liquid discharge systems have become a necessity
for all the industries generating liquid effluents.
Common effluent treatment plants in most areas
have a limited capacity. The zero liquid discharge
systems are normally incorporated to treat the
R.O. reject streams.
Zero liquid discharge plants consist of a combination
of different types of evaporators depending upon
the nature of liquid and it's contents. The waste
liquid is concentrated to the maximum level in
the evaporators which may be either falling film
or forced circulation or a combination of both.
The number of stages depends upon the quantity
of liquid to be handled. The water evaporated
from the evaporators is condensed in the condenser
and can be reused in the process.
The concentrated liquid is then
dried in either a spray dryer or a agitated thin
film dryer. The dry product obtained in powder
form can either be used as a by-product or can
be sent for land filling.