16.1 Humans generate waste that other organisms cannot use

• In an ecological system, plant materials, nutrients, water and energy are inputs within the environment.

• In human systems, inputs are similar but may contain materials manufactured by humans as well. – These inputs and materials are used to produce goods

• Outputs include anything not useful or consumed and nonuseful products generated within the system are called waste.

How can we define what is useful?

• The detritivores recycle the waste from animals and plants.– Using the energy and nourishment they obtain from

them and turning the remainder into compost or topsoil.

– Ex. Dung beetles live on the energy and nutrients within elephant dung. • In the natural world this isn’t waste its food

• Even humans make use of animal waste.– Fertilizer, heat and cooking fuel.

• In most situation, the waste of one organism becomes a source of energy for another.

The throw away society • Humans are the only organisms that produce

waste others cannot use. – Because of this we need learn why materials generated

by humans become waste and what that waste contains.

• Until a country becomes wealthy, it generates little waste.

• In 1900 in the united states, virtually all metal, wood and glass materials were recycled.– Broken stools would be used for fire wood.

Baby boomer

• After WW II and the rapid population growth , consumption patterns changed.

• The increasing industrialization and wealth made it possible for people to purchase household conveniences that could be used and throw away

• The population were urged to throw away old products and replace them with new models.

Planned obsolescence• This was an example of planned obsolescence.– The design of a product so that it will need to be replaced

within a few years.• This became typical from toasters to cars.

• This lead to more convenient goods, such as throw away napkins, plates, forks, etc.– All replaced reusable towels or kitchen utensils

• Household materials changed to objects that obtained mixtures of different materials. – This made it harder to be recycled

• This made the U.S the leader of the “throw-away-society”– The number one reason is because of planned obsolescence.

Municipal solid waste (MSW) • Municipal solid waste- is refuse collected by

municipalities from households, small businesses, and institutions such as schools, prisons, and hospitals.

• The environmental protection agency (EPA) estimates that approximately 60% of MSW comes from residences and 40% from commercial sources.

• From 1960-2008 the total amount of MSW generated in the USA increased from 80 million metric tons to 232 million metric tons per year.

MSW• The increase is from growth in population and

individuals have been generating increasing amounts of MSW.

• In 2008, the total amount of MSW actually decreased by a small amount. – Average waste generation was 2.0 kg (4.5 pds) of MSW

per person per day. • Waste generation varies by season of the year.• Also by, Socioeconomics status of the individual

generating the waste• Even geographic location within the country.

MSW• There are many other kinds of waste that are

generated in the US– Agricultural waste, mining waste and industrial waste

• Waste generation in much of the rest of the world stands in contrast to the United States. – In Japan each person generates an average of 1.1 kg of MSW

each day. – Developing countries is 0.55 kg (1.2 pds) per person per day. – Developed countries is 0.8-2.2 kg (1.8-4.8 pds) per person

per day. – Some indigenous people create no waste per day.– The rest (2%) ends up in a landfill or waste pile.

Content of the solid waste stream

• MSW is comprised of the things we use and then throw away

• The goods that we use are generally a combination of organic items, fibers, metals and plastics, made from petroleum. – Waste is generated from any manufacturing

process.– Waste is also generated from packaging and

transporting goods

Solid Waste Stream• Depending on what products are used can remain

in the consumer use system for a long time. – Ex. Ceramic plate or drinking mug last for 5-10 years.– Disposable paper cup leaves the system within minutes

or hours after it is used.• No matter what, all products wear out lose their

value or discarded which will then enter the waste stream.– The flow of solid waste that is recycled, incinerated,

placed in solid waste landfill, or disposed of in another way.

Solid Waste Stream• Composition of municipal solid waste shows the

data for MSW composition in the US in 2008 by category. – The category “Paper” comprise 31% of the 231 million

metric tons of waste generated before recycling. • Good news is that a fraction of paper in the solid waste stream

has been decreasing.• Less than a decade ago paper was 40%.

– Organic materials other than paper product make up another large category.• Yard waste and food scraps comprising 26%

– Wood accounts for 7%. • Not including paper, 33% of current MSW could be composted.

E-Waste• Electronic waste (E-Waste) is one component of

MSW that is small by weight but very important and rapidly increasing.

• Consumer electronics account for roughly 2% of the waste stream. – TV, computers, portable music players, and cell phones. – E-Waste effects the environment far greater than their

represented by their weight. • Older-style cathoderay tube (CRT) T.V or computer

monitor contains 1-2 kg of the heavy metal lead as well as other toxic metals such as mercury and cadmium.

E-Waste• These toxic metals can be extracted but there is little

formalized infrastructure or incentive to recycle them. – Many communities have begun voluntary programs to divert

3-waste from landfills. • It cost more to recycle a computer than to put it in a

landfill. – In the U.S, electronically devices are not easily dismantled

after they are discarded.• In 2007, EPA estimates 18% of TV and computers were

sent to recycling facilities. • The rest are generally sent to China – Adults and kids separate valuable metals from electronics

using fire and acids with no protective clothing and no respiratory gear.

– Even if you do recycle them, there is a good chance they won’t be recycled properly.

The three R’s and composting divert materials from the waste stream

• In the 1990’s, USA began to promote the diversion of material to the waste stream.

• The promotion was the phrase “Reduce, Reuse and Recycle.– The three R’s– This incorporates an approach to the subject of solid

waste management, with each technique presented in the order of benefit to the environment.• From the most desirable to the least.

Reduce• Reduce is the first choice amongst the R’s.– This is because reducing inputs is the optimal way to

decrease solid waste generation.

• This strategy is also known as waste minimization and waste prevention.

• Source reduction seeks to reduce waste by reducing, in the early stages of design and manufacture, the use of materials destined to be MSQ. – Even if it is toxic and otherwise. – Is also increases energy efficiency because it produces

less waste to begin with.– Fewer resources are being expended, so it provides economic benefits

Source reduction • Source Reduction can be implemented both on

individual and on corporate or institutional levels. – Ex. If an instructor has two pages of handout material

for a class, just by making it two sided saves 50% of paper uses.

– Another, send the papers electronically making the students refrain from printing them out.

• Source reduction in manufacturing will result from reducing the materials that go into packaging. – If new packaging can use less material protecting a

product, than successful source reduction has occurred.

Source Reduction with manufactures (CD’s)

• Consider the incremental source reduction that occurred with purchasing music:– CD’s used to be packaged in large plastic sleeves that

were 3X’s the size of the CD. – Today most CD’s are wrapped with a small amount of

plastic material that just covers the CD case that reduces the waste.

– Buying MP3’S annihilates any waste with a CD and its packaging.

– All of these are examples of Source Reductions.

Source Reduction with material substitution.

• In an office, workers use paper cups for drinking water and coffee. – Providing every worker with a reusable mug will reduce

MSW. • This could also be considering reuse, but it does reduce the

amount of MSW.

– One might think that it’ll just use more energy to clean the mugs.• This may be true for the first 50 uses of the mugs, but after

that you’ll reach a break even point.

– Another way is replacing a ceramic mug with a plastic mug.

Source Reduction with material substitution.

• The plastic mug takes less energy to manufacture. – Its lighter and less energy used to transport it.– Also, switching oil-based paint that contains toxic

petroleum derivatives to relatively nontoxic latex paint is a form of source reduction.

Subaru• Car manufacturer Subaru of America utilizes all

aspects of Reduce, Reuse and Recycle.– Their strategy is called Zero-Waste manufacturing plant. – They manufactured 200,000 automobiles in the US in

2009 and claimed to send no waste to landfills.

• They reuse materials such as shipping boxes and packaging material.– Reclaims solvents and chemicals after they are no longer

useful. – Remaining 1% that they can’t do anything with is

converted into energy, in a waste-to-energy plant.

Reuse• Reuse- allows a product or material that will be

disposed off to be cycled within a system longer before becoming an output. – It increases the mean residence time of an object.

• Reuse is still common in many countries. – It was common for the US before we became a “throw-

away society” and in some areas we still do.– Ex. Newspaper is used for art projects and animal

bedding.– Flew markets, swap meets, etc. are agents of Reuse.

Recycle• Recycling – the process by which materials destined

to become MSW are collected and converted into raw materials that are then used to produce new objects.

• There are two categories with recycling:– Closed-loop– Open-loop

• Closed-loop recycling- the recycling of a product into the same product– Aluminum cans are an example.• They’re collected, brought to a plant, melted down into new

aluminum cans.

Recycle (open loop recycling)

• Open-loop recycling- one product is recycled into another product.– Plastic coke bottles recycled into a polar fleece jacket. – Even though this is avoiding the landfill, it doesn’t

reduce demand for the raw material to make plastic for new bottles.• In this case its petroleum.

• Recycling in the last 25 years, in the US, have been a popular trend that tends to increase as the time passes.

Recycling

• Today, we recycle 1/3 of MSW. – Japan, recycling rates are closer to 50%. – Some US recycling rates of 60% for their campuses.

• Extracting resources from Earth requires energy time, and usually a considerable financial investment. – This process produces pollution.

• But it makes since for manufactures to utilize resources that have already been extracted.

Recycle

• When this happens, a lot of things are happening.– Reduces land mining if we’re dealing with a type

of metal (aluminum or tin)– When you do this, you reduce energy required to

transport or process mined ore.

• There are some problems with Recycling though.

Disadvantages of recycling

• Recycling requires time, processing, cleaning, transporting and possible modification before the waste is usable as raw material.– Because of this it requires more energy than

reducing or reusing materials. – Because of this New York City made a controversial

decision in 2002 that suspended glass and plastic recycling.

– This is a good example on how there is not always a market for recycled goods.

Don’t be drinking hatorade against Recycle.

• Just because its least of the R’s and it does require more energy in some cases, doesn’t mean you need to give it up– It works well for paper and aluminum.– It also encourages people be aware of

consumption patterns

Compost • There is another diversion for waste to ovoid the

landfill. – It is compost

• Compost- is organic matter that has decomposed under controlled conditions to produce an organic-rich material that enhances soil structure , cation exchange capacity and fertility. – it does take up space, but prevents green house gases.

• Vegetables, grass, animal manure, paper fibers not destined for recycling are good for composting.

Compost • Just because something is biodegradable doesn’t

mean they are good for composting– Meat and dairy products do not decompose easily, smell

and attract rodents.

• To encourage rapid decomposition, the ratio of carbon to nitrogen must be 30:1– It supports microbial activity.

• Layer dry material such as leaves or dried cut grass with wet material such as kitchen vegetables. – This will provide the correct carbon to nitrogen ratio

Compost

• The composting process does take time and space.

• Source separation can be an inconvenience, or impossible.

• In certain environments, storing materials before they are added to the compost pile can attract flies and vermin.

• It can also attract unwanted animals like BEARS!

Most solid waste is buried in landfills or incinerated

• In developed countries, it is extremely rare for dumps to be open.– But in developing countries, they are not so rare

because they can not afford landfills and they are considered health hazard.

• In the 1930’s, the US were opposed to open dumps, so they dug holes and put the MSW in it.– These were called Landfills. – The problem with this is that is removed soil, sand or

other earth material used for construction purposes

Landfills • Nobody considered what type of waste were in the

landfills– These MSW could generate harmful runoff and leachate

• Leachate is the water that leaches through the solid waste and removes various chemical compounds with which it comes into contact.

• They also didn’t realize the harm a landfill could cause when located near sensitive features of the landscape.– Such as aquifers, rivers, streams, drinking water, etc.

Landfills

• A third of our waste is recovered through reuse and recycling.– More than half is discarded!– The remainder is converted into energy through

incineration.– It should be noted that Reused, recycled and

composting has been increasing in US.

Landfills

• Sanitary landfills are engineered ground facilities designed to hold MSW with as little contamination of the surrounding environment as possible.

• These generally utilize a variety of technologies that safeguard against the problems of dumps. – They are lined with Clay or plastic.

• These impede water flow and retain positively charged ions, such as metals.

Sanitary landfill

• A system of pipes is constructed below the landfill to collect leachate.– These are sometimes recycled back into the landfill.

• A cover of soil and clay, called a cap, is installed when the landfill reaches capacity.

• Rainfall and other water inputs are minimized.– This is because excess water in the landfill causes a

greater rate of anaerobic decomposition.– And consequent methane release.

Sanitary landfill

• Also, there is a greater likelihood that some of that water will leave the landfill as leachate.

• If leachate exceeds certain toxicity standards, then it must be treated as toxic waste.

• The most important component of landfills is controlling inputs.– Materials destined for a landfill are those least likely

to cause environmental damage through leaching or generating methane.

– Also materials that are difficult to recycle.

Sanitary landfill• Aluminum and other metals may contribute to

leaching should never go into a landfill– Plus, they are valuable as recyclables.

• Any organic material shouldn’t go into landfills as well.– They produce methane gas, which contribute to the

green house effect.

• The MSW added to landfill is compacted into cells.– This reduces the volume of solid waste, increasing

capacity

Sanitary landfill

• When the landfill is full, it must be closed off from the surrounding environment.– This is so input and output of water are reduced or

eliminated.

• Some air and water may enter from the outside environment when it is capped.– But it should be minimal if it was well designed and

properly capped.– The design of these landfills encourages the water to

flow off the sides rather than into it.

Sanitary Landfills • Closed landfills can be reclaimed. – Some sort of herbaceous, shallow-rooted vegetation is

planted on the topsoil layer, both aesthetic reasons and to reduce soil erosion.

• Construction on the landfill is normally restricted for many years.– Parks, playgrounds and golf courses have been built on

reclaimed landfills.

Sanitary Landfills• Constructing a sanitary landfill cost a lot! – Private enterprises or municipality sets up a Tipping fee

to get back the money spent.– A tipping fee, is a fee charged to every truck that tips its

MSW load in a landfill.

• Tipping Fees actually gives an economic incentive to reduce the amount of waste that goes in the landfills. – This encourages individuals to separate recyclables. – IF tipping fees become too high, and regulations too

stringent, illegal dumping of waste materials may happen.

Choosing a site for a Sanitary Landfill• It should be located in a soil rich in clay.

– Reduces the migration of contaminants

• Located away from rivers, streams and other bodies of water and drinking supplies.

• Also should be located away from population centers.– This keeps minimal risk to people from animal scavengers

and truck transporting the waste. – To keep this energy efficient, it must be considered in

siting.– Distance from a population center increases, so does the

amount of energy required to move MSW to landfills.

Siting• Siting- is a designation of a location.• Siting is always highly controversial and sometimes

politically charge.– This is because of their unsightliness and odor

• A lot of wealthy and politically powered people have the motto “not-in-my-backyard.”– NIMBY– Because of this, the site may not be chosen because it

meets the safety criteria– Rather its neighbors lack the resources to combat the

politics

Problems with Landfills• Of course already noted, the political aspect with

populations that do not have the resources to object to it.

• No mater how careful the design is there is always a possibility that leachate will contaminate underlying and adjacent waterways. – The EPA estimates that virtually all landfills in the US

have Leaching. • Even after the landfill is closed. • The amount of leaching, the substances that have leached out,

and how far will travel are impossible to know in advance.

Problems with Landfills• Public perception is that landfill contaminants pose

a great threat to human health. – The EPA has ranked this risk as fairly low compared to

other risks • Global warming and air pollution.

• When landfills are covered, the Oxygen is used up and anaerobic decomposition begins. – This method produces methane and carbon dioxide– Besides being green house gases, it is highly explosives.– Landfills are vented so that methane does not

accumulate in highly explosive quantities. – Some operators collect the methane and use it for

energy.

Incineration • Because of the problems with landfills, people have

turned to incineration.– More than three quarters of the material that

constitutes municipal solid waste is easily combustible• This is because paper, plastic, food and yard are composed

largely of carbon, hydrogen and Oxygen.

• Incineration- is the process of burning waste materials to reduce their volume and mass and sometimes to generate electricity or heat. – An efficient incinerator operating under ideal conditions

may reduce the volume of solid waste by up to 90%– Also reduce the weight by 75%

The Basics

• MSW is sorted and certain recyclables are diverted to recycling centers. – The remain material is dumped from a refuse truck

onto a platform where materials are identified and removed• These materials are metals.

• A grate transfers the waste to a furnace. • Heat is released as combustion converts the waste

into CO2 and H20.– These are released in the atmosphere.

Ash

• The end product of combustion is Ash. – Ash is the residual nonorganic material that does not

combust during incineration.

• Bottom Ash is the residue collected underneath the furnace.

• Fly Ash is the residue collected beyond the furnace. • Because incineration often does not operate under

ideal conditions, ash typically fills 1/25 the volume of the precombustion material.

Ash contaminants

• Disposal of this ash is determined by its concentration of toxic metals. – Ash is tested for toxicity by leaching it with a weak

acid– If leachate is low in contaminants it can be

disposed in a landfill. • If it is safe, it’ll be used for road construction or

ingredients in cement. • IF deemed toxic, ash goes to a special ash landfill

designed specifically for toxic substances.

Metals and such

• Metals and other toxins in the MSW may be released to the atmosphere or remain in the ash.– This depends on the pollutant, specific incineration

process and type of technology used.

• Exhaust gases from the combustion process move through collectors to reduce emissions in atmosphere.

• Acidic gases (HCl) are scrubbed, neutralized and treated further before disposal.

Heat Energy

• Incineration also releases a great deal of heat energy that is often used in a boiler. – The boiler is right beside the furnace – This is so it’ll heat the incinerator or generate

electricity.• It uses process that is similar to coal, natural gas or

nuclear power plants.

• This is called Waste-to-energy system– When heat generated by incineration is used rather

than released in the atmosphere.

The dark side of Incineration• Tipping fees are charged in the incinerators just like

the landfills– For the same reasons.– They are higher in incinerators vs landfills.

• NIMBY issues are the same with incinerators. • They may release air pollutants like organic

compounds from the incomplete combustion of plastics and metals. – Some scientist believe incinerators are poor compared

to Landfills. • This is because the ash is more concentrated toxins than the

MSW

The dark side of incinerators.

• Incinerators require a large quantities of MSW on a daily basis in order to burn efficiently and to be profitable

• Because of this, communities will be less likely to encourage recycling.

• Incinerations should only be used as a last resort. • It is difficult to have a uniform burn– This is because the contents of MSW are extremely

variable and lumped all together.

Hazardous waste requires special means of disposal

• Hazardous waste- is liquid, solid, gaseous or sludge waste material that is harmful to humans or ecosystems. – The EPA states that over 20,000 hazardous waste

generators in the U.S. produce 36 million metric tons (40 million tons) of hazardous waste a year.

– Only 5% of that waste is recycled.

• The majority of H. waste is by-products of industrial processes.– Textile production, cleaning of machinery and

manufacturing of computer equipment. – Also by dry cleaners, automobile services and small farm

(Cont)

• Even households generate H. waste– 1.5 million metric tons per year in U.S– Includes oven cleaners, batteries, and lawn

fertilizers.

• All of these have a greater likelihood of causing harm to humans or ecosystems.– In relation to newspaper or plastic bottles.

Handling and treatment of hazardous Waste

• There are no regular collection sites for H. waste. – Homeowners and small businesses are asked to

keep their hazardous waste in a safe location until periodic collections are held.

• Treatment and disposal of H. waste is more expensive and harder to dispose of than regular MSW.

(cont.)

• H. waste must be treated before disposal.– Treament- making it less environmentally harmful.

• There are no truly good options for disposing of H. Waste.

• The most beneficial is source reductions. (Don’t create the waste anyway.) – Also the lease expensive.

Legislative Response• Regulation and oversight of the handling of H.

waste falls under two pieces of federal legislation.– U.S. Resource Conservation and Recovery Act (RCRA)– Comprehensive Environmental Response, Compensation

and Liability Act (CERCLA) • This is also refered to as the superfund act.

• In 1976, RCRA expanded previous solid waste laws.• Main goal, protect human health and natural

environment by reducing or eliminating H. waste.– Under RCTA’s provision for “Cradle-to-grave tracking”,

the EPA maintains lists of hazardous wastes.

RCRA and CERCLA (superfund)

• They work with businesses, state and local authorities to minimize and track until H.waste is disposed of properly.

• CERCLA or Superfund act, was passed in 1980 and amended in 1986.

• It imposes a tax on the chemical and petroleum industries. – Revenue is used to cleanup of abandoned and

non-operating H. waste sites.

Life-Cycle Analysis

• Life-cycle analysis is an important systems tool that looks at the materials used and released throughout the lifetime of a product.– From procurement of raw materials through their

manufacture, use and disposal.– It is also called the cradle-to-grave analysis.

• The main goal is to help a community determine whether incineration is more or less desriable than using a landfill. – Eg. Comparing a paper cup to a polystyrene cup.

Life-Cycle Analysis impossibilities • There are problems in determining the overall

environmental impact of a specific material. – Ex. Not possible to determine nitrogen oxides released

from incinerating food waste are better or worse vs amount of methane in landfills.

• Waste contains food matter is impossible to compare the full environmental impact

• Same problem with compared to types of pollution generated by producing the paper cup vs plastic cup. – Ultimately the best choice for disposing of food waste

is compost.

Life-cycle analysis for economic and energy.

• Life-cycle analysis is not able to determine absolute environmental impact.

• But it is for assessing economic and energy considerations.– For a glass manufacturing plant may be better to

receive $5 for a ton of glass than to pay a $65 per ton tipping fee.

• The analysis should also consider the energy content of energy content of fuels used.– As well as the pollution generated in transportation.

Life-cycle analysis

• Whether direct or indirect, there is always a cost to waste disposal.– Normally, disposal of recyclables costs less.– However, costs change depending on many factors,

including market conditions.• Ex. May not be a market for recycled newspapers in the US, but

in a year a huge increase in Japanese causing price to go up in the U.S.

• It is essential for municipalities to have many choices and to be able to modify these choices as market environments change.

Life-cycle analysis for economic and energy.

• This should be compared with the monetary, energy and pollution savings achieved if the new glass was made from recycled glass vs raw material.– Reconciling all these competing factors is very challenging

and the ultimate decisions are highly debatable.

• In some parts of the country, cost of waste disposal is covered by local taxes.

• In other locations, municipalities, businesses, or households may have to pay directly for disposal of their solid waste.

Alternative ways to handle waste

• Its important to develop as many options as possible with handling waste.

• Integrated Waste Management- employs several waste reduction, management, and disposal strategies in order to reduce the environmental impact of MSW.

• These include a major emphasis on source reduction and include any combination of recycling, composting, use of landfills, incineration and other methods.

Integrated waste management steps

• Starting with source reduction during manufacturing and procurement of items

• Then behavior related to use and disposal can be considered and possible altered in order to obtain the desired outcome. – Less generation of MSW.– With this approach, no community should be forced into

any one method of waste disposal.

• If the municipality is free to consider all options, it can make the choice or choices that are efficient cost effective, and least harmful to the environ.

Alternative ways to handle waste

• Holistic waste management assess existing practices in order to minimize waste generation, before, during and after manufacturing.

• Beyond this, manufacturers of durable goods should develop plans for disassembling the goods when they are no longer useful.– These are automobiles, computers, appliances and

furniture.

• Parts or materials can be recycled without become part of the waste stream.

(Cont.)

• Many organisms in the natural world produce very hard, inpactresistant materials without producing waste. – Turtles with their shells.

• Humans should examine how a tortoise creates such a hard shell without the production of toxic wastes.– Humans can use this exmaple as a goal for other kinds

of production where no toxic wastes are produced.