AN OVERVIEW OF WATER AND WASTEWATER TREATMENT

become fashionable is Pollution Prevention, the fact remains that what we are doing
is removing unwanted contaminants from water, whether it be to meet drinking
water purposes, or to meet a discharge standard to a local (nonpotable) water body.
The contaminants may be caused by man, or they simply exist from nature. Either
way, we are applying technologies aimed at removing these constituents, and
ultimately these concentrated forms of pollutants require disposal. In this regard,
physical methods alone are quite limited, because they represent a non-destructive
form of treatment. Their objective is both to remove suspended contaminants and
to concentrate them within the limitations of the technology or hardware. From that
point on, further concentration is required in order reconstitute the collected
contaminants in a form that can be readily handled for ultimate disposal and or
destruction. This is known as dewatering. But as noted above, water often contains
much more than just suspended matter.
For newcomers to this subject, there is a section of general questions for thinking
and discussing among your colleagues. These will help reinforce some of the
general concepts and principles covered in this first chapter, and help you to
prepare for the more technical discussions that follow.
56 WATER AND WASTEWATER TREATMENT TECHNOLOGIES
Objective of
Treatment
Method or Technology
b) For whole-house system, remove by absorption via special
macroporous Type 1 anion exchange resin regenerated with
NaC1. up to 3 ppm
c) Above 3 ppm, constant chlorination with full retention time,
followed by filtration and/or dechlorination
Gelatinous Slime l'
i
t Hydrocarbon Sheen
Murky
a) Destroy iron bacteria with a solution of hydrochloric acid,
then constant chlorination, followed by activated carbon
filtration or calcite filter.
b) Potassium permanganate chemical feed followed by
MnZ/anthracite filter
[Same as Petroleum]
TASTE
a) For mud, clay, and sediment - use a calcite or pumicite
filter, up to 50 ppm
b)
For sand, grit, or clay - use a hydrocyclone, sand trap,
and/or install new well screen
Salinity a) There is no commercial residential treatment for sodium
I over 1 800 ppm
t
b) Deionize drinking water only with disposable mixed bedanion/
cation resin; or
c) Reverse osmosis for drinking and cooking water only; or
d) Home distillation system for drinking water.
Medicine
Chemical Tastes
(Other)
Single faucet activated carbon filter or whole-house tank-type
activated absorption filter . . . . . . . . . .
Pesticides-herbicides" Activated carbon filter will absorb
limited amount. Must continue to monitor the product water
9 closely
SOME GENERAL COMMENTS
So there we have it - a broad overview of a complex subject that spans both
technical and legal arenas. Much of the discussions have focused on drinking water,
but from this point forward we will depart from the subject and only address this
in passing. Recognize that there are a large number of technologies that are applied
to treating water. The combination of technologies needed for a water treatment
application depend on what we are ultimately trying to achieve in terms of final
water quality.
Although the term pollution control has fallen out of favor today and what has