

Construction site hazardous solid waste (including waste chemical materials and their packaging materials, welding rods, waste glass fiber cloth, waste aluminum foil paper, waste polyurethane core board waste, industrial cotton cloth, oil gloves, oily cotton yarn and cotton cloth, paint brushes, waste asphalt pavement, used thermometers, etc.) 

② Laboratory waste liquid containers, chemical reagent waste materials; 

③ Waste residues from cleaning tools, waste residues from mechanical maintenance and repair fluids; 

④ Office area: used carbon paper, used ink cartridges of the copier, used ink cartridges of the printer, used toner cartridges, used color ribbons, used batteries, used disks, used computers, used fluorescent light tubes, used correction fluid. 

2. The garbage is classified into three categories based on its nature. 

⑴ Reutilization of construction materials means using them in their original form without the need for further processing, and they can be used to produce the same or similar products. 

Including: waste paper, wooden flooring, wood panels, wood products, precast concrete components, ironware, blocks, bricks and stones, ventilation pipes, reinforcing bars, steel materials, etc. 

(2) Reusable construction materials refer to those that cannot be used directly after being damaged but can be recycled after processing. 

Including: wall materials, partition wall materials, ceiling materials, insulation materials, concrete, etc. 

(3) Hazardous and non-recyclable waste refers to toxic batteries, chemicals, etc. 

II. Methods for Handling Solid Waste 

The treatment of solid waste usually involves the use of physical, chemical, biological, physicochemical and biochemical methods to convert solid waste into a form suitable for transportation, storage, utilization or disposal. 

The goal of solid waste treatment is to achieve harmless disposal, reduction in volume, and resource utilization. 

Solid waste is the most difficult to handle among the "three types of waste". This is because the components it contains are extremely complex, and its physical properties (volume, fluidity, uniformity, degree of pulverization, moisture content, calorific value, etc.) are also highly variable. To achieve the goals of "harmlessness, reduction, and resource utilization", considerable difficulties will be encountered. 

The general methods for preventing and controlling solid waste pollution include first controlling the amount of waste generation, such as gradually reforming the urban fuel structure, controlling the consumption of raw materials in factories, improving the service life of products, and increasing the recovery rate of waste; secondly, conducting comprehensive utilization, treating solid waste as a resource and energy, and if it cannot be utilized, it will be compressed and treated without toxicity to become final solid waste, and then buried or dumped at sea. The main methods include compaction, crushing, sorting, solidification, incineration, biological treatment, etc. 

1. Compaction: Compaction is a widely used pre-treatment method for reducing the volume of solid waste. It is a pre-treatment technology that reduces the volume of waste, lowers transportation costs, and extends the lifespan of landfill sites. For example, items such as cars, cans, and plastic bottles are typically subjected to compaction treatment first. Some waste materials that may cause operational problems, such as tar, sludge, or liquid substances, are generally not suitable for compaction treatment. 

2. Crushing: In order to reduce the size of the waste materials entering incinerators, landfills, composting systems, etc., it is necessary to crush the solid waste in advance. Due to the crushing process eliminating large voids, the size is uniform and the texture is also uniform, which is convenient for compaction during the landfill process. 

There are many methods for crushing solid waste, including impact crushing, shear crushing, compression crushing, friction crushing, as well as low-temperature crushing and mixed crushing, etc. 

3. Sorting Technology: Sorting is an important means for achieving the resource utilization and reduction of solid waste. Through sorting, useful materials can be selected out for utilization, while harmful substances can be separated; another approach is to separate waste of different particle sizes. 

The basic principle of sorting is to separate materials based on their various differences. For instance, separation can be achieved by utilizing the magnetic and non-magnetic differences in waste materials; by differentiating based on particle size; or by separating based on density differences, etc. 

According to different properties, various mechanical devices can be designed and manufactured to sort solid waste. The sorting methods include manual picking, screening, gravity separation, magnetic separation, eddy current separation, and optical separation, etc. 

4. Solidification treatment: Solidification is a process of harmless treatment where harmful solid waste is fixed or encapsulated within an inert solidification matrix by adding a solidification material to the waste. The treated solidification product should possess excellent impermeability, good mechanical properties, as well as resistance to leaching, resistance to dry-wet conditions, and resistance to freeze-thaw cycles. 

Depending on the type of base material, it can be classified as solvent-cured, asphalt-cured, glass-cured or gel-cured, etc. 

5. Incineration and Pyrolysis: Incineration is a comprehensive treatment process involving high-temperature decomposition and deep oxidation of solid waste. The advantage is that a large amount of harmful waste is decomposed and transformed into harmless substances. Utilizing the thermal energy from this process has become an important development trend in the treatment of solid waste. 

6. Biological Treatment: Biological treatment involves the use of microorganisms to decompose organic solid waste, thereby making it harmless. It also converts organic solid waste into energy, food, feed, and fertilizer. It can also be used to extract metals from waste and slag, making it an effective technical method for solid waste stabilization and resource utilization. 

III. Measures for the Treatment of Solid Waste 

Recoverable solid waste 

Used steel bars, iron wires, iron nails, used fasteners, and used steel pipes can be sold by contacting relevant waste recycling companies. 

(2) Waste templates, waste templates, waste paper (paper packaging materials), etc. can be contacted with paper-making enterprises for use in paper production, or with canteens and factories for use as fuel. 

(3) Sand and gravel can be used for backfilling or for concrete materials containing stones. 

(4) Waste tiles, stones, etc. can be used for backfilling. 

(5) The old safety nets can be contacted with waste collection companies for recycling and reprocessing of the plastic products. 

(6) The leftover food and dishes can be collected in containers and then contacted with the breeding farm to be used as animal feed. 

(6) The scrapped cables and glass can be sent to waste disposal companies for recycling and reuse in the production of other products. 

(8) Discarded electrical equipment, discarded measuring instruments, plastics, etc. can be contacted with waste disposal companies for dismantling and classification, and then used for the remanufacturing of other products. 

2. Non-recyclable, non-toxic and harmless solid waste 

The fallen dust is collected and sieved. Then it is mixed in a certain proportion with the mortar mixture for reuse. 

(2) Concrete waste, brick waste, and dry sand and gravel can be used for site backfilling. The concrete waste collected during the construction process can be used as raw materials to lay recycled permeable concrete pavement. 

(3) The remaining garbage can be handed over to the environmental protection department for unified disposal. 

⑷ Measures for handling slurry and construction waste 

A mud storage pool is set up on site to collect and store the mud. The waste mud must be transported out by a dedicated mud truck to prevent leakage and spillage from causing pollution. 

② Select cooperative units with the capability of storing and processing mud. It is strictly prohibited to discharge mud into ponds, rivers or ditches. 

③ The transportation and disposal of construction waste must be carried out by units that have obtained approval from the environmental protection department and possess the necessary qualifications. During the transportation process, the vehicles must be equipped with measures to prevent dust from flying and to prevent spillage. 

3. Recycle toxic, harmful and dangerous waste materials 

The waste paint cans, after being processed by the relevant departments, can be contacted with waste disposal companies for use in the re-production of products. For packaging materials such as paint, glue, release agents, and oil, they can be recovered by the manufacturers. 

4. Non-recyclable toxic, harmful and dangerous waste materials 

Expired paint, employee's household garbage, empty ink bottles from printers, discarded chemical materials for decoration and installation, used batteries, used welding rods, scrapped light bulbs and tubes, etc., which are toxic and harmful and cannot be recycled, must be stored in special containers on site for centralized disposal. The storage location must be far away from water sources, canteens, and bathrooms. After classification, they should be handed over to the environmental protection department (professional department) for unified handling by them. 

5. Domestic garbage and other solid waste 

Reduce the generation of waste. For the waste that has been produced, it must be centrally stored in sealed garbage bins for processing and recycling to prevent environmental pollution. 

⑴ Reduction of waste involves controlling the generation of waste at its source, such as restricting the use of consumer packaging or plastic bags, recycling packaging materials, and encouraging the reduction and recycling of resources in the production process; 

(2) Comprehensive utilization of waste. Gradually establish and improve the recycling network for used materials, converting waste into valuable resources. For example, recycling used paper, metal, glass, and plastic to turn waste into treasure.