Solid Waste Classification and Management Strategies

Solid Waste Classification by Composition

Solid waste, in terms of its composition, can be classified as follows:

Organic Wastes

This includes all waste of biological origin that was once alive or part of a living being. It is biodegradable, meaning it decomposes naturally and quickly. Examples include leaves, twigs, shells, food scraps, and fruit and vegetable remains.

Inorganic Wastes

This category comprises all non-biological waste. Due to their chemical characteristics, these materials undergo natural decay very slowly. Many are natural but not biodegradable, such as plastic containers, glass, and cans.

Hazardous Waste

This refers to any waste, whether organic or inorganic, that constitutes a potential hazard (e.g., flammable, toxic, reactive, and corrosive) to the environment, natural resources, or human health. Therefore, it must be treated specially. Examples include infectious medical material, acids, and corrosive chemicals.

Radioactive Waste

This is any waste containing or contaminated with residues that emit radiation. Such radiation can affect biological processes and cause genetic defects, cancer, etc.

Note on Paper and Cardboard

Paper and cardboard, though derived from organic sources, are typically treated as inorganic for recycling purposes due to their specific processing requirements. The exception includes paper napkins and food-soiled paper, which are considered organic material.

Solid Waste Management Strategies

Effective waste management involves several key mechanisms:

• Storage containers
• Collection
• Transportation
• Waste treatment

It is during the treatment phase that distinctions between waste types become crucial:

Organic Waste Treatment

For organic waste, treatment can involve composting or utilization as biomass for energy generation, both aimed at recycling these materials. Composting is the biochemical and mechanical degradation of organic matter through the action of microorganisms (such as bacteria and fungi) to form a stable biochemical compound called compost. While its quality as a standalone fertilizer may be low, it is valuable as a peat substitute to improve soil properties.

Inorganic Waste Treatment

For inorganic waste, treatment focuses on reuse (where the waste is processed and used for its original purpose, e.g., glass bottles are treated and reused as bottles) and recycling (where the waste is used in manufacturing processes different from its original formation, e.g., plastic containers are crushed and used to manufacture pipes).

Hazardous and Toxic Waste Treatment

For toxic and hazardous waste, high-temperature incineration is often used. Secure landfill sites are also employed, located on geologically stable land, with impermeable liners and drainage systems to collect leachate. The management of these wastes is typically carried out by specialist companies that collect and treat them, ensuring secure incineration or storage. Many of these residues, after treatment, can be used as feedstock for other processes, extending their usefulness.