Techniques for waste management
La gestión de los residuos urbanos, industriales y comerciales tradicionalmente han consistido en la recolección, seguido por la disposición en vertedero "Vertedero (basura)"). Dependiendo del tipo de residuo y el área, el proceso puede continuar con un tratamiento específico. Este tratamiento puede consistir en reducir su peligrosidad, recuperar material para el reciclaje, producir energía, o reducir su volumen para una disposición más eficiente.
Los métodos de recolección varían ampliamente entre países diferentes y regiones, y sería imposible describir todos ellos. Por ejemplo, en España existen desde el típico cubo de plástico que es recogido diariamente por un camión hasta un sistema de recolección neumática que aspira los desechos a una velocidad de 100 km/h hasta un centro de transferencia donde es recogida por los medios de transporte") convencionales. Muchas áreas, sobre todo aquellas menos desarrolladas, no tienen un sistema de recolección formal en el lugar.
Otro métodos son los de recogida de residuos puerta a puerta, recogidas específicas de residuos (pilas, medicamentos, aceites, aparatos eléctricos y electrónicos) y la utilización de puntos limpios.
Los métodos de disposición también varían extensamente. En Australia, el método más común de disposición de basura sólida son los vertederos "Vertedero (basura)"), por ser un país grande con una densidad de población baja. Por contraste, en Japón es más común la incineración, al ser un país pequeño y con escaso terreno libre.
Una vez recogidos los residuos en sus diferentes fracciones se transportan hasta sus destinos finales que pueden ser destino de valorización de residuos o de eliminación de residuos.
Los primeros, son instalaciones cuyo objetivo es recuperar en la medida de lo posible los materiales mediante su reciclaje o la recuperación de energía.
Las instalaciones de eliminación son destinos como depósitos controlados o vertederos o incineradoras.
Dump
Placing waste in a landfill (also called a garbage dump or, due to the influence of English, a sanitary landfill[11]) is the most traditional method of managing it, and remains a common practice in most countries. Historically, landfills were established in disused quarries, abandoned mines, etc.
A properly designed and well-managed landfill can be a hygienic and relatively cheap method of managing waste in a way that minimizes its impact on the local environment. Older, poorly designed or poorly managed landfills can generate adverse environmental impacts such as wind-blown trash, attraction of insects, and the generation of leachate that can contaminate groundwater. Another byproduct of landfills is landfill gas (composed primarily of methane gas and carbon dioxide), which is produced by the decomposition of organic remains in garbage. This gas can create odor problems, kills surface vegetation, and is a greenhouse gas.
Design features of a modern landfill include methods of containing slurry, such as clay or plastic that scratches the material. Garbage is compressed to increase its density and covered, with layers of soil, to prevent attracting animals (such as mice or rats) and reduce the amount of garbage blown by the wind. In many landfills, a gas extraction system is also installed, using perforated tubes, after closure to extract it from the decomposing materials. The gas is pumped out of the landfill through pipes and burned in an internal combustion engine to generate electricity. Igniting the gas is a better environmental solution than releasing it directly into the atmosphere, as this removes methane, which is a much more harmful greenhouse gas than carbon dioxide.
Another important problem is that city councils, especially in urban areas, find it very difficult to find land to establish new landfills due to opposition from the owners of adjacent plots. Few people want a landfill next to their plot. Solid waste collection has therefore become more expensive, as waste must be transported further away for disposal (or managed by other methods).
This fact is increasing concern about the environmental impact due to excessive consumption of products, and has led to great efforts to minimize the amount of waste sent to landfill. These efforts include recycling, converting waste to energy, designing products that use less material, and legislation requiring manufacturers to be responsible for product recall and packaging costs (see Product Stewardship and Extended Producer Responsibility). For example, in industrial ecology, where material traffic between industries is studied, the byproducts of one industry can be a raw material for another, which results in a reduction in final waste.
Some futurologists have predicted that landfills could one day be excavated: as some resources become increasingly scarce, it could be profitable to excavate these landfills to obtain materials that were previously discarded as worthless. A related idea is the establishment of a 'selective' landfill that contains only one type of waste (for example vehicle tires), as a long-term storage method.
Incineration
Incineration is a garbage collection method that involves burning garbage at high temperatures. Incineration and other high temperature treatment systems are described as "thermal treatment." In effect, the incineration of waste materials converts garbage into heat, gaseous emissions and solid residual ash. Other types of heat treatment include pyrolysis and gasification.
A waste-to-energy, or Waste-to-Energy (WtE), plant is a modern term for an incinerator that burns waste in a high-efficiency furnace to produce steam and/or electricity and incorporates modern air pollution control systems and continuous emission monitors. This type of incinerator is sometimes called an energy-from-waste (EfW) incinerator.
Incineration is popular in countries like Japan where land is a scarce resource. Sweden has been a leader in the utilization of energy generated by incineration since 1985. Denmark also makes extensive use of WtE incineration in generating heat and electricity that is used for district heating.
Incineration is carried out both on a small scale and on a larger scale such as industry. It is recognized as a practical method of disposing of certain hazardous waste materials (such as biological waste from hospitals), although this is a controversial method in many places due to issues such as the emission of gaseous waste contaminants.
Zero Waste Technology
It consists of the construction, start-up and audit of a processing plant for the final disposal of Urban Solid Waste. Urban solid waste, in the new Waste Law (Law 10/1998, of April 21, on Waste) using them as inputs for a productive process, in this case, materials for construction, paving, infrastructure works, etc.
In said plant, the R.S.U. They are preselected according to their composition. On the one hand, metals, aluminum, glass, paper, cardboard, plastics are set aside for recycling, and on the other hand, those R.S.U. susceptible to being transformed into construction materials (organic, rubble, wood, rubber, etc.), through the method of solidification and stabilization of waste. Solidification and stabilization is achieved by applying the system called microencapsulation. The latter consists of mixing, kneading, molding and shaping the R.S.U. non-recyclable with a binder that acts as a confiner through an appropriate process. The product obtained through this process is called “Compound”. It has the same or better characteristics than its similar ones for obtaining construction materials and at a significantly lower cost.
Composting and anaerobic digestion
Organic matter decomposes aerobically (composting), with a high presence of oxygen, or anaerobically (methanation), with no or very little presence of oxygen.
Composting consists of the aerobic decomposition (with oxygen) of organic waste such as plant and animal remains, excrement and slurry, through the massive reproduction of thermophilic aerobic bacteria that are naturally present anywhere. The resulting organic material can be recycled as agricultural fertilizer.
There is a wide variety of composting and methanation methods and hybrid methods with aerobic and anaerobic phases.
The biggest problem with this method is being sure that the organic waste is clean, that is, that it does not contain any substance (e.g. heavy metals) that could affect health if it enters the food chain through agriculture.
Biological mechanical treatment
Biological mechanical treatment (BMT) is a type of technology that combines mechanical classification and biological mechanical treatment of waste. BMT is also sometimes called TBM - Mechanical Biological Treatment - although this simply refers to the order of treatment.
The "mechanical sorting" element can be a tape. Here, recyclable elements of the waste chain that can be varied (such as metals, plastics and glass) are separated from hazardous waste such as oil, car batteries, etc., or processed to produce a fuel with high calorific value, called Solid Recovered Fuel (SRF) that can be used in cement kilns or power plants. Systems that are configured to produce CSR include Herhofand Ecodeco. There is also a way to use waste with high direct calorific value as a fuel replacement. It is a common misconception that all TMB processes produce CSR. It's not like that. Some systems like ArrowBio simply recover recyclable items from the trash into a form that can then be used for recycling. Mechanical treatment refers to the homogenization of waste for biological treatment.
The "biological" element refers to anaerobic or aerobic digestion. In the case of pure organic waste, we speak of composting (see above). Anaerobic digestion "breaks down" the biodegradable components of garbage to produce biogas. Biogas can be used to generate renewable energy. More advanced processes like the ArrowBio Process allow for large gas and green energy production without the production of CSR. This is thanks to the processing of waste in water. Biological can also refer to aerobic degradation in which the organic part of the waste is treated with aerobic microorganisms, thus eliminating the potential danger to the environment and human health. Furthermore, due to the degradation of organics to carbon dioxide and steam, it lacks biogas. Due to the total lack of biogas, this process is highly recommended for a clean development mechanism.
With the combustion of the fraction with high calorific value, green energy can be produced in special incinerators. Due to the absence of high technology, carbon credits can be produced safely and with minimal investment.
Pyrolysis and gasification
Pyrolysis and gasification are two forms of thermal treatment in which waste is heated to high temperatures with a limited amount of oxygen. The process is carried out in a sealed container under high pressure. Converting material into energy is more efficient than direct incineration; energy is generated that can be recovered and used, much more than in simple combustion.
Pyrolysis of solid waste converts the material into solid, liquid and gaseous products. Liquid oil and gas can be burned to produce energy or refined into other products. The solid residue can be refined into other products such as activated carbon.
Gasification is used to convert organic materials directly into a synthetic gas (syngas) made up of carbon monoxide and hydrogen. The gas can be burned directly to produce steam or in a heat engine to produce electricity. Gasification is used in biomass power plants to produce renewable energy and heat.