Villanueva Waste Disposal 2

7/31/2019 Villanueva Waste Disposal 2

1/42


2/42

Waste DisposalHigh-consumption technological societies tend to generate copious

quantities of wastes. In the United States alone each person

generates, on average, about 4.6 pounds(more than 2 kilograms) of

what is broadly called garbage everyday. That represents an

increase of more than 70% over 1960 per capita waste production.

Every five years, each average American generates a mass of waste

greater than the mass of the Statue of Liberty. Most of the 40

billion gallons of water withdrawn daily by public water

departments ends up as sewage-tainted wastewater, and more

concentrated liquid wastes are generated by industry. Each day, the

question of where to put the growing accumulations of radioactive

waste materials becomes more pressing. Proper secure disposal of

all these varied wastes is critical to minimizing environmentalpollution.


3/42

Solid Waste The principal sources of solid waste in the United States are shown in

figure 16.1. More than 50% of the waste are linked to agricultural actvities,with the dominant component being waste from livesstock.Most of the thiswaste is not highly toxic except when contaminated with agriculturalchemicals, nor isit collected for systematic disposal. The volume of the

problem, therefore is seldom realized. The other major waste source is the mineral industry, which generates

immense quantities of spoils,tailings, slag and other rock and mineralwastes. Materials such as tailings and spoils are geenrally handled onsite,as for example when surface mines are reclaimed. The amount of wasteinvolved makes long-distance transportation or sophisticated treatment of

the wastes uneconomical. The weathering of mining wastes can besignificant water-pollution hazard, depending on the nature of the rocks,with metals and sulifuric acid among the principal pollutants. Shileding thepulverized rocks from rapid weathering with a soil cover is a commoncontrol/disposal strategy. In addition, certainchemicals used to extractmetals during processing are toxic and require special handling in disposal

like other industrial wastes.


4/42

Non-mining industrial wastes likewise command a relatively largeshare of attention because many industrial wastes are highly toxic.

Most of the highly publicized unsafe hazardous waste disposal sites

involve improper disposal of industrial chemical wastes. While

industrial wastes may supply the largest volumes of toxic materials,

municipal waste is far from the harmless. Aside from the organicmaterials like food waste and paper, a wide variety of poisons is

used in every household: corrosive cleaning fluids, insecticides and

insect repellants and so on. These toxic chemicals together

represents a substantial, if more dilute, potential source of pollution

if carelessly handled.


5/42

Municipal Waste

Disposal A great variety of materials

collectively make upthe solid-

waste diposal problem that

costs municipalities severalbillion dollars each year. The

complexity nof the waste-

disposal problem is thus

compounded by the mix of

diffrent materials to be dealtwith. The best disposal method

for one kind of waste may not

be appropriate for another.


6/42


7/42

A long-established method for solid-waste disposal thatdemands a minimum of effort and expense has been the

open dump site. Drawbacks to such facilities are fairly

obvious, especially to those having the misfortune to live

nearby. Open dumps are unsightly, unsanitary and

generally smelly ; they attract rats, insects, and other

pests. There are fire hazards. Surface water percolating

through the trash can dissolve out or leach, harmful

chemicals that are then carried away from the dump site.


8/42

Municipal Solid Waste Composition


9/42

Sanitary

Landfills The major share of municipal solid

waste in the United State ends up in

sanitary landfills. The method has

been in used seen the earlytwentieth. In basic sanitary landfill

operation, a layer of compacted

trash is covered with a layer of

earth at least once a day. The earth

cover keeps out vermin and helpsto confine the refuse. Landfills have

generally been sited in low places-

natural valleys old abandoned

gravel pits, or surface mines.


10/42

Incineration Incineration as a means of waste disposal provides a partial solution tothe space requirements of landfills. However, it is an imperfect solution,since burning wastes contributes to air pollution, adding considerablecarbon dioxide ( co2) if nothing else. At moderate temperatures,incineration may also produce variety of toxic gases, depending on whatis burned. For instances, plastics when burned can release chlorine gasand hydrochloric acid, both of which are toxic and corrosive, or deadlyhydrogen cyanide: combustion of sulfur-bearing organic matterreleases sulfur dioxide ( so2) : and so on.

A further benefit of incineration can be realized if the heat generatedthereby is recovered. For years, European cities have generated

electricity using waste-disposal incinerators as the source of heat. Thecombined benefits of land conservation and energy production have ledto extensive adoption of incineration in a number of European nations.


11/42

The United States has been slower to adopt his practice, probably

beacuse of more abundant supplies of other enrgy sources.Still, growing number of U.S cities and individuakl companies have put

the considerable quantity of heat energy released by an incinerator to

good use. Considerable public resistance tonew incineratorsexists,

however, which is part of the reason that it may take three to five years

from inception to opening of doento reduce waste accounted for 12.6% of

municipal solid-waste disposal in the United States.


12/42

Ocean Dumping A variant of land-based incineration is shpboard incineration nin the openocean. Following combustion, unburned materails are simply dumped at sea.This method has bbeen applied to stock-piles of particularly hazardouschemical wastes. A 1981 report of the Environmental Protection Agenmcydescribed the teachnique as promising for a variety of reasons, making the

statement that it has a minimal impact on the environment by removing thedestruction site far from populated raes so that emissions are absorbed by theoceans. And noting that offshore incinerators not handicapped by emissioncomntrol requirements that applyto land-0based units. Could be evry cost-effective. The desirability of this method palinly depends on ones point of view.It does not much matter if carbon dioxide is added to the air over land or in theatmosphere.

Ocean dumping without prior incineration has also been used for chemicalwastes, municipal garbage, and other refuse. The potential for water pollutionis obvious,. In some cases, too, shifting currents have brought the waste back toshore rather tahn dispersing it in the oceans as intended. Increasing recognitionof the dangers of dumping untreated wastes in the sea led


13/42

Reducing Solid-

Waste Volume The sheer volume of the solid-waste disposal problem has ledto a variety of attempts to

reduce it. Advocates this sequence of

approaches to municipalwastes:

1. Source reduction

2. Recovery of materials forcomposing or recycling

3. disposal , whether bycombustion or landfill.


14/42

At the disposal stage, another volume-reductionstrategy is compaction, either in individual homes

with trash compactors or at large municipal

compaction facilities. Less available sites. However, it

also means no reuse of any potentially recoverablematerial, and the slower decay of organic material .


15/42

Organic matter can be turned to good use through

composting, a practice long familiar to gardeners andfarmers. Many kinds of plant wastes and animals

manures can be handled this way. Partial

decomposition of the organic matter by the

microorganism produces a crumbly, brown materialrich in plant nutrients.

Finish composed is a very useful soil additive,

improving soil structure and water- holding capacity

as well as adding nutrients.


16/42

Handling Non-toxic

Organic Matter Onsite disposal, for example, with a home in sink

garbage disposal unit-is not really disposal at all. The

practice merely diverts some organic matter to

become part of the water pollution problem.

The organic-matter content of the water is increased

and more of a load is placed on municipal sewage-treatment


17/42

RecyclingRecycling and reuse are also waste

reduction strategies. Glass is notmade from scarce commodities but

just as quartz in a weathering-

resistant mineral, silica-rich isvirtually indestructible in dumps

and landfills and along road sides.


18/42

Recycling all glass beverages containers would reduce

over 5 million tons per year the amount of glass

contributing to the solid-waste disposal problem.

Imposing deposits on beverages containers can alsoprovides a financial incentive not to litter. In Oregon,

passage of a mandatory deposit law for the beverage

containers reduced the idea in 1971, nine other states

have followed suit.


19/42

Paper might also be

recycled more

extensively. In the

United States, about

54% of the paper andpaperboard we discard

is recycled, and an

estimated 35% of paperused has some recycled

content.

Pl i i b


20/42

Plastics continue to be

something of a disposal

problem, though much less of

one than they were believed to

be a decade or more ago. The

same durability that makes

them useful also except by

high-temperature combustion.

Some degradable plastics have

been developed to breakdown

in the environment after a

period of exposure to sunlight,

weather, and microbial activity

but these plastics are suitable

only for applications where

they need only to hold together

for a short period of time.


21/42

Another difficulty in recycling plastics is similar to

theproblem with different steels: A mix of plastics,

when reprocessed, is unlikely to have quite the

right properties for any of the applications from

which the various scrap plastics were derived.

Still the blend may be suitable for other uses, such as

plastic piping, plastic lumber or a shredded plastic

stuffing for upholstery.


22/42

O h t f ilit ti


23/42

One approach to facilitating

plastic recycling is to mark those

plastics that can be more easily

recycled with the triangular

symbol of three arrows head-to-tail that is widely used to

represent recycling, and identify

the basic type of plastic by a

number(1,2,3,etc.)

A remaining obstacle is that theremust exist an identifiable market

or demand for a particular

plastic in order for its recycling

to be economically feasible: so a

given municipal waste hauler

might be able to collect soda

bottles and milk jugs for

recycling but not foam packing

materials

A l d l i i


24/42

A recycled aluminum can is

likely to come back as a new

aluminum can, a recycled glass

bottle as a refilled or

remanufactured bottle. A

plastics properties tend to

change during recycling,

however, and recycled plastic

may be less strong then new

plastic. So a soda bottle may be

recycled, but it will be

transformed into something

else-such as fiber for carpeting,

plastic trash bags, or plastic

lumber for park benches.


25/42

These particular interest in finding uses for the plastic-

rich residue from the shedders used to chew up junked

cars. Once the metals are extracted from the shreddedproduct, most of the remaining 150 to 200 kilograms( 300

to 400 pounds) of material that will make the whole

process more economically practical.

Where recovery of materials from municipal refuse is

desired, source separation is generally necessary. This

means that individual homeowners, businesses, and other

trash generators must sort that trash into categories-paper, plastic, glass and so on-prior to collection.


26/42

Recycling may conflict in some measure with otherwaste-disposal objectives. For example, recycling

combustion materials reduces the energy output of

municipal incinerators used to generate power. Paper

recycler are already encountering this problem, andas users are found for recycled plastics, and the same

difficulty may arise with those materials

There are also international


27/42

There are also internationalexchanges of material forrecycling, though precisedata are not always

available. One recognizedarea of growing concern ise-cycling, recycling ofelectronic waste. Theconcern relatesparticularly to toxicelements in electronics:lead in cathode-ray tubesand circuit boards:

cadmium insemiconductors: mercuryin switches, circuit boards,lamps and batteries: andmore.


28/42

Some materials are toodifficult to reuse efficiently,for reasons already outlined,

and these will continue torequire ultimate disposal.Beyond municipal wastes aretoxic by-products ofindustrial processes that are

not themselves useful, or aretoo toxic for safe handlingduring extensive processing.These require more-specialized and careful

disposal. Also, many of thehighly toxic industrial wastesare liquids rather than solid,which may require somewhatdifferent handling from solid

wastes.


29/42

Toxic Waste

Disposal Toxic waste problems come in many forms, often

liquid ones. A notable example is the problem of usedoil. Presently, over 1 billion gallons of used lubricants

derived from petroleum are generated in the United

States each year; 40% of this waste is poured into the

ground or into storm drains, and the fate of another20% is unknown.


30/42

Another high-volume problem, but a localized one,is liquid animal waste from stockyards, pig farms,

and other facilities where large numbers of animals

are concentrated. However, the two major types of

liquid wastes are sewage, which is discussed in asubsequent section and the more concentrated

highly toxic, liquid waste by products or industrial

processes-acid, bases, organic solvents and so on.


31/42

Handling of toxic liquid

wastes has historically

tended to follow one of twodivergent paths. The dilute

and disperse approach,

based on the assumption

that, if toxic substancesare sufficiently diluted,

they will be rendered

harmless, has been the

rationale behind much

dumping into oceans and

large lakes and rivers.


32/42

The opposite approach the

concentrated and contain

alternative. Thoughtlessdisposal of concentrated

wastes followed by

inadequate containment has

led to disasters like LoveCanal, New York City.

The disposal sites frequently

were not evaluated with

respect to their sustainabilityas toxic-waste disposal sites

and over the loner term the

waste were not contained.


33/42

Secure Landfills

Waste disposal specialist have believed that, in

principle, it is possible to design a secure landfill site

for toxic solid and liquid wastes.

The waste are put in sealed drums before disposal.

Beneath the drums are layers of plastic and/ or

compacted clay to contain any unexpected leaks. Well s

and piping are installed so that the ground water

below and around the site can be checked periodically

for any sign of leakage of the waste chemicals.


34/42

Chemical and biological

reactions in the waste and

leachate can rupture or

decompose plastic, and thestress caused by the weight

of wastes and cover can

fracture a clay hard to

contain.


35/42

Deep well

disposal This method has been

practiced since World

War II. The rock unitselected to receive thewastes must berelatively porous and

permeable and it mustbe isolated by low-permeability layers.


36/42

Dee well dis osal


37/42

Sewage treatment


38/42

Problems arising from organic matter in

water include oxygen depletion and algal

bloom. This problems and concern aboutthe spread of disease through biological

contamination of drinking-water supplies by

pathogenic (disease-causing)organismsprovide the motivation for effective sewage

disposal.

Sewage treatment


39/42


40/42

Septic

SystemWastes are first transferred to a

settling tank in which solid settle out,

to be broken down slowly through

bacterial action. The remainingliquid carries a load of dissolve

organic matter and of

microorganisms- some pathogenic-

whose metabolism requires little or

no oxygen. The dissolved organicmatter represents food for those

microorganisms. The liquid is

allowed to seep out through porous

pipes into the soil of the leaching

field or adsorption field.

Prepared by:


41/42

Prepared by:

Thank youforviewing!


42/42

Villanueva Waste Disposal 2

Documents

Transcript of Villanueva Waste Disposal 2