Fundamentals of solid waste

This comprehensive document provides an in-depth exploration of Fundamentals of solid waste —materials discarded in solid or semi-solid states—and their classification based on origin and type. It covers the various categories of solid waste, including domestic, commercial, industrial, agricultural, biomedical, hazardous, and e-waste, detailing their sources and characteristics. The content also highlights the sources of solid waste, ranging from residential and commercial establishments to institutional, industrial, and municipal activities. Additionally, it discusses the composition of municipal Fundamentals of solid waste (MSW), examining variations influenced by income levels, social customs, and geographical conditions.

Q. What is Fundamentals of solid waste?

Definitions of Solid Waste

Solid waste is defined as material that is discarded in a solid or semi-solid state and is non-soluble. This includes garbage, refuse, sludge and other domestic materials from residential area as well as Waste generated from industrial, commercial, agricultural, and mining activities Fundamentals of solid waste.

Classification of Solid Waste

Q. what are the classification of solid waste?

Domestic Waste:

The solid wastes that originate from single and multi-family household units. Wastes are produced from household activities like cooking, cleaning, repairs, and hobbies. redecoration and waste includes vegetable remains, fruit peelings, empty containers, packaging materials, clothing, old books, writing/new paper, old furnishings Fundamentals of solid waste etc.

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. Wastes consist of leftover food, glasses, metals, ashes, paper, plastic etc.

Institutional waste:

This mainly consists of paper, plastic, glasses, etc., generated from educational, Wastes are generated from administrative and public buildings, including schools, colleges, offices, prisons, and similar establishments. It includes waste which are classified as garbage and rubbish Fundamentals of solid waste.

Industrial Waste:

Industrial waste refers to the byproducts generated from industrial activities, including materials rendered useless during manufacturing processes in factories, mills, and mining operations. It encompasses a wide variety of substances specific to each industry.

Construction Waste:

Construction and demolition (C&D) waste refers to materials produced during the construction, repair, and demolition of residential, commercial, and other structures. C&D waste includes concrete, bricks, tiles, stone, soil, rubble, plaster, drywall, wood, plumbing fixtures, non-hazardous insulation, plastics, wallpaper, glass, metals (such as steel and aluminum), asphalt, and more Fundamentals of solid waste.

Agricultural Waste:

Waste material generated from agricultural activity or Agro industry residues, e.g. straw, husk, tree pruning etc. This mainly consists of spoiled food grains, vegetables, agricultural residues, litter, and other waste produced in fields, orchards, vineyards, farms, and similar areas Fundamentals of solid waste.

Bio-Medical Waste:

The waste generated by hospitals, nursing or maternity homes, clinics, This includes waste generated during diagnosis in dispensaries, veterinary institutions, pathological laboratories, and blood banks. treatment or immunization of human beings or animals or in research activities which is potentially Biomedical waste refers to waste that is hazardous to human health and the environment Fundamentals of solid waste.

Hazardous Waste:

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. Common examples include solvents, paints, and pesticides, whose used containers are often combined with municipal waste, eventually becoming part of the urban waste stream Fundamentals of solid waste.

Toxic Waste:

Toxic waste is any unwanted material in all forms that can cause harm (e.g., by being inhaled, swallowed, or absorbed through the skin). Mostly generated by industry, consumer products like televisions, computers, and phones contain toxic chemicals that can pollute the air and contaminate soil and water Fundamentals of solid waste.

Street Sweepings:

This term applies to wastes that are collected from streets, walkways, alleys,
parks and vacant lots. Street waste comprises paper, cardboard, plastic, dirt, dust, leaves, and other organic matter Fundamentals of solid waste.

E-waste:

E-waste is any refuse created by discarded electronic devices and components as well as substances involved in their manufacture or use. Examples of e waste include computers, office electronics, entertainment devices, mobile phones, televisions, refrigerators, and similar items.

Sources of Solid Waste

Q. what are the sources of solid waste?

Following are the sources of solid waste:

Residential: This includes wastes from residential houses like dwellings; apartments etc. and consisting of leftover food, vegetables peels, plastic, clothes, ashes etc.

Commercial: This refers to waste produced by establishments such as restaurants, hotels, motels, stores, markets, auto repair shops, and medical facilities, comprising leftover food, glass, metal, ashes, and similar materials Fundamentals of solid waste.

Institutional: This includes waste coming from educational, administrative and public buildings like
prisons etc. and consisting of paper, plastic, glasses etc.

Municipal: This mainly refers to waste from various municipal activities like construction and demolition, street cleaning, landscaping etc. and consisting of leaf matter, dust, building debris, waste water treatment plant residual sludge etc.

Industrial: This mainly consists of waste generated from various industrial activities and consisting of process wastes, ashes, construction and demolition wastes, hazardous wastes etc.

Agricultural: This includes wastes coming from fields, orchards, vineyards, farms etc. and It consists of agricultural residues, spoiled vegetables and grains, litter, and similar materials Fundamentals of solid waste.

Open areas: This primarily includes waste from streets, alleys, parks, playgrounds, beaches, and similar public spaces.

Composition of solid waste

The composition of municipal solid waste differs across the globe.Even within the same country, the composition of municipal solid waste varies from one place to another, depending on factors such as social customs, standard of living, geographical location, and climate. MSW is heterogeneous in nature, comprising diverse materials generated from various activities. However, making general observations can still provide valuable insights and conclusions Fundamentals of solid waste.

The major constituents are paper and other organic matter.
Metal, glass, ceramics, plastics, textiles, dirt, and wood are commonly present, though their proportions vary based on local conditions.
Paper waste tends to increase with higher national income levels.
Putrescible organic matter (food waste) is more prevalent in low-income countries compared to high-income countries.
Moisture content is also higher in low-income countries Fundamentals of solid waste.

Physical and Chemical Characteristics

Q. what are the characteristics of physical and chemical change?

1. Physical Characteristics

Specific Weight (Density):

Specific weight, also known as density, is the weight of a material per unit volume (kg/m³). Typically, it applies to uncompacted waste and varies based on geographic location, season, and storage duration. The density generally ranges from 50 to 290 kg/m³. Knowledge of waste density is essential for designing all aspects of the solid waste management system Fundamentals of solid waste.

Moisture Content:

Moisture content in solid waste is expressed as a percentage of the wet weight of Municipal Solid Waste (MSW) and typically ranges from 5% to 60%. Increased moisture raises the weight of the waste, leading to higher collection and transportation costs. Therefore, waste should be protected from rainfall or external water sources. Moisture content is also a key factor in assessing the economic viability of incineration, as additional energy is required to evaporate the water and heat the resulting wapour Fundamentals of solid waste.

Particle Size and Distribution:

The size and distribution of waste components are critical for material recovery processes, especially when using mechanical methods such as trommel screens and magnetic separators. The particle size typically ranges between 1 cm and 50 cm.

Field Capacity:

Field capacity is the maximum amount of moisture a waste sample can retain under gravity’s influence. It is a significant factor in determining leachate formation in landfills. Field capacity generally ranges from 50% to 60% for uncompacted mixed residential and commercial wastes, depending on decomposition and pressure levels Fundamentals of solid waste.

Permeability of Compacted Waste:

Permeability, or hydraulic conductivity, of compacted waste governs the movement of liquids and gases in landfills, making it an essential property in waste management.

2. Chemical Characteristics:

Primarily used for combustion and waste-to-energy (WTE) calculations, they are also applied to estimate biological and chemical behaviors. Waste comprises both combustible (e.g., paper) and non-combustible materials (e.g. glass).

Lipids: This group includes fats, oils, and grease, predominantly sourced from garbage, cooking oils, and fats. With high heating values of approximately 38,000 kJ/kg, lipid-rich waste is ideal for energy recovery. As lipids become liquid at temperatures slightly above ambient, they contribute to the liquid content during waste decomposition. Despite being biodegradable, their breakdown rate is slow due to their low water solubility Fundamentals of solid waste.

Carbohydrates: Found mainly in food and yard waste, carbohydrates include sugars and sugar polymers (e.g., starch, cellulose), with a general formula of (CH2O)x. These compounds biodegrade easily into carbon dioxide, water, and methane. Decomposing carbohydrates attract flies and rats, so they should not remain exposed for extended periods.

Proteins: Composed of carbon, hydrogen, oxygen, and nitrogen, proteins contain an organic acid paired with a substituted amine group (NH2). They are largely present in food and garden waste. The partial breakdown of proteins can release amines, resulting in unpleasant odors.

Heating Value: To assess waste material’s suitability as fuel for incineration, its heating value is evaluated in kilojoules per kilogram (kJ/kg). This is determined using the Bomb calorimeter test, which measures the heat generated from combusting a dry sample at a constant temperature of 25°C. As the temperature during combustion exceeds 100°C, water transitions into vapor form, despite the test temperature being below water’s boiling point.

Natural Fibers : These are found in paper products, food, and yard wastes, containing natural compounds like cellulose and lignin that are resistant to biodegradation. (Note that paper contains almost 100% cellulose, cotton is over 95%, and wood products contain over 40%.) Due to their high combustibility, with a significant proportion of paper and wood products, they are ideal for incineration. The calorific value of oven-dried paper products ranges from 12,000 to 18,000 kJ/kg, while wood has around 20,000 kJ/kg, which is approximately half that of fuel oil, which is 44,200 kJ/kg Fundamentals of solid waste .

pH: Fresh solid waste typically has a pH near 7. As decomposition occurs, it becomes more acidic, while stabilized solid waste tends to have an alkaline pH.

Proximate Analysis:

Moisture loss (temperature held at 105°C).
Volatile Combustible Matter (VCM) (temperature increased to 950°C in a closed crucible).
Fixed Carbon (the residue left after VCM).
Ash (heated at 950°C in an open crucible).

Fusing Point of Ash: The temperature range for clinker formation (carbon and metal agglomerates) is between 2000°C and 2200°C.

Ultimate Analysis: Identifies the molecular composition (C, H, N, O, P, etc.).

Energy Content: Calculated through laboratory tests using calorimeters.

Solid Waste Management Hierarchy

The following stages outline the SWM hierarchy:

Prevention: This involves avoiding the use of raw materials that result in significant solid waste and selecting alternative materials that produce less waste.

Reduction: At the top of the SWM hierarchy is waste minimization or reduction at the source, which focuses on reducing the amount of waste generated. This step is crucial because it is the most effective way to lower the volume of waste, reduce handling costs, and mitigate environmental impacts Fundamentals of solid waste.

Reuse: The next best option is reusing materials repeatedly for the same purpose.

To promote waste reduction, reuse, and recycling, the following measures are suggested:

Manufacturers of both domestic and non-domestic products, including food and non-food items, should be encouraged to use reusable packaging materials. This way, packaging can be collected and reused after the product is delivered.
Consumers should be offered incentives and discounts for returning packaging or bottling materials in good condition to producers or retailers to encourage reuse Fundamentals of solid waste.

The cost of items with packaging materials should differ from those without packaging, offering consumers the choice to purchase products at a lower cost without packaging.

Recycle: Recycling is vital for reducing the demand for natural resources and the amount of waste that ends up in landfills. This stage involves the collection, sorting, and processing of recyclable materials into new products.

Recovery: Recovery involves transforming waste into valuable products, such as compost or energy. By processing waste, the need for landfill space is reduced. Activities like recycling and composting fall under this stage Fundamentals of solid waste.

Disposal: Disposal is the final option, considered only after all other methods of managing waste have been exhausted. This may include landfilling or incineration.

Management and Functions of Management

Management is the process of planning, organizing, staffing, leading, and controlling resources to achieve organizational goals efficiently and effectively. It involves setting objectives, arranging resources, motivating employees, and ensuring tasks align with plans. These functions work together to coordinate efforts and drive success use in Management and Functions of Management.

Civil Engineer Role in Effective Landfill & Solid Waste Management

In the realm of environmental sustainability and urban development, landfill and solid waste management have become critical areas of focus. Amidst growing concerns about waste disposal and its impact on the environment, civil engineering emerges as a pivotal discipline driving innovative solutions.