SOLID WASTE MANAGEMENT BY COOLEST CHRIS PART TWO

CHAPTER TWO

2.0 Literature Review

Over the past years man has begun to consider the importance of his environment and his impact on it.Solid waste problems began from the early man throwing fruit core .The resultant consequence of this modern civilization is the accumulation of these surplus wastes which in turn constitutes a problem of pollution, unsightliness public health and fire hazards. This problem of solid wastes control, management and disposal techniques had denied many solutions locally and nationally in Nigeria and most other internationally countries.

Aribisala(2004) defined solid waste management as the discipline associated with  controlling the generation,storage,collection,transfer and transport, processing and disposal of solid waste in a manner that is in accordance with the best principles of health,economics,engineering,conseration,aesthetics and other environmental considerations. And that is also responsive to public attitudes.

Solid waste is the unwanted or useless solid materials generated from combined Residential, industrial and commercial activities in a given area. It may be categorized according to its origin (domestic, industrial, commercial, construction or institutional); according to its contents (organic material, glass, metal, plastic paper etc.); or according to hazard potential (toxic, non-toxin, flammable, radioactive, infectious etc.).(Ramachandra, T.V, Shruti, B, (2006).

            Waste may be defined as any solid ,liquid or gaseous substance ,that remains a residue or an incidental by-product of the processing of the substance and for which no use can be found by the organism or system that produces it(Allaby,1998).In other words ,wastes are substances or objects discarded as worthless or unwanted, defective and of no further value to the user to be disposed of(Ekpoh,2009).Wastes may also be defined as used ,discarded and unwanted materials by the producer. It could take the forms of refuse, garbage and sludge (Leton and Omotosho, 2004).

Management of solid waste reduces or eliminates adverse impacts on the environment and human health and supports economic development and improved quality of life. A number of processes are involved in effectively managing waste for a municipality. These include monitoring, collection, transport, processing, recycling and disposal.

The federal government of Nigeria in 1988b created theFederal Environment protection Agency (FEPA) through the promulgation of decree 58 with the main aim of protecting, preserving and restoring the ecosystem of the federal republic of Nigeria .the decree gave the agency the power to do the following “They were to establish effluent limitations, criteria, guidelines, specifications and standards to protect thequality of Nigerian resources

Waste is anything which is no longer of use to the disposer .it can be defined as any unavoidable material resulting from an activity which has not immediate economic demand and which must be disposed of (NISP 2003)

Waste is commonly classified into 3:-

1) Solid

2) Liquid

3) Gaseous wastes

Solid wastes are residual from homes, businesses and institutions and referred to as trash, garbage that are no longer of any relevance to the disposer.

In Nigeria taking Ugbowo in Benin city as an example ,the system works but not effective in tackling the growing population and curbing the indiscriminate dumping of solid waste ,solid waste control management have been adopted by various government  agencies like the local government :-the state government waste disposal board and some federal government waste disposal board.

2.1 Classification of Solid Waste

Classification of wastes is described below: - (Source:-Manual on Municipal Solid Waste Management, 2000).

Some of the major various classification of solid waste is as follows:

1. MunicipalWaste

2. Domestic /Residential Waste

3. Commercial Waste

4. Garbage

5. Rubbish

6. Institutional Waste

7. Ashes

8. Bulky Wastes

9. Street Sweeping

10. Dead Animals

11. Construction and Demolition Wastes

12. Industrial Wastes

13. Hazardous Wastes

14. Sewage Wastes

15. Biomedical/Hospital Waste

16. Plastics.

Solid waste is the material generated from various human activities and which is

Normally disposed as useless and unwanted.

A comprehensive classification of wastes is described below:-

1. Municipal Waste:

Municipal waste includes waste resulting from municipal activities and services such as street wastes, dead animals, market wastes and abandoned vehicles. However, the term is commonly applied in a wider sense to incorporate domestic wastes and commercial wastes.

2. Domestic I Residential Waste:

This category of waste comprises the solid wastes that originate from single and multi-family house hold units. These wastes are generated as a consequence of house hold activities such as cooking, cleaning, repairs, hobbies, redecoration, empty containers packaging, clothing, old books, paper and old furnishings.

3. Commercial Waste:

Included in this category are solid wastes that originate in offices, wholesale and retail stores, restaurants, hotels, markets, warehouses and other commercial

Establishments. Some of these wastes are further classified as garbage and others as rubbish.

4. Garbage:

Garbage is the term applied to animal and vegetable waste resulting from the handling, storage, sale, cooking and serving food. Such wastes contain putrescible organic matter, which produces strong odours and therefore attracts rats, flies and other vermin. It requires immediate attention in its storage, handling and disposal.

5. Rubbish:

Rubbish is general term applied to solid wastes originating in households, commercial establishments and institutions, excludingGarbage& ashes.

6. Institutional Waste:

Institutional wastes are those arising frominstitutions such as schools, universities, hospitals and research institutes. It includes wastes, which are classified as garbage andrubbish, as well as wastes, which areconsidered to be hazardous to public health and to the environment.

7. Ashes:

Ashes are the residues from the burning of wood, coal, charcoal, coke and other Combustible materials for cooking and heating in houses, institutions and small industrial establishments. When produced in large quantities at power generation plants and factories, these wastes are classified as industrial wastes. Ashes consist of a fine powdery residue, cinders and clinker oftenMixed with small pieces of metal and glass.

8. Bulky Wastes:

In this category are bulky household wastes, which can’t be accommodated in the normal storage containers of households. For this reason they require special collection. In developed countries residential bulky wastes include household furniture and “white goods” appliances such as stoves, washing machines and refrigerators, mattresses and springs, rugs, TV sets, water heaters, tires, lawn mowers, auto parts, tree and brush debris, and so forth.

9. Street Sweeping:

This term applies to wastes that are collected from streets, walkways, alleys, parks and vacant lots. In the more affluent countries manual street sweeping has virtually disappeared but it still commonly takes place in developing countries, where littering of public places is a far more widespread andAcute problem. Street wastes include paper, cardboard, plastic, dirt, dust, leaves and other vegetable matter.

10. Dead Animals:

This is term applied to dead animals that die naturally or accidentally killed. This categorydoes not include carcass and animal parts from slaughterhouses, which are regarded asindustrial wastes. Dead animals are dividedinto 2 groups, large and small. Among the large animals are Horses, Cows, Goats, and Sheepand the like.

11. Construction and Demolition Wastes:

Construction and demolition wastes are the waste materials generated by the construction, refurbishment, repair and demolition of houses, commercial buildings and other structures. It mainly consists of earth, stones, concrete, bricks, lumber, roofing materials, plumbingmaterials, heating systems and electrical wires and parts of general municipal waste stream, but when generated in large amounts at building and demolition sites, it is generally removed by contractors for filling low lying areas and by urban local bodies for disposal at landfills.

12. Industrial Wastes:

In this category are the discarded solid material of manufacturing processes andindustrial operations. They cover a vast range of substances which are unique to eachindustry. For this reason they are consideredseparately from municipal wastes. However, solid wastes from small industrial plants and ash from power plants are frequently disposedof at municipal landfills.

13. Hazardous Wastes:

Hazardous wastes may be defined as wastes of industrial, institutional or consumer origin which because of their physical, chemical or biological characteristics are potentially dangerous to human and the environment. In Some cases although the active agents may be liquid or gaseous, they are classified as solid waste because they are confined in solid containers.

14. Sewage Wastes:

The solid by-products of sewage treatment are classified as sewage wastes. They are mostly organic and derive from the treatment of organic sludge from both the raw and treated sewage. The inorganic fraction of the raw Sewage such as grit is separated at a preliminary stage of treatment, but because it entrains putrescible organic matter which may contain pathogens, must be buried/disposed off without delay.

15. Biomedical/Hospital Waste:

Hospital waste is generated during the diagnosis, treatment, or immunization of human beings or animals or in research activities in these fields or in the production or testing of biological. It may include wastes like sharps, soiled waste, disposables, anatomical waste, cultures, discarded medicines, chemical wastes, etc.

16. Plastics:

Plastics, due to their versatility in use and impact on environment can be grouped under a different category of solid waste. Plastic with its exclusive qualities of being light yet strong and economical, has invaded every aspect of our day-to-day life.

2.2Properties of Municipal Household Waste

 2.2.1 Physical Properties

1) Specific Weight (Density)

Specific weight is defined as the weight of a material per unit volume (e.g. kg/m3, lb. /ft3); usually it refers to uncompacted waste. It varies with geographic location, season of the year, and length of time in storage.

Table 2.1:    Typical Specific Weight Values (source: Google)

2) Moisture Content

The moisture in a sample is expressed as percentage of the wet weight of the solid waste material

Analysis Procedure:

1)      Weigh the aluminum dish

2)      Fill the dish with SW sample and re-weigh

3)      Dry SW + dish in an oven for at least 24 hrs.At 105°C.

4)      Remove the dish from the oven; allow cooling in a Desiccator and weighing.

5)      Record the weight of the dry SW + dish.

6)      Calculate the moisture content (M) of the SW sample

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Table 2.2:                          Moisture Contents of Wastes (source: Google)

3) Particle Size and Distribution

The size and distribution of the components of wastes are important for the recovery of materials, especially when mechanical means are used, such as trommel screens and magnetic separators. For example, ferrous items which are of a large size may be too heavy to be separated by a magnetic belt or drum system.

4) Field Capacity

The total amount of moisture that can be retained in a waste sample subject to the downward pull of gravity

Figure 2.1 Diagram illustrating Field Capacity   (Source: Google)

FIGURE 2.2 Photo of Leachate (Source: Google)

Field capacity is critically important in determining the formation of leachate in landfills. It varies with the degree of applied pressure and the state of decomposition of wastes, but typical values for uncompacted commingled wastes from residential and commercial sources are in the range of 50 - 60%.

2.2.2 Chemical Properties ofMSW

Chemical properties of MSW are very important in evaluating the alternative processing and recovery options:

1) Proximate Analysis

Proximate analysis for the combustible components of MSW includes the following tests:

Ø  Moisture (drying at 105 oC for 1 h)

Ø  Volatile combustible matter (ignition at 950 oC in the absence of oxygen)

Ø  Fixed carbon (combustible residue left after Step 2)

Ø  Ash (weight of residue after combustion in an open crucible)

Table 2.3             Typical Proximate Analysis Values (% by weight) (source: Google)

Type of waste	Moisture	Volatiles	Carbon	Ash
Mixed food	70	21.4	3.6	5.0
Mixed paper	10.2	75.9	8.4	5.4
Mixed plastics	0.2	95.8	2.0	2.0
Yard wastes	60.0	42.3	7.3	0.4
Glass	2.0	-	-	96.99
Residential MSW	21	52	7	20

2) Fusing Point Of Ash

Fusing point of ash is the temperature at which the ash resulting from the burning of waste will form a solid (clinker) by fusion and agglomeration.

Typical fusing temperatures: 1100 - 1200 Oc.

Figure 2.3 Photo of Solid Clinker of Ash (Source: Google)

Figure 2.4 Process of forming Solid Clinker (Source: Google)

3) Ultimate Analysis

Involves the determination of the percent C (carbon), H (hydrogen), O (oxygen), N (nitrogen), S (sulfur) and ash. Thedetermination of halogens is often included in an ultimate analysis. The results are used to characterize the chemical composition of the organic matter in MSW. They are also used to define the proper mix of waste materials to achieve suitable C/N ratios for biological conversion processes.

2.2.3Biological Properties of Municipal Household Waste

The organic fraction of MSW (excluding plastics, rubber and leather) can be classified as:

1)      Water-soluble constituents - sugars, starches, amino acids and various organic acids

2)      Hemicellulose - a product of 5 and 6-carbon sugars

3)      Cellulose - a product of 6-carbon sugar glucose

4)      Fats, oils and waxes - esters of alcohols and long-chain fatty acids

5)      Lignin - present in some paper products

6)      Lignocellulose - combination of lignin and cellulose

7)      Proteins - amino acid chains

2.3 Biodegradability of Municipal Household Solid Waste

The most important biological characteristic of the organic fraction of MSW is that almost all the organic components can be converted biologically to gases and relatively inert organic and inorganic solids.

The production of odours and the generation of flies are also related to the putrescible nature of the organic materials. These will be discussed when talking about landfill processes.

2.4Mechanics of Municipal Household Waste Management

The mechanics of solid waste management are sub divided into:

Ø  Solid waste generation

Ø  Solid waste storage

Ø  Collection of solid waste

Ø  Treatment of solid waste

Ø  Final disposal of solid waste

           

2.4.1Municipal Solid Waste Generation

Municipal waste consists to a large extent of waste generated by households, but may also include similar wastes generated by small businesses and public institutions and collected by the municipality; this part of municipal waste may vary from municipality to municipality and from country to country, depending on the local waste management system.

For areas not covered by a municipal waste collection scheme the amount of waste generated is estimated.

2.4.2 Storage and Collection

Storage and collection of waste are some of the more visible signs of successful or unsuccessful solid waste management systems. If successful, the result is clean surroundings and good public sanitation; if unsuccessful, litter and poor public sanitation are everywhere self-evident to the knowledgeable observer. Good public sanitation begins with a properly designed and operated waste storage and collection system. The institution of successfulstorage and collection systems in developing countries requires not only a knowledge of appropriate technologies and operating practices, but also recognition of the types of problems faced by these countries relevant to storage and collection.

Table 2.4Descriptions of the main collection systems

2.4.3 Municipal Household Waste Treatment

Mechanical biological treatment (mbt) is a generic term for an integration of several mechanical processes commonly found in other waste management facilities such as Materials Recovery Facilities (MRFs), composting or Anaerobic Digestion plant. MBT plant can incorporate a number of different processes in a variety of combinations. Additionally, MBT plant can be built for a range of purposes. This section provides an overview of the range of techniques employed by MBT processes.

The Aim oftheMBT Processes

Some typical aims of MBT plants include the:

1.      Pre-treatment of waste going to landfill;

2.      Diversion of non-biodegradable and biodegradable MSW going to landfill through the mechanical sorting of MSW into materials for recycling and/or energy recovery as refuse derived fuel (RDF);

3.      Diversion of biodegradable MSW going to landfill by:

4.      Reducing the dry mass of BMW prior to landfill;

5.      Reducing the biodegradability of BMW prior to landfill;

6.      Stabilization into a compost-like output (CLO) 2 for use on land;

7.      Conversion into a combustible biogas for energy recovery; and/or

8.      Drying materials to produce a high calorific organic rich fraction for use as RDF.

                                        

MBT plants may be configured in a variety of ways to achieve the required recycling, recovery and biodegradable municipal waste (BMW) diversion performance.

Figure 2.5 illustrates configurations for MBT plant and highlights the process steps.

2.4.4Waste Preparation

Residual waste requires preparation before biological treatment or sorting of materials can be achieved. Initial waste preparation may take the form of simple removal of contrary objects, such as mattresses, carpets or other bulky wastes, which could cause problems with processing equipment down-stream.

Table 2.5    aSummary ofthe Different Techniques Used For Waste Preparation

Technique	Principle	Key Concerns
Hammer Mill	Material significantly reduced in size by swinging steel hammers.	Wear on Hammers. Pulverizing and ‘loss’ of glass / aggregates. Exclusion of pressurized containers.
Shredder	Rotating knives or hooks rotate at a slow speed with high torque. The shearing action tears or cuts most materials.	Large, strong objects can physically damage the shredder. Exclusion of pressurized containers.
Rotating Drum	Material is lifted up the sides of a rotating drum and then dropped back into the center. Uses gravity to tumble, mix, and homogenize the wastes. Dense, abrasive items such as glass or metal will help break down the softer materials, resulting in considerable size reduction of paper and other biodegradable materials.	Gentle action – high moisture of feedstock can be a problem.
Ball Mill	Rotating drum using heavy balls to break up or pulverize the waste.	Wear on balls. Pulverizing and ‘loss’ of glass / aggregates.
Wet Rotating Drum with Knives	Waste is wetted, forming heavy lumps which break against the knives when tumbled in the drum.	Relatively low size reduction. Potential for damage from large contraries.
Bag Splitter	A relatively gentle shredder used to split plastic bags whilst leaving the majority of the waste intact.	Not size reduction. May be damaged by large strong objects.

2.4.5 Waste Separation

A common aspect of many MBT plant used for MSW management is the sorting of mixed waste into different fractions using mechanical means. As shown in Figure 1, the sorting of material may be achieved before or after biological treatment. No sorting is required if the objective of the MBT process is to pre-treat all the residual MSW to produce a stabilized output for disposal to landfill.

Sorting the waste allows an MBT process to separate different materials which are suitable for different end uses. Potential end uses include material recycling3, biological treatment, energy recovery through the production of RDF/biomass, and landfill. A variety of different techniques can be employed, and most MBT facilities use a series of several different techniques in combination to achieve specific end use requirements for different materials.

Table 2.6 Different Separation Techniques (source: Google)

Figure 2.6 Optical plastics separation. (Source: Image courtesy of New Earth Solutions Ltd)

2.4.5 Biological Treatment

The biological element of an MBT process can take place prior to or after mechanical sorting of the waste, as illustrated in Figure 1. In some processes all the residual MSW is biologically treated to produce a stabilized output for disposal to landfill and no sorting is required. Table 2.7 below outlines the key categories of biological treatment.

Table 2.7: Biological Treatment Options

Figure 2.7 Bio-stabilization halls. (Source: Image courtesy of New Earth Solutions Ltd)

2.4.6Waste Disposal

You will find there are eight major groups of waste management methods, each of them divided into numerous categories. Those groups include source reduction and reuse, animal feeding, recycling, composting, fermentation, landfills, incineration and land application. You can start using many techniques right at home, like reduction and reuse, which works to reduce the amount of disposable material used.

Let’s take a look at some of the things that you should know about waste management.

1) Landfill

The Landfill is the most popularly used method of waste disposal used today. This process of waste disposal focuses attention on burying the waste in the land. Landfills are found in all areas. There is a process used that eliminates the odors and dangers of waste before it is placed into the ground. While it is true this is the most popular form of waste disposal it is certainly far from the only procedure and one that may also bring with it an assortment of space.

2) Incineration/Combustion

Incineration or combustion is a type disposal method in which municipal solid wastes are burned at high temperatures so as as to convert them into residue and gaseous products. The biggest advantage of this type of method is that it can reduce the volume of solid waste to 20 to 30 percent of the original volume, Decreases the space they take up and reduce the stress on landfills. This process is also known as thermal treatment where solid waste materials are converted by Incinerators into heat, gas, steam and ash. Incineration is something that is very in countries where landfill space is no longer available, which includes Japan.

3) Recovery and Recycling

Resource recovery is the process of taking useful discarded items for a specific next use. These discarded items are then processed to extract or recover materials and resources or convert them to energy in the form of useable heat, electricity or fuel.

Recycling is the process of converting waste products into new products to prevent energy usage and consumption of fresh raw materials.

Recycling is the third component of Reduce, Reuse and Recycle waste hierarchy. The idea behind recycling is to reduce energy usage, reduce volume of landfills, reduce air and water pollution, reduce greenhouse gas emissions and preserve natural resources for future use.

4) 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.

5) Composting

Composting is the controlled aerobic decomposition of organic matter by the action of microorganisms and small invertebrates. There are a number of composting techniques being used today. These include: in vessel composting, windrow composting, vermicomposting and static pile composting. The process is controlled by making the environmental conditions optimum for the waste decomposers to thrive. The rate of compost formation is controlled by the composition and constituents of the materials i.e. their Carbon/Nitrogen (C/N) ratio, the temperature, the moisture content and the amount of air.

6) Anaerobic Digestion

Anaerobic digestion like composting uses biological processes to decompose organic waste. However, where composting can use a variety of microbes and must have air, anaerobic digestion uses bacteria and an oxygen free environment to decompose the waste. Aerobic respiration, typical of composting, results in the formation of Carbon dioxide and water. While the anaerobic respiration results in the formation of Carbon Dioxide and methane. In addition to generating the humus which is used as a soil enhancer, Anaerobic Digestion is also used as a method of producing biogas which can be used to generate electricity.

7)Waste to Energy (Recover Energy)

Waste to energy (WtE) process involves converting of non-recyclable wasteItems into useable heat, electricity, or fuel through a variety of processes.

This type of source of energy is a renewable energy source as non- recyclable waste can be used over and over again to create energy. It can also help to reduce carbon emissions by offsetting the need for energy from fossil sources. Waste-to-Energy, also widely recognized by its acronym WtE is the generation of energy in the form of heat or electricity from waste.

8) Avoidance/Waste Minimization

The easier method of waste management is to reduce creation of waste materials thereby reducing the amount of waste going to landfills.

Waste reduction can be done through recycling old materials like jar, bags, repairing broken items instead of buying new one, avoiding use of disposable products like plastic bags, reusing second hand items, and buying items that uses less designing.

2.5The 4r’s Of Solid Waste Management-Reduce, Reuse, Recycle, Recovery

Waste Reduction and Reuse

Waste reduction and reuse of products are both methods of waste prevention. They eliminate the production of waste at the source of usual generation and reduce the demands for large scale treatment and disposal facilities. Methods of waste reduction include manufacturing products with less packaging, encouraging customers to bring their own reusable bags for packaging, encouraging the public to choose reusable products such as cloth napkins and reusable plastic and glass containers, backyard composting and sharing and donating any unwanted items rather than discarding them.

All of the methods of waste prevention mentioned require public participation. In order to get the public onboard, training and educational programs need to be undertaken to educate the public about their role in the process. Also the government may need to regulate the types and amount of packaging used by manufacturers and make the reuse of shopping bags mandatory.

Recycling

Recycling refers to the removal of items from the waste stream to be used as raw materials in the manufacture of new products. Thus from this definition recycling occurs in three phases: first the waste is sorted and recyclables collected, the recyclables are used to create raw materials. These raw materials are then used in the production of new products.

Recovery

Resource recovery is the selective extraction of disposed materials for a specific next use, such as recycling, composting or energy generation in order to extract the maximum benefits from products, delay the consumption of virgin resources, and reduce the amount of waste generated

2.6List of Standing Beneficial Uses

[1] Unadulterated wood, wood chips bark, or sawdust when these materials are used as mulch, landscaping, animal bedding, erosion control, wood fuel production, a bulking agent at a compost facility operated in compliance with part 7035.2836, or as a substitute for wood.

[2] Unadulterated newspaper and newsprint when used as animal bedding, insulation, or as a substitute for paper products.

[3] Uncontaminated glass when used as a sandblast agent.

[4]Unusable latex paints, characterized as high solid content, off-specification colors, sour, frozen, or poor quality, when used to produce processed latex pigment for use as an additive for the production of ASTM-specified specialty Cement.

[5] Reclaimed glass and porcelain fixtures when used as a substitute for conventional aggregate or subgrade applications in accordance with Minnesota Department of Transportation Standard Specifications for Construction 2000 Edition, 3138.2 A2.

[6] Crumb rubber when used in asphalt paving or applications where it is used as a substitute for rubber or similar elastic material.

[7] Tire shreds when used as lightweight fill in the construction of public roads in accordance with Minnesota Statutes, section 115A.912, subdivision 4.

[8] Tire chips when used as a substitute for conventional aggregate in construction Applications when the ratio of this substitution is no greater than one to one by volume. This does not include use of tire chips as general construction fill or clean fill.

[9] Uncontaminated recognizable concrete recycled concrete and concrete products and brick when used for service as a substitute for conventional aggregate.

[10] Salvaged bituminous when used as a substitute for conventional aggregate in accordance with Minnesota Department of Transportation Standard Specifications for Construction 2000 Edition, 3138.2 A2.