Corporate Ethanol Plant

Contact Us

Praj Industries Limited,
"Praj Tower" 274 & 275/2,
Bhumkar Chowk-Hinjewadi Road,
Pune : 411057, INDIA.
Phone : 020-71802000 and


Wastewater Solutions

While wastewater treatment systems form the tail end of the process, Praj’s offerings are concerned with this factor right from the beginning. A basket of technologies and systems, guided by environmental concerns of individual regions and feedstock, are available. The solutions include primary, secondary and tertiary treatment and Zero Liquid Discharge Systems using 4R (Reduce, Recover, Reuse, Recycle) principles.


Wastewater Treatment ZLD solutions for Sugar based distilleries

Option - 1

Option - 2

Wastewater Treatment ZLD solutions for starch based distilleries

Sugar based Distillery / Ethanol Plant :


Starch based Distillery / Ethanol Plant :


EcoMet Biomethanation

Biomethanation involves conversion of organic compounds present in the effluent using a genera or consortium of bacteria under anaerobic conditions. The bacteria breaks the organic compound into methane gas and carbon dioxide. Praj offers Continued Stirred Reactors (CSTR) and Up-flow Anaerobic Sludge Blanket Reactor (UASB) systems for biomethanation.

Biomethanation followed by Power Generation

Biogas generated from the biomethanation system is fired in the biogas engine to generate electricity. Presence of H2S in Biogas results in corrosion of Engine Parts. Most Gas Engine requires H2S below 250 ppm (0.025% v/v) in biogas.

EcoMet UF Anaerobic Biological System

Process condensate / spent lees generated is treated in biomethanation process. The treated condensate is passed through MBR followed by UF to reuse it in the process plant.

Biomethanation process is common for both sugar and starch based distilleries.

Concentration followed by Vinasse Boiler

Concentration followed by Vinasse (spent mash/ wash) boiler for steam and power generation


Raw Spent-wash (Vinasse) from the distillation plant having 16-17% w/w solids is concentrated to 55-60% w/w solids before firing into a specially designed boiler. The evaporation plant designed and supplied by Praj incorporate self-cleaning fluidized bed heat exchanger which ensures extended operations. The Vinasse boiler is offered in association with reputed boiler manufacturers.

Concentrated Molasses Solids (CMS)

The vinasse from molasses distillery contains potassium, sodium, phosphorous, etc. which has fertilizer value. To obtain this fertilizers, Vinasse is concentrated to 35 to 55% w/w in multiple effect evaporators. The concentrated Vinasse is enriched and formulated based on local soil condition by addition of mineral fertilizers like di-ammonium phosphate and Urea prior to applying to the fields through self-propelled sprinklers.

Biomethanation followed by Aeration

Thin slops are first sent to the biomethanation plant where organic matter is digested anaerobically to produce biogas. The overflow from this system is then sent to aerobic biological system where it is treated in 2 stage aerobic system for further BOD/COD reductions

Distillers Wet Grains & Solubles (DWGS)

Thick slops are fed to the decanter section resulting into wet cake. Thin slops from decanter are concentrated to produce syrup. The mixture of cake and syrup is called DWGS. It has a limited shelf life with moisture content of around 65-70% w/w.

Distillers Dried Grains & Solubles (DDGS)

To increase shelf life as well as to reduce volume and transportation cost, drying of DWGS is undertaken. In the drying process, dry product with 8 to 12% w/w moisture is produced which known as DDGS (Distillers Wet Grain and Solubles). Energy source for drying is steam or hot air. Vapor integration is implemented for energy saving.

For this purpose, different types of dryers like Steam Tube Bundle Dryer, Flash Dryer and Direct Fired Rotary Dryer can be used.

Ecovap Evaporators


Praj offers a number of options for concentration and evaporation of vinasse/effluent from sugar and starch based distilleries as below:

  • Falling Film
  • Rising Film
  • Forced Circulation
  • Flubex Self-cleaning fluidized bed heat exchanger based evaporation system for scaling / fouling liquids

These systems are partly / fully integrated with distillation plant, dehydration plant and /or DDGS Dryer for optimizing the energy needs.

ECOREC-MF Membrane Separation System

Praj offers cross flow membrane separation system (ECOREC-MF) developed exclusively for this application.

The system generates two streams
  • Permeate suitable for recycle to fermentors.
  • Concentrate (Reject) which can be used for composting.

  • Special high quality membranes specific to the application.
  • Compact and skid mounted unit.

BSW Zero Liquid Discharge (ZLD) Process

PRAJ’s patented Biomethanated Spent Wash (BSW) Evaporation technology is a eco friendly green technology. It is a combination of thermo-chemical conditioning of BSW followed by Advanced Falling Film / Forced Circulation Evaporation Technology. The system is designed to operate for longer duration without cleaning. This technology also ensures Zero Liquid Discharge (ZLD) Process.

BSW Pre treatment

BSW conditioning prior to evaporation is done by dual step thermo-chemical process. Step one contains Flash Stripper System with innovative Disk and Donut (S&D) type trays with low temperature vacuum flash. Step two consists of chemical treatment in the reactor designed to reduce scaling and fouling in evaporation system.

Condensate Polishing

The process condensate from surface condenser is polished in an in-built Polishing Unit using stripper. Polished BSW process condensate is recycled for process and utility applications.