The increasing amounts of waste ___1___
by the nations of the world have many environmental
scientists worried about the future. As populations grow
and the production of waste increases, there is ___2___
space for landfills and more waste overflowing into
water supplies and the atmosphere. In recent years,
many cities have made concentrated ___3___
to reduce their waste load. A modern integrated
waste-management system often includes source reduction
( reducing the amount of waste produced ), recycling,
and composting programs to complement existing landfills
and incineration plants.
Recycling is the utilization of wastes as raw
materials ___4___
the manufacture of new products. It has already had a
noticeable ___5___
on the business of waste disposal. Composting is the
natural process in which biodegradable materials are
decomposed by microbes and converted into soil. Another
waste volume reducing system is phyrolysis, a plant
operation that burns garbage in an oxygen-free
environment, and in the process, produces fuel sources
that serve as substitutes for petroleum products. |