Solid waste management

SMITA SHUKLAASSISTANT PROFESSOR

N.I.E.T GR. NOIDA

WASTE MANAGEMENT

WASTE

WASTE

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

INDUSTRIAL PRODUCTION

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

PROBLEMS CAUSED BY IMPROPER DISPOSAL OF WASTE

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

Þ typhoid, plaguepoisonous materialsflammable materials

Irreversible environmental damage in ecosystemsterrestrial and aquaticair pollution (incineration)water pollution (land burial)

Technical and environmental difficulties + administrative, economic and social problems

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

DEFINITION OF SOLID WASTE

Solid waste is generally defined as non-soluble

material that is discarded in a solid or semi-solid form. This includes garbage, refuse, sludge and other discarded domestic materials, as well as waste from industrial, commercial, agricultural and mining operations.

Basic terms related to solid waste

1. Ash : the non-combustible solid by-products of incineration or other burning process.

2. Bulky waste: large wastes such as appliances, furniture, and trees and branches, that cannot be handled by normal MSW processing methods.

3. Co-disposal: the disposal of different types of waste in one area of a landfill or dump. For instance, sewage sludges may be disposed of with regular solid wastes.

4. Biodegradable material : any organic material that can be broken down by microorganisms into simpler, more stable com-pounds. Most organic wastes (e.g., food, paper) are biodegradable.

5. Compost : the material resulting from com posting. Compost, also called humus, is a soil conditioner and in some instances is used as a fertilizer.

6. Composting : biological decomposition of solid organic materials by bacteria, fungi, and other organisms into a soil-like product.

7. Disposal : the final handling of solid waste, following collection, processing, or incineration. Disposal most often means placement of wastes in a dump or a landfill.

8. Environmental risk assessment (EnRA) : an evaluation of the interactions of agents, humans, and ecological resources. Comprised of human health risk assessment and ecological risk assessment, typically evaluating the probabilities and magnitudes of harm that could come from environmental contaminants.

9. Environmental impact assessment (EIA) : an evaluation designed to identify and predict the impact of an action or a project on the environment and human health and well-being. Can include risk assessment as a component, along with economic and land use assessment.

Sources and Types of Solid Wastes

Sources of solid wastes in a community are: • Residential • Commercial • Institutional • Construction and Demolition • Municipal Services • Treatment Plant Sites • Industrial • Agricultural

Sources and Types of Solid Wastes

Types of solid wastes Typical facilities, activities, locations where wastes are

generated

Source

Food wastes, paper, cardboard, plastics, textiles, leather, yard wastes, wood, glass, metals, ashes, special wastes (e.g., bulky items, consumer electronics, white goods, batteries, oil, tires), and household hazardous wastes

Single and multifamily dwellings

Residential

Industrial process waste, scrap materials, etc. Non - industrial waste including food wastes, construction and demolition wastes, rubbish, ashes , hazardous wastes, ashes, special wastes

Light and heavy manufacturing, fabrication, construction sites, power and chemical plants

Industrial

Table 1: Sources and Types of Solid Wastes within a Community

Sources and Types of Solid Wastes

Types of solid wastes Typical facilities, activities, locations where wastes are generated

Source

Paper, cardboard, plastics, wood, food wastes, glass, metals, special wastes, hazardous wastes

Stores, hotels, restaurants, markets, office buildings, etc.

Commercial

Same as commercial Schools, hospitals, prisons, government centers

Institutional

Wood, steel, concrete, dirt, etc. New construction sites, road repair, renovation sites, demolition of buildings, broken pavement

Construction and Demolition

Table 1: Sources and Types of Solid Wastes within a Community (Cont’d)

Sources and Types of Solid Wastes

Table 1: Sources and Types of Solid Wastes within a Community (Cont’d) Types of solid wastes Typical facilities, activities, locations where wastes are

generated

Source

Street sweepings; landscape and tree trimmings; general wastes from parks, beaches, and other recreational areas; sludge

Street cleaning, landscaping, parks, beaches, other recreational areas, water and wastewater treatment plants

Municipal Services (excluding treatment facilities)

Spoiled food wastes, agricultural wastes, rubbish, hazardous waste.

Field and row crops, orchards, vineyards, dairies, feedlots, farms, etc.

Agricultural

Nature of Municipal Solid Waste

Organic (Combustible)

Inorganic (non-combustible) Putrescible

Recyclable

Hazardous Infectious

Functional Elements:

The activities involved with the management of solid wastes from the point of generation to final disposal have been grouped into six functional elements.

(i)   Waste generation(ii)  On site handling, storage and processing(iii) Collection(iv)  Transfer and transport(v)   Processing and recovery(vi)  Disposal 

Functional element DescriptionWaste generation Those activities in which materials are

identified as no longer being of value and are either thrown away or gathered

together for disposalOn site handling, storage and

processingThose activities associated with the handling, storage and processing of solid wastes at or near the point of

generation.Collection Those activities associated with

gathering of solid wastes and the hauling of wastes after collection to the

location where collection vehicle is emptied.

Transfer and transport Those activities associated with (i) Transfer of wastes from the smaller collection vehicle to larger transport equipment and (ii) The subsequent

transport of the wastes, usually over long distance, to the disposal site.

Processing and recovery Those techniques, equipment and facilities used both to improve the

efficiency of other functional elements and to recover usable materials,

conversion products.

Disposal Those activities associated with ultimate disposal of solid wastes, including wastes collected and transported

directly to a landfill site, semisolid waste from treatment plants.

Solid waste generation

Solid wastes include all solid or semisolid material that is no longer considered of sufficient value to retain in a given setting.

Factors that affect generation rates

• Season of the year• Frequency of collection• Characteristics of the population• Public attitude• Geographical location

Disposal of solid waste

• Mechanical volume reduction or Compaction - Mechanical compactors are used to compress the waste materials so as to form bales that can be placed in big containers.

• Incineration or thermal volume reduction - Combustible waste such as plastics, cardboard and rubber are subjected to burning at high temperature in hearth furnaces. If not carried out properly incineration results in air pollution.

• Open dumping - It is done in low lying areas and outskirts of city. This method has various disadvantages as it causes foul smell due to release of obnoxious gases. Moreover it becomes breeding ground for flies, mosquitoes which causes various health hazards.

• Destructive distillation or pyrolysis – Heating the solid waste under anaerobic conditions is referred to as pyrolysis. The organic waste spilt up in fractions of CO, CO2, CH4 and tar.

• Land filling- Solid waste is dumped into low lying areas in the upper layers of the earth’s surface and spread in thin layers. With course of time decomposition of the organic matter occurs and there is conversion to stabilized end products. It is a simple and economical method.

• Land farming – In this method the organic waste is either applied on top of the land or injected below the soil surface where it undergoes bacterial decomposition.

1.On-site Handling, On-site Storage2.Collection services: types and methods3.Vehicle and labor requirements4.Types of Collection systems (hauled container

system, stationary container system)

Solid Waste Collection and Transport

ON-SITE HANDLING: Activities associated with the handling of SW until

they are placed in the containers used for storage before collection

ON-SITE STORAGE:Factors considered:

1. Container Locations2. Public health3. Aesthetics4. Types of containers used5. Methods of Collection

Factors considered1.)Types of Containers:

- Depend on: Characteristics of SW collected

E.g. Large storage containers (Domestic SW: flats/apartment)

Containers

Large containers on a roller (Commercial/Industrial)

• Collection frequency

• Space available for the placement of containers

Residential; refuse bags (7 -10 litres)

- Rubbish bins - 20 -30 litres- Large mechanical containers - more commonly used

to cut costs (reduce labor, time , & collection costs)- must be standardized to suit collection equipment.

2.)Container Locations:

-side/rear of house- special enclosures (apartment)- Basement (apts. in foreign countries)/ newer

complexes

3.) Public Health:- relates to on-time collection to avoid the spread of

diseases by vectors, etc.

4.) Aesthetics: -must be pleasing to the eye (containers must be

clean, shielded from public’s view).

5.)Collection of SW:Malaysia (other developing nations) - labor

and capital intensive.- Major problems:

–Poor building layouts–Road congestion - time cost, transport

costs.–Physical infrastructure–Old containers used (leaky/ damaged)–Absence of systematic methods (especially

at apartments, markets)

Collections were made by:1. Municipal/ District Council2. Private firm under contract to municipal3. Private firm contract with private residents

TYPES OF COLLECTION:

• Municipal Collection Services:a) Residential: i) Backyard collection (100-120 liters)

– Quickest/ economical– Crew: 1 driver + 1 or 2 collectors

ii) House-to-house collection where refuse bags used in 20-30 liter bins.

iii) High-rise apartment or flats, specially designed communal storage or roll-on-roll-offs (RORO’s).

iv) Future trend: mechanically-equipped trucks.

b) Commercial-Industrial Collection Services ( > 12 m3 )

i. Large movable and stationary containersii. Large stationary compactors (to form bales)

Collection Frequency

Residential areas : everyday/ once in 2 days

- communal/ commercial : daily- food waste - max. period should not exceed :

• the normal time for the accumulation of waste to fill a container

• the time for fresh garbage to emit fouls odor• the length of fly-breeding cycle ( < 7 days).

TYPES OF COLLECTION SYSTEMSon the basis of their mode of operation

1. Hauled Container System (HCS)2. Stationary Container System (SCS)

1) HCS:- Container is hauled to disposal sites, emptied,

and returned to original location or some other location

- Suitable for areas where higher waste generation

- Types: » Hoist truck : 2 - 10 m3

» Tilt frame container: 10 - 40 m3 - » Trash trailer - for heavy, bulky rubbish

(construction, commercial, usually open top container);

» 2 crew per vehicle.

• The container is sited at a location. In accordance with some cycle, the container is picked up and hauled off to the disposal area where the container is emptied and returned to the original location.

• The truck had no container; the container is carried by the truck.

Advantages:• - Useful when the generation rate is high and the

containers are large.• - May eliminate spillage associated with multiple

smaller containers.• - Flexible. Need more capacity, use a larger container.

Disadvantage:- If the containers are not filled, low utilization

rate.

- Types:

• Hoist truck – In the past, hoist trucks were widely used at military installations, with the advent of self-loading collection vehicles, this system is applicable only in limited number of cases.

• Tilt-frame - Assembly on truck allows sliding of large containers on and off the truck.

• Trash-trailer-The slider assembly is not part of the truck, but part of the trailer.

2. SCS: The container used to store waste remain at the point of

generation; except when moved to other location to be emptied.

Types include:

Mechanically-loaded system- System with self loading compactors.

Manually-loaded collection vehicle(more common). - This loading method is used in the collection of residential

wastes & litter.

Used for residential/commercial sites.

Vehicle with internal compaction mechanism or un-compacted (open top lorry - side loaded).

The major advantage is that the vehicle does not travel to the disposal area until it is full yielding higher utilization rates.

The major disadvantages include:• The system is not flexible in terms of picking

up bulky goods.• Wastes e.g. demolition, that may damage the

relatively delicate mechanisms.• Large volume generations may not have room

for storing large containers

SWM - strategies to improve

• Increasing number of vehicles and staff

• Rearranging work areas to increase productivity

• Opening up new tenders for newer development areas

• Repairing vehicles

• Upgrading drainage-cleaning performance

Equipment (avg. life 5-7 years)

• Residential collection vehicle (SCS) - packer truck; most compact waste

• Rear loaders - larger hopper less necessary with elimination of larger, bulky items

• Side loaders - 2 person crew (driver and loader) • Mechanically loaded

• Front Loader, residential waste place in bin then cycled (loaded and compacted)

Mechanically loaded side loader

Front Loader

Rear Loader

• Commercial (SCS) - self loaders (rear, side, front) • Commercial (HCS) Hoist truck; small operations, few pickup locations, bulky items Tilt frame - large containers, wide use Trash trailers - heavy rubbish

Hoist Truck Trash Trailer

Collection Vehicles

Side loader

Grapple trucks

HCS: Conventional mode

There are Two Types of HCS Systems

• Conventional - the system described in the text.  A round trip starting from the time the truck arrives at a waste generation site would be:1.Pickup the container, pc2.Drive to the disposal site with the used container, h3.Empty the container at the disposal site, s4.Drive to the generation site with the empty container, h5.Return the empty container to the pickup location in step 1, uc6.Drive to the next pickup location with an empty truck (no

container), dbc• Note that in order to include all of the collection activities in

the round trip, the starting and stopping points are different.

Swap container

• The service vehicle arrives at a service location with an empty container.  It replaces the used container with the empty one and then hauls the used one to the disposal site. A round trip starting from the time the truck leaves the disposal site would be:– drive to the pickup location with an empty container on the

truck, h– unload the empty container, pickup the used container,

reposition the empty container, (uc+pc+zc)– drive to the disposal site, h– empty the container at the disposal site, s 

The round trip sequence is now complete.  After the at-site time, the vehicle will start the round trip sequence again and drive to the next site.

Operational Sequence of SCS

A. Definition of Terms1.) Pickup (Phcs or scs)

Phcs: The time spent:- driving to the next container after an empty container has

been deposited.- the time spent pickup the loaded container.- the time required to redeposit the container after it has

been emptied.Pscs: Refers to the time spent loading the vehicle, beginning with the stop to load the first container and ending when the last container has been loaded.

2.) Haul (h)Does not include actually picking up the loaded

container or redepositing the empty container nor the time spent at the location where the waste is unloaded.

HCS- The time required to reach the location where the waste will be emptied, starting when the container has been loaded on the truck and continuing through unloading until the truck arrives at the location where the empty container is to be redeposited.

SCS - The time required to reach the location where the full vehicle will be emptied and continuing until the truck arrives at the location where the first container will be emptied for the next route.

3.) At-Site (s) The time spent at the site (landfill,transfer

station) where the system is unloaded including waiting time.

4.) Off-Route (W)• Non-productive activities- Necessary - Check in, check out, meeting, breaks.- Unnecessary - Personal errands, extended coffee

breaks• Typically 15%

B. Hauled Container System Equations : Thcs = (Phcs + s + h) The time required for a trip is the sum of the

pickup time, the time on site and the haul time. The haul time is essentially a function of the

distance traveled.The pickup time may be expressed as follows: Phcs = pc + uc + dbc

In plain English, the pickup time is the sum required to pickup the container, to unload the container and drive between containers (p+u+d).

4. Collection RoutesA. General Use a heuristic (common sense), trial and error approach consistent with

the philosophy of collecting the most waste with least resources in the context of constraints such as equipment breakdowns, holidays and vacations, good labor practices and the following guidelines:

- Crew size and vehicles must be known and coordinated.- Routes should begin and end near arteries- Topographic and physical boundaries should be route boundaries.- Start at the top of a hill and work downward.- Last collection point should be near disposal site.- Traffic problems should be dealt with early in the morning.- Extremely large load should be dealt with early in the morning

B. Layout of Collection Routes

• Location maps showing data concerning the sources including location, collection frequency, number of containers.

• Data analysis, try to balance the routes in accordance with pickups and time.

• Preliminary layout of routes, start at the depot and do a route. An idea of truck capacity vs. loads is in order.

• Fine tune the preliminary design.

• Functional element of transfer and transport refers to the means, facilities used to effect the transfer of wastes from one location to another, usually more distant, location.

• Contents of relatively small collection vehicles are transferred to larger vehicles that are used to transport the waste over extended distances either to Materials Recovery Facilities( MRFs) or to disposal sites.

Transfer and Transport

Generation

Collection

Transport

Final disposal

Transfer

• Transfer and transport operations are also used in conjunction with MRFs to transport recovered materials to markets or waste-to-energy facilities and to transport materials to landfills.

• Today, with rising labor, operating, and fuel costs and the absence of nearby solid waste disposal sites, transfer stations are becoming common.

Need for transfer operations

Factors that make the use of transfer operations attractive:

• Occurrence of illegal dumping due to excessive haul distances

• Location of disposal sites relatively far from collection routes

• Use of small-capacity collection vehicles • Existence of low-density residential service areas • Use of a hauled container system with relatively small

containers for collection of wastes from commercial sources

• Use of hydraulic or pneumatic collection systems

Types of Transfer Stations Transfer stations are used to accomplish the transfer of

solid wastes from collection and other small vehicles to larger transport equipment.

Depending on the method used to load the transport vehicles, transfer stations may be classified into three general types;

Direct-load Storage-load Combined direct-load and discharge-load

Storage-load

Direct-load

Combined direct-load & discharge-load

Direct-load transfer station with compactors

Figure - Direct-load transfer station equipped with stationary compactor

Direct-load transfer station with compactors

Storage-load transfer station

Figure - Storage-load transfer station with processing and compaction facilities

Means of Transport Motor vehicles, railroads and ocean-going vessels are the

principle means used to transport solid wastes.

Vehicles used for transport should satisfy the following requirements;

Wastes must be transported at minimum cost Wastes must be covered during hauling operation Vehicles must be designed for highway traffic Vehicles capacity must be such that the allowable weight limits are

not exceeded Methods used for unloading must be simple and dependable

Transfer Stations - Istanbul

Collection vehicles (Unloading)

Compactor

Transport to landfill - Istanbul

Transport vehicle in transfer station

Transport vehicle in landfill

Is a transfer facility appropriate for your community?

Compare the costs and savings associated with the construction and operation of a transfer facility.

Benefits: Lower collection costs Reduced fuel and maintenance costs for collection

vehicles Increased flexibility in selecting disposal facilities The option to separate and recover recyclables or

compostables at the transfer site The opportunity to shred or bale wastes before disposal

Possible drawbacks: Difficulty with sitting and permitting, particularly

in urban areas. Construction and operation costs may make them

undesirable for some communities.

Transfer Station Design

Important factors in the design of transfer stations; Type of transfer operation An adequate area is necessary in case of waste recovery

Storage and throughput capacity requirements Collection vehicles do not have to wait too long to unload

Equipment and accessory requirements

Sanitation requirements

Transfer Station Design

Location of Transfer Stations

Transfer stations should be located;

As near as possible to the solid waste production areas to be served. Within easy access of major arterial highway routes as well as near

secondary or supplemental means of transportation . Where there will be a minimum of public and environmental objection to

the transfer operations. Where construction and operation will be most economical. Additionally, if the transfer station site is to be used for processing

operations involving materials recovery and/or energy production, the requirements for those operations must also be assessed.

Processing Techniques & Equipments

• PURPOSE OF PROCESSING

The processing of wastes helps in achieving the best possible benefit from every functional element of the solid waste management (SWM) system and, therefore, requires proper selection of techniques and equipment for every element.

Accordingly, the wastes that are considered suitable for further use

need to be paid special attention in terms of processing, in order that we could derive maximum economical value from them.

The purposes of processing, essentially, are:-

(i) Improving efficiency of SWM system: Various processing techniques are available to improve the efficiency of SWM system. For example, before waste papers are reused, they are usually baled to reduce transporting and storage volume requirements.

In some cases, wastes are baled to reduce the haul costs at disposal site, where solid wastes are compacted to use the available land effectively.

If solid wastes are to be transported hydraulically and pneumatically, some form of shredding is also required. Shredding is also used to improve the efficiency of the disposal site.

(ii) Recovering material for reuse:

Usually, materials having a market, when present in wastes in sufficient quantity to justify their separation, are most amenable to recovery and recycling.

Materials that can be recovered from solid wastes include paper, cardboard, plastic, glass, ferrous metal, aluminium and other residual metals.

(iii) Recovering conversion products and energy:

Combustible organic materials can be converted to intermediate products and ultimately to usable energy.

This can be done either through incineration, pyrolysis, composting or bio-digestion.

Initially, the combustible organic matter is separated from the other solid waste components .

Once separated, further processing like shredding and drying is necessary before the waste material can be used for power generation.

Having described the need for waste processing, we now discuss how waste processing is actually carried out.

MECHANICAL VOLUME AND SIZE REDUCTION

Mechanical volume and size reduction is an important factor in the development and operation of any SWM system.

The main purpose is to reduce the volume (amount) and size of waste, as compared to its original form, and produce waste of uniform size.

Volume reduction or compaction

• Volume reduction or compaction refers to densifying wastes in order to reduce their volume. Some of the benefits of compaction include:

Reduction in the quantity of materials to be handled at the disposal site;

Improved efficiency of collection and disposal of wastes; Increased life of landfills; Economically viable waste management system.

• Disadvantages associated with compaction:

Poor quality of recyclable materials sorted out of compaction vehicle;

Difficulty in segregation or sorting (since the various recyclable materials are mixed and compressed in lumps);

Bio-degradable materials (e.g., Leftover food, fruits and vegetables) destroy the value of paper and plastic material.

Equipment used for compaction

• Based on their mobility, we can categories the compaction equipment used in volume reduction under either of the following:

(i) Stationary equipment: This represents the equipment in which wastes are brought to, and loaded

into, either manually or mechanically. In fact, the compaction mechanism used to compress waste in a

collection vehicle, is a stationary compactor.

According to their application, stationary compactors can be described as light duty(e.g., those used for residential areas), commercial or light industrial, heavy industrial and transfer station compactors.

• Usually, large stationary compactors are necessary, when wastes are to be compressed into:

Steel containers that can be subsequently moved manually or mechanically;

Chambers where the compressed blocks are banded or tied by some means before being removed;

Chambers where they are compressed into a block and then released and hauled away untied;

Transport vehicles directly.

(ii) Movable equipment:

This represents the wheeled and tracked equipment used to place and compact solid wastes, as in a sanitary landfill.

Let us now move on to the discussion of compactors used in the transfer station.

Compactors

• According to their compaction pressure, we can divide the compactors used at transfer stations as follows:

(i) Low-pressure (less than 7kg/cm2) compaction: This includes those used at apartments and commercial establishments,

bailing equipment used for waste papers and cardboards and stationary compactors used at transfer stations.

In low-pressure compaction, wastes are compacted in large containers.

Note that portable stationary compactors are being used increasingly by a number of industries in conjunction with material recovery options, especially for waste paper and cardboard.

(ii) High-pressure (more than 7kg/cm2) compaction:

Compact systems with a capacity up to 351.5 kg/cm2 or 5000 lb/in2 come under this category.

In such systems, specialized compaction equipment are used to compress solid wastes into blocks or bales of various sizes.

The volume reduction achieved with these high-pressure compaction systems varies with the characteristics of the waste.

When wastes are compressed, their volume is reduced, which is normally expressed in percentage and computed by equation:-

Volume Reduction (%) = Vi – Vf / Vi *100

The compaction ratio of the waste is given in equationCompaction ratio = Vi / Vf

where Vi = volume of waste before compaction, m3 and Vf =

volume of waste after compaction, m3

The relationship between the compaction ratio and percent of volume reduction is important in making a trade-off analysis between compaction ratio and cost.

Other factors that must be considered are final density of waste after compaction and moisture content.

The moisture content that varies with location is another variable that has a major effect on the degree of compaction achieved.

In some stationary compactors, provision is made to add moisture, usually in the form of water, during the compaction process.

Selection of compaction equipment • To ensure effective processing, we need to consider the

following factors, while selecting compaction equipment:

Characteristics such as size, composition, moisture content, and bulk density of the waste to be compacted.

Potential uses of compacted waste materials. Design characteristics such as the size of loading chamber,

compaction pressure, compaction ratio, etc. Operational characteristics such as energy requirements,

routine and specialized maintenance requirement, simplicity of operation, reliability, noise output, and air and water pollution control requirement.

Site consideration, including space and height, access, noise and related environmental limitations.

Size reduction or shredding This is required to convert large sized wastes (as they are

collected) into smaller pieces.

Size reduction helps in obtaining the final product in a

reasonably uniform and considerably reduced size in comparison to the original form.

In the overall process of waste treatment and disposal, size reduction is implemented ahead of:-

• Recovering materials from the waste stream for recycling.

• Making the waste a better fuel for incineration waste energy recovery facilities.

• The size reduction techniques, coupled with separation techniques such as screening, result in a more homogeneous mixture of relatively uniform size, moisture content and heating value, and thereby improving the steps of incineration and energy recovery.

• Reducing moisture, i.e., drying and dewatering of wastes

Type Mode of action Application

Small grinders Grinding, mashing Organic residential solid wastes

Chippers Cutting, slicing Paper, cardboard, tree trimmings, yard waste, wood, plastics

Large grinders Grinding, mashing Brittle and friable materials, used mostly in industrial operation

Jaw crushers Crushing, breaking Large solids

Shredders Shearing, tearing All types of municipal wastes

Cutters, Clippers Shearing, tearing All types of municipal wastes

Hammer mills Breaking, tearing, cutting, crushing

All types of municipal wastes

Figure - Hammer Mill: An Illustration

Selection of size reduction equipment The factors that decide the selection of size reduction

equipment include the following:

• The properties of materials before and after shredding.

• Size requirements for shredded material by component.

• Method of feeding shredders, provision of adequate shredder hood capacity (to avoid bridging) and clearance requirement between feed and transfer conveyors and shredders.

• Types of operation (continuous or intermittent).

• Operational characteristics including energy requirements, routine and specialized maintenance requirement, simplicity of operation, reliability, noise output, and air and water pollution control requirements.

• Site considerations, including space and height, access, noise and environmental limitations.

Besides mechanical techniques of compaction and shredding to reduce the volume and size of wastes, there are also chemical processes through which we can reduce the volume of wastes, which we will touch upon next.

Chemical volume reduction

• Chemical volume reduction is a method, wherein volume reduction occurs through chemical changes brought within the waste either through an addition of chemicals or changes in temperature.

• Incineration is the most common method used to reduce the volume of waste chemically, and is used both for volume reduction and power production.

• These other chemical methods used to reduce volume of waste chemically include pyrolysis, hydrolysis and chemical conversions.

Note that prior to size or volume reduction, which we discussed, the component separation is necessary to avoid the problem of segregating or sorting recyclable materials from the mixed and compressed lumps of wastes and the poor quality of recyclable materials sorted out of compaction vehicles.

COMPONENT SEPARATION

Component separation is a necessary operation in which the waste components are identified and sorted either manually or mechanically to aid further processing. This is required for the:

• Recovery of valuable materials for recycling; • Preparation of solid wastes by removing certain components

prior to incineration, energy recovery, composting and biogas production.

The most effective way of separation is manual sorting in

households prior to collection. In many cities (e.g., Bangalore, Chennai, etc., in India), such systems are now routinely used.

The municipality generally provides separate, easily identifiable containers into which the householder deposits segregated recyclable materials such as paper, glass, metals, etc …

Air separation • This technique has been in use for a number of years in

industrial operations for segregating various components from dry mixture.

• Air separation is primarily used to separate lighter materials (usually organic) from heavier (usually inorganic) ones.

• The lighter material may include plastics, paper and paper

products and other organic materials. Generally, there is also a need to separate the light fraction of organic material from the conveying air streams, which is usually done in a cyclone separator.

The light fraction may be used, with or without further size reduction, as fuel for incinerators or as compost material.

There are various types of air classifiers commonly used, some of which are listed below:

(i) Conventional type: This, is one of the simplest types of air classifiers:

In this type, when the processed solid wastes are dropped

into the vertical chamber, the lighter material is carried by the airflow to the top while the heavier materials fall to the bottom of the chamber.

Figure - Conventional Type

The control of the percentage split between the light and heavy fraction is accomplished by varying the waste loading rate, airflow rate and the cross section of chambers.

(ii) Zigzag air classifier: An experimental zigzag air classifier, shown in Figure below, consists of a continuous vertical column with internal zigzag deflectors through which air is drawn at a high rate:

Zigzag Air Classifier

Zigzag Air Classifier

Shredded wastes are introduced at the top of the column at a controlled rate, and air is introduced at the bottom of the column.

As the wastes drop into the air stream, the lighter fraction is fluidized and moves upward and out of column, while the heavy fraction falls to the bottom.

Best separation can be achieved through proper design of the separation chamber, airflow rate and influent feed rate.

(iii) Open inlet vibrator type:

(iii) Open inlet vibrator type:

In this type of air classifier, the separation is accomplished by a combination of the following actions:

Vibration: This helps to stratify the material fed to the separator into heavy and light components.

Due to this agitation, the heavier particles tend to settle at the bottom as the shredded waste is conveyed down the length of the separator.

Inertial force: In this action, the air pulled in through the feed inlet imparts an

initial acceleration to the lighter particle, while the wastes travel down the separator as they are being agitated.

• Air pressure: This action refers to the injection of fluidizing air in two or

more high velocity.

It has been reported that the resulting separation is less sensitive to particle size than a conventional vertical air classifier, be it of straight or zigzag design

An advantage of this classifier is that an air lock feed mechanism is not required and wastes are fed by gravity directly into the separator inlet.

Selection of air separation equipment

The factors that are to be considered for selecting air separation equipment include the following: -

Characteristics of the material produced by shredding equipment including particle size, shape, moisture content and fiber content.

Material specification for light fraction. Methods of transferring wastes from the shredders to the air

separation units and feeding wastes into the air separator.

Selection of air separation equipment

Characteristics of separator design including solids-to-air ratio, fluidizing velocities, unit capacity, total airflow and pressure drop.

Operational characteristics including energy requirement, maintenance requirement, simplicity of operation, proved performance and reliability, noise output, and air and water pollution control requirements.

Site considerations including space and height access, noise and environmental limitations.

So far, we have studied the separation of solid waste components by air separation. We will next learn about the separation of wastes based on their magnetic properties.

Magnetic separation

• The most common method of recovering ferrous scrap from shredded solid wastes involves the use of magnetic recovery systems.

• Ferrous materials are usually recovered either after shredding or before air classification .

• When wastes are mass-fired in incinerators, the magnetic separator is used to remove the ferrous material from the incinerator residue.

• Magnetic recovery systems have also been used at landfill disposal sites.

Equipment used for magnetic separation

• Various types of equipment are in use for the magnetic separation of ferrous materials. The most common types are the following:

(i) SUSPENDED MAGNET: In this type of separator, a permanent magnet is used to attract

the ferrous metal from the waste stream.

When the attracted metal reaches the area, where there is no magnetism, it falls away freely. This ferrous metal is then collected in a container.

This type of separation device is suitable for processing raw refuse, where separators can remove large pieces of ferrous metal easily from the waste stream.

Figure - Suspended Type Permanent Magnetic Separator

(ii) Magnetic pulley:

This consists of a drum type device containing permanent magnets or electromagnets over which a conveyor or a similar transfer mechanism carries the waste stream.

The conveyor belt conforms to the rounded shape of the magnetic drum and the magnetic force pulls the ferrous material away from the falling stream of solid waste.

Figure - Pulley Type Permanent Magnetic Separator

Selection of magnetic separation equipment

We must consider the following factors in the selection of magnetic separation equipment:

Characteristics of waste from which ferrous materials are to be separated (i.e., the amount of ferrous material, the tendency of the wastes to stick to each other, size, moisture content, etc.)

Characteristics of the separator system engineering design, including loading rate, magnet strength, conveyor speed, material of construction, etc.

Operational characteristics, including energy requirements, routine and specialized maintenance requirements, simplicity of operation, reliability, noise output, and air and water pollution control requirements.

Locations where ferrous materials are to be recovered from solid wastes.

Site consideration, including space and height, access, noise and environmental limitations.

Screening

• Screening is the most common form of separating solid wastes, depending on their size by the use of one or more screening surfaces .

• Screening has a number of applications in solid waste resource and energy recovery systems .

• Screens can be used before or after shredding and after air separation of wastes in various applications dealing with both light and heavy fraction materials.

• The most commonly used screens are rotary drum screens and various forms of vibrating screens .

Figure - Rotary Drum Screen

Note that rotating wire screens with relatively large openings are used for separation of cardboard and paper products,

while vibrating screens and rotating drum screens are typically used for the removal of glass and related materials from the shredded solid wastes.

Selection of screening equipment

• The various factors that affect the selection of screens include the following:

Material specification for screened component.

Location where screening is to be applied and characteristics of waste material to be screened, including particle size, shape, bulk, density and moisture content.

Operational characteristics, including energy requirements, maintenance requirements, simplicity of operation, reliability, noise output and air and water pollution control requirements.

Site considerations such as space and height access, noise and related environmental limitations.

The efficiency of screen can be evaluated in terms of the percentage recovery of the material in the feed stream by using Equation :-

Recovery (%) = U Wu / F Wf *100 where U = weight of material passing through screen (underflow) kg/h;

F = weight of material fed to the screen, kg/h; Wu = weight fraction of material of desired size in underflow; Wf = weight fraction of material of desired size in feed.

Wf = Weight of sample / Weight of material fed to the screen Wu = Weight of sample in underflow / Total weight of material in

underflow

The effectiveness of the screening operation can be determined by: Effectiveness = recovery *rejection

where, rejection = 1 – recovery of undesired material = 1 – U( 1- Wu) / F( 1- Wf )

Therefore, the effectiveness of screen is: Effectiveness = U* Wu/ F* Wf *[1- U(1- Wu)/ F( 1- Wf )]

Other separation techniques

• Besides the mechanical techniques we studied earlier for segregating wastes, there are others. A description of some of these other separation techniques is given below:

(i) Hand-sorting or previewing: Previewing of the waste stream and manual removal of large sized materials is necessary, prior to most types of separation or size reduction techniques.

This is done to prevent damage or stoppage of equipment such as shredders or screens, due to items such as rugs, pillows, mattresses, large metallic or plastic objects, wood or other construction materials, paint cans, etc.

(ii) Inertial separation: Inertial methods rely on ballistic or gravity separation principles to separate shredded solid wastes into light (i.e., organic) and heavy (i.e., inorganic) particles.

Figure - Ballistic Inertial Separator

Figure - Inclined Conveyor Separator

(iii) Flotation: In the flotation process, glass-rich feedstock, which is produced by screening the heavy fraction of the air-classified wastes after ferrous metal separation, is immersed in water in a soluble tank .

Glass chips, rocks, bricks, bones and dense plastic materials that sink to the bottom are removed with belt scrappers for further processing.

Light organic and other materials that float are skimmed from the surface.

These materials are taken to landfill sites or to incinerators for energy recovery .

Chemical adhesives (flocculants) are also used to improve the capture of light organic and fine inorganic materials.

(iv) Optical sorting: Optical sorting is used mostly to separate glass from the waste stream,

And this can be accomplished by identification of the transparent properties of glass to sort it from opaque materials (e.g., Stones, ceramics, bottle caps, corks, etc.) in the waste stream.

An optical sorting machinery is, however, complex and expensive.

Figure 5.11 Simplified Scheme of Electronic Sorter

So far, we discussed component separation through air classifiers, magnetic separators, screens, and hand sorting, flotation, optical sorting and inertial separators.

Now, in case, however, the waste consists of moisture, we need to remove it for efficient management. It is in this regard that drying and dewatering are considered the most appropriate means of removal of moisture. We will study this next….

DRYING AND DEWATERING

• Drying and dewatering operations are used primarily for incineration systems, with or without energy recovery systems.

• These are also used for drying of sludges in wastewater treatment plants, prior to their incineration or transport to land disposal.

• The purpose of drying and dewatering operation is to remove moisture from wastes and thereby make it a better fuel .

• Sometimes, the light fraction is pelletised after drying to make the fuel easier to transport and store, prior to use in an incinerator or energy recovery facility.

DRYING

• The following three methods are used to apply the heat required for drying the wastes:

(i) Convection drying: In this method, hot air is in direct contact with the wet solid waste

stream.

(ii) Conduction drying: In this method, the wet solid waste stream is in contact with a heated

surface.

(iii) Radiation drying: In this method, heat is transmitted directly to the wet solid waste stream

by radiation from the heated body.

Of these three methods, convection drying is used most commonly.

Figure - illustrates a rotary drum dryer used in the cement industry:

• As above figure illustrates, a rotary drum dryer is composed of a rotating cylinder, slightly inclined from the horizontal through which the material to be dried and the drying gas are passed simultaneously.

• The drying of material in a direct rotary dryer occurs in the following stages: -

Heating the wet material and its moisture content to the constant-rate drying temperature.

Drying the material substantially at this temperature.

Heating of material to its discharge temperature and evaporation of moisture remaining at the end of the stage.

• The retention time in the rotary drum is about 30 – 45 minutes. The required energy input will depend on the moisture content, and the required energy input can be estimated by using a value of about 715 KJ/kg (or 1850 Btu/1b) of water evaporated.

Factors, we need to consider in the selection of a drying equipment that include the following:

Properties of material to be dried.

Drying characteristics of the materials, including moisture content, maximum material temperature and anticipated drying time.

Nature of operation, whether continuous or intermittent. Specification of final product, including moisture content.

Operational characteristics, including energy requirements, maintenance requirements, simplicity of operation, reliability, noise output and air and water pollution control requirements.

Site considerations such as space and height access, noise and environmental limitations.

DEWATERING

• Dewatering is more applicable to the problem of sludge disposal from wastewater treatment of plants .

• But may also be applicable in some cases to municipal/industrial waste problems.

• When drying beds, lagoons or spreading on land are not feasible, other mechanical means of dewatering are used.

• The emphasis in the dewatering operation is often on reducing the liquid volume.

• Once dewatered, the sludge can be mixed with other solid waste, and the resulting mixture can be:

Buried in a landfill. Incinerated to reduce volume . Used for the production of recoverable by-products; Used for production of compost.

Centrifugation and filtration are the two common methods for the dewatering of sludge.

Sludges with solid content of a few percent can be thickened to about 10 – 15% in centrifugation

And about 20 – 30% in pressure filtration or vacuum filtration.

SUMMARY • We discussed various processing techniques that are

used in SWM system to improve the efficiency of operation, recovery of resources, i.e., usable materials, and recovery of conversion product and energy.

• We began our discussion with the importance of processing techniques and the nature of equipment involved for the purpose.

SUMMARY

• Subsequently, we discussed mechanical volume and size reduction techniques and touched upon chemical volume reduction.

• We also studied about some component separation techniques (air separation, magnetic separation, screening, etc.).

• So, now we have closed the unit with a discussion on drying and dewatering, i.e., the processing techniques used for removing varying amounts of moisture present in solid wastes.

METHODS OF DISPOSALS

These are the following methods for disposal of the solid waste.

• LAND FILLS• INCINARATION• BIOLOGICAL REPROCESSING• RECYCLING• OCEAN DUMPING• PLASMA GASSIFICATION

LAND FILL

• It is the most traditional method of waste disposal.

• Waste is directly dumped into disused quarries, mining voids or borrow pits.

• Disposed waste is compacted and covered with soil to prevent vermin and wind-blown litter.

• Gases generated by the decomposing waste materials are often burnt to generate power.

• It is generally used for domestic waste.

ADVANTAGES

• Landfill site is a cheap waste disposal option for the local council.

• Jobs will be created for local people.

• Lots of different types of waste can be disposed of by landfill in comparison to other waste disposal methods.

• The gases given off by the landfill site could be collected and used for generating power.

DISADVANTAGES

• The site will look ugly while it is being used for landfill.

• Dangerous gases are given off from landfill sites that cause local air pollution and contribute to global warming.

• Local streams could become polluted with toxins seeping through the ground from the landfill site.

• Once the site has been filled it might not be able to be used for redevelopment as it might be too polluted.

LAND REQUIRED FOR DISPOSAL OF MSW

EMMISION OF METHANE FROM LANDFILL

INCINERATION

• Incineration is a waste treatment process that involves the combustion of solid waste at 1000C.

• waste materials are converted into ash, flue gas, and heat.

• The ash is mostly formed by the inorganic constituents of the waste and gases due to organic waste.

• the heat generated by incineration is used to generate electric power.

ADVANTAGES

• Minimum of land is needed compared to other disposal methods.

• The weight of the waste is reduced to 25% of the initial value.

• No risk of polluting local streams and ground waters as in landfills.

• Incineration plants can be located close to residential areas.• Gases are used to generate power.

DISADVANTAGES

• Expensive

• Required skilled labor.

• The chemicals that would be released into the air could be strong pollutants and may destroy ozone layer (major disadvantage).

• high energy requirement

INCINERATION PLANT OBERHAUSEN, GERMANY

OCEAN DUMPING

• Ocean dumping is the dumping or placing of materials in the ocean, often on the continental shelf.

• A wide range of materials is involved, including garbage, construction and demolition debris, sewage sludge, dredge material, waste chemicals, and nuclear waste.

• Sometime hazardous and nuclear waste are also disposed but these are highly dangerous for aquatic life and human life also.

ADVANTAGES

• Convenient • Inexpensive • Source of nutrients for fishes and marine

mammals.• Vast amount of space is available.• All type of wastes are disposed.

DISADVANTAGES

• There are three main direct public health risks from ocean dumping:

(1) Occupational accidents, injuries, and exposures

(2) Exposure of the public to hazardous or toxic materials washed up on beach sand.

(3) Human consumption of marine organisms that have been contaminated by ocean disposal.

(4) Highly dangerous for aquatic life.

BIOLOGICAL REPROCESSING

• Materials such as plants, food scraps, and paper products can be decomposed into the organic matter.

• The organic matter that is produced from this type of recycling can then be used for such things as landscaping purpose or agricultural uses.

• Usually this method of recycling is done by putting the

materials in a container and let to stay there until it decomposes.

RECYCLING

• It is basically processing or conversion of a waste item into usable forms.

• Recyclable materials include many kinds of glass, paper, metal, plastic, textiles, and electronics.

• But recycling is not a solution to managing every kind of waste material.

• For many items like plastic bags, plastic wrap, yogurt cups, margarine container etc. recycling technologies are unavailable or unsafe.

ADVANTAGES

• Reduction of air and water pollution.

• Reduction in the release of harmful chemicals and greenhouse gases from rubbish.

• Saves space required as waste disposal landfill.

• Reduce financial expenditure in the economy.

• It helps in conserving a lot of energy resources like petroleum and coal deposits.

SAVING THROUGH RECYCLING

• When aluminum is recycled - considerable saving in cost.

• Making paper from waste saves 50% energy.

• Every tone of recycled glass saves energy equivalent to 100 liters of oil.

• Recycling about 54 kg of newspaper will save one tree.

PLASMA GASIFICATION

• Plasma gasification is another form of waste management.

• Plasma is a primarily an electrically charged or a highly ionized gas. Lighting is one type of plasma which produces temperatures that exceed 12,600 °F.

• With this method of waste disposal, a vessel uses characteristic plasma torches operating at +10,000 °F which is  creating a gasification zone till 3,000 °F for the conversion of solid or liquid wastes into a syngas.

• During the treatment solid waste by plasma gasification, the waste’s molecular bonds are broken down as result of the  intense heat in the vessels and the elemental components.

• Thanks to this process, destruction of waste and dangerous materials is found. This form of waste disposal provides renewable energy and an assortment of other fantastic benefits.

WHAT IS PLASMA?• Fourth state of matter.• It is an ionized gas at high temperature, capable of conducting current due to free electrons.• Created by applying an electric arc to a low- pressure gas.• Lightning is an example from nature.

PLASMA TORCHES• Consists of a tungsten rod

(cathode) and a water-cooled copper (anode).

• Shaped in the form of a nozzle.• Gas is introduced in the electrode gap and a dc arc is

established between the electrodes to create plasma.

COMPOSTING

• Composting is the controlled biological decomposition of organic matters, such as food and yard wastes, into humus, a soil-like material.

• Composting is nature's way of transforming organic waste (such as kitchen vegetable scraps, soiled paper and yard trimmings) into new soil.

The role of composting in MSW disposal

• The composting methods can potential deal up to 25% of the MSW (U.S., 2000)

• The suitable (such as kitchen vegetable scraps, soiled paper and yard trimmings) materials can be turned into compost in 8 to 24 weeks;

Source reduction

Definition Source reduction, also known as waste prevention

or pollution prevention, is the elimination or reduction of waste before it is created.

It involves the design, manufacture, purchase or use of materials and products to reduce the amount or toxicity of what is thrown away.

The need of source reduction

(1) Shortage of suitable landfill space; In many areas, no suitable land is available for landfills development.

(2) The development of new landfill site is expensive; New landfills often resisted due to public concerns over groundwater contamination, odors, and truck traffic;

• The most effective way to solve the problem is by reducing waste in the first place,i.e. Stopping waste before it happens.

• Source reduction first, recycling and composting second, and disposal in landfills or waste combustors last.

THE PRACTICE IN SOURCE REDUCTION

• Purchasing long-lasting goods;

• Seeking products and packaging that are as free of toxics as possible;

• Redesigning products to use less raw material in production, have a longer life, or be used again after its original use;

• Reusing items is another way to stop waste at the source;

Benefits of source reduction and reuse

• Saving natural resources;• Reducing toxicity of waste;• Reducing costs;

Summary

• The lifestyle should be changed;• The degree to which any method will be use will

depend on economics, changes in technology, and citizen awareness and involvement.

Bioremediation : 

Is defined as the process whereby organic wastes are biologically degraded under controlled conditions to levels below concentration limits established by regulatory authorities.

• Bioremediation makes effective better approach possible. Either by destroying or render them harmless using natural biological activity.

• Relatively low cost • Low technology techniques • Generally has general public acceptance • Can often be carried out on site –no transport

Drawbacks • May not be effective on all contaminants• Time duration – relatively long • Expertise required to design and implement –

although not technically complex

 

Qualities of : 

• Qualities of Microorganisms Environment• Able to degrade hydrocarbons • Able to fix nitrogen No secondary/side effects • Presence of accessory nutrients (N P K Fe)• Absence of heavy metals Adequate O2, Temperature,

pH

SOLID WASTE MANAGEMENT HIERARCHY

Siting criteria

SUMMARY

Solid waste is hazardous to health so it has to be handled carefully and disposed properly in order to protect our health and to maintain good environment.

Bio Medical Waste Management

Bio-Medical waste

Definition :

Acc to bio medical waste rules ,1998 of India“ bio-medical waste” means any waste which is generated during the diagnosis, treatment or immunization of human beings or animals or in research activities pertaining there to or in the production or testing of bio medicals.

Any unwanted residual material which cannot be discharged directly, or after suitable treatment can be discharged in the atmosphere or to a receiving water source, or used for landfill is waste. (Wilson, 1981)

Sources of health care waste

Government/private hospitals Nursing homes Physician/dentist office or clinic Dispensaries Primary health care centers Medical research and training centers animal./slaughter houses labs/research organizations Vaccinating centers Bio tech institutions/production units

Definition• Hospital waste: refers to all waste, biological or non biological, that is

discarded and is not intended for further use .

• Medical waste: refers to materials generated as a result of patient diagnoses, treatment, immunization of human beings or animals .

Definition• Infectious waste: are the portion of medical waste that could transmit an ‘infectious disease’.

•Pathological waste : waste removed during surgery/ autopsy or other medical procedures including human tissues, organs, body parts, body fluids and specimens along their containers.

MAGNITUDE OF THE PROBLEM

GLOBALLY- Developed countries generate 1 to 5 kg/bed/day

Developing countries: meager data, but figures are lower. 1-2kg/pt./day

WHO Report: 85% non hazardous waste : 10% infective waste

: 5% non-infectious but hazardous. (Chemical, pharmaceutical and radioactive)

INDIA:-No national level study - local or regional level study shows hospitals generate

roughly 1-2 kg/bed/day

WASTE CATEGORY TYPE OF WASTE TREATMENT AND

DISPOSAL OPTION

Category No. 1 Human Anatomical Waste (Human tissues, organs, body parts) Incineration@ / deep burial*

Category No. 2

Animal Waste(Animal tissues, organs, body parts, carcasses, bleeding parts, fluid, blood and experimental animals used in research, waste generated by veterinary hospitals and colleges, discharge from hospitals, animal houses)

Incineration@ / deep burial*

Category No. 3

Microbiology & Biotechnology Waste (Wastes from laboratory cultures, stocks or specimen of live micro organisms or attenuated vaccines, human and animal cell cultures used in research and infectious agents from research and industrial laboratories, wastes from production of biologicals, toxins and devices used for transfer of cultures)

Local autoclaving/ microwaving / incineration@

CATEGORIES OF BIOMEDICAL WASTE

Category No. 4

Waste Sharps (Needles, syringes, scalpels, blades, glass, etc. that may cause puncture and cuts. This includes both used and unused sharps)

Disinfecting (chemical treatment@@ / autoclaving / microwaving and mutilation / shredding

Category No. 5Discarded Medicine and Cytotoxic drugs (Wastes comprising of outdated, contaminated and discarded medicines)

Incineration@ / destruction and drugs disposal in secured landfills

Category No. 6

Soiled Waste (Items contaminated with body fluids including cotton, dressings, soiled plaster casts, lines, bedding and other materials contaminated with blood.)

Incineration@ / autoclaving / microwaving

Category No. 7

Solid Waste (Waste generated from disposable items other than the waste sharps such as tubing, catheters, intravenous sets, etc.)

Disinfecting by chemical treatment@@ / autoclaving / microwaving and mutilation / shredding

Problems Related to bio medical waste in India

Classification of health care waste

INFECTIOUS WASTE

Lab cultures Waste from isolation wards Tissues(swabs) Materials/equipments of infected patients

Pathological waste

• Excreta• Human tissues/fluids• Body parts• Blood or body fluids

Sharp waste

Needles Infusion Sets Scalpels Knives Blades Broken Glass

Pharmaceutical waste

• Expired Pharmaceuticals• Contaminated Pharmaceuticals• Banned Pharmaceuticals

Genotoxic waste

Waste Containing Cytotoxic Drugs(often Used In Cancer Theraphy)

Genotoxic Chemicals

CHEMICAL WASTE Lab reagents Film developer Expired disinfectants Expired solvents

WASTE WITH HIGH CONTENT OF HEAVY METALS

Waste with high content of heavy metals Batteries Broken thermometers Blood pressure guages etc

PRESSURIZED CONTAINERS Gas cylinders Gas catridges Aerosol cans

RADIOACTIVE WASTE Radiotherapy/lab research liquids Contaminated glass wares, packages,

absorbent papers

Hospital waste disposal

202

• Hospital waste management is a part of hospital hygiene and maintenance activities. In fact only 15% of hospital waste i.e. "Biomedical waste" is hazardous, not the complete.

• But when hazardous waste is not segregated at the source of generation and mixed with nonhazardous waste, then 100% waste becomes hazardous

Treatment and Disposal Methods of Hospital Waste

203

Bio =

Biodiversity

What does “Bio” means?

Biodiversity

Diversity = Variety

What does “Diversity” means?

INTRODUCTION

The term Biodiversity was first coined by Walter G. Rosen in 1986.

The biosphere comprises of a complex collections of innumerable organisms, known as the Biodiversity, which constitute the vital life support for survival of human race.

Biological diversity, abbreviated as biodiversity, represent the sum total of various life forms such as unicellular fungi, protozoa, bacteria, and multi cellular organisms such as plants, fishes, and mammals at various biological levels including gens, habitats, and ecosystem .

There are three types of biodiversity

Diversity of Species

Diversity of Ecosystem

Diversity of Genes

DISTRIBUTION OF BIODIVERSITY

Flora and fauna diversity depends on-

Climate Altitude Soils Presence of other species Most of the biodiversity

concentrated in Tropical region.

BIODIVERSITY HOTSPOTS:

A region with high biodiversity with most of spices being Endemic.

India have two Biodiversity Hotspots- East Himalayan Region and Western Ghat.

BENEFITS OF BIODIVERSITY

Consumptive value: Food/Drink Fuel Medicine Better crop varieties Industrial MaterialNon-Consumptive Value: Recreation Education and Research Traditional value

Ecological services: Balance of nature

Biological productivity

Regulation of climate

Degradation of waste

Cleaning of air and water

Cycling of nutrients

Control of potential pest and disease causing species

Detoxification of soil and sediments

Stabilization of land against erosion

Carbon sequestration and global climate change

Maintenance of Soil fertility

THREATS TO BIODIVERSITY

Natural causes: Narrow geographical area Low population Low breeding rate Natural disastersAnthropogenic causes: Habitat modification Overexploitation of selected

species

Pollution Hunting Global warming and climate

change Agriculture Domino effect

RECENT ISSUES ON BIODIVERSITY

Some 75 per cent of the genetic diversity of crop plants been lost in the past century. Some scientists estimate that as many as 3 species per hour are

going extinct and 20,000 extinctions occur each year. Roughly one-third of the world’s coral reef systems have been

destroyed or highly degraded. About 24 per cent of mammals and 12 per cent of bird species are

currently considered to be globally threatened. More than 50 per cent of the world’s wetlands have been drained,

and populations of inland water and wetland species have declined by 50per cent between 1970 and 1999.

CONSERVATION OF BIODIVERSITY

Biodiversity inventories Conserving Biodiversity in protected Habitats-• In situ conservation• Ex situ conservation Seed Bank, Gene Bank, Pollen Bank, DNA

Bank

Gene Bank

zoo

Bandhavgarh National Park

Restoration of Biodiversity Imparting Environmental Education Enacting, strengthening and enforcing Environmental

Legislation Population Control Reviewing the agriculture practice Controlling Urbanization Conservation through Biotechnology

BIODIVERSITY IN INDIA

Categories No. of Indian Species

% of Indian species Evaluated

Species Threatened In India

Mammals 386 59 41%

Birds 1219 _ 7%

Reptiles 495 73 46%

Amphibians 207 79 57%

Freshwater Fish 700 46 70%

CONCLUSION

Biodiversity is our life. If the Biodiversity got lost at this rate then in near future, the survival of human being will be threatened. So, it is our moral duty to conserve Biodiversity as well our Environment. Long-term maintenance of species and their management requires co-operative efforts across entire landscapes. Biodiversity should be dealt with at scale of habitats or ecosystems rather than at species level.

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