Praj Industries offers green solution for effluent treatment woes in Tirupur

Being a textile belt, Tirupur (Tamil Nadu) faced the crisis of severe pollution of water bodies due to discharged coloured effluent from the bleaching and dyeing units. More than 600 bleaching and dyeing units remained closed for almost two years for want of reliable solution. Though various technologies were implemented, none could solve the ground water pollution problem effectively. This extended the closure of textile dyeing clusters till the installation of the Zero Liquid Discharge (ZLD) unit by Pune-based Praj Industries which has helped to build confidence for reopening of the textile units in compliance with the pollution norms.
 
Praj is one of the leading global players offering innovative solutions to significantly add value in water and wastewater treatment plants, bio-ethanol, bio-diesel, and brewery. Building on its expertise, Praj’s ZLD system, which is energy efficient with proprietary evaporation technology, caters to the various industrial process effluents such as RO reject, complex effluents, cooling tower blow down, etc. The entire basket of technology is available with Praj which forms an integrated part of ZLD system including pre-treatment, biological treatment, tertiary treatment, reverse osmosis, evaporation, crystallisation etc. Praj’s constant focus is always on recycle & reuse of water with its value added technologies.
 
Praj successfully commissioned a 100KLD ZLD plant at Veerapandi Common Effluent Treatment Plant (CETP), Tirupur.  Praj has supplied ZLD technology based on Multi effect evaporation system for Textile CETP treated effluent. The entire plant was designed, engineered, fabricated, erected and commissioned by Praj on turnkey basis. The final end products are process condensate and salts which are of reusable quality. The reject of existing RO system is first preheated and then fed to the evaporation system in forward feed manner. Praj provided special proprietary designed forced circulation evaporator system.

Block Diagram of the ZLD scheme for Veerapandi CETP (Textile Effluent)
 























Praj ECOVAP system is suitable for operating at higher solid concentration & viscosity. Suspended solid slurry and precipitating salts can be handled by this system with no chocking issues and with less cleaning cycles.

Outlet parameters:

ECOVAP evaporation system

Parameters	Quantity
Feed	4300 kg/hr
Feed concentration	5.4%
Product concentration	30%
Condensate flow	3526 kg/hr
Product flow	774 kg/hr

 
In order to arrive the most appropriate solution, Praj deployed the best resources and efforts. This involved periodic collection and testing of effluent samples, study of existing effluent treatment plants, developing customised processes & engineering solutions and demonstrating the efficacy of the solution of the first plant at Veerapandi.

Advantage of the scheme: Process condensate purity: Process condensate is directly mixed with RO permeate which is recycled back to process. Hence, further treatment is not required for the process condensate Constantly getting 25% w/w solids after second effect. These salts are recovered and reused back in the process resulting in reduction in consumption of salts in the process and vice versa benefiting the environment. Prior to this installation salt quality in terms of w/w solids was not consistent. It resulted in choking of the equipment and, hence, complete recovery of salt was not possible. The salts recovered from the CETP plant are being reused by the dyeing units, resulting into considerable savings in operating cost. Long cleaning frequency cycle upto 20 days

(This was featured in Business Standard newspaper on August 30, 2013)