Future Trends in Wastewater Treatment
In the U.S. EPA Needs Assessment
Survey, the total treatment plant design capacity is projected to increase by
about 15 percent over the next 20 to 30 years . During this period, the U.S.
EPA estimates that approximately 2,300 new plants may have to be built, most of
which will be providing a level of treatment greater than secondary. The design
capacity of plants providing greater than secondary treatment is expected to
increase by 40 percent in the future (U.S. EPA, 1997). Thus, it is clear that
the future trends in wastewater treatment plant design will be for facilities
providing higher levels of treatment.
Some of the innovative treatment
methods being utilized in new and upgraded treatment facilities include vortex
separators, high rate clarification, membrane bioreactors, pressure-driven
membrane filtration (ultra filtration and reverse osmosis), and ultraviolet
radiation (low-pressure, low- and high-intensity UV lamps, and medium-pressure,
high-intensity UV lamps). Some of the new technologies, especially those
developed in Europe, are more compact and are particularly well suited for
plants where available space for expansion is limited.
years, numerous proprietary wastewater treatment processes have been developed
that offer potential savings in construction and operation. This trend will
likely continue, particularly where alternative treatment systems are evaluated
or facilities are privatized. Privatization is generally defined as a
public-private partnership in which the private partner arranges the financing,
design, building, and operation of the treatment facilities. In some cases, the
private partner may own the facilities. The reasons for privatization, however,
go well beyond the possibility of installing proprietary processes. In the
United States, the need for private financing appears to be the principal
rationale for privatization; the need to preserve local control appears to be
the leading pragmatic rationale against privatization.