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Waste and its disposal


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Waste and its disposal

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Waste and its disposal

  1. 1. 1Waste(trash, garbage, rubbish, refuse)Wastes are items we (individuals, offices, schools, industries, hospitals) don’t need anddiscard. Sometimes there are things we have that the law requires us to discard because theycan be harmful. Waste comes in infinite sizes—some can be as small as an old toothbrush, oras large as the body of a school bus.Everyone creates waste, although some people are veryenvironmentally conscious and create very little. Likewise, some countries do a very goodjob creating less waste and managing the rest. Others are pretty horrible and have createdhuge environmental problems for the people and animals living there.Did you know?Europe creates about over 1.8 billion tonnes of waste each year. This means each personcreates about 3.5tonnes on average.Did you know?In 2010, Americans generated about 250 million tons of trash and recycled and compostedover 85 million tons of these material, equivalents to a 34.1% recycling rate (see Figure 1and Figure 2). On average, we recycled and composted 1.51 pounds out of our individualwaste generation of 4.43 pounds per person per day. —EPA, USA.All over the world, communities handle their waste or trash differently. Some commonmethods of managing their waste include landfilling, recycling and composting. Othercommunities strongly embark on waste reduction and litter prevention/control aimed atreducing the production of waste in the first place. Some communities also engage in waste-to-energy plants and hazardous waste disposal programs.Types of wasteGenerally, waste could be liquid or solid waste. Both of them could be hazardous. Liquid andsolid waste types can also be grouped into organic, re-usable and recyclable waste.Let us see some details below:Liquid type:Waste can come in non-solid form. Some solid waste can also be converted to a liquid wasteform for disposal. It includes point source and non-point source discharges such as stormwater and wastewater. Examples of liquid waste include wash water from homes, liquidsused for cleaning in industries and waste detergents.Solid type:Solid waste predominantly, is any garbage, refuse or rubbish that we make in our homes andother places. These include old car tires, old newspapers, broken furniture and even foodwaste. They may include any waste that is non-liquid.
  2. 2. 2Hazardous type:Hazardous or harmful wastes are those that potentially threaten public health or theenvironment. Such waste could beinflammable (can easily catch fire), reactive (can easilyexplode), corrosive (can easily eat through metal) or toxic (poisonous to human and animals).In many countries, it is required by law to involve the appropriate authority to supervise thedisposal of such hazardous waste. Examples include fire extinguishers, old propane tanks,pesticides, mercury-containing equipment (e.g, thermostats) and lamps (e.g. fluorescentbulbs) and batteries.Organic type:Organic waste comes from plants or animals sources. Commonly, they include food waste,fruit and vegetable peels, flower trimmings and even dog poop can be classified as organicwaste. They are biodegradable (this means they are easily broken down by other organismsover time and turned into manure). Many people turn their organic waste into compost anduse them in their gardens.Recyclable type:Recycling is processing used materials (waste) into new, useful products. This is done toreduce the use of raw materials that would have been used. Waste that can be potentiallyrecycled is termed "Recyclable waste". Aluminium products (like soda, milk and tomatocans), Plastics (grocery shopping bags, plastic bottles), Glass products (like wine and beerbottles, broken glass), Paper products (used envelopes, newspapers and magazines, cardboardboxes) can be recycled and fall into this category.Waste can be alsosegregated as :1. Biodegradable and2. No biodegradable.Biodegradable waste includes organic waste, e.g. kitchen waste, vegetables, fruits, flowers,leaves from the garden, and paper.Non-biodegradable waste can be further segregated into:a) Recyclable waste – plastics, paper, glass, metal, etc.b) Toxic waste – old medicines, paints, chemicals, bulbs, spray cans, fertilizer and pesticidecontainers, batteries, shoe polish.c) Soiled – hospital waste such as cloth soiled with blood and other body fluids.Toxic and soiled waste must be disposed of with utmost care.Biodegradable waste is a type of waste which comprises of waste streams that are availablefor biodegradation. These wastes typically originate from plants, animals and other livingorganisms.It can be commonly found in municipal solid waste (sometimes called biodegradablemunicipal waste [BMW] )Green waste
  3. 3. 3Food wastePaper wasteBiodegradable plasticsOther biodegradable wastes include:Human wasteManureSewageSlaughterhouse wasteSources of waste1. Municipal sources of waste (MSW): This includes trash or garbage fromhouseholds, schools, offices, market places, restaurants and other public places.Theyinclude everyday items like food debris, used plastic bags, soda cans and plastic waterbottles, broken furniture, grass clippings, product packaging, broken home appliancesand clothing.2. Medical/Clinical sources of waste: Medical/clinical waste normally refers to wasteproduced from health care facilities, such as hospitals, clinics, surgical theatres,veterinary hospitals and labs. They tend to be classified as hazard waste rather thangeneral waste.Items in this group include surgical items, pharmaceuticals, blood, bodyparts, wound dressing materials, needles and syringes3. Agricultural sources of waste: Typically, this is waste generated by agriculturalactivities. These include horticulture, fruit growing, seed growing, livestock breeding,market gardens andseedling nurseries.Waste items in this group include emptypesticide containers, old silage wrap, out of date medicines and wormers, used tires,surplus milk, cocoa pods and corn husks.4. End-of-life Automobiles:When cars are all old and not working again, where do theyend up? Many people just leave them to rust in the fields, but there is a better way todeal with them. In many cities, these vehicles are sent to the plant, where all theremovable parts are taken out for recycling. The rest is flattened up and shredded intopieces for recycling. The last bits that cannot be used again is sent to a landfill.5. Industrial sources of waste: Since the industrial revolution, the rise in the number ofindustries manufacturing glass, leather, textile, foods, electronics, plastic and metalproducts has significantly contributed to waste production. Take a look at the things inyour home, every item there was probably manufactured and possibly, waste wasproduced as a result.6. Construction/demolition sources of waste: Construction waste is that resulting fromthe construction of roads and building. Sometimes old buildings and structures arepulled down (demolished) to make space for new ones. This is particularly commonin old cities that are modernizing. This is called demolition waste.Waste items includeconcrete debris, wood, earth, huge package boxes and plastics from the buildingmaterials and the like.7. Electronic sources of waste: This is waste from electronic and electrical devices.Think of DVD and music players, TV, Telephones, computers, vacuum cleaners andall the other electrical stuff in your home. These are also called e-waste, e-scrap, or
  4. 4. 4waste electrical and electronic equipment (WEEE)Some e-waste (like TV) containslead, mercury, cadmium, and brominated flame retardants. These are harmful tohumans and the environment. It is therefore important that the right authorities ensurethe proper disposal of such waste.How is waste treated and disposed OffWaste management simply means the collection, transport, processing or disposal, managingand monitoring of waste materials to minimize its consequences on humans andenvironment.There are several methods of managing all the various types of waste. Some ofthese methods cause additional harm to the environment, but not doing anything is not anoption.Let us see below two common ways of managing waste:a. Incineration methodb. Landfillsc. Recyclingd. Sustainability methode. Composting/ Biological reprocessing methodf. Energy recovery methodIncineration methodThis simply means burning waste. This method is common in countries with limited landfillspace. Incineration chambers can be small for domestic use, but there are large ones formunicipal use as well. It is great for treating waste with contamination (like those fromhospitals) and hazardous waste from factories, but the method produces too much carbondioxide (see our air pollution lesson). Modern incineration processes are more efficient andrelease less dioxin than home fireplaces and backyard barbecues. This method is verycommon in Denmark, Germany and the Netherlands. This method is effective, but expensive.Sanitary Landfills as waste disposal:Generally, this term means a large piece of land away from living places where all the wastefrom a town is deposited. But there is more to landfills. Proper landfill management involvessorting out all the waste (waste separation), and sending only the waste that cannot berecycled and composted to the site.Proper landfills, are also lined at the bottom to minimize the leakage of soil pollutants andother toxins from getting into the water table. This method is effective, but expensive anddifficult.In many towns, sorting is not done, and all the waste (paper, food, diapers, glass) is mixed upand deposited. That is a problem because, glass, and plastics take thousands of years todecompose. Additionally, the landfills soon become full, smelly and unsafe for theenvironment.
  5. 5. 5Proper waste management is not cheap, but it is something we all have to get involved anddiscuss it. The effect of not getting involved can be catastrophic to our health andenvironment.RecyclingRecycling is processing used materials (waste) into new, useful products. This is done toreduce the use of raw materials that would have been used. Recycling also uses less energyand great way of controlling air, water and land pollution.Effective recycling starts with household (or the place where the waste was created). In manyserious countries, the authorities help households with bin bags with labels on them.Households then sort out the waste themselves and place them in the right bags forcollection.This makes the work less difficult.Waste items that are usually recycled include:Paper waste: Paper waste items include books, newspapers, magazines, cardboard boxes andenvelopes. Click here to see how paper is recycled.Plastic waste:Items include plastic bags, water bottles, rubber bags and plastic wrappers.Glass waste: All glass products like broken bottles, beer and wine bottles can be recycled.Aluminium waste:Cans from soda drink, tomato, fruit cans and all other cans can berecycled. Did you know: Recycling just 1 ton of aluminium cans conserves more than 207million Btu, the equivalent of 36 barrels of oil, or 1,665 gallons of gasoline. —EPAWhenthese are collected, the are sent to the recycling unit, where all the waste from each type arecombined, crushed, melted and processed into new materials.Importance and benefits of waste recyclingRecycling is beneficial in many ways including:Recycling helps protect the environment:This is because the recyclable waste materialswould have been burned or ended up in the landfill. Pollution of the air, land, water and soilis reduced.Recycling conserves natural resources:Recycling more waste means that we do not dependtoo much on raw (natural) resources, which are already massively depleted.Recycling saves energy: It takes more energy to produce items with raw materials than fromrecycling used materials. This means we are more energy efficient and the prices of productscan come down.Recycling creates jobs: People are employed to collect, sort and work in recyclingcompanies. Others also get jobs with businesses that work with these recycling units. Therecan be a ripple of jobs in the municipality.
  6. 6. 6Here is how paper waste is recycled:1. Collection, transportation and storage: The biggest task for paper recycling companiesis probably the collection, transporting and sorting of waste paper.This is because wealways add paper to other waste items and get them contaminated with food, plasticsand metals. Sometimes collected paper is sent back to the landfills because they aretoo contaminated for use. Try to keep waste paper in separate grades at home or in theoffice —example, do not mix newspapers and corrugated boxes up.All paperrecovered is sent to the recycling center, where it is packed, graded, put into bales andsent to the paper mill. At the mill, all the paper is stored in a warehouse until it isneeded.2. Re-pulping and Screening (say re-pal-pin and skree-nin): From the storage shelves,they are moved into a big paper-grinding machine called a vat (pulper). Here thepaper is chopped into tiny pieces, mixed with water and chemicals and heated up tobreak it down into organic plant material called fibre. After, it is screened to removecontaminants such as bits of plastic and globs of glue.3. Deinking (say dee-in-kin): This involves ‘washing’ the pulp with chemicals to removeprinting ink and glue residue. Sometimes, a process called floatation is applied tofurther remove stubborn stains and stickies. Floatation involves the use of chemicalsand air to create bubbles which absorb the stickies in the pulp.4. Refining, Bleaching and Colour Stripping:Refining involves beating the recycled pulpto make them ideal for paper-making. After refining, additional chemicals are addedto remove any dyes from the paper. It is then bleached to whiten and brighten it up.5. Paper making: At this stage, the pulp is ready to be used for paper. Sometimes newpulp (virgin pulp) is added to give it extra strength and smoothness. Water is added tothe pulp and sprayed onto a large metal screen in continuous mode. The water isdrained on the screen and the fibres begin to bond with each other. As it movesthrough the paper-making machines, press rollers squeeze out more water, heat themdry and coat them up.6. They are then finished into rolls.Aluminium recyclingIn recent time, there has been a massive improvement in recycling aluminium cans. In 2003,Americans recycled 62.6 billion aluminium cans. Those cans, placed end-to-end, could make171 circles around the earth. Every minute, averages of 105,800 aluminium cans are recycled.That is how important can recycling has become.what is involved here? Here is it...Collection: Local councils provide special can recycling containers (bins) that are clearlymarked. This helps people to know what to place in them. These cans include soda, fruit andvegetable cans. Trucks come for these at pick up spots to the recycling centres. Cans mayalso be metallic or steel, but people do not know the difference.
  7. 7. 7Preparation: At the collection centre, a huge magnet is rolled over them as they move on theconveyor belt to pull out all the metal and steel cans. Only the aluminium cans are washed,crushed, condensed in to 30-pounds briquettes for other companies for further processing.The rest is also sorted and sent to their appropriate recycling centres.Melting: The crushed cans are loaded into a burning furnace, where all printing and designson the cans are removed, melted and blended with new (virgin) aluminium. The molten(liquid) aluminium is poured into moulds and made into bars called ingots.Sheets: The ingots are then fed into powerful rollers, which flatten them into thin sheets ofaluminium of about 25.4 in thickness. These thin sheets are rolled into coils and sold or sentto can-making factories.It is estimated that cans collected at collection points take up to 60 days to be appear in theshops again as new cans containing your favourite soda, juice or food.How is glass recycled?Recycling glass starts in your home. There is a reason why many local councils providedifferent containers for green, brown, plain glass and even glass from broken windows. Thereason is that they are all made very differently and mixing them can create huge problems atthe recycling centre.1. Collection: Many cities have collection spots. Trucks may also pick them up fromyour home, or you may be required to drop them off at a point in your town. In allcases, try to do what the authorities have suggested. So, be sure you know the variousglass types that are collected from your home. Always wash and separate them intothe required grades for collection.2. Cleaning and Crushing: The glass is transported to the processing plant wherecontaminants such as metal caps and plastic sleeves are removed. Different grades aretreated separately. Clean glass is then crushed into small pieces called cullet. Cullet isin high demand from glass manufacturers. It melts at a lower temperature and it ischeaper than raw glass materials.3. Ready for use: The cullet is then transported to glass-making factories. Here, it ismixed with sand, soda ash and limestone. It is heated at very high temperature andmelted into liquid glass. This liquid is then poured into moulds that give glass itsshape.Glass is used for many things—depending on what grade they were recycledfrom. A few items made of recycled glass include fibre-glass, countertops, bottles andjars.Sustainability methodThe management of waste is a key component in a business ability to maintaining ISO14001accreditation. Companies are encouraged to improve their environmental efficiencies eachyear by eliminating waste through resource recovery practices, which are sustainability-related activities. One way to do this is by shifting away from waste management to resource
  8. 8. 8recovery practices like recycling materials such as glass, food scraps, paper and cardboard,plastic bottles and metal.Composting/ Biological reprocessing methodWith the right conditions (air and moisture), organic waste such as food and plant materialscan be decomposed by bacteria, fungi, worms and organisms. Decayed organic matter ishumus. Yard waste such as grass and flower clippings can also be composted. Compostingcomes in two kinds: bin/pile composting and worm composting.Energy recovery methodThe energy content of waste products can be harnessed directly by using them as a directcombustion fuel, or indirectly by processing them into another type of fuel. Thermaltreatment ranges from using waste as a fuel source for cooking or heating and the use of thegas fuel (see above), to fuel for boilers to generate steam and electricity in a turbine.Pyrolysis and gasification are two related forms of thermal treatment where waste materialsare heated to high temperatures with limited oxygen availability. The process usually occursin a sealed vessel under high pressure. Pyrolysis of solid waste converts the material intosolid, liquid and gas products. The liquid and gas can be burnt to produce energy or refinedinto other chemical products (chemical refinery). The solid residue (char) can be furtherrefined into products such as activated carbon. Gasification and advanced Plasma arcgasification are used to convert organic materials directly into a synthetic gas (syngas)composed of carbon monoxide and hydrogen. The gas is then burnt to produce electricity andsteam. An alternative to pyrolisis is high temperature and pressure supercritical waterdecomposition (hydrothermal monophasic oxidation).Avoidance and reduction methods/ Waste minimizationAn important method of waste management is the prevention of waste material being created,also known as waste reduction. Methods of avoidance include reuse of second-hand products,repairing broken items instead of buying new, designing products to be refillable or reusable(such as cotton instead of plastic shopping bags), encouraging consumers to avoid usingdisposable products (such as disposable cutlery), removing any food/liquid remains fromcans, packaging and designing products that use less material to achieve the same purpose(for example, light weighting of beverage cans).Waste minimization is the process and the policy of reducing the amount of waste producedby a person or a society. Waste minimization involves efforts to minimize resource andenergy use during manufacture. For the same commercial output, usually the fewer materialsare used, the less waste is produced. Waste minimisation usually requires knowledge of theproduction process, cradle-to-grave analysis (the tracking of materials from their extraction totheir return to earth) and detailed knowledge of the composition of the waste.Effects of waste and bad waste disposalEnvironmental Effects:Imagine we all throw garbage, junk and rubbish away anyhow. Imagine there was noauthority to supervise waste management activities from all the sources mentioned earlier.
  9. 9. 9Imagine we all just sent our rubbish to the landfill, or just dumped them in a nearby river.What do you? A think will happen disaster!Surface water contamination: Waste that end up in water bodies negatively change thechemical composition of the water. Technically, this is called water pollution. This will affectall ecosystems existing in the water. It can also cause harm to animals that drink from suchpolluted water.Soil contamination: Hazardous chemicals that get into the soil (contaminants) can harmplants when they take up the contamination through their roots. If humans eat plants andanimals that have been in contact with such polluted soils, there can be negative impact ontheir health.Pollution: Bad waste management practices can result in land and air pollution and can causerespiratory problems and other adverse health effects as contaminants are absorbed from thelungs into other parts of the body.Leachate: Liquid that forms as water trickles through contaminated areas is called Leachate.It forms very harmful mixture of chemicals that may result in hazardous substances enteringsurface water, groundwater or soil.Economic EffectsMunicipal wellbeing: Everyone wants to live and visit places that are clean, fresh andhealthy. Cities with poor sanitation, smelly and with waste matter all over the place do notattract good people, investors and tourists. Such cities tend to have poor living standards.Recycling revenue: Cities that do not invest in recycling and proper waste control miss out onrevenue from recycling. They also miss out on job opportunities that come from recycling,composting and businesses that work with them.