Page 559 - Industrial Wastewater Treatment, Recycling and Reuse

Industrial Wastewater Treatment, Recycling, and Reuse—Past, Present and Future 529

energy using equipment that is easily maintained and cost effective com-
pared to existing treatment methods.
• Trained manpower: Trained manpower is essential for the smooth assim-
ilation, installation, operation, and maintenance of any technology.
Wastewater treatment, recycling, and reuse are interdisciplinary
endeavors that require input from chemistry and engineering. In view
of the complex ETP of today, training is essential so that plants operate
efficiently without cost intensive maintenance and breakdowns. Often, a
gap is observed between the plant personnel and the people responsible
for instruments and computers. Different groups, often lack good under-
standing of each other’s role in the larger operation and in issues such as
technological knowledge and software application. A suitable training
can help to bridge this gap for smooth plant operation.
At this juncture, it might be useful to re-examine the knowledge and devel-
opments resulting from our experience using industrial wastewater treat-
ment technologies. Despite several advances in various technologies and
mathematical modelling, present day water treatment still involves a set of
sequential treatment operations applied to a single wastewater stream con-
sisting of the wastewater from all process operations. In the absence of the
concept and technologies of wastewater reuse, these processes are fed by
freshwater (see Figure 14.1).
The described treatment process can be improved in several ways.
Decentralizing water treatment and exploring opportunities to treat the
effluent as close to the point of generation as possible is one of the most
promising ones. It is also possible to reuse the wastewater from one process
in another part of the process, without providing additional prior treatment
or after treating it immediately after the process step in which it is generated.
In such a scheme, some pollutants are removed from streams closer to the
point of generation, and the partially treated water can then be reused in later
stages. This treatment arrangement is schematically illustrated in Figure 14.2.

Process plant
Process 1
Wastewater treatment plant
Process 2
Fresh water Primary Secondary Tertiary Disposal /
Discharge
...
Each of these may comprise several operations
Process N
Figure 14.1 Schematic of conventional wastewater treatment arrangement.