This seminar topic “Solid Waste Management and Disposal system” is based on the research on what solid waste is all about, how it is managed and its methods of disposal systems. Research on this topic enable us to know that solid wastes are discarded solid materials such as scraps of plastic, rubbers nylon, paper, etc. Also, the collection and processing of these wastes as well as disposal constitute the management of solid wastes. The disposal systems tell us the methods of disposing solid wastes and where they are disposed as well as the transportation of the collected materials. From this seminar,solid wastes are separated into various components and recycled to produce good and usable products. The effective waste management and disposal system result into a clean and healthy environment for living, reduces the spread of diseases and aids the growth of the economy.
WHAT IS SOLID WASTE?
The United States Environmental protection Agency defined a solid waste as any uselss, unwanted or discarded material with insufficient liquid content, EPA (1975). Because of its sticky nature, a solid Waste has the quality of accumulating, and physically insulting the environment. Omuta (1988), defined a solid as plastic, rubber, paper, glass, etc arising from domestic, trade, commercial, agricultural and industrial activities. Moreso, solid matter that are created by human or animal activities and which are disposed because they are considered useless are known as solid wastes. Most of the solid wastes like plastic, robber, etc. are non. Biodegradable which means that they do not get broken down through organic processes thus, when they accumulate, they pose a health threat to the people. According to Eze (1995), a solid waste means any refuse, gabbage and other discarded materials resulting from community, agricultural and industrial operations.
CLASSIFICATION OF SOLID WASTES
According to Umeh (1991), solid wastes have potential to cause harmful effect if not properly managed. He classified solid wastes into the following.
- Garbage: decomposable wastes
- Rubbish: non-decomposable wastes such as plastic, Rubber,etc.
- Ashes: residues from combustion of solid fuels
- Dead animals.
- Large wastes: Wastes from construction and demolition of structures.
- Industrial wastes: such materials like scraps of plastic, rubber etc.
- Agricultural wastes: farm animals manure and crop residues.
However, according to Bernade (1987), solid waste can be classified into different classes depending on their sources:
- Household waste which is generally classified as municipal waste.
- Industrial waste as hazardous wastes
- Biomedical waste as infections waste.
SOLID WASTES MANAGEMENT PRACTICES
Solid wastes management practices can be divided into two namely:
1. The management of the wastes in the areas where they are generated.
2. The management of the wastes at dumping grounds.
Solid wastes management practices include the issues that are related to wastes generation, storage, collection and removal from collection points. Moreso, solid wastes management practice is an issue that cuts across every sector of the economy. It is an aspect that has been generating concern in the Chemical Industry which has become a challenge to the Chemical Engineers. Advocates of Environmental protection Agency have drawn the attention of the national policy –maker to the health hazards and potential dangers to natural resources caused by the inadequate management of wastes, Anard (1999). There is a wide variation in both the physical and chemical nature of wastes generated as one goes from one household to another or one industry to another.
Furthermore, waste management is a serious environmental problem that has been the subject of several studies, conferences, strategic meetings and debates. According to Tanaka (1998), the purpose of waste management is to preserve the living environment and improve public health through the restriction of wastes discharge, appropriate sorting, storage, collection, transport, recycling, etc. of wastes and conservation of clean living environment. Thus, wastes management practices are expected to contribute significantly to the conservation of the living environment and maintenance of a high standard of public hygiene.
SOLID WASTES COLLECTION METHODS
The methods vary widely among different countries and regions. These includes:
1. CURBSIDE COLLECTION: In this method, every urban domestic household is provided with three bins. One for recyclables, another for general wastes and the third for garden materials. These bins may be provided by the government if requested or individuals.
2. ENVAC COLLECTION: This is the convey of refuse via under ground conduits using a vacuum system.
Moreso, domestic wastes collection services are often provided by local government authorities or by private companies.
The issue of waste disposal has become one of the most crucial matters confronting the society. Public concern on this issue continued to be expressed daily through the medial such as news paper, magazine, radio and television, Anon (1995). The scientist has spent much time to analyze various stages of waste control systems which are applicable to today’s waste generation and disposal means. The indiscriminate dumping of refuse by many or individual on unapproved or unauthorized areas such as the ground, street corners constitute a big problem to the society. This refuse emits bad odour that is harzardous to man’s health. Moreso, the disposal of waste is a problem. This problem continues to grow with the growth of population and development of industries. Disposal of wastes in open pits have become routine in majority of places some of the methods of disposal systems include incineration, recycling, sustainability, biological reprocessing, energy recovery and avoidance & reduction method.
Furthermore, the problem of solid waste disposal is as a result of increasing urbanization coupled with colonial policy on urban planning. It was observed that before our contact with the Europeans that each household was responsible for keeping its immediate environment clean. Today, traditional dumps have disappeared and the open space converted to housing. However, alternate arrangement has been made for proper solid waste disposal which includes composting, land filling, incinerations and recycling.
SOLID WASTES MANAGEMENT PRINCIPLES
1. WASTE HIERARCHY: The waste management hierarchy refers to “3Rs which means, Reduce, Reuse and Recycle. This classifies waste management in terms of waste minimization. The waste hierarchy remains the cornerstone of most waste minimization strategies. The aim is to extract the maximum practical benefits from products and to generate the minimum amount of wastes. The hierarchy diagram is shown below.
2. POLLUTER PAYS PRINCIPLE: This is a principle where the polluting party pays for the impact caused to the environment. Also, a waste generator pays for the disposal of the wastes.
3. TALORIES DECLARATION PRINCIPLE: This is a declaration for sustainability concerned with unprecedented scale and speed of environment pollution, degradation and depletion of natural resources.SOLID WASTE MANAGEMENT AND DISPOSAL SYSTEMS