What is Waste?What is Waste?

TypesTypes

1.Solid Waste 1.Solid Waste

2. Liquid Waste2. Liquid Waste

3. Gaseous Waste

Classification of Waste

• On the basis of Physical State– Solid Waste– Liquid Waste– Gaseous Waste

• According to Original Use– Food Waste– Packaging Waste etc.

• Material– Glass– Paper etc.

• Physical Properties– Compostable– Combustable– Recyclable

• Sources– Domestic– Commercial– Industrial

• Safety Level– Hazardous– Nonhazardous

classification on the basis of source is widely adopted and is used.

classification on the basis of source is widely adopted and is used.

Sources of Solid Wastes• Agricultural Waste : Waste arising from

agricultural practice.• Mining Waste: Mainly inert material from mineral

extracting industries.• Energy Production Waste: Waste from energy

production units including ash from coal burning.• Industrial Waste: Wastes generated by various

industries.

• Dredging Waste: Organic and mineral wastes from dredging operations.

• Construction and Demolition Waste: Bricks, brick bats, concrete, asphaltic material, pipes etc.

• Treatment Plant Waste: Solids from grit chambers, sedimentation tank, sludge digesters of waste water treatment plant.

• Residential Waste: Garbage including food waste, paper, crockery and ashes from fires, furniture.

• Commercial Waste: Similar to residential wastes produced from offices, shops, restaurants etc.

• Institutional Waste: Similar to residential wastes plus hazardous, explosive, pathological and other wastes which are institution specific (hospital, research institute etc.)

Hazardous WasteThe waste which can• Contribute to increase in mortality• Can cause irreversible illness• Can pose potential hazard to human healthis called hazardous waste.Hazardous waste can be classified as • Radioactive substances• Chemicals• Biological Wastes• Flammable waste• Explosives

There are four characteristics which make the waste hazardous category

1. Ignitability2. Corrosivity if pH 2 or ≥ 12.53.Reactivity:- A waste exhibits the characteristics of

reactivity if a representative sample of the waste has the following properties

• Reacts violently with water• Forms explosive mixture with water• When mixed with water, generates toxic gases,

fumes or vapours• Reacts at a standard temperature or pressure

Characteristics of Hazardous WasteCharacteristics of Hazardous Waste

4. Toxicity:- The limits for a waste to be toxic for different contaminants are shown in the table.

• If the concentration of a particular constituent into the ground water as a result of improper management exceeds the above limits, then it is called as

toxic.

Contaminant Max. Concentration (mg/l)

Arsenic 5.0

Barium 100.0

Benzene 0.5

Cadmium 1.0

Lead 5.0

Mercury 0.2

Vinyl chloride

0.2

Municipal Solid WastesMunicipal Solid Wastes

•MSW refers to all wastes collected by local authority or municipality and is the most diverse category of waste.

•MSW refers to all wastes collected by local authority or municipality and is the most diverse category of waste.

•Comprises all wastes except agricultural, mining, energy production and dredging wastes.•Comprises all wastes except agricultural, mining, energy production and dredging wastes.

Characteristics of Solid Waste

•Solid waste generated by a society may be inert, biologically active or chemically active.

•Agricultural waste is primarily biologically active. It is generated in large quantities and remains uniformly dispersed on land surface area.

•Mining waste is primarily inert and is also generated in large volumes. However it accumulates continuously at mining sites.

•Solid waste generated by a society may be inert, biologically active or chemically active.

•Agricultural waste is primarily biologically active. It is generated in large quantities and remains uniformly dispersed on land surface area.

•Mining waste is primarily inert and is also generated in large volumes. However it accumulates continuously at mining sites.

•Industrial wastes-generated in industrial area - are highly industry specific. -usually comprise of chemicals and

allied products, rubber, plastic, metals, petroleum and coal products etc.

•Industrial wastes-generated in industrial area - are highly industry specific. -usually comprise of chemicals and

allied products, rubber, plastic, metals, petroleum and coal products etc.

• MSW is generated at densely populated urban centres and are most heterogenous.

• Predominant constituents of MSW are paper, food, wastes, plastics, glass , metals and inert material.

• In developing country like india, 40% waste is compostable, 40% inert material

• In developed countries, paper forms a major part of MSW followed by compostable matter. The inert material content is low.

Management of Solid waste

There are two fundamental objectives of solid waste management.To minimize the waste.To manage the waste still produced.

Waste Characterization• - Waste characterization means

finding out how much paper, glass, food waste, etc. is discarded in your waste stream

• -Waste characterization information helps in planning how to reduce waste, set up recycling programs, and conserve money and resources

Solid waste Characterisation• Physical and chemical composition -vary depending on

sources and types of solid wastes.

• Nature of the deposited waste in a landfill will affect: gas and

leachate production and composition by: -

-virtue of relative proportions of degradable and non-

degradable components,

-the moisture content

-the specific nature of the bio-degradable element.

• Waste composition will effect both gases and the trace

components.

The important parameters to characterise the waste are

• Waste composition• Moisture content• Waste particle size• Waste density• Temperature and pHThese parameters affect the extent and rate of

degration of waste. The typical approximate analysis for MSW are show below.Moisture 20%Volatile matter 53%Fixed carbon 7%Glass, metal and ash 20%

• Physical Properties• Temperature range and distribution• Insoluble components• Colour• Odour• Foamability• Corrosiveness• Radioactivity

• Flow data for total discharge• Avg. daily flow rate• Duration and level of minimum flow rate• Maximum rate of change of flow rate

Meaningful characterisation information can only be obtained through proper analysis of representative samples or through the use of online water quality monitoring instrumentation.

Meaningful characterisation information can only be obtained through proper analysis of representative samples or through the use of online water quality monitoring instrumentation.

Chemical Composition• Organic and inorganic components by compounds or

classes• COD, Total organic carbon, BOD• Specific problem ions(As, Bo, Cd, Cr etc.)• Specific problem organic e.g. phenol, certain pesticides,

benzidine etc.• Total dissolved salts• pH, acidity, alkanity

• Nitrogen, Phosphorous• Oils and greases• Oxidizing or reducing agents• Surfactants• Chlorine demand

Biological Effects• Biochemical oxygen demand• Toxicity• Pathogenic bacteria

Chemical Composition• Organic and inorganic components by compounds or

classes• COD, Total organic carbon, BOD• Specific problem ions(As, Bo, Cd, Cr etc.)• Specific problem organic e.g. phenol, certain pesticides,

benzidine etc.• Total dissolved salts• pH, acidity, alkanity

• Nitrogen, Phosphorous• Oils and greases• Oxidizing or reducing agents• Surfactants• Chlorine demand

Biological Effects• Biochemical oxygen demand• Toxicity• Pathogenic bacteria

Solid Waste CompositionPHYSICAL COMPOSITION

• Waste composition• Moisture content• Waste particle size • Waste density • Temperature • pH

CHEMICAL COMPOSITION

1. Proximate analysisa. Moisture (loss at 1050C for 1 h)b. Volatile matter (additional loss on ignition at 9500C)

c. Ash (residue after burning)d. Fixed carbon (remainder)2. Fusing point of ash3. Ultimate analysis, percent of C (carbon),

H (hydrogen), O (oxygen), N (nitrogen), S (Sulphur), and ash

4. Heating value

Chemical Composition

• Important in evaluating alternative processing and recovery options.

• Wastes can be thought of as a combination of semi moist combustible and non-combustible materials.

• If solid wastes are to be used as fuel, the four most important properties to be known are:

1. Proximate analysis

2. Fusing Point of Ash

• Defined as that temperature at which the ash resulting from the burning of waste will form a solid (clinker) by fusion and agglomeration.

• Typical fusing temperature for the formation of clinker from solid waste range from 2000 to 2200oF (1100 to 1200oC).

3. Ultimate analysis of a waste • Component typically involves the determination of

the percent C (carbon), H (hydrogen), O (oxygen), N (nitrogen), S (sulphur), and ash.

• Due to concern over the emission of chlorinated compounds during combustion, the determination of halogens also done

• The results of the ultimate analysis are used: -To characterise the chemical composition of the

organic matter in MSW. -To define the proper mix of waste materials to achieve

suitable C/N ratios for biological conversion processes.

Factors Influence Waste Composition:• Geographical location

• Standard of living

• Energy source

• Weather

Waste Generation Rates

SIGNIFICANCE:To obtain data that can be used to determine

the total amount of waste to be managed

- Measure of quantities in terms of weights

Factors Influence Waste Generation Rates:

• Socioeconomic development

• Degree of industrialization

• Climate• Greater the economic wealth and the higher

percentage of urban population, the greater the amount of solid waste produced

• Low income countries have the lowest percentage of urban populations and the lowest waste generation rates

• Geographic location• Season of the year• Frequency of collection• Characteristics of population’• Extend of Recycling• Attitude of people

Other Factors affect Waste Generation Rates:

Methods for determining Waste Generation Rates

1. Load count analysis In this method , no: of individual load and

corresponding vehicle characteristics are noted over a specific period of time

Waste contents areunloaded for sorting

Appropriate mass of material is selected randomly

Each load is separated manually by component example - Wood, concrete, plastic, metal, etc.

Components are separated

Each component is weighed and weights recorded

Generated Waste = Disposed (Collected) Waste +

Diverted Waste

2. Weight – Volume Analysis

• Weighing and measuring each load- provide information on density of various solid forms at different volumes

3.Material Balance Analysis- A system boundary around the unit to be

studied is drawn- All activities that affect waste generation is

identified- Rate of waste generation associated with

these activities studied

GROUND WATER CONTAMINATION

1. SOURCES OF GW CONTAMINATION2. TRANSPORT MECHANISMS IN GW

CONTMINATION ( VERY VERY IMPORTANT)3. ISOTHERMS4. EFFECTS OF SOIL CONTAMINATION

STUDY FROM PHOTOSTAT