Presentation on theme: "Solid Waste Mark D. Sobsey ENVR 890-2 Spring, 2009."— Presentation transcript:
Solid Waste Mark D. Sobsey ENVR 890-2 Spring, 2009
What is Solid Waste? Municipal Solid Waste (MSW) AKA: “trash” or “garbage” Includes: Durable goods, e.g., tires, furniture Nondurable goods, e.g., newspapers, plastic plates/cups; containers and packaging, e.g., milk cartons, plastic wrap; and other wastes, e.g., Yard waste, food. Common household waste, as well as office and retail wastes Excludes industrial, hazardous, and construction wastes Solid Waste – USA - 1989
Solid Waste Definition and Classification Any material which is not needed by the owner, producer or processor. Classification: Domestic waste Factory or industrial waste E-waste (electronic waste) Construction waste Agricultural waste Food processing waste Biomedical waste Nuclear waste Sewage solids (sludge, biosolids, compost, etc.)
Typical Solid Waste Categories Paper waste: packaging, newspapers, corrugated boxes, office paper, magazines, etc. Biological waste: food wastes: animal or vegetable E-waste- electronics such as computers, telephones, TVs, monitors, music systems, etc. Industrial liquid wastes: dry cleaning solvents, motor oil, tannery wastes, distillary waste, thermal power plant cooling water, etc. Plastic wastes: bags, bottles, buckets, packaging, etc. Metal wastes: cans, sheet metal, tools, fasteners, etc. Nuclear waste: unused materials from nuclear power plants Medical wastes: solids, liquids, gases, bodily wastes, infectious agents, radioactive wastes, etc.
What Happens to The Stuff No One Wants? Philadelphia’s Municipal Waste Odyssey A 16 year journey for a cargo ship containing Philadelphia MSW –Eleven countries –Four continents Several governments refused the cargo Eventually, 25,000 tonnes of flyash came back to Philadelphia’s MSWL In 2002, the cargo ship returned to the USA
French Aircraft Carrier Clemenceau: A waste-laden ghost ship nobody wanted December, 2005, The Clemenceau, a 27,000-ton warship loaded with asbestos, PCBs, lead, mercury, and other toxic chemicals Bound for the India scrapyard of Alang (Bhavnagar district, Gujarat) –Environmental regulations lax and few workers' rights Many shipping nations lack proper waste management policies, rules and regulations –Where rules exist, they may not be enforced. Basel Convention (1989) –International treaty prohibiting the export of hazardous waste from rich to poor countries Greenpeace raised awareness campaigned against the ship in India as well as in France French President Chirac eventually announced a dramatic recall of the Clemenceau
Options for Municipal Solid Waste Management Landfills –Engineered areas where waste is placed into the land. Waste combustors –Facilities that burn MSW at a high temperature, reducing waste volume and generating electricity Some facilities blend MSW with other fuels Transfer Stations –Facilities where municipal solid waste is unloaded from collection vehicles and briefly held MSW is then reloaded onto larger, long-distance transport vehicles for shipment to landfills or other treatment or disposal facilities
Municipal Solid Waste Landfills Engineered facilities (in design and operation) Located, designed, operated, and monitored to protect the environment and human exposure to MSW –Designed to contain and biodegrade the waste –Protect the environment from contaminants which may be present in the solid waste stream. Landfill siting plan –Intended to prevent landfill siting in environmentally- sensitive areas On-site environmental monitoring systems –Monitor for evidence of groundwater contamination and for landfill gas –Many new landfills collect solid waste leachate (liquid emanating from the waste and recycle or store it. –Many new landfills collect potentially harmful landfill gas emissions and convert the gas into energy (it is combustible).
Landfill Properties, Practices and Policies Location restrictions –ensure they are built in suitable geological areas away from faults, wetlands, flood plains, or other restricted areas. Composite liners requirements –In the USA: includes a flexible membrane (geomembrane) overlaying two feet of compacted clay soil lining the bottom and sides of the landfill, Protects groundwater and the underlying soil from leachate releases. Leachate collection and removal systems –located above the composite liner to remove leachate from the landfill for recycling, treatment and disposal.
Landfill Properties, Practices and Policies Ban disposal of some toxic and hazardous materials –Paints, cleaners/chemicals, motor oil, batteries, and pesticides. Leftover portions of them are “household hazardous waste” Hazardous to health and the environment if mishandled Many municipal landfills have household hazardous waste drop-off stations for these materials. Unwanted household appliances (white goods) –Refrigerators or window air conditioners containin ozone- depleting refrigerants and their substitutes. –USA: federal disposal procedures for white goods with refrigerants. Electrical waste also collected separately; not landfilled. –Contains radioactive and toxic chemicals –Not biodegradable
Landfill Properties, Practices and Policies Operating practices –compacting and covering waste frequently with several inches of soil Reduce odor; control litter, vectors (e.g., insects, and rodents) Groundwater monitoring –Required testing of groundwater wells to determine if wastes escape Closure and postclosure management requirements –Cover landfills and provide long-term management of closed landfills. Corrective action provisions –control and clean up landfill releases –achieve groundwater protection standards Financial assurance –Funding for environmental protection during and after landfill closure
Bioreactor Landfills Operated to rapidly transform and degrade organic waste by microbial processes Increase waste degradation and stabilization through the addition of liquid and air Differs from the traditional “dry tomb” municipal landfill approach. Three different general types of bioreactor landfill configurations: Aerobic: –Leachate is removed from the bottom, piped to liquids storage tanks, and re-circulated into the landfill in a controlled manner. –Air is injected into the waste mass, using vertical or horizontal wells, to promote aerobic activity and accelerate waste stabilization.
Bioreactor Landfills Anaerobic –Add moisture to the waste mass as re-circulated leachate or other sources to obtain optimal moisture levels. –Anaerobic biodegradation oxygen to produces landfill gas Primarily methane can be captured to minimize greenhouse gas emissions and for energy projects. Hybrid (Aerobic-Anaerobic) Accelerates waste degradation by employing a sequential aerobic-anaerobic treatment Rapidly degrades organics in the upper sections of the landfill Collects gas from lower sections. Hybrid operation results in earlier onset of methanogenesis compared to aerobic landfills
Bioreactor Landfills Accelerate the decomposition and stabilization of waste. Leachate is injected to stimulate natural biodegradation processes. Other supplemental liquids such as stormwater, wastewater, and wastewater treatment plant sludges are often added to maintain moisture content –Enhance microbiological processes by controlling moisture content –Differs from landfills that just recirculate leachate for liquids management. Landfills recirculating leachate may not operate as optimally. Moisture content is the most important factor for accelerated decomposition. Maintain optimal moisture content near field capacity (~35-65%) –Add liquids when necessary to maintain that percentage. The moisture content, combined with the biological action of naturally occurring microbes decomposes the waste. –The microbes can be either aerobic or anaerobic. –Side effect: production of landfill gas (LFG) such as methane at higher rate than traditional landfills.
Potential Advantages of Bioreactor Landfills Waste decomposition and biological stabilization can occur in a much shorter time than in a traditional “dry tomb” landfill –Potential decrease in long-term environmental risks and landfill operating and post-closure costs. –Decomposition and biological stabilization in years vs. decades in “dry tombs” Lower waste toxicity and mobility due to both aerobic and anaerobic conditions Reduced leachate disposal costs A 15-30 % gain in landfill space due to an increase in density of waste mass Significant increased LFG generation that, when captured, can be used for energy use onsite or sold Reduced post-closure care
Bioreactor Landfill Gas - LFG LFG of bioreactor landfill consists primarily of: –Methane, carbon dioxide, lesser amounts of volatile organic chemicals and/or hazardous air pollutants LFG is generated earlier in the process and at a higher rate than in the traditional landfill. The bioreactor LFG is generated over a shorter period of time LFG emissions decline as accelerated decomposition depletes the source waste faster than in traditional landfills. The net result: bioreactor landfill produces more LFG overall than does the traditional landfill.
MSW Combustion or Incineration Controlled burning process that reduces solid waste volume; Called refuse derived fuel (RDF) facilities Properly equipped, they can convert water into steam to fuel heating systems or generate electricity. They are equipped to recover recyclables (e.g., metals, cans, glass) first Then the combustible fraction is shredded into fluff for incineration. IN USA >20% of MSW incinerators use RDF. Contrast with mass burning: –MSW is introduced "as is" into the combustion process –Considerable air pollution is produced –Some mass burn facilities have no air pollution controls
RDF Facilities and Air Pollution Control Pollution control technologies reduce gases emitted into the air: –Scrubbers: devices using a liquid spray to neutralize acid gases –Filters: remove tiny ash particles –Burning waste at extremely high temperatures: destroys chemical compounds and pathogens. –Regular testing to ensures that residual ash is non- hazardous before being landfilled. About 10% of the total ash formed in the combustion process is used for beneficial use such as daily cover in landfills and road construction
Solid Waste Transfer Stations Facilities where MSW is unloaded from collection vehicles and briefly held. Held waste is reloaded onto larger, long-distance transport vehicles for shipment to landfills or other treatment or disposal facilities. Pros: –Combining loads of several individual waste collection trucks into a single shipment saves money on labor and operating costs of waste transport the to a distant disposal site. –Reduces the total number of vehicular trips traveling to and from the disposal site. Cons: –Can cause increased traffic in areas located. –If not properly sited, designed and operated they can cause problems for residents living near them and cause hazards on the roads they travel.
Backyard Burning Burning of household trash by residents on their own property. Trash typically burned includes paper, cardboard, food scraps, plastics, and yard trimmings –any materials that would otherwise be recycled or sent to a landfill. Burning often occurs in a burn barrel, homemade burn box, wood stove, outdoor boiler, or open pit. Air emissions from backyard burning are released directly to the atmosphere without being treated or filtered. Common in developing countries
Why People Burn Household Waste People burn trash for various reasons It is easier than hauling it to a local disposal site They avoid paying for regular waste collection service. In some places it is the only way a rural dweller can easily get rid of/manage their waste. In developed countries like the USA, many state, local and tribal governments prohibit or restrict some or all backyard burning of waste. Even where restrictions exist, however, many people continue to burn.
Health Risks of SW Burning Burning waste is harmful to health and the environment. Research indicates it to be far more harmful to health than previously thought. Increases the risk of heart disease, aggravates respiratory ailments such as asthma and emphysema, and cause rashes, nausea, or headaches. Produces harmful quantities of dioxins, a group of highly toxic chemicals that settle on crops and in waterways –Eventually winds up food to impact health
Waste Barrel Burning and Dioxins Typically, dioxins are absent in materials before incineration. They are produced when waste is burned. Significantly higher dioxin levels are created by burning SW in barrels than in municipal incinerators. Burn barrels get limited oxygen so burn at low temperatures Produces dioxins, much smoke (carbonaceous particulates) and other pollutants. Large, regulated incinerators have stringent pollution control systems that reduce dioxin emissions primarily by preventing their formation. Backyard burning is also hazardous because it releases pollutants at ground level, where they are more readily inhaled or incorporated into the food chain.
Dioxin Exposure and BYB Dioxins and "dioxin like“ cds: 30 highly toxic chlorinated organic chemicals. Produced naturally in small quantities, but primarily from human activity. Industrial processes, ex. chlorinated chemical manufacture & metal smelting Largest quantified source is uncontrolled burning of HH trash (BYB). Only small amounts of chlorinated materials in waste are needed to support dioxin formation when burning. So, even when materials containing high levels of chlorine, such as PVC, are removed from HH trash, burning the waste still creates dioxins Almost all HH waste contains trace amounts of chlorine.
BYB and Dioxin Exposure Pathways Much of the dioxins created and released into air by BYB settle on plants The plants are eaten by food animals, dioxins are stored in their fatty tissue. People are exposed by eating meat, fish, and dairy products, –especially those high in fat. Dioxins then accumulate in the fats of dairy cows, beef, poultry, and swine, making human consumption of these harmful chemicals difficult to avoid. BYB occurs most commonly in rural farming areas where dioxin emissions can more easily be deposited on animal feed crops and grazing lands.
Dioxins and Human Health Dioxins are classified as persistent, bioaccumulative, and toxic pollutants (PBTs). PBTs are highly toxic, long-lasting substances that accumulate in the food chain to levels harmful to human and ecosystem health. Persistent: remain in the environment for extended periods of time. Bioaccumulative: concentrations increase moving up the food chain. –Animals at the top of the food chain (such as humans) tend to have the highest dioxin concentrations in their bodies. Dioxins are potent toxicants that potentially produce a broad spectrum of adverse effects in humans. They alter the fundamental growth and development of cells, leading to many kinds of adverse health impacts. Reproduction and development Immune suppression Disruption of hormonal systems Cancer
Particulate Pollution Particulate matter, or PM Microscopic particles released by open burning Particles are small enough to enter the lungs –Less than or equal to 10 um in diameter –Cause numerous health problems Aggravate respiratory conditions such as asthma and bronchitis Associated with cardiac arrhythmia (heartbeat irregularities) and heart attacks. People with heart or lung disease, the elderly, and children are at highest risk from exposure to particles.
Polycyclic Aromatic Hydrocarbons - PAH A group of chemicals commonly found in particulate matter (or smoke and soot) released from backyard burning. Formed from the incomplete combustion of certain materials. Some are carcinogenic
Volatile Organic Compounds-VOC VOCs are produced by open burning. Many VOCs are harmful to humans. They also contribute to ground-level ozone pollution, i.e., smog Smog can worsen respiratory, heart, and other existing health problems. Inhaling certain VOCs can lead to eye, nose, and throat irritation; headache; loss of coordination; nausea; and damage to liver, kidney, and central nervous system.
Carbon Monoxide Carbon monoxide (CO) at low levels of exposure causes a variety of neurological symptoms: headache, fatigue, nausea, and vomiting.
Hexachlorobenzene (HCB) A highly persistent environmental toxin that degrades slowly in air Undergoes long-range atmospheric transport Bioaccumulates in fish, marine animals, birds, lichens, and animals that feed on fish or lichens. Based on animal toxicological studies, long-term low-level exposures may –damage the developing fetus –cause cancer (A probable human carcinogen) –lead to kidney and liver damage –cause fatigue –Cause skin irritation
Ash Ash residue can contain toxic metals such as mercury, lead, chromium, and arsenic. These metals can be toxic when ingested. Ingestion of hazardous amounts of lead can cause high blood pressure, cardiovascular problems, kidney damage, and brain damage. –Lead is a potent neurotoxin to infants and children –Causes developmental disorders, decrements in IQ, learning disabilities People scatter ash in their gardens or bury it on their property Garden vegetables can absorb and accumulate the metals in ash, which can make them hazardous to eat. Children playing in the yard or garden can incidentally ingest soil containing these metals. Rain can wash ash into ground and surface water, contaminating drinking water and food.
Methods to Reduce Solid Waste Source reduction –Alter the design, manufacture, or use of products and materials to reduce the amount and toxicity of what gets thrown away. Recycling –Sorting, collecting, and processing materials to manufacture and sell them as new products. Composting –Decomposing organic waste, such as food scraps and yard trimmings, with microorganisms (mainly bacteria and fungi) to produce compost. Compost is the biologically stabilized residual organic material that can be used as a soil amendment or as a medium to grow plants.