CH. 13. Solid-Waste Management. 13.1. Introduction. SOLID WASTE Definition Categories Examples Municipal solid waste (MSW).
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70 % of MSW (valuable material such as glass, metal, and paper) could be recycled, however, only one-third of it was recycled in 2010, the rest was either incinerated or landfilled.
In 2010, Americans generated 250 million tons of trash
Waste disposal increased
1,350-1,606 lb/person/year in 1980-2010
Amount of MSW generated by typical families (in one week) around the world
If we are running out of space and contaminating our groundwater by burying our trash, and contaminating the air by burning our waste, What can we do?
Recycle paper, glass, and metal (pizza boxes are not recyclable!)
Compost organic waste at home
Consume less, 30% of our waste is composed of packaging!
Solid waste management in Ukraine
A useful handbook for reducing solid waste. http://www.epa.gov/epawaste/wycd/catbook/index.htm
The objective of an Integrated Solid Waste Management is to avoid the use of landfill
and incineration resources as much as possible as means of waste disposal. Thus, what it
proposes is to reduce the amount of trash we generate by consuming as less as possible and reusing what we already own (or for instance visiting garage sales), and finding alternative programs such as recycling and composting. The final desired resource would be waste disposal such as incineration and landfill.
In the USA, the total amount of municipal solid waste generated increased from 88 million
of tons in 1960 (2.6 pounds/person/day) to 250 million of tons in 2010 (4.4 pounds/person/day), however you can observe in the chart above, that in 2005, the generation of waste per capita, and thus the total amount of waste generated per year, leveled off. This shows that we are doing well watching the amount of waste we generate, but there still so much work to be done.
Solid waste disposed in rivers reaches the ocean and finally concentrates along the beaches in Mumbai, India.
Industrial waste (used engine oil) in a ditch in Male’, Maldives contaminates the groundwater.
<10% in 1980
to 34% in 2010
Potential disease transmission in a local grocery and meat market beside disposed waste in Haiti.
A bicycle that recycles metal!
Typical percentage that makes up municipal solid waste (MSW).
Quantities of generated and recovered waste in 2010.
Physico-chemical and biological characteristics.
E. Coli contamination usually starts at slaughterhouses.
Research conducted by Novotny et al. (2004) shows species of bacteria present in fish that are sources of human infections. These organisms are generally found in fish markets, floors, and fish boxes, specially during the summer.
Materials recovery facility
Construction and demolition
Storage is the immediate stage after generation, or before final disposal or recycle/reuse. Storage duration depends on the collection process, which varies from once to twice per week. There are many designs for storing waste. The table below summarizes the most common containers for solid waste storage.
Different categories of storage containers:
Municipal solid waste storage containers
Rubbish skip is used to transfer the waste to special vehicles or for door-to-door collection.
Dumpsters are large steel containers used to transfer the waste to large transportation trucks.
Solid waste is stored without safety precautions in many countries.
Storage of hazardous materials
There are various storage units such as containers, tanks, drip pads, waste piles, surface impoundments, or containmentbuildings designed to house chemicals, flammables, solvents, paint, explosives, and other hazardous materials. The storage of hazardous materials need to comply the regulatory requirements specified by RCRA (Resource Conservation and Recovery Act).
Storage of hazardous materials in buildings.
Federal regulations allow small quantity hazardous waste generators (100-1000kg) to store the waste for up to 270 days without permit.
Front-end loading vehicles are commonly used for commercial collection
Side- and rear-end loading vehicles are commonly used for residential collection
Collection of solid waste in developing countries is more inefficient. Most of the budget is spent in collection and yet, they are not able to collect all the generated waste. Collection varies from household level (called primary), where waste is collected from individuals using bicycles, handcarts, private trucks, horses, etc. as medium of transportation and then put into community collection containers. The secondary collection system is then performed by the city council using small mechanical vehicles, trucks, and tractors.
Solid waste management in Africa.
Collection of solid waste in developing countries
Street sweeping in developing countries
Biodegradable plastic containers are marketed as compostable, but they don’t completely degrade and may in fact contaminate the compost.
Composting systems perform best when the carbon-to-nitrogen ratio is in the range of 20-40 (C:N 20:1 to 40:1), which means that carbon content is 20-40 times larger than nitrogen. Table 13.11 in your textbook shows nutrient content of various materials used in composting.
Learn how to compost correctly: http://greenliving.nationalgeographic.com/compost-correctly-2358.html
Materials recovery facility.
Glass breaker screen
Commingle conveyor belt
Eddy current separator
Glass cleanup system
Landfill decomposition pathways:
Initial adjustment phase: Microorganisms adjust to the landfill conditions.
Transition phase: Transformation from aerobic to anaerobic environment.
Acid formation phase: Volatile organic acids are formed during biodegradation of organic waste.
Fermentation phase: Generation of carbon dioxide, hydrogen sulfides, methane, and ammonia due to microbial reactions of organic acids.
Maturation phase: Biodegradation stops or develops at lower rate. Leachate production is lower as well.
Typical anatomy of a landfill
Incineration, also called waste-to-energy, is one of the most widely used methods to dispose combustible waste by using high temperatures (800-1050C) to convert waste into flash, flue gas, and heat. The process can be optimized by using waste with high energy content, low moisture, and low ash content.
Volume of waste is reduced (~80-85%) so landfills are avoided
Water content in waste can be used as steam to heat systems or generate electricity
Cost of transportation of municipal solid waste is reduced
High construction and operating costs.
Fly ash and generated particles need to be eliminated from the resultant emissions before releasing to the air by air pollution control equipment
Toxins such as dioxins, furans, mercury, volatile metals, nitrous oxides are also released during the combustion process and need to be eliminated before releasing to the air.
5. The resultant gases are clean and follow federal air quality regulations.
3. Steam formed inside the incinerator is recovered to fuel turbines to produce energy
4. Toxic compounds and particlesare captured to ensure good quality of the released air
2. Burning process. Temperatures range 800-1050C. Initial volume of the waste is reduced 80-85%
1. Municipal solid waste. Includes paper, textiles, rubber, leather, wood, etc.
6. Ashes are recovered and disposed in landfills
How much energy does recycling save?
How to identify hazardous waste