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
·
Garbage disposal
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.
Reduction Approach:
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.
Problems:
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.
Advantages:
·
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
Disadvantages:
·
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
3) Incineration
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.
Advantages:
·
It captures
energy that would otherwise be lost.
·
It requires less
land than landfills and Dumps.
Disadvantages:
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.