Zero liquid discharge

What is Zero liquid discharge ?

About Zero Liquid Discharge (ZLD) For Distillery Industry
  • Distillery sector is one of the 17 categories of major polluting industries identified by Ministry of Environment and Forest, Govt of India.
  • There are > 300 distilleries in the country.
  • Total installed capacity of about 2500 million kilo litres of ethanol per annum.


Incineration processes are based on the concept that concentrated distillery spent wash (60% w/w) will burn on its own without any external input of energy. In other words, the incineration process of 60% (w/w) concentrated spent wash is considered to be self-sustaining. There are two basic approaches for concentrating spent wash :
(a)Concentration and incineration with steam generation, and
(b)Direct contact evaporation and incineration

The concentrated spent wash is subsequently incinerated in a specially designed boiler. One of the alternatives for recovering heat from flue gases would be to send the flue gases to a waste-heat boiler. Steam generated there could be used to concentrate raw spent wash to 60% w/w concentration in a multiple effect evaporator system.