Chapter 5: Solid Waste Management

Introduction

       Solid waste can be defined as any solid or semi-solid substance or object resulting

from human or animal activities, discarded as useless or unwanted. It is an extremely

mixed mass of wastes, which may originate from household, commercial, industrial or

agricultural activities.

       Unmanaged heaps of waste cause adverse impacts to the environment as well as

human health. Waste is a serious health hazard and lead to the spread of infectious

diseases. Unattended waste lying around attracts flies, rats, and other creatures that in

turn spread disease. Air pollution is another factor to be considered. Normally it is the

wet waste that decomposes and releases a bad odour. This leads to unhygienic conditions

and thereby to a rise in the health problems. Other than this, co-disposal of industrial/

residential hazardous waste with municipal waste can expose people to chemical and

radioactive hazards. Uncollected solid waste can also obstruct storm water runoff,

resulting in the forming of stagnant water bodies that become the breeding ground of

disease. Wastes dumped along roads, riverbanks, abandoned quarries, seas, and lakes

with the inevitable effect of contaminating water supplies as well as the whole aquatic

chain.

       Solid waste is a broad term, which encompasses all kinds of waste such as Municipal

Solid Waste (MSW), Industrial Waste (IW), Hazardous Waste (HW), Bio-Medical Waste

(BMW) and Electronic waste (E-waste) depending on their source & composition. It

consists of organic and inorganic constituents which may or may not be biodegradable.

TYPES OF SOLID WASTES

Solid waste includes domestic wastes, municipal wastes, commercial wastes, garbage,

rubbish, ashes, construction and demolition wastes, industrial wastes, hazardous wastes,

hospital wastes and sewage.

Domestic wastes :

These wastes are generated by household activities such as cooking, cleaning, repairs,

redecoration, empty containers, packaging, clothing, old books, newspapers, old

furnishings, etc.

Commercial wastes :

Solid wastes generated in offices, wholesale stores, restaurants, hotels, markets,

warehouses and other commercial establishments. These are further classified into

garbage and rubbish.

Institutional wastes :

Wastes generated from institutions such as schools, colleges, hospitals, research

institutions. The waste includes garbage, rubbish and hazardous wastes.

Municipal wastes :

Wastes generated due to municipal activities and services such as street waste,

deadanimals, market waste and abandoned vehicles. Generally, the term is used in a

wider sense to incorporate domestic wastes, institutional wastes and commercial wastes.

Garbage:

It includes animal and vegetable wastes due to various activities like storage, preparation

and sale, cooking and serving. These are biodegradable.

Ashes:

Residues from the burning of wood, charcoal and coke for cooking and heating in houses,

institutions and small industries. Ashes consist of a fine powdery residue, cinders and

clinker often mixed with small pieces of metal and glass.

Rubbish :

Apart from garbage and ashes, other solid wastes produced in households, commercial

establishments, and institutions are termed as rubbish.

Bulky wastes:

Bulky wastes are large household appliances such as cookers, refrigerators and washing

machines as well as furniture, crates, vehicle parts, tyres, wood, trees and branches. The

bulky metallic wastes are sold as scrap metal but some portion is disposed as sanitary

landfills.

Street wastes:

Street wastes include paper, cardboard, plastic, dirt, dust, leaves and other vegetable

matter collected from streets, walkways, alleys, parks and vacant plots.

Dead animals :

It includes animals that die naturally or accidentally killed. It does not include carcass and

animal parts from slaughterhouses as these are considered as industrial wastes.

Construction and demolition wastes:

Major components of the construction materials are cement, bricks, cement plaster, steel,

rubble, stone, timber, plastic and iron pipes.

Industrial wastes:

These are discarded solid material of manufacturing processes and industrial operations

and are considered separately from municipal wastes. However, solid wastes from small

industries plants and ash from power plants are frequently disposed of at municipal

landfills. Major producers of industrial wastes are the thermal power plants producing

coal ash, integrated iron and steel mills producing blast furnace slag and steel melting

slag, non-ferrous industries like aluminium, zinc and copper producing red mud and

tailings, sugar industries generating press mud, pulp and paper industries producing lime

and fertilizer and allied industries producing gypsum. Management of industrial solid

waste is not the responsibility of local bodies. Industries generating solid wastes have to

manage by themselves and are required to obtain prior permission from the respective

state pollution control boards under relevant rules.

Solid Waste Generation

According to the Ninth Malaysia Plan 2006-2010 report, the amount of solid waste

generated in Peninsular Malaysia increased from 16,200 tonnes per day in 2001 to 19,100

tonnes per day in 2005. This amount is estimated to increase to 30,000 tonnes per day in

2020. On average, at this time a Malaysian generate 0.8 kg of solid waste per day.

(Source: Ministry of Housing and Local Government, 2008).

The composition of solid waste

Rate of solid waste composition varies between areas because it is influenced by several

factors, among which the socio-economic and lifestyle. On the average composition of

household solid waste in Malaysia are as follows:

The classification of solid waste:

These types of solid waste can be classified into several parts such as;

Table 5.1 The classification of solid waste

The sources of solid waste:

All this kind materials would be found at the sources areas:

• Residential areas: village, housing area, flats, and so on.

• Industrial areas: factories, stores, etc.

• Commercial areas: shopping mall, supermarket, and so on.

• Institutional areas: college, school, kindergarten and so on.

• Construction/ demolition: construction site and demolition site

• Municipal services: uptown, night market, and so on.

• Process: manufacturing activity, etc.

• Agriculture: plantation activity, livestock activity, vegetation activity, etc.

The quantity of MSW in Malaysia:

It is estimated that solid waste generated in small, medium and large cities and

towns is about 0.1 kg, 0.3-0.4 kg, and 0.5 kg per capita per day respectively. According to

Kathirvele et al (2003), the generation rate ranges from 0.5-0.8 kg/person/day to 1.7

kg/person/day in major cities. The 9th Malaysia plan reported that the average per capita

generation has increased from 0.67 kg/person/day in 2001 to 0.8 kg/person/day in 2005

[RMK9]. Nazeri [2002] stated that the waste generation in peninsular Malaysia has

increased from 16,200 tons per day to 19,100 tons per day. Assuming a 3.6 percent

growth, in 2020 the amount is expected to be 31,000 tons/day [NSP 2005].

The main element in MSW management:

The activities associated with the management of municipal solid wastes from the

point of generation to final disposal can be grouped into the six functional elements: (a)

waste generation; (b) waste handling and sorting, storage, and processing at the source;

(c) collection; (d) sorting, processing and transformation; (e) transfer and transport; and

(f) disposal.

Waste Generation: Waste generation encompasses activities in which materials are

identified as no longer being of value (in their present form) and are either thrown away

or gathered together for disposal. Waste generation is, at present, an activity that is not

very controllable. In the future, however, more control is likely to be exercised over the

generation of wastes. Reduction of waste at source, although not controlled by solid

waste managers, is now included in system evaluations as a method of limiting the

quantity of waste generated.

Waste Handling, Sorting, Storage, and Processing at the Source: The second of the

six functional elements in the solid waste management system is waste handling, sorting,

storage, and processing at the source. Waste handling and sorting involves the activities

associated with management of wastes until they are placed in storage containers for

collection. Handling also encompasses the movement of loaded containers to the point of

collection. Sorting of waste components is an important step in the handling and storage

of solid waste at the source. For example, the best place to separate waste materials for

reuse and recycling is at the source of generation. Households are becoming more aware

of the importance of separating newspaper and cardboard, bottles/glass, kitchen wastes

and ferrous and non-ferrous materials.

On-site storage is of primary importance because of public health concerns and

aesthetic consideration. Unsightly makeshift containers and even open ground storage,

both of which are undesirable, are often seen at many residential and commercial sites.

The cost of providing storage for solid wastes at the source is normally borne by the

household in the case of individuals, or by the management of commercial and industrial

properties. Processing at the source involves activities such as backyard waste

composting.

Sorting, Processing and Transformation of Solid Waste: The sorting, processing and

transformation of solid waste materials is the fourth of the functional elements. The

recovery of sorted materials, processing of solid waste and transformation of solid waste

that occurs primarily in locations away from the source of waste generation are

encompassed by this functional element. Sorting of commingled (mixed) wastes usually

occurs at a materials recovery facility, transfer stations, combustion facilities, and

disposal sites. Sorting often includes the separation of bulky items, separation of waste

components by size using screens, manual separation of waste components, and

separation of ferrous and non-ferrous metals.

Waste processing is undertaken to recover conversion products and energy. The

organic fraction of Municipal Solid Waste (MSW) can be transformed by a variety of

biological and thermal processes. The most commonly used biological transformation

process is aerobic composting. The most commonly used thermal transformation process

is incineration.

Waste transformation is undertaken to reduce the volume, weight, size or toxicity

of waste without resource recovery. Transformation may be done by a variety of

mechanical (eg shredding), thermal (e.g. incineration without energy recovery) or

chemical (e.g. encapsulation) techniques.

Transfer and Transport: The functional element of transfer and transport involves two

steps: (i) the transfer of wastes from the smaller collection vehicle to the larger transport

equipment and (ii) the subsequent transport of the wastes, usually over long distances, to

a processing or disposal site. The transfer usually takes place at a transfer station.

Disposal: The final functional element in the solid waste management system is disposal.

Today the disposal of wastes by land filling or uncontrolled dumping is the ultimate fate

of all solid wastes, whether they are residential wastes collected and transported directly

to a landfill site, residual materials from Materials Recovery Facilities (MRFs), residue

from the combustion of solid waste, rejects of composting, or other substances from

various solid waste-processing facilities. A municipal solid waste landfill plant is an

engineered facility used for disposing of solid wastes on land or within the earth’s mantle

without creating nuisance or the highest rank of the ISWM hierarchy is waste

minimization or reduction at source, which involves reducing the amount (and/or

toxicity) of the wastes produced. Reduction at source is first in the hierarchy because it is

the most effective way to reduce the quantity of waste, the cost associated with its

handling, and its environmental impacts.

The characteristics of MSW:

The characteristics of MSW substituted into two main parts that are:

4.5 PHYSICAL CHARACTERISTICS

(i) Density: The knowledge of density is important for the design of all elements

of the solid waste management systems like storage, transport and disposal.

For example for a known volume of the solid waste its density gives us the

idea about the requirement of the truck in tonnage. Every truck or similar

vehicle has a permitted load capacity say 12 ton or so which it can carry

according to law. In developed countries as their waste is light so compaction

reduces the cartage charges substantially. The density varies significantly from

source to the disposal site because of handling, change in moisture content,

densification due to vibration of movement, disturbance by animals and birds

(scavengers) etc. The following table gives some data from MSWM for density

of municipal solid waste in some Indian cities.

Table 4.6 Density of Municipal Solid Waste produced in some Indian Cities.

It is evident from the above table that density is more in Jaipur waste as because

of dessert conditions there is more sand and other inorganic heavy matter. These

figures are only indicative and are to be verified before the actual design of a

system. Actually it is very important that the solution to any SWM problem should

be site specific and time specific. The same city may show different composition

after some years.

(ii) Moisture content: Moisture content of the solid waste is expressed as the

weight of moisture per unit weight of wet material.

Moisture content varies generally from 20 to 45% depending upon the climatic

conditions and level of city (income group) etc. The increase of moisture content

increases the weight and thus the cost of transportation and thus the storage section

should take care of it.

(iii) Calorific value: Calorific value is the amount of heat generated from combustion

of a unit weight of a substance, expressed as kilo calorie per kilogram.

The calorific value is determined in the laboratory by Bomb Calorimeter. Table

4.3 shows typical values of the residue and calorific value for the different

components of the municipal solid waste.

If the energy is to be recovered or the waste is to be disposed, by incineration

(controlled burning) the following points should be considered:

• Organic matter gives energy only in dry condition.

• The moisture content as free water reduces the dry organic matter per kilgram

and hence requires a significant amount of energy for evaporation.

• The ash content of the waste reduces the proportion of dry organic material

per kilogram of waste. It also retains some heat.

So for economical recovery of energy the waste should contain minimum amount

of moisture, ash and other inorganic matter.

These are the significance of determination of physical characteristics.

4.6 CHEMICAL CHARACTERISTICS

The chemical characteristics of solid waste are determined for assessing the treatment

process. Mainly three chemical characteristics are determined, chemical, bio-chemical

and toxicological.

• Chemical quantities of solid waste in Indian urban centres are pH, nitrogen,

phosphorus, and potassium (N-P-K), total carbon, carbon/nitrogen ratio,

calorific value.

• Bio-chemical characteristics include carbohydrate, proteins, natural fiber, and

biodegradable factor.

• Toxic characteristics include heavy metals, pesticides, insecticides etc.

Consideration of lipids (fats, oils and grease) should also be done as they are of

a very high calorific value (about 38000 Kcal/kg). These days synthetic organic

materials like plastic have become a significant component of solid waste accounting

for 5-7%. In India the plastic is non-biodegradable and thus poses a great problem.

It chokes the drains and if burnt it produces poisonous gases. The thin plastic sheets

and bags are not recycled as the cost of making it dirt & oil free makes the process

uneconomical.

All the above considerations of characteristics are required to design, conceive and

assess the most appropriate ways of transportation, the requirements of treatment,

extraction of energy and the safe, sanitary way of disposal for the protection of

environment

The generation of MSW in Malaysia:

The rate of waste generation in Malaysia is increasing, covering community

activities such as commercial, institutional, industrial and markets. It is also related to the

economic level of different sectors in the community such as squatters, low, medium and

high class residential area. The rate varies according to the type of waste generators and

land use. Depending on the economic status of the area, the per capita solid waste

generation rate varies from 0.45 to 1.44 kilogram per capita per day.

The generation of municipal solid waste by the public is a function of socio-

economic background either the buying power or income level, cultural background,

locality either urban or rural setting and the environment awareness. Some of the

contributing factors to increasing Malaysian MSW generation rate are relatively due to

population growth, rapid urbanization, economic growth and its multicultural society that

celebrates various festivals.

The process of handling of MSW:

As the economic activity and population increases, the management of solid waste

is becoming a serious problem in all municipalities. Public health, air pollution, odor

disturbance, hazardous gas emissions are among the common phenomena occurring in

urban areas. In general, MSW disposal requires an adequate environmental control from

waste collection to disposal and finally regular monitoring of disposal sites. The local

authority in most of the municipalities in Malaysia is responsible for the collection

service of solid waste, even though some municipalities or city hall (for example Kuala

Lumpur City Hall) has outsourced to private companies. The monitoring of the overall

MSW management however, is still under their responsibility. The situation of MSW

management in Malaysia is similar to other Asian countries. These processes are being

managed, directly or indirectly at all three levels of government: federal, state and local

authority; that a part of this department has their own role to establish.

1. Role of the State Government

• State-level policy and formulation programme;

• Consultation and coordination with federal government;

• Promotion and coordination of local authority cooperation;

• Allocation of land and facilities;

• Approval of inter-state movement of waste and location of facilities;

• Assisting, monitoring and auditing local authorities;

• Financial and other assistance for local authorities;

• Formation of coordinating MSW committee.

2. Role of the Local Authorities

• Assist state government in formulation of policies;

• Enforce SWM legislation at the local level;

• Monitor, audit and enforce concessionaire service levels;

• Incorporate local requirements in operational plans;

• Raise public awareness and promote education on waste minimization and

recycling;

• Provide advice on planning, sitting and operating local facilities;

• Enforce laws on illegal dumping, littering and open burning;

• Collect tariffs and make payments as appropriate;

• Collect, collate and disseminate appropriate data and information

3. Role of Services Provider

• Cooperate and assist government and local authorities in implementation of

policies;

• Continuously improve expertise and efficiency;

• Promote and develop expertise and efficiency of sub-contractors;

• Adopt a long-term business vision for adequate levels of equipment, facilities

and service levels;

• Self-regulate and minimize the need for local authority intervention;

• Promote public education and awareness;

• Promote waste minimization and reduction strategies;

• Collect, collate and disseminate useful data;

The MSW collection method:

In collection, solid waste is picked up and placed into empty containers with separate

parts for recyclable materials. Then, the collection vehicles collect the waste around the

disposal centers manually before disposing into the disposal sites. The party that had a

responsible to handle this part of MSW management such as city employees (municipal

collection- city council, district council, city hall, etc), collectors from private firms that

contract with city government (contract on colnicipal collection- Alam Flora Sdn. Bhd., )

or collector s from private firms that contract with private residents (private collection).

There three basic methods are: (1) curbside or alley pickup, (2) set-out,set-back

collection, and (3) backyard pickup or tote barrel method.

I. The curbside or alley pickup

The quickest and most economical point of collection.Using standard container

that has been design by city council.It costs only one half as much as backyard

collection.The crews collect from both sides of the street at the same time.When

the containers must be placed at the curb or in alley for pickup, and how long

they may remain after pickup, it usually specify by the municipal ordinances or

administrative regulations. Common limits are out by 7 a.m and back by 7 p.m..

When solid wastes are loaded in curbs or alleys, work progresses rapidly. A

typical crew consists of a driver and two collecters. Aside from the cost advantage

of this method, it is also eliminates the need for the collectors to enter private

property, and amount of service given each homeowner is relatively uniform.

However, many citizens dislike having to set their solid waste out at certain times

and object to the unsightly appearance on the streets.

II. Set-out, set-back pickup collection

These kind of method eliminates most of the disadvantages of the curb method,

but it does require the collector to enter private property. This method consist of

the following operations: (1) Collectors have to enter property, (2) Set out crew

carries full containers from resident storage location to curb/ alley before

collection vehicle arrives, (3) Collection crew load their refuse into vehicle, (4)

Set-back crew return the container to storage area. Any of the crew may be

required to do more than one step or the homeowner may required to do one of

the steps. This method has not been shown to be more economical or

advantageous than the backyard method.

III. Backyard pickup or tote barrel method

Backyard pickup is usually accomplished by the use of tote barrels. In this

method, the collector enters the resident’s property, dumps the container into a

tote barrel, carries it to the truck, and dumps it. The collector may collect refuse

from more than one house efore returning to the truck to dump. The primary

advantage of this system is in convenience to homeowner. The major

disadvantages is the high cost. Many homeowners object to having the collectors

to enter their private property.

Disposal methods

       Improper and unscientific techniques adopted for MSW disposal are economically

non - viable and socially unacceptable, due to this selection of proper disposal method is

necessary. Quantity and characteristics of the MSW are two major factors, which are to

be considered as the basis for the design of efficient, cost effective and environmentally

compatible disposal method. One can choose the appropriate disposal method which is

generally categorized as follows

For large Scale disposal:

i)Open dumps

       The cheapest and the oldest easy method of MSW disposal is 'open dumping' where

the waste is dumped in low - lying areas on the city outskirts and leveled by bull - dozers

from time to time. Open dumping is not a scientific way of waste disposal. Open dumps

refer an uncovered site used for disposal of waste without environmental controls. The

waste is untreated, uncovered, and not segregated. In spite of its simplicity in execution,

the financial involvement for this traditional method of waste management has been quite

high particularly for the big metropolis. Uncontrolled, open dumps are not a sound

practice. Open dumps are exposed to flies and rodents. It also generates foul smell and

unsightly appearance. Loose waste is dispersed by the action of wind. Drainage from

dumps contributes to pollution of surface and ground water and also the rainwater run-off

from these dumps contaminates nearby land and water thereby spreading disease. A

WHO Expert Committee (1967) condemned dumping as “a most unsanitary method that

creates public health hazards, a nuisance, and severe pollution of the environment.

Dumping should be outlawed and replaced by sound procedures”.

ii)Landfill

       Disposing of waste in a landfill involves burying the waste, and this remains a

common practice in most countries. Landfills are generally located in urban areas where a

large amount of waste is generated and has to be dumped in a common place. The

equipment required to operate is relatively inexpensive and can be used for other

municipal operations as well serious threat to community health represented by open

dumping or burning is avoided. Landfills were often established in abandoned or unused

quarries, mining voids or borrow pits. Unlike an open dump, it is a pit that is dug in the

ground. The waste is dumped and the pit is covered at the dumping ground with debris/

soil and spread evenly in layers. At the end of each day, a layer of soil is scattered on top

of it and some mechanism, usually an earthmoving equipment is used to compress the

garbage, which now forms a cell. Thus, every day, garbage is dumped and becomes a

cell. The organic waste undergoes natural decomposition and generates a fluid, which is

known a leachate, and is very harmful to the ecosystem. After the landfill is full, the area

is covered with a thick layer of mud and the site can thereafter be developed as a parking

lot or a park.

Sanitarylandfills

       An alternative to landfills or modern landfill which solves the problem of leaching to

some extent is a sanitary landfill which is more hygienic and built in a methodical

manner. Designed “landfill” means a waste disposal site for the deposit of residual solid

waste in a facility designed with protective measures against pollution of ground water,

surface water and air fugitive dust, wind-blown litter, bad odour, fire hazard, bird

menace, pests or rodents, greenhouse gas (Methane) emissions, slope instability and

erosion. These are lined with materials that are impermeable such as plastics and clay,

and are also built over impermeable soil. Deposited waste is normally compacted to

increase its density and stability, and covered to prevent attracting vermin (such as mice

or rats). Many landfills also have landfill gas extraction systems installed to extract the

landfill gas. Gas is pumped out of the landfill using perforated pipes and flared off or

burnt in a gas engine to generate electricity. Fully operated landfills may even enhance

property values. Constructing sanitary landfills is very costly and they are having their

own problems.

       By and large, crude dumping of waste is done in the most of the cities without

following the principles of sanitary landfilling. As negligible segregation of waste at

source takes place, all waste including hospital infectious waste generally finds its way to

the disposal site. Quite often industrial hazardous waste is also deposited at dump sites

meant for domestic waste. The waste deposited at the dump site is generally neither

spread nor compacted on a regular basis. It is also not covered with inert material. Thus,

very unhygienic conditions prevail on the dump sites. The workers handling waste do so

in highly unhygienic and unhealthy conditions. Leach ate if not treated properly it

penetrates the soil and, if not prevented, pollutes the ground water.

iii)Incineration

       The process of burning waste in large furnaces at high temperature is known as

incineration. Incineration is a disposal method that involves combustion of waste

material. Incineration and other high temperature waste treatment systems are sometimes

described as "thermal treatment". Incineration is carried out both on a small scale by

individuals and on a large scale by industry. It is used to dispose of solid, liquid and

gaseous waste. Incineration facilities generally do not require as much area as landfills.

Waste-to-energy or energy-from-waste is broad terms for facilities that burn waste in a

furnace or boiler to generate heat, steam and/or electricity. At the end of the process all

that is left behind is ash. It is recognized as a practical method of disposing of certain

hazardous waste materials (such as biological medical waste).

       Combustion in an incinerator is not always perfect and there have been concerns

about micro pollutants in gaseous emissions from incinerator stacks. Particular concern

has focused on some very persistent organics such as dioxins which may be created

within the incinerator. Both the fly ash and the ash that is left in the furnace after burning

have high concentrations of dangerous toxins such as dioxins and heavy metals.

Disposing of this ash is a problem. Cost of incinerator and additional investment on

pollution control devices make the process capital - intensive. Under Indian conditions

large scale incineration plants are economically non - viable in view of their capital -

intensive character and the low calorific value of city garbage available.

For Small Scale disposal:

i) Composting

       Decomposition and stabilization of solid organic waste material has been taking

place in nature ever since life appeared on this planet. Composting is the process of

decomposition and stabilization of organic matter under controlled condition. Waste

materials that are organic in nature, such as plant material, food scraps, and paper

products, can be recycled using biological composting and digestion processes to

decompose the organic matter. It is a biological process in which micro-organisms,

mainly fungi and bacteria, convert degradable organic waste into humus like substance.

The resulting organic material is then recycled as mulch or compost for agricultural or

landscaping purposes. In addition, waste gas from the process (such as methane) can be

captured and used for generating electricity. The intention of biological processing in

waste management is to control and accelerate the natural process of decomposition of

organic matter. There is a large variety of composting and digestion methods and

technologies varying in complexity from simple home compost heaps, to industrial-scale

enclosedvessel digestion of mixed domestic waste. Methods of biological decomposition

are differentiated as being aerobic or anaerobic methods, though hybrids of the two

methods also exist.

       Organic matter constitutes 35%–40% of the municipal solid waste generated in India.

This waste can be recycled by the method of composting, one of the oldest forms of

disposal. Apart from being clean, cheap, and safe, composting can significantly reduce

the amount of disposable garbage. Each one MT of wet garbage can yield 200 to 300 kgs.

of organic fertilizer. It increases the soil's ability to hold water and makes the soil easier

to cultivate.

       Vermi-composting is very successful at community level but it is yet to develop at

commercial scale. Manual composting is carried out in smaller urban centres. Although

mechanical composting plants were set up in cities but presently, only few plants out of

them continues to be in operation. The High cost of mechanical composting plants and

the non - utilization of by-products are among the factors which make the process an

uneconomic proposition. The most critical link in the process of composting is the

segregation operation. Hand sorting of garbage at the compost plant is expensive and

unsanitary.

       Depending upon the availability of land and its topography, economic viability,

Types of waste, quantity of waste and social conditions; one can choose any one or more

or Combination of two of the said techniques for waste disposal.

Landfill Sitting, Design, Operation Maintenance and Post-Closure Maintenance:

In planning a landfill it is useful to think about the facility in terms of four key phases

from initial concept to final closure. These phases are:

1. Sitting

2. Design

3. Construction, operation, and environmental monitoring

4. Closure and post-closure.

The key considerations for sound management of the facility are listed in the adjoining

box. Attention to these issues is important for achieving safe and effective MSWM at the

landfill. Such sound management can be enhanced by the judicious use of resources at

each phase of landfill development.

1. Sitting

Sitting can be one of the most difficult processes in the landfill process.

The main considerations are:

Capacity: In the sitting process, the available land area is a key consideration. In

order to minimize the transaction costs associated with design, permitting, sitting,

and closure and post-closure requirements, it is desirable to have a facility that

will operate for at least two to three years. In practice, many short-term facilities

turn into long-term facilities, so it is important that all aspects of the sitting

process be observed even when planning a short-term controlled dump. Ideally, a

site should be sought with sufficient capacity for 10 - 20 years of operation,

particularly in the case of sanitary landfills.

Higher environmental standards are increasing the construction, operation,

and closure costs of landfills. In combination with a landfill capacity crisis in

some countries, these factors are leading to the construction of regional landfills

that can respond to environmental concerns in a cost-effective way. Such regional

landfills serve a larger region than would normally be served by a municipal

landfill. These considerations apply in developing countries as well as

industrialized ones. The construction and use of transfer stations will reduce the

higher transport costs brought about by the use of more distant, regional landfills.

Public involvement in the sitting process: Public opposition can be strong and

protracted. The planner must be prepared to involve potentially affected

communities in the sitting process. He or she must establish a dialog and working

relationship with representatives from the candidate communities and address

their concerns in the design and implementation of the landfill plan.

Hydro-geology: It is desirable to take advantage of the geology of a site. In

particular, the types of soil and rock underlying the landfill and the thickness of

each soil layer can restrict the migration of the leachate toward groundwater and

reduce the concentration of contaminants. For example, clay soils significantly

slow the migration of leachate and can reduce the concentration of heavy metal

contaminants. A bedding of igneous rock also serves to contain leachate. Sand, on

the other hand, will do little to slow leachate migration and has little capacity to

remove contaminants.

Cover material: The availability of cover material is also an important

consideration in the sitting decision. As discussed in the section on landfill

operations below, the compacted MSW must be covered by 15-30 centimeters of

soil at the end of each day's operations. This creates a large demand for cover

material and can lead to prohibitive costs if this soil has to be trucked over

distances far from the landfill site.

Access: To contain hauling costs and discourage the use of illegal dump sites, it is

important that a landfill be located reasonably close to the area it is designed to

serve. At the same time, sitting a landfill too close to a populated area will expose

local residents to the environmental and health threats that landfills may pose.

Since urban areas are growing rapidly, especially in developing countries, an area

near the edge of existing settlements will very likely be too close to populated

areas in the foreseeable future. The ideal location would therefore be sufficiently

far from the city to allow for future population growth, but close enough to be

reasonably accessible.

In many cases, the use of transfer stations within a city can facilitate the sitting of

a landfill at a greater distance from population centers. The Collection and

transfer part of the Sound Practices section addresses the issue of transfer stations

in further detail. The roads that provide access to a landfill must be adequate to

handle the types and quantity of vehicles that will be used. Planning a landfill

requires evaluation of existing and new roads, and must include provision for

maintenance of the roads needed to reach the site.

Accessibility notwithstanding, the geological considerations described above are

paramount in ensuring the environmental soundness of a landfill. Even when it is

necessary to site a landfill far from a city, the expense that results from additional

road construction and increased hauling costs may well be less than the cost of

remediating a contaminated drinking water supply.

Proximity to airports: A landfill should not be sited closer than two kilometers

from the nearest airport. Birds converging at the landfill may pose a problem for

aircraft and the landfill may pose other problems for airport operations if the

facilities are located too close to each other. The required separation may be

larger depending on the size and type of the landfill and of the airport.

2. Design

The design of a landfill will significantly affect its safety, cost, and

effectiveness over the lifetime of the facility. These considerations may have

different implications for controlled dumps and sanitary landfill facilities. The

facility should be designed to operate effectively given the mix of capital, labor,

and expertise available to its owners. Thus, labor-intensive controlled dumps

should be designed where capital is severely limited, labor is available at low cost,

and there is a shortage of expertise and infrastructure to service a highly

mechanized facility. Such conditions prevail in the cities of many developing

countries. However, an appropriately designed facility can still avail such cities of

safe and dependable land filling.

a) Capacity

Planned capacity may not be protected by zoning and land use

restriction guarantees provided by municipal authorities.

The landfill planner must use the designated site strategically to

minimize the risk of future incursion by municipal development

and maximize the total area available for land filling over the

lifetime of the facility.

Municipal planners must also ensure that appropriate sites with the

required capacity are always available for future needs

b) Public/private ownership/operation

Owned and operated by local governments or other public

agencies.

Available in the private sector, municipal planners should explore

the option of privatizing landfill operations on a contractual basis.

Should be weighed carefully as it involves issues of cost recovery

and the payment of fees for tipping privileges at the landfill.

c) Monitoring and control of leachate

A key factor in safe landfill design and operation.

The natural decomposition of MSW, in combination with rain

infiltration into the site, causes potentially toxic contaminants to

flow toward the bottom of the landfill.

The geology of a site can exacerbate or reduce the amount of

leachate that enters the environment.

A variety of wastes can contribute contaminants to landfill leachate

such as paint pigments, household batteries and etc.

Figure 5.1: Classification of different level of landfill in Malaysia

d) Monitoring and control of landfill gas

Landfill gas is primarily a mixture of methane and carbon dioxide

produced by the decomposition of organic matter in the MSW.

Landfill liners help keep methane from escaping from the landfill

and help maintain the anaerobic conditions necessary for methane

production.

e) Access and tipping area

Fencing should be designed to restrict unauthorized access to the

landfill and to keep out vermin and stray animals.

The perimeter of the facility should be patrolled to minimize

vandalism.

A staffed gate should be the point of entry to the facility for

vehicles and any waste pickers.

Separate provisions must be made for access to emergency

vehicles and equipment.

f) Pre-processing and waste picker policy

Mechanical equipment, such as compactors and bulldozers should

be restricted to separate resource recovery facilities or prohibited

altogether from the site.

Alternatives may be provided for the displaced workers and

operating procedures set for safe landfill operations.

Reduces the risks to sorters from the equipment and activity at the

active cell.

Reduces the amount of material that has to be transported to the

cell.

g) Operations and safety manuals

The provision of ongoing monitoring and control of the facility

after its useful life is an unavoidable reality of landfill

management.

To ensure their continued safety to the health of surrounding

communities and the environment for periods that may exceed 30

years after their closure.

Cost recovery programs may be instituted during the operation of

the facility to provide funding for these activities.

h) Closure and post-closure plans

The provision of ongoing monitoring and control of the facility

after its useful life is an unavoidable reality of landfill

management.

To ensure their continued safety to the health of surrounding

communities and the environment for periods that may exceed 30

years after their closure.

Cost recovery programs may be instituted during the operation of

the facility to provide funding for these activities

i) Community relations program

The designer should establish a program for ongoing dialog with

the community.

Should be based on transparency in landfill operations and

procedures and a commitment to addressing community concerns.

Some facilities offer give-backs to their host community such as

free street paving to compensate for the heavy vehicles in transit to

the landfill and others.

3. Construction, operation, and environment monitoring

Construction

The amount and type of construction depends on the class of landfill, on physical

conditions at the site, and on local regulatory requirements. Construction issues

include:

construction of access roads

erection of fences, gates, and the tipping area

site preparation for the diversion of precipitation and the control of runoff

installation of the leachate and gas monitoring systems

installation of the leachate and gas treatment systems

construction of administrative offices, physical plant, and other buildings at

the facility

preparation of the general working area, including:

o land clearing, grading, and excavation

o compaction of the base and application of the liner installation of the

leachate collection system

Operation

Operations at the landfill may be classified into three main areas:

– Gate operations: include weighing and recording gate receipts, tipping (if

direct access to the working cell is not available), pre-processing

(including materials recovery and composting if practiced at the site), and

the transportation of the tipped waste to the lift site at the working cell.

– Cell operations includes:

- Tipping: either of waste directly transported by the haul vehicle or of

residues preprocessed at the gate area and transported to the cell.

- Spreading and compacting: This may be done manually by workers

with rakes and weighted rollers. Mechanical spreaders and compactors

are also available. These achieve much higher compaction than manual

means. However this equipment is costly and requires specialized

maintenance. For many cities in developing countries, manual

spreading and compacting is a sound practice. The reader is directed to

the waste management literature for further details on spreading and

compacting operations and equipment.

- Daily cover: It is important to cover new MSW at the end of the day

with a layer of soil or compost. This can sometimes be done by

applying a 15-30 centimeter layer of soil that was excavated earlier or

by using fine construction and demolition residue handled elsewhere at

the site. This daily cover is used to control disease vectors such as rats

and insects, reduce blowing of waste and odors, and slow down the

infiltration of rainwater. It also results in more gas generation, which

may or may not be desirable.

– Administration: where all the vehicles and any waste pickers need to be

register on administration center/office/post guard to keep recording the

flow of in and out record at landfill areas.

4. Closure and post-closure

Finally when the landfills are full, they must be covered with a low permeable cap

in order to prevent the rainwater from filtering through and mix with the waste

which would lead to more leachate production. A continuous monitoring of the

groundwater quality and the methane gas buildup at the closed landfill site is

required in order to prevent the environmental problems associated with those. In

the United States, the minimum post-closure maintenance and monitoring period

is 30 years. But as concern has been shown by Allen (2001), the waste in the

landfill might take longer time period to reach its stabilization state than the

mandatory aftercare period and the durability of the liner is yet to be sure. Thus,

there is a possibility of pollutants leaching through the liner and contaminate the

environment. This is especially critical for the “dry tomb” type of landfill where

the waste degradation has been slowed down and its impacts has been prolonged

to a longer time period which could take a century to reach its stabilization.

The Concepts Of 4R’s:

Methods of waste reduction, waste reuse and recycling are the preferred options when

managing waste. There are many environmental benefits that can be derived from the use

of these methods.

I. Reduction

Waste reduction should have a top priority in the solid waste management

hierarchy. It reduces the amount and the toxicity of waste before them

entering the municipal waste stream. By designing, manufacturing,

purchasing, or using materials in ways that reduce the amount or the

toxicity of trash created, less waste is generated and fewer natural

resources are used. Waste prevention, or “source reduction,” is the strategy

behind reducing and reusing waste. By reducing, consumers and industry

can save natural resources and reduce waste management costs. The

success of source reduction is very much depended on the attitude of

producers and consumers which involves legislation, social perception,

education and so on. Along with the increasing living standard,

Malaysians are developing the “use and throw” consumption behavior

where there are more and more disposable products being consumed. This

consumption pattern should be inverted in order to reduce the waste from

entering the waste stream.

Benefits of Reduction

Saves natural resources. Waste is not just created when

consumers throw items away. Throughout the life cycle of a

product from extraction of raw materials to transportation to

processing and manufacturing facilities to manufacture and use

waste is generated. Reusing items or making them with less

material decreases waste dramatically. Ultimately, fewer materials

will need to be recycled, combusted for energy, or land filled.

Reduces toxicity of waste. Selecting nonhazardous or less

hazardous items is another important component of source

reduction. Using less hazardous alternatives for certain items (e.g.,

cleaning products and pesticides), sharing products that contain

hazardous chemicals instead of throwing out leftovers, reading

label directions carefully, and using the smallest amount necessary

are ways to reduce waste toxicity.

Reduces costs. The benefits of preventing waste go beyond

reducing reliance on other forms of waste disposal. Preventing

waste also can mean economic savings for communities,

businesses, organizations, and individual consumers.

II. Reuse

Reuse is often part of the waste prevention strategy, stopping waste at the

source by preventing or delaying a material’s entry in the waste collection

and disposal system. Reusing the product in the same application for

which it was originally intended saves energy and sources. Utilization

value of any item should be known to people who are using it. For

example, a plastic bag can carry groceries home from market over and

over again, and polystyrene cup might be used several time before

disposal. Private sector involvement should be encouraged, repairing

facilities should be offered so goods can be used as per its utilization

value. Large production companies such as Electronic appliances, gadgets

etc should establish the collection centre, where damaged items can be

repaired & reuse

III. Recovery

Recovery of materials means removing municipal solid waste from waste

stream for the purpose of recycling (Franklin Associates,1999). The

distinction between source reduction and recovery is the former prevents

waste from entering the waste stream while the later retrieves the

recyclables from the waste stream.

IV. Recycling

Recycling turns materials that would otherwise become waste into

valuable resources. Collecting used bottles, cans, and newspapers and

taking them to the curb or to a collection facility is just the first in a series

of steps that generates a host of financial, environmental, and social

returns. Some of these benefits accrue locally as well as globally.

Benefits of Recycling

Recycling reduces the need for landfill and incineration.

Recycling prevents pollution caused by the manufacturing of

products from virgin materials.

Recycling saves energy.

Recycling decreases emissions of greenhouse gases that contribute

to global climate change.

Recycling conserves natural resources such as timber, water, and

minerals.

Recycling helps sustain the environment for future generations.

Steps to Recycling a Product

Recycling includes collecting recyclable materials that would otherwise be

considered waste, sorting and processing recyclables into raw materials

such as fibers, manufacturing raw materials into new products, and

purchasing recycled products.

Collecting and processing secondary materials, manufacturing recycled-

content products, and then buying recycled products creates a circle or

loop that ensures the overall success and value of recycling.

Step1. Collection and Processing

Collecting recyclables varies from community to community, but there are

four primary methods: curbside, drop-off centers, buy-back centers, and

deposit/refund programs.

Regardless of the method used to collect the recyclables, the next leg of

their journey is usually the same. Recyclables are sent to a materials

recovery facility to be sorted and prepared into marketable commodities

for manufacturing. Recyclables are bought and sold just like any other

commodity, and prices for the materials change and fluctuate with the

market.

Step2. Manufacturing

Once cleaned and separated, the recyclables are ready to undergo the

second part of the recycling loop. More and more of today’s products are

being manufactured with total or partial recycled content. Common

household items that contain recycled materials include newspapers and

paper towels; aluminum, plastic, and glass soft drink containers; steel

cans; and plastic laundry detergent bottles. Recycled materials also are

used in innovative applications such as recovered glass in roadway asphalt

(glass-halt) or recovered plastic in carpeting, park benches, and pedestrian

bridges.

Step3. Purchasing Recycled Products

Purchasing recycled products completes the recycling loop. By “buying

recycled,” governments, as well as businesses and individual consumers,

each play an important role in making the recycling process a success. As

consumers demand more environmentally sound products, manufacturers

will continue to meet that demand by producing high-quality recycled

products. Learn more about recycling terminology and to find tips on

identifying recycled products.

Mini Experiment

Experiment1: Evaluate the waste production

Problem: How to evaluate the waste production?

Instruction: For determining the quantity of waste that requires collection and disposal,

you have to select a sample area and measure the waste generated at household level.

Material needed:

- Sample containers (eg, plastic bags),

- Weighing scales,

- Buckets,

- Gloves,

- Data sheets, marker pens.

Procedure:

1. Collect the waste generated in the selected areas from houses once a day at a fixed time

for 7 successive days to evaluate variation in waste generation in a week. The number of

households to be selected depends on the size of the town.

2. Weigh the production of each household and record the weight in the data sheets

according to the numbers of inhabitants per household. (g/ house/day)

3. Finally remember to dispose all the waste properly and clean the equipment used.

4. Repeat 1. to 3. everyday for the duration of the study.

Result: Refer Appendix 1.

Experiment2: Evaluate the waste density

Problem: How is the weight of 1 m3 of waste?

Instruction: Waste density information when coupled with waste generation rates

expressed by weight, allow the payload capacity of the collection equipment to be

estimated.

Material needed:

- Sample containers (eg, plastic bags),

- Weighing scales,

- Buckets,

- Gloves,

- Data sheets, marker pens.

Procedure:

1. Select a container whose volume is known

2. Weight the empty container (kg)

3. Fill up the container with waste.

4. Weight the full container (kg)

5. Weight of the waste = Weight of the full container – Weight of the empty container

6. Waste density (kg/m3) = Weight of the waste ÷ Volume of the container

Result: Refer Appendix 2

Experiment 3: Evaluate the waste composition

Problem: How to evaluate the waste composition?

Material needed:

- A plastic sheet to spread waste over it for sorting

- Gloves (for workers handling the waste)

- Buckets whose weight is known

- Weighing scale to weigh the waste with an accuracy of 100 grams

Procedure:

1. Collect samples of waste from household, classes, resident areas and etc.

2. Spread the sample over the plastic sheet.

3. Separate the waste on the plastic sheet into different types (e.g.

vegetables/putrescibles matter, paper, textiles, plastics, grass/leaves/wood,

leather/rubber, metals, glass/ceramic, miscellaneous). Put then the separated waste

into different buckets for weight measurement.

4. Measure the weight of each type of waste and record it in the data sheet.

5. Repeat steps 3. , and 4. for each sample.

6. Dump all the waste properly and clean the equipment used.

7. Repeat steps 1. to 6. everyday for the duration of the study.

Result: Refer Appendix 3

References:

Gilbert M. Masters; Introduction To Environmental Engineering and Science; 2nd

edition (1998); Prentice Hall

Mackenzie L. Davis, David A. Cornwell; Introduction To Environmental

Engineering; 3rd edition (1998); McGraw-Hill

Act 672; Laws of Malaysia; SOLID WASTE AND PUBLIC CLEANSING

MANAGEMENT ACT 2007 Solid Waste Management; view on

http://www.unep.or.jp/ietc/ESTdir/Pub/MSW/index.asp

Sewerage and Solid Waste Project Unit. 2000. The solid waste management

program: Sewerage and Solid Waste Project Unit, Barbados; view on

http://www.solid.gov.bb/Resources/Brochures/Programme/program02.asp

http://dl.dropbox.com/u/21130258/resources/InformationSheets/

WasteDisposal.htm

http://www.unep.org/ietc/InformationResources/Publications/

SolidWasteManagementPublication/tabid/79356/Default.aspx

http://www.unep.or.jp/ietc/ESTdir/Pub/MSW/index.asp

http://www.epa.gov/epawaste/conserve/rrr/reduce.htm

http://www.epa.gov/epawaste/conserve/rrr/recycle.htm

Allen, A. (2001). Containment landfills: the myth of sustainability. Engineering

Geology, 60, 1-4,3-19

Franklin Associates (1999). Characterization of municipal solid waste in the

United States: 1998 update. Report No. EPA-530. Kansas.

Zamali Tarmudi, Mohd Lazim Abdullah and Abu Osman Md Tap; An overview

of Municipal Solid Wastes Generation In Malaysia; Jurnal Teknologi, 51(F) Dis.

2009; Universiti Teknologi Malaysia

Chung Tsung Ping; Malaysia Developing A Solid Waste Management, Model For

Penang; February 2008; Published by the United Nations Development Program

(UNDP), Malaysia; view on http://www.undp.org.my/uploads/SWM-

2008_final.pdf

Sanitary Landfills: Toward Sustainable Development; LUMES 2000-2001;

Mentore Vaccari and Daniela Giardina; DEVELOPMENT OF AN

APPROPRIATE STRATEGY FOR THE SANITATION SECTOR: THE CASE

OF MUNICIPAL SOLID WASTE MANAGEMENT:2006

Dr. K.H. Chua, Endang Jati Mat Sahid, Dr. Y. P. Leong; Sustainable Municipal

Solid Waste Management and GHG Abatement in Malaysia; Institution of Energy

Policy and Research, UNITEN; 2011

Agamuthu, P. and Fauziah S.H.; Solid waste: Environmental Factors and Health;

Institute of Biological Sciences, Faculty of Science, UM;2008

Agamuthu, P. (2001) Solid waste: principles and management with Malaysian

case studies. Kuala Lumpur: University of Malaya Press.

Rami El-Sherbiny, Ahmed Gaber, and Mahmoud Riad; Chapter7: Waste

Management; 2011