How Landfills Works

HOW LANDFILLS WORK

­You­ have just finished your meal at a fast food restaurant and you throw your uneaten food, food wrappers, drink cup, utensils and napkins into the trash can. You don't think about that waste again. On trash pickup day in your neighborhood, you push your can out to the curb, and workers dump the contents into a big truck and haul it away. You don't have to think about that waste again, either. But maybe you have wondered, as you watch the trash truck pull away, just where that garbage ends up.

Americans generate trash at an astonishing rate of 4.6 pounds (2.1 kilograms) per day per person, which translates to 251 million tons (228 million metric tons) per year [source: EPA]. This is almost twice as much trash per person as most other major countries. What happens to this trash? Some gets recycled or recovered and some is burned, but the majority is buried in landfills. In this article, we will examine how a landfill is made, what happens to the trash in landfills, what problems are associated with a landfill and how these problems are solved.

Operations

  During landfill operations the waste collection vehicles are weighed at a weighbridge on arrival and their load is inspected for wastes that do not accord with the landfill’s waste acceptance criteria. Afterward, the waste collection vehicles use the existing road network on their way to the tipping face or working front where they unload their load. After loads are deposited, compactors or dozers are used to spread and compact the waste on the working face. Before leaving the landfill boundaries, the waste collection vehicles pass through the wheel cleaning facility. If necessary, they return to the weighbridge in order to be weighed without their load. Through the weighing process, the daily incoming waste tonnage can be calculated and listed in databases. In addition to trucks, some landfills may be equipped to handle railroad containers. The use of 'rail-haul' permits landfills to be located at more remote sites, without the problems associated with many truck trips.

  Typically, in the working face, the compacted waste is covered with soil daily. Alternative waste-cover materials are several sprayed-on foam products and temporary blankets. Blankets can be lifted into place with tracked excavators and then removed the following day prior to waste placement. Chipped wood and chemically 'fixed' bio-solids may also be used as an alternate daily cover. The space that is occupied daily by the compacted waste and the cover material is called a daily cell. Waste compaction is critical to extending the life of the landfill. Factors such as waste compressibility, waste layer thickness and the number of passes of the compactor over the waste affect the waste densities.

Impacts

  A large number of adverse impacts may occur from landfill operations. These impacts can vary: fatal accidents (e.g., scavengers buried under waste piles); infrastructure damage (e.g., damage to access roads by heavy vehicles); pollution of the local environment (such as contamination of groundwater and/or aquifers by leakage and residual soil contamination during landfill usage, as well as after landfill closure); offgassing of methane generated by decaying organic wastes (methane is a greenhouse gas many times more potent than carbon dioxide, and can itself be a danger to inhabitants of an area); harbouring of disease vectors such as rats and flies, particularly from improperly operated landfills, which are common in developing countries; injuries to wildlife; and simple nuisance problems (e.g., dust, odour, vermin, or noise pollution).

Packaging Waste Management

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Present Scenario:
Packaging, as a strategic business tool, is the key for enhancing product characteristics and safety of the product. During last decade, packaging industry has grown exponentially. While quality improvement and better technology adoption are visible, one can also see a lot of packaging waste lying all around. Packaging waste, its collection and disposal have become an environmental challenge. Packaging waste comprise a wide range of materials that are derived from multiple items used as packaging material. Selection of appropriate waste characterization and processing technologies can tell us about the composition of waste and the action necessary to address the issues. Presently, the packaging material waste is being managed along with municipal solid waste.

Packaging and especially food packaging has considerable impact on health and environment. Styrofoam or Polystyrene (PS), Polyvinyl chrolide (PVC), Polypropylene (PP), Polyethylene Terapthalate (PET) and several others are reported to be unsafe as food and beverage packaging since polystyrene breaks down to styrene at low temperatures and often PVC has unpolymerised residual vinyl monomers in them, both of which are highly carcinogenic. All chlorinated plastics emit dioxins and furans and others benzene and ethylene oxide when incinerated besides emitting monomers like styrene, hydrogen chloride, vinyl monomers & pthlates. PET and other plastics like HDPE, LDPE and Polycarbonate having Bisphenol A leach into food and beverages even at room temperatures especially when aerated and other drinks are stored in them. Thermosets like Melamine are also known to give off acids and hydrocarbons into foods. Pigments (such as red, pink, black etc) in such packaging materials containing hexavalent Chromium, Mercury, Cadmium and Lead are carcinogenic and could harm the endocrine and neurological systems. If recycled plastics(thermoplastics) are used even in small quantities in the manufacture of food and beverages packaging, they cause major harm to human health as the contaminated recyclate can leache toxic hydrocarbons such as pesticides, fertilizers, lube oils, paints and heavy metals into the edible contents packed in them. Similarly when PVC is used for blood bags or for making dialysis units, they are known to cause toxicity in patients due to leaching of pthalates, which are plasticizers, into the blood. Similarly Poly Ethylene Glucose Saline sets are known to leache out unpolymerised hydrocarbons which could be detrimental to patients, causing allergies and lengthening their stay in hospitals.

The thermoplastics like HDPE, LDPE, PVC, PP, PS, PET or any of the thermosets are not bio-degradable. These are, sometimes, starch-filled to give the impression that they are degradable but they end up being more harmful for the environment than the non-biodegradable polymers. Plastics like Polylactic Acid (PLA) and other biopolymers made from natural starches like potato starch, oils like corn oil or palm oil are known to be completely biodegradable. PLA requires higher temperatures and specific moisture content to biodegrade. These biopolymers are expensive and are as yet not used in India on a commercial basis except in manufacture of drugs and absorbable sutures.
Fused Aluminum and plastic are used for packaging food materials. PolyAl is completely non-degradable and emits toxic fumes on burning. It could cause infertility of soil, if it gets imbedded in it, reducing permeability, porosity and fertility of the soil.
Food and Beverages packaging are high volume but may have low weights, making up only 15-20% of all packaging. They are flimsy and disposable and highly visible since they are directly disposed in the environment and are found scattered everywhere. Packaging material can be broadly classified as food and non-food packaging materials.


Recommendations:

• A study should be initiated for estimating the quantity and characteristics of each type of packaging material in the waste stream, major sources of its generation and existing disposal methods being practiced.
• A policy on packaging waste management system with the participation of all stakeholders should be developed.
• Studies on a framework for promoting clean recycling policy for packaging waste should be developed by using Life Cycle Analysis (LCA) methods.
• Guidelines/Rules should be brought out to involve large scale retailers and user industries from pharmaceuticals, processed food industries etc. in devising strategies for managing these wastes. Bureau of Indian Standards (BIS) should be requested to frame standards for manufacture and use of packaging with the idea that their reuse and recycling should not be hazardous to human health and the environment.
• Plastic packaging material should be characterized and their processing recommended after proper hazard assessment as also material from other Packaging materials viz., tetra pack, paper, pharma, glass and metals.
• There is a need to prescribe standards for non-plastic packaging as well plastics.
• Quantification and characterization of non-plastic packaging waste reaching landfill should be carried out and their recycling potential should be assessed and safe technologies for the same recommended.
• A comprehensive legislation on packaging waste should be initiated.
• Handling of any post-consumer waste is an issue which has a collective responsibility for producers, consumers, regulators, policy makers and enforcement agencies. Therefore, conducting mass awareness programmes for manufacturers, consumers, regulators, policy makers and citizens would have to be initiated.
• Strategies for recovering energy by incineration of packaging waste should be discouraged and banned.
• Design safer packaging, sorting, separating, reuse, recycling and safe reprocessing should be encouraged and promoted.

(Source: Report of the Committee to Evolve Road Map on Management of Wastes in India, Ministry of Environment and Forests, New Delhi, March, 2010. Available at: http://www.environmentportal.in/files/Roadmap-Mgmt-Waste.pdf)

Industrial Waste Management India