Solid, toxic and hazardous waste 21

objectives Identify the major components of waste stream Explain the difference between dumps, sanitary landfill, modern secure landfills Understand what hazardous and toxic waste are and how we dispose of them Outline some ways we can destroy or permanently store hazardous waste. Evaluate the options for hazardous wastes management.

Questions to answer What are solid waste and hazardous waste. What is the difference between them? Describe the difference between an open dump, sanitary landfill, and a modern secure hazardous waste disposal site. Describe some concern about waste incineration . Describe some ways that we can reduce the waste stream to avoid the disposal problem. What are brownfields? Why are landfill sites becoming limited. What is composting? List some benefits and draw backs of recycling wastes.

SOLID WASTE Solid waste is generally made up of objects or particles that accumulate on the site where they are produced. Solid waste includes domestic, commercial, industrial, agriculture, and mining waste. Solid waste are primarily non toxic. HAZARDOUS AND TOXIC WASTE Hazardous and toxic waste are injurious to both human health and environmental quality so it must be recycled or detoxified. Hazardous and toxic waste are fatal to humans and animals, carcinogenic, mutagenic or teratogenic, ignitable ,corrosive and explosive.

WASTE STREAM AND ITS COMPONENT The waste stream is a term that describe the steady flow of varied waste. It is the final resting place of toxic and non toxic wastes. Waste stream is the combination of organic material, food waste, junked car, worn out furniture, news paper, magazines, metal, glass, plastic food and beverage container, wood, concrete, bricks, spray paint can, pesticides, batteries, cleaning solvent, smoke detector, pcbs and plastic that produce dioxins. Waste stream is the source of valuable resource but due to improper disposal methods valuable things are mixed and crushed with the toxic material.

WASTE DISPOSAL METHODS

OPEN DUMPS It release the hazardous and toxic material in to the air and water. Most developed countries forbid the open dumping but illegal dumping is still a problem. It is a dominant method of waste disposal in the developing countries.

OCEAN DUMPING It is a chronic problem and it is nearly uncontrollable.

LANDFILLS Historically it was a convenient and inexpensive waste disposal method but now a days it become less convenient and more expensive method. Rising land prices , shipping costs as well as increasingly demanding landfill construction and maintenance requirements are making this a more expensive method.

SANITARY LANDFILLS In the sanitary landfill waste disposal is regulated and controlled and refuse is covered with a layer of dirt .An impermeable clay or plastic lining underlies to prevent the seepage of toxic material in to the ground water.

SECURE LANDFILLS The first line of defense in the secure land fills is the compacted clay layer in the bottom which is impermeable to the ground water and safely contain the waste. A layer of gravel is spread over the clay liner and perforated drains pipes are laid in a grid to collect any seepage that escape.

EXPORTING WASTE Industrialized nations in the world export the hazardous and toxic waste to the less develop countries . Although the industrialized nation agreed to stop shipping hazardous and toxic waste to the less develop country but the practice still continued .

INCINERATION It is a type of waste disposal method in which hazardous and toxic waste is burnt this technology is also known as energy recovery or conversion of waste into energy the steam generated in incineration process is converted into electrical energy.

Types of incinerator Refuse derived fuel : In this process refuse is sorted and burnable and unburnable material are separated from each other before combustion. Mass burn : In this process each and every thing is burnt present in the waste stream.

CONCERN ABOUT INCINERATION PROCESS The incinerator ash contain high level of dioxin, lead ,cadmium and other toxic material which is threat for environmental contamination. Incineration process produces energy but also causes pollution.

Shrinking the waste stream

RECYCLING It is the re processing of discarded materials into the new useful products in some recycling process reuse the material for the same purpose but some recycling process turn old material into entirely new products .

Benefits of recycling It save money, energy, raw material and land space while also reducing pollution . It encourage the individual awareness and responsibility for the refuse produce it also reduces the volume of waste stream and litter. it also reduces our demand for raw resources . Drawbacks of recycling Contamination is the problem associated with the recycling . A principle obstacle to the recycling is weak or unstable markets for recycled plastic, paper, and other materials .

COMPOSTING It is a large scale recycling which allow aerobic decomposition of the organic debris and converted into a nutrient rich soil amendment . Compost is a useful material but its market value is low.

DEMANUFACTURING It is an additional strategy to reduce the waste stream.It is necessary for the appliances and electronic waste such as TV sets , computers, refrigerators, air conditioners, cell phones, printers. Demanufacturing is a key to reducing the environmental cost of electronic waste and appliances .

Reusing Reusing is more efficient than recycling and it is the reuse of materials in their present form it also save the cost and energy of remaking the reusable refillable bottle is the most efficient beverage container we have . This is better for the environment than remelting and more profitable for the local community.

superfund It is a revolving fund to finance the cleanup of some of our worst hazardous waste sites . The superfund was established by the comprehensive environmental response , compensation , and liability act (CERCLA) of 1980 . Many sites on the superfund's national priority list are abandoned factories or dumps without this fund , sites would languish for years or decades while the courts decided who was responsible to pay for the cleanup . This fund was financed by taxes on producers of toxic and hazardous waste . Industries opposed this tax because the current manufacturers are not responsible for the original contamination . In 1995 the congress agreed to lead the tax expire .

Brownfield It is the large area of contaminated properties that have been abandoned or not being used up to their potential because of suspected pollution . For years no one was interested in redeveloping the brownfields because of liability risk . It present both liability and opportunity. Who would buy a property knowing that they might be forced to spend years in litigation and negotiation and be forced to pay millions of dollars for the pollution they did not create . Even if a site has been cleaned to the current standard there is worry that the additional pollution might be found in the future . Some experts recommended that the best solution is to simply cover the surface with clean soil and enclosed the property with fence to keep the people out . The reusing contaminated properties can play a significant role in rebuilding old cities and creating jobs and preventing the needless destruction of open space .

Processing of hazardous waste Hazardous waste must be processed . We can reduce the waste generation in our home by choosing less toxic materials. buy only those things which we need. PRODUCE LESS WASTE The safest and least expensive way to avoid the hazardous waste problem is to avoid creating the waste in the first place . Manufacturing process can be modified to reduce or eliminate the waste production . Recycling and reusing also eliminate the pollution and hazardous waste . Many waste products of one process or industry are valuable commodity in another.

CONVERT TO LESS HAZARDOUS SUBSTANCES There are several process available to convert the hazardous substances to less toxic substances Physical treatment isolate the substance. charcoal absorb toxin. Distillation separate the hazardous component from the aqueous solution . Precipitation and immobilization in ceramics , glass , or cement isolate toxin from the environment so that they become essentially non hazardous . One of the few ways to dispose of metal and radioactive material is to fuse them in silica at high temperature to make a stable and permeable glass that is suitable for long term storage . Incineration is a quick way to dispose of many kinds of hazardous waste . Chemical processing transform the material into non toxic form . Chemical processing include neutralization , removal of metal or halogen and oxidation . Biological processing include bioremediation , phytoremediation and biodegradation etc.

Store permanently There are various materials that can not be destroyed completely . We have to store them properly . There are various methods to store the waste material . Retrievable storage Retrievable storage mean placing the waste storage container in a secure building, salt mine, or bed rock cavern where they can be inspected periodically and retrieved .

Toxic substances in our home Bug spray Weed killers Insect poison Mercury thermometers Nickel cadmium batteries Paints with lead or mercury Hair spray Gasoline fuel oil and brake fluid Furniture polish Metal cleaner Paint thinner Glue with solvent Nail polish remover Fertilizers Glass cleaner

Alternatives to hazardous house hold chemicals Chrome cleaner use vinegar Copper cleaner lemon juice Furniture polish rub in olive Ceramic tile cleaner baking soda Pest control soap and water solution

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