Ultrafiltration and reverse osmosis membrane technologies from Koch Membrane Systems, Inc, are being used by two of India's largest leather-tanning factories to increase the amount of wastewater they can reuse during processing.
Eastern Chrome Tanning Corp (ECTC) and N. M. Zackriah & Co Ltd (NMZ), located in the city of Ambur, have operated wastewater recovery plants using the UF system with hollow fiber membranes and RO with spiral membranes for more than a year.
This region, within Tamil Nadu State, is one of India's primary leather tanning regions, and chronically faces water shortages, so the availability of process water for the tanning operations is of major concern to the factories.
Leather tanning presents difficult wastewater treatment challenges. Converting raw hides into finished leather suitable for clothing, baggage, and other consumer items requires large amounts of chemicals such as lime, sulfite, caustic, enzymes, salt, and acid. The tanning process also produces large amounts of wastewater that must be treated before being reused or discharged, in order to protect the environment and the local water supply from contamination.
"Hollow fiber UF membranes reduce SDI and turbidity and remove suspended solids in the pretreated wastewater, thereby providing an ideal feed water for the downstream spiral RO system that removes most of the dissolved solids and small molecular weight organic components," says Samir Chaubal, KMS regional sales manager for India, commenting on the advantages of using membranes to treat leather tanning wastewater. "As a result, the recovered wastewater is of a higher quality than is typically available as tap water for these factories."
The wastewater recovery system at both sites was designed and installed by Polutech Ltd, an associate company of the Murugappa Group in Chennai, India. Polutech provides manufacturing equipment including turnkey projects for water and wastewater treatment systems.
"UF and RO membranes supplied by KMS for these projects have met all performance expectations and additional wastewater recovery plants of this type will be installed in the future," says Mr. Ravichandran, senior manager/marketing and operations for Polutech.
The capacities of the ECTC and NMZ wastewater recovery plants are 250 m³/day (65,000 gpd) and 75 m³/day (20,000 gpd), respectively. The ECTC UF plant uses 7 KMS TARGA® 8-72-35-PMX cartridges on a single cartridge rack and a two-pass RO system (4/2) with a total of 30 KMS 8822XR-365 and KMS 2822SS-360 seawater reverse osmosis membranes. The NMZ UF plant uses 2 KMS TARGA 8-72-35-PMX cartridges on a single cartridge rack and a two-pass RO system (2/1) with a total of 24 KMS 4820 HR and KMS 1820 SS reverse osmosis membranes.
"Technology supplied by Koch Membrane Systems has played a key role in helping these companies make improvements to their wastewater programs," says Ravichandran. "Benefits of the wastewater recovery are twofold. Wastewater disposal is reduced and concurrently recovered wastewater provides a reliable source of high quality water for process operations."
Based on the success of these operations, KMS will also provide systems to another wastewater recovery plant at M. A. Khizar Hussain and Sons, a large tanning factory located in Vellore, Tamul Nadu. The capacity of this wastewater recovery plant is 610 m³/day (160,000 gpd). This plant uses biological treatment, coagulation, sand filtration, ultrafiltration consisting of TARGA-10 cartridges, and a combination of nanofiltration and reverse osmosis technology.
More than 20 additional systems are currently being evaluated, and are expected to be installed, within the next two years.
