Solid waste and Landfill Management

Presented by

M.Sai Vijay Krishna(202114022)

R.V.G.K Gowda(202114023)

Topics to be covered

• Solid waste

• Sources and their Classification

• Composition

• Characteristics

• Solid waste management

• Methods of solid waste disposal

Solid waste

Solid waste

• Solid waste is defined as discarded solid fraction produced

from domestic, commercial, trade, industrial, agricultural,

institutional, mining activities and public services.

• Handling the problem of solid waste in an efficient manner is

known as the solid waste management.

• The organic matter (night soil, excreta, food, vegetable, paper)

can be converted into useful biogas and compost.

• The problem is of separating it from the inorganic waste like

ashes, rubbish, non bio-degradable waste.

• Segregation – Producer end – Punishment.

Continued. .

• Efficient collection and transportation are essential parts of

solid waste management.

• There is no effective door to door collection system or a self

motivated culture of putting the waste in the bins.

• As a result most of the budget (60-70%) available with

municipalities is used for street sweeping and 20-30% for

transportation.

• So very less amount (5%) for scientific treatment of collected

waste.

• Open dumping – Leachates, burning – Harmful gases.

Sources

Domestic/Residential waste

Cooking , cleaning etc

Municipal waste

Street sweepings, dead animals

Commercial waste

Offices, restaurants

Institutional waste

Colleges, universities

Garbage

Animal vegetable wastes from food

preparation

Ashes

Bulky waste

Burning of wood, coal.

Street sweepings

Paper, plasticDead animals

Construction and demolition waste

Industrial wastes

Manufacturing process wastes

Hazardous waste

Waste from hospitals, radio active waste.

Sewage waste

Solid by-products of sewage treatment

Composition & Characteristics of solid

waste

• The composition and characteristics of municipal

solid waste is not same throughout the world and

even in the same country it changes from place to

place and time to time.

• It depends upon the living standard, social customs,

location of a place, climate and weather conditions.

• Quantity and Composition of waste changes among

different income groups.

Physical characteristics

• Density

Important for the design of all the elements of the SWM.

Varies significantly from source to disposal site(Handling)

• Moisture content

Weight of moisture to unit weight of wet material.

20-45 % , increase in moisture causes high density and

transportation costs

Chemical characteristics

• Chemical : pH, N-P-K, C/N, total carbon etc.

Calorific value

– Amount of heat generated by combustion of unit weight of

solid waste (kcal / kg).

– Bomb calorimeter.

• Bio chemical

– Biodegradable factor, carbohydrates, proteins etc.

• Toxic characteristics

– Heavy metals, pesticides, insecticides.

These characteristics are required to

• Design

• Conceive and assess the most appropriate

ways of

• Transportation

• The requirements of treatment

• Extraction of energy

• Safe, sanitary way of disposal for the

protection of Environment.

Solid Waste Management(SWM)

The solid waste management has the following components:

Identification of waste and its minimization at the source

Collection, segregation and storage at the site of collection

Transportation

Treatment

Energy recovery and Disposal

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1.Identification of waste and its minimization at the source

• Identification helps in further process of transportation, treatment and disposal.

• Ex: Hazardous waste should be treated in different manner than ordinary SW.

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Contd..

• Minimization of waste production is the best strategy.

• Examples1. Footwear making Industry-->Waste Rubber can

be reused to make Toys2. Thermal Power plants --> fly ash can be used in

fly ash bricks, cement as binder.3. Food Waste in Hotels/Hostels --> Making Bio-

gas by anaerobic digestion4. Kitchen Waste in a household --> as Composts

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Contd…

• The mentioned methods/examples can also be adopted on large scale

• But, firstly waste is collected, transported and then utilized which incurs a large cost.

• So, it is always preferable to minimize waste production by reusing, recycling of waste at the source itself.

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2.Collection, segregation and storage at the site of collection

• Main problem of SWM is Collection.

• Household waste consists of all types of general waste.

• No scientific , clean , hygienic, efficient practice of waste collection

• No penalty on throwing wastes

• spitting on streets, defecating, throwing wastes here and there even if collection bins are provided. Hence waste collection is a big problem

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Contd…

• In our country, Waste is handled manually

• Sweeps with poor design broom sticks

• Discharging of harmful chemicals, dyes, metals, heavy metals, organic matter in the open drains to pollute land and river water

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Contd…• Best way is Segregation of waste at the generation point.

• Segregation: Collecting it in different bins or plastic bags.

• Domestic waste: Reusable (paper, plastic, metal etc) Non reusable (Organic-kitchen waste, Inorganic-dust, dirt etc)

• Fixing two separate containers bins or bags for separatingorganics and Inorganic

• Organics: for energy recovery, Composts.

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3. Transportation of SW

• Transportation must be done in closed containers.

• Transportation of solid waste should be done through the technically competent and well reputed contractors under the supervision of experienced and honest municipal authorities and watchful citizens.

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4. Treatment of SW

• The waste has to be treated before disposal for the protection of environment.

• Biodegradable waste can be processed by composting, vermi-composting, anaerobic digestion.

• Anaerobic Digestion: foul gases are evolved, dirty offensive dark colored fluid is also generated: called Leachate.

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Contd…

• Solid waste contains both Municipal waste and Industrial Waste

• Small Scale Industries: Generates huge solid waste, No Individual treatment plants.

• So, Combined effluent treatment plants are to be operated by local bodies & funded by industries in proportion.

• Economical treatment.

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5.Energy Recovery and Disposal

• Most common methods of energy recovery and disposal for non hazardous solid waste are

--Incineration, composting and Landfill

• Final Disposal: No more conversion, remains as waste and unused.

• Before putting on Land If it has some biodegradable fraction then compost (organic manure) should be made out it.

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Contd…

• Organic Manure: Environmental friendly, provides micronutrients that increase soil fertility.

• Vermi-Composting: If this work is done more efficiently by some special worms then it is known as vermi-Composting.

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INCINERATION

• Incineration means burning of solid waste in controlled conditions.

• It is more efficient than usual practice of burning solid waste in open burning.

• Incinerator: enclosed device using controlled flame combustion

• Incineration uses heat to convert complex toxic organic compounds in to mostly CO2 and water.

• Combustion Temperatures: 760 – 870 oC• Modern Incinerators: 1650 oC to convert metal and

glases into ashes

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Incineration System

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Factors to be controlled

• Thermal feed rate

• Waste feed rate

• Minimum combustion gas temperatures

• Suspended particulate matter (SPM)

• Other Air pollutants

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Advantages

• Volume and weight reduced (approx. 90% vol. and 75% wt reduction)

• Waste reduction is immediate, no long term residency required

• Incineration can be done at generation site

• Air discharges can be controlled

• Ash residue is usually non-putrescible, sterile, inert

• Small disposal area required

• Cost can be offset by heat recovery/ sale of energy

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Disadvantages

• High capital cost

• Skilled operators are required (particularly for boiler operations)

• Some materials are noncombustible

• Some material require supplemental fuel

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Flue gas pollutants

• Particulates

• Acid Gases

• NOx

• CO

• Organic Hazardous Air Pollutants

• Metal Hazardous Air Pollutants

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Devices

• Electrostatic Precipitator

• Baghouses

• Acid Gas Scrubbers

• Wet scrubber

• Dry scrubber

• Chemicals added in slurry to neutralize acids

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Landfill Technology

• The most Common and Easy way of disposal of SW

• The decomposition of Solid waste produces gases (Methane) and dark colored water (leachate)

• The two major environmental concerns in a landfill are gases and leachate.

• Harmful chemicals (if present in solid waste)and Leachate mix with ground water and rain water.

• Appears costly, but for long life time it is efficient.

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Liner purposes

• To prevent leachate from seeping into groundwater

• To prevent landfill gas from migrating out of the landfill

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Under Construction

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Composting

• Composting is the biological decomposition of organic waste such as food or plant material by bacteria, fungi, worms and other organisms under controlled aerobic conditions.

• The end result of composting is an accumulation of partially decayed organic matter called humus.

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Contd…

• The organic matter (consisting of carbon, hydrogen, nitrogen, oxygen, and sulfur) has a tendency of being converted into inorganic matter as the later is a stable form.

• The food, excreta and other organic waste gets decomposed (changed into inorganic form) and produce gases like biogas (mainly methane) and solids of decomposition like sulfates, nitrates, phosphates etc.

• Compost is more useful as it contains the nutrients like N, P, K as well as the micronutrients.

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Contd…

• Organic matter can be decomposed in two ways in the presence of oxygen or in the absence of oxygen, composting (aerobically or anaerobically)

• Aerobic: micro-organisms oxidize the organic compounds to carbon dioxide, nitrite and nitrates (Exothermic)

• Anaerobic: Bacteria, while metabolizing the nutrients, break down the organic compounds through a process of reduction (The gases evolved are mainly CH4 and CO2)

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Vermi-Composting

• The stabilization of organic solid waste through special earthworm by conversion of the organic matter to worm casting

• Pheretima sp, Eisenia sp, and Perionyx excavatussp.

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Contd…

• Earthworms feed on any organic waste and consume two to five times of their body weight, excrete the mucus coated undigested matter as wormcasts

• Wormcasts consists of organic matter that has undergone physical and chemical breakdown through the muscular activity that grinds the material to a particle size of 1 to 3 micron.

• The nutrient present in the wormcast are easily soluble in water and are thus readily available for the plant growth

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Contd…

• Special worms survive in the temperature range of 20- 40 oC and moisture range of 20-80%.

• do not survive in pure organic substrate containing more than 40% fermentable organic substances.

• So fresh waste is mixed with partially or fully stabilized waste

• Unfavorable Conditions: particle size of biomass and extent of its decomposition, very high temperature increase, anaerobic condition, toxicity of decomposition products, etc.

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Contd…

• The worms are also adversely affected by high concentrations of such heavy metals as cadmium, chromium, lead and zinc

• Due to these problems the vermi-compostin is successful more on the household level (vegetables etc, organic waste) than the municipality level.

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Energy recovery from MSW

• Energy is recovered from organic matter presentin waste by incorporating suitable techniques.

Along with gain of energy , Other benefits:

• The total quantity of waste gets reduced by nearly60 to 90% depending upon the characteristics ofwaste and the adopted process.

• As the quantity reduces the demand for landrequired for landfill as disposal also reduces.

• The cost of transportation also reduces as thequantity reduces.

• The overall environmental pollution reduces.

Basic techniques of energy recovery

• Thermo-chemical conversion:

This process entails thermal decomposition oforganic matter to produce either heat energy or fuel oilor gas.

• Useful for wastes containing high percentage of organic non-biodegradable matter and low moisture content.

• Technological Option: Incineration,pyrolysis/gasification.

Bio chemical conversion

This process is based on enzymatic

decomposition of organic matter by microbiological

action to produce methane gas or alcohol.

• Preferred for wastes having high percentage of

organic bio-degradable (putrescible) matter and high

moisture content.

• Technological Options: Anaerobic Digestion also

known as Biomethanation.

Parameters effecting Energy Recovery

• Physical and chemical characteristics and desirable ranges.

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