SOLID WASTE MANAGEMENT
Problems posed by Solid Waste Disposal:
It is expensive.
For example, the
· Solid waste disposal often takes up valuable and costly land.
· Landfills pollute groundwater while incinerators cause air pollution
and incineration represent a waste of valuable resources.
Sustainable management of Solid Wastes:
Three approaches can be adopted to attain a sustainable management of Solid Wastes. These include:
a) Reduction Approach - which calls for lower levels of material consumption in society.
b) Reuse and …
c) Recycling Approach - which attempts to maximize the life span of a material in the production-consumption cycle.
This approach calls for reduction in the per capita consumption of natural resources through one or more of the following approaches.
· Purchase more durable items
· Buy more efficient products - automobiles, houses and appliances.
· Cut consumption by reducing luxury items.
· Manufacturers can reduce the sizes of their products so to cut down on material used per unit
Reuse and Recycle Approach
· Advocates of the Reuse approach calls for a continuous use of materials in an attempt to cut down on the consumption of new resources. For example, boxes, clothes, appliances that may be trash-bound could be donated to others for reuse.
· Recycling is another form of Reuse but usually involves some form of conversion from one state of the material to another. For example, in recycling, a glass will have to be crushed and melted before it will be used to make a new glass.
Composting: a form of recycling that occurs when organic matter such as kitchen wastes, yard waste (leaves and branches) and even paper and cardboard are allowed to decompose.
EVOLUTION IN METHODS OF URBAN WASTE DISPOSAL
1) Open Waste Dumps
Dumps are open sites where trash are deposited and occasionally burned to reduce the volume of the accumulating garbage. Earliest form of waste disposal currently abandoned in economically advanced countries but common in poor developing countries.
1. Attracts rats and flies
2. Wind shifts brings an odorous smell to offend residents living close
to the dump
3. Burning the garbage causes black smoke, filled with toxic
byproducts from burning rubber, plastic etc to fill the air.
4. Rain and snow melt trickle through the garbage and carry
materials into surface and groundwater supplies
2) Sanitary Landfills
A sanitary landfill is an excavation, or a hollow in the ground in which garbage is dumped, compacted and covered daily with a fresh layer of dirt.
· It reduces odors caused by the rotten garbage and prevents air pollution caused by periodic burning of waste in an open dump.
· Because a soil layer is placed over the trash, compacted, and then generally sloped to reduce water percolation into the garbage, groundwater contamination can be greatly reduced.
· The protective layer of soil also reduces insects and other pests that could carry disease.
The garbage can
also be reclaimed - returned to some previous use. For
example, a stadium or a shopping mall can be built on the site. In
· If the soil or rock is permeable, there could be a considerable seepage that would lead to groundwater pollution.
· Rotten debris produces methane, which is a potentially explosive gas.
· Requires large tracts of expensive land
It is a system in which unseperated trash - containing plastics, metals, paper, yard waste and glass - is burned and the heat produced during combustion is often used to generate steam for industrial processes, home heating or electrical power generation.
· It captures energy that would otherwise be lost.
· It requires less land than landfills and Dumps.
Incinerators that burn plastics and other materials containing chlorine emit a dangerous class of compounds called Dioxins that have been linked to cancer and weakens the immune system.