The bulk water treatment processes described in Section 4B produce water that is good enough to drink, and which is vastly better than that drunk by millions of people in the developing world. Nevertheless, it is not good enough for many people,
and greater degrees of purification are accordingly necessary to satisfy these needs. This is true for drinking water, the subject of this part of Section 4, and for water to be used in industrial processing (covered in Section 4D).
The major concerns among consumers are colour, odour and taste, the presence of which in tap water has driven the market for bottled water to such high levels (coupled, of course, with its portability). A more important concern should be the
presence of pathogenic micro-organisms, but this only hits the public consciousness when there is a disease outbreak.