Municipal solid waste, shorted as MSW, is also called as urban solid waste. It refers to the solid waste which is generated during people’s daily life and municipal activities in urban areas. The waste usually comes from households, commercial life, reassurance, hotels, tourist industry, transportation, industry and water supply and drainage system in cities.
The most common municipal solid waste includes waste plastic, rubber products, waste vehicles, waste paper, sewage sludge, construction waste and household waste (such as waste appliances), medical wastes, e-waste, etc.
Characteristics of Municipal Solid Waste
- Large amount, great variety, complex components. Solid waste in urban areas has become a very important issue in many countries where the process of urbanization is fast. As populations and industrial manufacturing activities increase in those areas, more and more waste will be generated accordingly. To much solid waste in urban areas have taken up to many land space of human. What’s worse, since the components of the municipal solid waste is complicated and sources of them have a great variety, disposal of them becomes quite difficult.
- Long-term and Potential hazard. Municipal solid waste cannot diffuse very fast, so the pollution they pose to soil, water and air is long-term and potential. The harmful components in solid waste can cause potential hazards to nature, people and animals. In water, some contaminants of the solid waste threat the lives of aquatic animal and plants and finally destroy the food chain in the aquatic ecosystem. Additionally, the contaminants will gain more power as the food chain lengthens, which is reflected on bio concentration. If we eat the contaminative plants or animals as food, the contaminants will concentrate in human body and cause harms to human health. This environmental hazard effects can spread from individual to the whole species, and finally break the whole eco balance and damage our natural resources.
- Recyclable. Even though municipal solid waste are hazardous, most of them are recyclable in certain ranges, times with certain technologies. They have the potential of being reused before a final disposal and have the value of recycling.
Disposal of Municipal Solid Waste
Traditional Ways to Dispose of Municipal Solid Waste
When we talk about where our garbage go, the first word you may think of will be landfill. Sanitary landfill refers to a landfill which controls landfill leachate and gas. A sanitary landfill will usually received an anti-seepage treatment which adds a special lining in the bottom of the landfill and adopts vertical anti-seepage on the walls to connect it to the natural water resisting layer, so as to form an independent drainage under the bottom of the landfill. The independent drainage prevent the underwater from being contaminated. All the landfill leachate will be collected and transited via special pipes directly to sewage treatment centers.
It seems that a sanitary landfill is a good way to dispose municipal solid waste. However, as land and space has becomes less and population of human increases, we do not have enough landfill areas or space for those solid wastes. Furthermore, sanitary landfill is actually not sanitary in some ways. For examples, it is inevitable that there will usually be a large volume of CO2, methane and a little of other pollutants on the landfills. So it is likely posing pollution to the surrounding environment and people.
2.High temperature composting.
So far most cities of China use static open composting to dispose of solid waste. It has low cost but actually poses much pollution to the environment. Moreover, composting, in most conditions, is suitable for organic wastes, which is only a part of municipal solid waste. There are also solid wastes like plastic, rubber tyres, glasses and paper cannot be used in composting.
Lots of solid waste have potential energy that can be recycled by burning. Solid waste after being burned down can reduce 80%-90% in volume. Some of the hazardous solid waste can also be sterilized through burning. Therefore, waste incineration is another popular method to dispose of solid waste.
But there’s still problems about incineration. Because of the complexity of the composition of municipal solid waste, different flammable wastes have different chemical and physical characteristics. It cannot be very sure that all of the waste is totally burnt. In addition, during the process of incineration, acid gases, ashes and some very hazardous compounds will be generated to destroy the surrounding environment. As a result, incineration is also not a very perfect way to dispose of municipal solid waste at present.
A Scientific and Sustainable Way to Dispose of Municipal Solid Waste We’re Looking for
As the natural resources in our planet reduce and our consumption increases, we have to create much more energy from the “waste” we have discarded. The above-said three traditional methods to dispose of municipal solid waste are definitely very important progresses we have made to save our planet. But there are disadvantages. To better utilize the municipal solid waste, we need a much more scientific and sustainable methods to dispose of them.
If we make a specific disposing plan for each kind of the solid waste according to their characteristics and materials, we can get a big improvement in efficiency and effects.
Plastic is featured with light weight and durability. It is hard to degrade in the nature by itself. If we dump it to the landfill, it will cause soft foundation and reduce the availability of the land. Besides, burning of plastic will pose a lot of harms to our environment. Therefore, recycling waste plastic seems much more important for the environment. For now, the available methods to dispose of plastic includes classification and collection, thermal energy recovery or chemical reduction. Recent years, there is a new type of recycling method for plastic has been founded, which is called as pyrolysis. Under a high temperature and oxygen-absent environment, plastic waste can be decomposed into fuel oil and carbide. This technology is now using widely to produce replaceable fuels from waste plastic.
Abandoned cars are actually having large potential of recycling and reusing. Take the United States for instance, there are 80% auto parts of the abandoned cars in the US can be recycled and reused after processing. More than 30 thousands recycling centers or companies in the US undertake the responsibility of abandoned cars recycling. The old auto parts, such as engine and motor can be retreated and sold on the market.
There are three types of paper that can be used to making recycled paper: mill broke, pre-consumer waste, and post-consumer waste. Mill broke is paper trimmings and other paper scrap from the manufacture of paper, and can be recycled in a paper mill. Pre-consumer waste is a material which left the paper mill but was discarded before it was ready for consumer use. Post-consumer waste is material discarded after consumer use, such as old corrugated containers, old magazines, and newspapers. Paper suitable for recycling is called as scrap paper which often used to produce moulded pulp packaging. The industrial process of removing printing ink from paper fibre of recycled paper to make deinked pulp is called deinking, an invention of the German jurist Justus Claproth. Scrap paper recycling is not very complicated comparing with other solid waste. As our forest resources get shrinking day by day, people have paid more and more attention to recycling of paper as well.
Construction waste refers to the solid waste generated during the building, rebuilding and demolition of constructions. Disposal and recycling of those waste varies according to different materials. Waste concrete or abandoned bricks or stones can be used to produce coarse and fine aggregate, such as new concrete, mortar, floor tiles, etc. Muck can be used as materials in foundation earth layer. Waste wood, which has been seriously damaged can be used to make paper or recyclable slab, and those which has no obvious damages can be reused as construction materials. Waste steel and other metals can be melted down and reprocessed.
Most of the construction waste can be properly recycled and reused. But before that, it usually spends much more time to sort them out clearly. As a big potential threaten to the air, water and soil of urban areas, construction materials should gain much more attention from human being.
E-waste refers to waste electrical and electronic equipment which are destined for reuse, resale, salvage, recycling, or disposal are also considered e-waste. Informal processing of e-waste in developing countries can lead to adverse human health effects and environmental pollution.
In many developed countries, electronic waste recycling usually first involves dismantling the equipment into various parts (metal frames, power supplies, circuit boards, plastics), often by hand, but increasingly by automated shredding equipment.
Also take the US for instance, e-waste disassembling has been very professional in this country. They have agencies or companies which are specialized in disassembling, which are capable of recycling circuit board and which are able to extract precious metals, etc. The recycling system of e-waste in the US can be a guide book for any country which want to do good job in e-waste recycling and processing.
Medical waste refers to the direct or indirect infectious, toxic or hazardous waste generated during the process of medical treatment, health care or other related activities. The components of medical waste are complicated and dangerous. At present, the most acceptable disposal method of medical waste is incineration. Besides, the collection, transportation, storage and disposal of the waste should be different from any other waste because of the extreme danger they have and complex virus they carry. The whole process of disposal shall be sealed without any leakage to make sure they are not posing any other pollution to the environment.
There’s another method to dispose of them for now such as pyrolysis. But before pyrolysis, the medical waste much be sterilized to make sure there is no hazardous components at all.
The kitchen residual mainly refers to the leftover or remains of meals, plastic containers, cans or papers. Plastic containers, cans and papers can be recycled using specific methods after separated from the kitchen residual. As for the leftover or meal remains, they can be used to make dehydrated feeds after the process of dehydration, feeding livestock after fermentation or generating biogas to be used in electricity generation process. Like most of the other organic wastes (such as wood, leaves, etc.), kitchen residual can also be used to produce bio gas through a fermentation system.
Japan has world top technology in disposing of kitchen residual. They have special local processing mold which means people can dispose of the waste in their own houses by the help of special designed food residual processors. Food is the paramount necessity of the people. As the development of modern economy of the whole worlds, food waste seems a common problem. Therefore, disposal of kitchen residual has become an important issue we should talk and a necessary way to save nature resources of our planet. There are still many things we can do to make our planet better.
If we want to dispose of each kind of municipal solid waste in a proper manner, we should firstly sort them our strictly and clearly. Waste separation and segregation will play the significant role in this part. Now many countries have implemented relevant laws or regulations of waste separation or have invested garbage separation facilities.
In 2016, the amount of municipal solid waste in large and medium cities of China was 188.5 million tons in total. In the whole world, the number is much more overwhelming. We still have a long way to go in fighting with municipal solid waste for our environment, thus, knowing more about municipal solid waste and learning more effective methods to dispose of them and recycling them into new energy for human to use is the only way to win the battle against it. GreenBeston, a company with decades’ experiences of recycling municipal solid waste will always here to help.