WASTE MANAGEMENTWASTE MANAGEMENT

WASTE

INDUSTRIAL PRODUCTION

• change the natural cycle of materials• use more and more materials • produce an ever increasing amount of waste

WASTE

• any material „thrown away”• regarded as useless and unwanted (at a certain time

and place)

PROBLEMS

• We loose our non-renewable natural resources

• We throw away a lot of material and energy present in waste

• We produce waste having a changed composition and characteristics as the raw materials used

• We pollute and poison the environment

PROBLEMS CAUSED BY IMPROPER DISPOSAL OF WASTE

Threat to public healthrodents, insects = vectors of diseases (transmit pathogens)

typhoid, plague

poisonous materials

flammable materials

Irreversible environmental damage in ecosystemsterrestrial and aquatic

air pollution (incineration)

water pollution (land burial)

Technical and environmental difficulties + administrative, economic and social problems

PROBLEMS WITH LAND DISPOSAL OF WASTE

too little space for disposal costs harm to the environment and public health landfills are unreliable in long run aesthetics public opposition

INTEGRATED WASTE MANAGEMENT IS NEEDED

• source reduction

• reuse

• resource recovery

• composting

• Incineration

• landfill

WASTE MANAGEMENT

Solve the technical and environmental difficulties, administrative, economic and social problems

Tasks to be done:–Planning–Design–Construction–Operation of facilities for

In the field of:–Collecting,–Transporting,–Processing,–Disposing of the waste material

TYPES OF WASTES

residential industrialcommercial

agricultural

mining

construction

Municipal solid waste Hazardous waste

MUNICIPAL SOLID WASTE

Refuse (municipal solid waste)All non-hazardous solid waste from a communityRequires collection and transport to a processing or disposal site

Ordinary refuse: garbage + rubbish

GarbageHighly decomposable food wasteVegetable + meat

RubbishGlass, rubber, tin cansSlowly decomposable or combustible material – paper, textile, wood

TrashBulky waste material that requires special handlingMattress, TV, refrigeratorCollected separately

Municipal solid waste

Ordinary refuse Trash

Garbage (15%)

Rubbish (85%)

Routine collection Special collection

Treatment or processing

Resource recovery and recycling

Final disposal

USA:300 million t/yr refuse (1990?) = 1.2 million tons/person/year

= 4000 km long convoy of 10-ton trucks

Hungary:Total waste: 84 million t/yr (2001)Municipal solid waste: 4 million t/yr (2001)Population: 10.2 million (8.2 t/pe/yr; 0.4 t/pe/yr)

COMPOSITION OF URBAN SOLID WASTE

paper

hard waste

plastics

metals

food waste

glass

wood

other

• 0,6 – 1,2 m3 waste / day / person

• 120 – 250 kg / m3 without compaction

• 40-50% is paper

HAZARDOUS WASTE

can cause serious illness, injury, death

serious threat to the environment

TOXIC WASTEGenerated by industry

Poisonous even in small amount

Arsenic, asbestos, heavy metals, dioxin, chloroform, etc

HAZARDOUS WASTE

REACTIVE WASTESUnstable, tend to react vigorously with air, water, etc.Reaction causes explosions, form toxic vapour and fumes

IGNITABLE WASTEOrganic solvents – benzene, tolueneBurn at relatively low temperaturesPresent an immediate fire hazard

CORROSIVEStrong alkaline and acidic substancesDestroy materials and living tissues by chemical reaction

HAZARDOUS WASTE

reactive wastes

ignitable waste

corrosive

• Can cause immediate harmful effects on living organisms or on the physical environment

• Problems related to transport, storage and disposal • Must be managed with special care

HAZARDOUS WASTE

INFECTIOUSBiological waste material

Human tissue from surgery, used bandages and hypodermic needles, microbial materials

Waste from hospitals and biological research centers

RADIOACTIVE Ionizing radiation harms living organisms

Persist in the environment for thousands of years before decay appreciably

Separated from other wastes

COLLECTION AND TRANSPORT

80% of the cost of waste management is spent for collection and transport

PROPER STORAGE PRIOR TO COLLECTION

– To protect public health (rodent, insects, odor)– Aesthetic reasons– Municipal waste – containers with tight lids– Containers and storage areas have to be washed– Waste has to be removed at least weekly – Individual residences – galvanized metal or plastic

containers– Apartment residences – larger portable containers – can be

removed and emptied into collection trucks

COLLECTION OF WASTE

responsibility of the local municipalityrefuse collection vehicles

enclosed, compacting type with a capacity of 15 m3

compaction: 50% reduction

frequency of collection and the point of pickup depends:type of communitypopulation densityland use in the collection area

combined collection of garbage and rubbish is cheaper for recycling it is essential to separateseparated collection!!! (paper, metal, plastic, glass, organics, chemicals, batteries)

TRANSPORT VEHICLES AND TRANSFER STATION

WASTE TREATMENT AND RESOURCE RECOVERY

Goals:1. Reduce the total volume and weight of material

that requires disposalHelp to conserve land resources

2. Change the form or characteristic of wasteComposting, neutralizing, shredding, incineration

3. Recover natural resources and energy in the waste material

Recycling and reuse!!! (it takes 17 trees to make 1 ton of paper)

Requiring extra costs!

REDUCE, RECYCLE, AND REUSE

Reduce waste production:“consuming and throwing away less” – partly proactive!

•better design of packages: 10%•recycling programs: 30%•composting: 10%•integrated waste management: 50%

ReuseUsage of the product itself without changing it’s form and composition. Works rather for trash than for daily garbage (old cloths, machinery, bottles, jars, boxes, tools…)

REDUCE, RECYCLE, AND REUSE

RecycleUsage of the resources (matter and energy) stored in the waste by processing it.

Recyclable garbagenewsprint (paper: 50% by weight, 70% by volume)

glass

aluminum cans and other metals

rubber

plastic

organic material – food waste

REDUCE, RECYCLE, AND REUSE

We have to separate recyclables in the households Packaging has to be minimized Recycled products has to be preferred

Lot of people don’t care

– Extra attention is needed

– Not enough information available for public

Not enough appropriate recycling centers

No separated transport (cost is high)

RECYCLING

-Not yet economical (regulations can help)Does not eliminate the waste disposal problem

non recyclable residueRequires selectionRecycled paper is never as good as new but can be used

+Protection of environment (eg. less harvesting of trees)Save our resources (they are less and less)Al cans, glass, rubber, plastic – more and better technologies for recyclingEnergy saving (96% of E is saved by recycling Al cans)

SOLID-WASTE DISPOSAL

• On-site disposal• Composting• Incineration• Open dumps• Sanitary landfills

ON-SITE DISPOSAL

MECHANICAL GRINDING OF KITCHEN FOOD WASTE

devices in the ww pipe system from a kitchen sinkground and flushed into the sewer system

- reduces the amount of handling food waste - easy and quick

- problem is transported (wwtp has to dispose)- hazardous liquid chemicals- illegal dumping in urban sewers

COMPOSTING

• biochemical process• organic materials decompose to a humuslike

material• aerobic organisms• in mechanical digesters• presence of oxygen• T can reach 65 c because of aerobic microbial action• V reduction = 50%• end product is compost or humus – utilizable

–like potting soil–earthy odor–can be used as soil conditioner

COMPOSTING

stabilize the organic material agricultural use no air pollution we save land

need for separation of organic waste

COMPOSTING

1. Sorting and separating• Isolate the organic, decomposable part

2. Size reduction• Shredding and pulverizing

• Relatively uniform mass of material• Optimize biological activity• Better handling, moisture control, aeration

3. Composting

4. Product upgrading

5. Marketing (low market need)

COMPOSTING

Open field composting

5-8 weeks

pile of solid waste (<3 m wide, < 2 m high)

mixed at least twice a week – aeration

65 °C – destroy most of pathogens

require large areas (250 000 pe – 24 ha)

COMPOSTING

Enclosed composting

Faster – 1 week

Requires less land

One or more enclosed tanks equipped with stirring devices rotating flows for mixing and aeration

Air can be used (blown into the waste)

INCINERATION

Reduction of combustible waste to inert residue by burning at high temperatures (900-1000 °C)

Chemical processCombustible part is combined with O2 CO2 + H2O (oxidation)

Releases energy

For complete oxidationwaste must be mixed with air

proper temperature for a certain length of time

INCINERATION

Residue

• Ash• Glass• Metal cans• Other unburned substances• 20% of the original waste volume• Gaseous products• Fly ash (cinders, mineral dust, soot)

INCINERATION

- effective conversion of large volumes of combustible

waste- Simple and robust process - Heat produced can be recovered

- Stream or electricity- Existing fossil fuels are preserved- Good in densely populated urban areas where large

sites suitable for landfilling are not available- May destroy certain types of hazardous waste material

INCINERATION

- need for separation of organic waste- air pollution- toxic ash- devices to trap the pollutants expensive- incineration itself is very expensive- adequate chimney heights are needed- suitable temperature is needed- high level technical supervision and skilled emloyees- use only in larger towns

AIR POLLUTION FROM INCINERATION

nitrogen oxides

sulfur oxides

carbon monoxide

heavy metals (Pb, Cd, Hg)

dust

INCINERATION

Burning 25% of USA’s waste = recycle and compost 75%

Economic viability depends on the sale of energy produced by burning

volume reduction with 75-95%maintenance and waste supply problems 50%

525 incineration plants in Europe in 1991Lots of them are simple mass burning systems without energy recovery