| Title of Process/ Know-how/ Product/Design/Equipment

Recovery of industrial grade sodium chloride and sodium sulphate using waste effluent of tannery & textile dyeing industries

IPR Status & Details:

IN 232395; IN 202011009669

Application/Uses/Problem being addressed

Due to these unresolved environmental issues, both of these sectors faced severe sanctions, including closure notice, from legal as well statutory bodies. This cost- effective and simple technology is useful for recovery of salt (>98.5% w/w NaCl) and sodium sulphate (>98.5% w/w Na2SO4) from solid waste of textile and leather industries. The recovered salt are suitable as raw material for various industrial applications such as soda ash, alkali, pulp and paper industry, textiles, de-icing and detergents etc.

Salient Technical Features including Competing Features/ Impact

The solid waste from textile/leather industries mainly contains sodium chloride and sodium sulphate along with minor organic and trace metal impurities. Sodium chloride and sodium sulphate have overlapping solubility and are difficult to separate by chemical or physical methods. The process involves mechanical washing of solid waste with saturated brine followed by crystallization of sodium sulfate and recycling of left out saturated brine for upgradation of subsequent batches of solid waste.

TRL Level & Scale of Development:- TRL 6 TRL Reference

6, Pilot scale (tannery);

9, commercial scale (6 KLPH plant is in operation using textile effluent

Business scope & opportunity (in terms of scale, cost, market etc.)

Through the process sodium chloride >98.5 wt% and sodium sulphate > 98.5 wt% purity are recovered in a cost effective manner. Both the products have good commercial value. Adoption of this technology will enable value recovery through sale of by-products and also mitigate increasingly critical issues, viz., environment, storage & space constraints. For both RO reject & solid waste, with minor site-specific variations, can be employed in conjunction with upcoming ZLD facilities to achieve complete waste management regime in tannery & textile dyeing sector, with improved economics. Generally, this type of proposed plant will be a waste disposal plant. Capital cost /Project cost may be partially funded by different agencies.

Environmental Considerations

For both the effluent, post primary & secondary treatment stages, sodium chloride and sodium sulphate are the major contaminants along with minor content of calcium & magnesium salts and soluble organics. Due to high pollutant loading, these effluents are not suitable for direct discharge & requires downstream treatment / processing.

Status of Licensing:

Licensed technology

Status of Commercialization:

Commercially operational in one of the textiles CETPs; shortly would be operational for tannery CETPs

Major Raw Materials Needed

Settling agents/additives, activated carbon etc.

Major Plant Equipment and Machinery Required

Belt conveyor, screw conveyor/ washer, chilling unit, Nutsche filter, crystallizer centrifuge, packing machine, mini loader etc.

Techno-Economics

Economically feasible

Technology Package

Technology package is ready and would be provided to the party at the time of technology transfer. License fee and other financial details are available on request

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